Okay, so this is lecture 9 am I right, 9 and the last thing we saw in last class was M PAM right, what is M PAM? So when you do M PAM signaling, so M is typically a power of 2, that is accepted. What is your signaling constellation, your basis is chosen to be? In this case when I have a lot of bandwidth compared to my signaling bandwidth, I have a lot of bandwidth to use, I can take my basis comfortably to be root 1 by T between 0 and T. We will see later on a case where the bandwidth is not so free, so it is a little bit tight, you will have to change your basis, but it is still work okay, so that is the first thing. And then once you have this basis, I can simply do a constellation description, I can, I have only a one dimensional signal space and that one dimensional signal space, I will simply pick out the points which are going to be the scaling factors for my basis okay, so those are what? For the M PAM it is going to be, so if you have 0 here, I am going to pick plus 1, plus 3, so on till what? Plus M minus 1 okay, you can check that you will have M by 2 points in this way okay, on the negative side it is going to be minus 1, minus 3, so on till minus M minus 1, once again M by 2 points on this side, overall remember 0 is not a point okay, so maybe I should just do, just to show that that is not a point, it is just an axis okay, so the other constellation points only, plus 1 through plus M minus 1 in steps of 2 and minus 1 through minus M minus 1 in steps of 2 okay, so all of them you can say occur with equal likelihood okay, I should also provide the information of how bits are being mapped into the constellation points right, so how many bits would you map here? Your N would be log M base 2 okay and your bit vector will be B1, B2 to BN okay, so in this case it is just log M base 2 and you have 2 power N possibilities which is equal to M and you have M points here, so right now we will not worry about what is the best way of mapping the bits to the symbols or some ways of doing it, but let us just say you pick a mapping, any mapping is okay as far as I am concerned okay, so you do that, you get a transmitting scheme okay, so how do you build a circuit which does your transmission? You first read your bits, depending on your bits, you pick one of your say scaling factors okay, so that multiplies your phi 1 of t okay, so you might think of all kinds of resistors and capacitors to build it, so in practice today most of these systems are built with in fact D2A converters okay, so what are you putting out ultimately at the end of the day? Putting out a waveform, so imagine sampling it with a huge sampling frequency okay, so then run a D2A and all you have to do is do a sample and hold on your D2A and pick different samples according to your modulation, so it can be easily programmed into a processor with digital output and converted that into a using a good D2A converter, so these modulators are done very differently okay, you do not have to worry about building complex analog circuits, of course if you build those analog circuits what is the advantage? You will be consuming very little power and all these things in your transmitter but people do not usually care, the flexibility in your transmitter is what is more important today, so you just put a processor, program your processor to put out a waveform like this okay, it is not too difficult to do that okay, so it can be done, so that is how usually you do it, so I can today think happily about my transmitter completely in terms of signal space and points, I do not have to worry so much about going into an actual implementation and all that okay, all that I will imagine is being done in a routine fashion okay, so that is the description, so one thing we know is accurately represented in the constellation is the average energy okay, so you can compute average energy assuming once again that all these bits are equally likely okay independent IID type bits, this will work out to if you do the computation it involves some careful summation right, it is not so trivial if you have to do a careful summation it will work out to M squared minus 1 by 3 okay, so it will work out like a square of an AP okay, so of an arithmetic progression right, so when you do that it is you have to use some tricks to make sure you know what the closed form expression is but it can be done okay, it will come out to M squared minus 1 by 3 okay, so that is the power, so bandwidth like I said I have been saying it is I am assuming it is enough, I am using enough bandwidth, I am using a lot of bandwidth maybe it is a lot of waste, we will not worry about that for now, what about the other things, the other thing I am worried about is bit rate right, so in every T seconds how many bits am I sending log M base 2 okay, so that is a lot of bits okay, so how do you increase that number, you increase M okay, so but you can also imagine for the same power, same energy when you increase M what happens right, energy is increasing right, so if you want to keep energy the same you cannot afford to increase M also, so there is a payoff to be played here okay, so noise I did not really talk about, noise would be again it would have just one dimension, so y is going to be equal to simply x plus n, n would be simply normal with 0 mean and variance and not by 2 okay, so these are the various parameters, you can do the conditional distributions for y given x very easily, each conditional distribution will be a Gaussian centered at that point with mean as the point that was transmitted and variance being n naught by 2 okay, so you can also do the joint distribution, the PDF for y itself which would be a mixture Gaussian, so all these things are descriptions for M pair okay, so hopefully this is clear okay, this is the rudimentary thing, so if at all you go into, you are given some bandwidth and power and if you have to construct a communication system, the first thing to try would be something like an M PAM okay, assuming you have enough bandwidth or assuming your T is large enough so that you are not taking too much bandwidth, that is the first short implementation without worrying too much about anything else, we do not know how to do the receiver right, we do not know how to do the complete receiver right, what is the first step of the receiver? The correlator right or integrate and dump basically, you integrate for a period of T, in this case the correlator becomes a simple integrate and dump, do you see that? It is just a constant, basis is a constant, so you will be just integrating your received signal from 0 to T and taking that value okay, so you know that step, from y how to go to x also is very clear, intuitively maybe it is very clear to you, just take the nearest point it will be okay, we have not seen that rigorously enough, we will see it so okay, so even at this point like at the ninth lecture, you know how to build a rudimentary communication system right, can you or can you not? At least theoretically you know how to do it, it is not very difficult and all these things like I said transmitters and receivers can be done with processors and completely digital, so you should be able to do it, you should be confident of being able to take a board which has a processor and a D2A converter, being able to do a PAM transmitter, it is nothing in it okay, as long as a transmitter is fast enough you can easily do it okay, same thing you should be able to do at the receiver, all you need is an integrator and dumping which can be done very easily in software also right, so it is just adding or how hard is it, you can do it, so this should be confident of being able to do okay, even in reality alright, so this is a very standard communication system, so M PAM is a very very commonly used system, so you can imagine 2 PAM is the simplest case, PPSK it is commonly used 4 PAM, 8 PAM and all that okay, as you go to larger and larger M, you are sending more bits at the same time but you are also using more energy okay, so if you can do that then it is fine alright, so that is the M PAM, the next thing I am going to talk about is another type of transmitter which is actually 2 dimensional, which is I think the 5th case we are looking at, it will go back once again to phase shift keying okay, we saw binary phase shift keying matched with 2 PAM but you can also expand it in different way to get what is called quadrature phase shift keying or QPSK okay, you can also call it 4 PSK if you want, that is another name okay, phase shift keying okay, so I think the way I have written it down I am going to do it slightly more painfully okay, so I am going to go back once again to the very basics and give you the signals first and then we will work out the basis elements, do the Gram-Smith once again just for completeness okay, N equals 2, so you are mapping 2 bits at a time okay, so you have 2 bits B1, B2 okay, 4 possibilities occurring with equal probability, 1 4th each okay, that is my assumption on this okay, so my X 00 T which is the signal corresponding to the bits 00 is going to be root 2 ES by T okay, I will go back to ES, cosine 2 pi F0 T between once again between 0 and T okay, so once I say this naturally, so the bandwidth assumption should come in naturally into your head, so this is going to occupy a lot of bandwidth okay, so I have to have all that bandwidth to be able to receive this X 00 of T at the receiver without any problems in the channel, so I am assuming that is happening, I have a lot of bandwidth and I am using a lot of bandwidth in this okay, so X 01 of T okay, so this F0, what is this F0, this F0 will take to be some M0 by T okay, some not necessary, some large frequency okay, so we will think of this as the center frequency okay, so for sending other bit combinations we will shift the phase of this sinusoid in the interval 0 to T okay, so we will be shifting the phase, but I will write it slightly differently, it is all the same, I can shift cos, I can get sin right, so I will write it in that form, but just to make the grams with more interesting, but you can also think of it as simply phase shifting with the cosine, there is no problem there, root 2 ES by T sin 2 pi F0 T between 0 and T okay, so you see it is clearly a pi by 2 phase shifted version of the previous one okay, so the X 11 of T is once again going to be minus root 2 ES by T cosine 2 pi F0 T, which is now what, a pi phase shifted version of the first one okay, and then you have X 10 T which is minus root 2 ES by T sin 2 pi F0 T which is a 3 pi by 2 phase shifted version of the so that is why it is called phase shift keying okay, so each bit combination tells you how much you have to phase shift by okay, so once again the bandwidth is large, assume my bits are uniform, so if you do Gram-Schmidt what will you get, yeah two basis functions, one will be the cosine, other will be the sin normalized right, so everything else is a multiple of that okay, but it is two dimensional, it is not one dimension okay, so that is the final result that you get okay, so if you do Gram-Schmidt the basis are okay phi 1 T which would be root 2 by T cos 2 pi F0 T okay, of course once again between 0 and T and phi 2 is root 2 by T sin 2 pi F0 T between 0 and T okay, so you get two basis and in terms of the basis every signal now becomes a two dimensional point right, so the signal space is two dimension, so if I were to write down the constellation you would have four points okay, so this is root ES minus root ES minus root ES and root ES again and the way I wrote it down if this represents phi 1, this represents phi 2 okay, so you are going to have this being 0 0, this being 0 1, this being 1 1 and this being 1 0 okay, so that is it, this is your constellation, this is QPSK, so I can write down the vector version of each of my signal points okay, so x 0 0 vector is what root ES 0, of course there is a transpose okay x 0 1 is 0 root ES okay x 1 1 is minus root ES 0 x 1 0 is 0 minus root ES okay, so there is nothing wholly about the way I have chosen my assignment 0 0 0 1 when you can choose any way you want, I just picked it like this, you can pick it in any other way, the constellation does not change, many of the properties do not change, maybe some minor properties change, it is not very relevant to us okay, so it is fine, we will keep it anyway we want okay, there is also another version of QPSK called offset QPSK, in that case the constellation is rotated by pi by 4 okay, so if you rotate this constellation by pi by 4 what will you get, these points will be on the four corners of a square okay, so that is offset QPSK, so if you go back using the same basis you will see your signals will all be shifted by pi by 4 phase, that is okay, that is not a big deal and that is supposed to have some advantages in some practical implementations in terms of signals that is supposed to be better, but phase is just relative, so what matters really is the difference between two phases, absolute phase itself is really no significance but the offset QPSK is supposed to have some advantages okay, so you can see why it is called phase shift king and all these things and you can also see it is different from four PAM right, it is very different from four PAM okay, it is first of all two dimensional things change a lot okay, so it is very different from four PAM hopefully you see that okay, one more thing you see is each signal has the same energy okay right, all the four signals you are transmitting, all of them have the same energy ES and the average energy is also ES, but in four PAM it did not work out like that, some signals have higher energy, some signals have lower energy and average works out to some number okay, so that is another point which is different about phase shift keying, that is one more reason why phase shift keying sometimes preferred okay, you have all the signals being over four PAM for instance okay, you might have a reason why you might want to send QPSK better than four PAM because all your signals will have the same energy, you do not have to worry about suddenly some signal having a larger energy okay, you can plan for the for every time properly okay, so that is PSK, so if you do for instance the model completely you will get the vector y equals the vector x plus n where x is uniform here, the reason why I am saying uniform is I am assuming my bits are uniform okay, so I am saying uniform on that, what is n? It is IID normal two dimensional which means zero and variance n naught by two, so once you know this you can do conditional PDFs for y1, y2 okay, so what will it be? It will be a circularly symmetric Gaussian centered on the transmitted point okay, so all that can be done, it is quite standard as well alright, so there is also a generalization for QPSK okay, so there is no reason why you have to divide the unit circle into just four different, pick only four points in the unit circle, you can pick any number of points, you can pick eight points, you can pick sixteen points without any problem, you can keep on increasing the number of points you pick and you will get more and more signal points in the constellation, you can increase m in that way okay, so that is the next step which is called MPSK okay, here m will take to be a power of two, there is no reason why it should not be a power of two okay, once again the basis vectors are the same as 4PSK okay, you have just cosine and sine okay, is that a question floating around, happy okay alright, so you have cosine and sine and I will just give you the constellation okay, so the same basis vectors phi 1, phi 2 as we had before and the constellation it is good to draw a circle so that you can pick out the points there okay, so I will take so I do not know if I have actually taken a proper, so I do not know I think okay, so I will just take four okay, so we will keep picking points like this, maybe you do not get a point and pi by two I do not know, so it just keeps on going like this, you pick at angles two pi by m, so this angle would be two pi by m okay, same angle here also okay, so on okay, so so an arbitrary point okay, so basically you pick m points on the unit circle, the unit circle, my circle got totally messed up okay, what are those m points, maybe root es okay, e power j two pi small m by capital M and m goes from zero to m minus okay, so those are my m points and notice how I wrote it down, I wrote it down as a complex number okay, so this is again very common way of referring to constellation points on in two dimensions right, in two dimensions you can think of a constellation point as being referred to by two coordinates okay x and y okay, so I can always write it as x plus j y which is which I think of as a complex number okay, so this is also very common when people write 2D constellations particularly, always think of your 2D constellation points as a complex number okay, so for the case when m equals 4, you will get back the original case okay, so two pi by 4 is pi by 2, so you will get the four points okay, so how do you think of the four points and four PSK in terms of complex numbers, zero j no, one j minus one minus j, so there are four points plus or minus one plus or minus j okay, so in the MPSK case you have e power j 2 pi m by m okay, so of course the root t s is floating around usually forget the root t s in most cases okay, is that clear, so then you have to map your log m base two bits into each of these constellation points and you can do that in any way you want okay, so this seems to have an advantage over m-pam what's the advantage, when you increase m in m-pam what happened, the energy increased but here the energy doesn't seem to have increased, so why would you ever pick m-pam over MPSK, yeah so okay, so yeah, so eventually you'll pay, you'll see I mean even though you've not paid in terms of e s, you'll pay in terms of some other quantity which is more fundamental, so actually it turns out the e s by n not, that ratio is what's important okay, so even if you don't pay in terms of e s, you'll pay finally in some way or the other okay, so another thing you've done here is you packed the points closer together okay, the distances between points also gotten very very low, so you're paying in terms of that also okay, so we'll later on see how to analyze it at that time, that time maybe it will be clear okay, what I want you to do now is to spend some time and write down the transmitted signal corresponding to the m-th point here in the constellation, what is the actual transmitted signal xm of t corresponding to the m-th point in the signal constellation, is that clear, every point in the signal constellation has to correspond to an actual signal right, what is the actual signal that is transmitted when you're sending the m-th point, that's what I want you to do, you know the basis, you know the factors, so you can multiply and find out what's the answer okay, so there's a possibility to simplify that, you can write it down as one cosine right, can you not, cosine 2 pi f naught t minus 2 pi m by m, do you see that okay, so this of course will have a root 2 e s by t on the outside to make sure things work out okay, so this is the signal corresponding to root e s e power j 2 pi m by m okay right, so this happens for m equals 0 to m minus 1 okay, so this defines everything, is that okay, that fine seems to be some, are you guys happy okay, it will work out like this okay, anything else they wanted to say, you can be smart about it and write it as real part, so that's what I'm going to ask you to do next, which is a little bit more confusing, I want you to write down the, once again I mean this is between 0 and t you know, okay I've been saying bandwidth is large but, assume bandwidth is large but finite, okay don't think of infinite bandwidth very strictly okay, so it's a passband signal, do you agree around f0, so assume around f0 some 10 by t is available for me, 10 by t or 20 by t and that's my bandwidth, I'm restricting it to that but, approximately I'm writing the answer as this okay, so that's what I'm doing, assuming that what is my complex baseband equivalent for this, so the reason why I'm asking you to assume that is last time people said it's not strictly passband, it's not divine, it's assume something like that and then give me an answer, yeah you'll have a minus, minus is quite irrelevant, you can even think of it as plus but anyway it doesn't matter, we'll retain that, so you'll see xm tilde of t will work out to something like this root 2 s by t e power minus j 2 pi m by m, this minus is quite I mean it's okay for m equals minus m 2 pi minus it will work out to the same thing, so minus is not so important but the fact is this complex number representation I had for each of my constellation points actually is what, it corresponds to something in the complex envelope okay, so it has a real signaling meaning also, so that's why in 2D it's good to think of it as complex numbers okay, so when you're processing in baseband, you're processing this complex number, you can think of it okay, so this is my complex envelope okay, of course between 0 and t to make sure everything works out okay, is this clear, of course for this complex, this number also you'll have a huge bandwidth around 0, maybe convince yourself that that's true okay, try to find the, well it's quite simple to see what the Fourier transform of this will be right, it's a constant thing, so you'll get a rect sync multiplied by some phase shift, so it'll be, since the in time domain it's complex and frequency domain you won't have symmetry and all that, it'll be a little bit weird, it'll be a shifted type thing, it won't be a proper sync around 0 okay, it'll be shifted by some arbitrary slight phase but you can work it out okay, it's not a big problem, try to spend some time on this and convince yourself you understand what I mean by all these bandwidth being huge okay, so in future we'll, what we will do is in fact you can see what can happen here, so what we'll do is in future we'll write down the signals pretty much in baseband okay, we don't even have to write down the passband equivalent signal okay, so I'll write down the signal in complex baseband, if I write down in complex baseband what is my basis right, my signal space is the regular complex plane, I don't have to worry about anything else okay, so I don't have to worry about the Gram-Schmidt, I don't have to worry about all this ortho normalization I did okay, so this will be a standard trick that people will use, it's always assumed that your bases are cos 2 pi f0 t and sin 2 pi f0 t for large enough f0 and then you think of your signal space and everything as complex numbers which represent the complex envelope in complex baseband okay, so you can also think of it that way, so in fact this basis will not even enter your picture, you won't even keep track of the actual signal and cos 2 pi f0 t and sin 2 pi f0 t, you don't have to worry about that at all, just worry about baseband okay, complex baseband in which case all you have to worry about is just the complex plane, all your signal constellations are in the complex plane okay, so that's a very common way to think about these things okay, but be very very careful when you think like that okay, every point actually corresponds to a actual signal that you are transmitting and you should know how to go to that okay, so you should know that but since this complex number and the complex envelope are all making a lot of sense, as you get used to these things you will tend to think of your entire signal constellation as just a complex number okay, it's made of complex numbers, but be very careful about the bandwidth that it implies what it means in terms of so many things okay, so be very careful about that but you can think of it as a complex number for ease of use and all that okay, so that's the motivation for this complex envelope thing all right, okay so let's do the final example, this is the final example yeah, final example which is also very very common and popular which is just the seventh one, which is called M squared QAM okay and M is the power of 2 okay, so it's also possible to have M QAM where M is the power of 2 okay, so for so what is the difference between M squared QAM where M is the power of 2 and M QAM where M is the power of 2 yeah only you have even power, so 8 for instance I won't have 8 QAM, 32 QAM, 128 QAM, I'm not allowing when I say M squared QAM, I'm only allowing what 4, 16, 64 and so on okay, it's also possible to have 32 QAM, it's used in several practical systems okay, I'll talk about that later okay, so it's just a minor modification of what is there okay, so we'll talk right now about M squared QAM and the best way to think about it is it's the pass band version of M PAM okay, so think of several analogies here if all these things are not hitting your heads or several analogies to keep in mind okay, as long as you're in base band you're doing base band real signals which means you roughly have only one dimension to work with okay, you don't have this complex number stop, so by going to pass band like in the PSK case, we somehow get two dimensions and we're able to deal with complex numbers in base band okay, right, I kept talking about it when I talked about base band equivalent, so all those things are happening now okay, so you can think of 4 PSK or QPSK as the pass band version of BPSK okay, so likewise here this M squared QAM will be the pass band version or the complex number version of M PAM okay, so the constellation set will look like this, I'll write down the complete one okay, it will be two dimensions again the same phi 1 and phi 2 okay, what is phi 1 and phi 2 cos 2 pi f not t sin 2 pi f not t for some large f not between 0 and t okay, so it works okay, so I'm going to do a few things here, so first I'm going to mark out points on the axis, these are not constellation points, these are just markers to keep me scale okay, so I'll mark out multiples of root ES okay, 1, 3 okay, no let me not do, let me not do root ES, this is too complicated, I'll just do 1, 3 so on till M minus 1 okay, likewise in the negative direction I'll do minus 1, minus 3 so on till minus M minus 1 okay, I'll do the same thing for the y-axis as well okay, 1, 3 so on till M minus 1, minus 1, minus 3 so on till minus M minus 1 okay, and all the points where I have these both these coordinates happening like intersections of all these points will be my actual constellation points, so what are my constellation points here, I'll pick all these guys, then those guys, these guys entire points okay, that's the first quadrant okay, I'll do the same thing for all four quadrants okay, so you see I get M square points right, I have M points on each axis, M times M would be M square okay, so you do it for all the quadrants okay, so I'm doing it just painfully once to write down the whole thing, those are my M square constellation points all right okay, so this is M square QAM okay, remember what are my phi 1 and phi 2, cos 2 pi f naught t between 0 and t, sine 2 pi f naught t in between 0 and t, and I'm justifying that by saying I have a lot of bandwidth so this basis will nicely fit in, there's no problem okay, in future we'll modify that okay, so we'll change to fit into a much tighter bandwidth, at that time this will make much more sense, but for now we'll simply take it as a large, so don't think of sine and cos as some, so the Fourier transform for the phi 1 will not be a delta okay, so I think roughly layer but actually be a sinc shifted at that post point okay, so it's a large bandwidth that you're occupying okay, okay, so that's the first point, so how do we describe arbitrary points in this constellation okay, so I had an index M for MPSK and I wrote e power j 2 pi M by M, here the best way people do it is a plus jb okay, a and b belong to what, plus or minus 1, plus or minus 3, so until plus or minus M minus 1 okay, so that's an arbitrary point in my M square QAM constellation, once again I'm thinking of a complex number okay, so you can motivate yourself about why this complex number is very meaningful by going to the complex envelope, you'll see the signal corresponding to a plus jb will have a convex envelope, in this case it'll be a minus jb or something, so it's every complex number there is a meaning in that, so that's okay okay, so what else, what else, this is an arbitrary point and what will be, so my x which is the transmitted vector will be actually 2x1 and x2, each xi is what, what's the pdf for each xi, I'll say it's uniform in plus or minus 1, plus or minus 3, so on okay, each xi is actually an M-PAM signal right, you can think of it that way okay, so it's, we have two of them, we'll say they are iid, so the distribution for x is clearly defined, it's 1 by M squared each point taking with equal probability okay, what will be expected value of mod x squared, yeah it'll once again be M squared minus 1 by 3 right, there's just two M-PAMs happening, so each of them will have an average of M squared minus 1 by 3, so it should be also an average, is that clear okay, so it's this analogy between M-PAM and M squared QM is very very useful, so you can in fact think of it as two PAM signals, but they will be sitting in one real passband signal as opposed to a M-PAM signal which usually you think of as a one real baseband signal right, so that's the difference between M squared QM and M-PAM okay, so and you know why this is possible right, why you can have a complex baseband being just one real passband, of course you are actually using both sides of the bandwidth when you go to the complex passband, you know to go to the passband version of a baseband signal okay, so those are all these things are possible, so all these correspondences you should make in your head, so in practice typically if you have a passband bandwidth it always makes sense to do QAM okay, some quadrature modulation, there's no point in doing a real modulation okay, so your complex envelope should actually be complex, so no point in keeping that real okay, you'll be wasting bandwidth if you actually have passband bandwidth okay, so you'll be wasting half the bandwidth if you force your complex envelope to be real okay, so you have to keep it complex so that your passband signal becomes real and still you work it out okay, so that's M squared QAM, any questions anything that's that I'm saying disturbing you for this baseband, passband, if it is then go back and read also, now we can also ask, it's a good time to ask something which is not clear okay, so maybe we'll do that once again, we'll do the passband signal and then the complex envelope for the QAM case assuming a large enough bandwidth around f0 okay, so what's my signal corresponding to a plus jb okay, so maybe I'll write it as xab of t, what is this signal okay, it'll work out to a times root 2 by t cosine 2 pi f0 t plus what, b times root 2 by t sine 2 pi f0 t between t between 0 and t right, this will be the actual signal that I'm transmitting corresponding to a and b chose a plus jb chosen as the constellation point, how will I choose the constellation point, yeah the bits right, the bits will be mapped to constellation points, how many bits can I map log M squared base 2 okay, so that many bits I'll take and map it into a constellation point, I should fix that map ahead of time okay in some way I fix it, fix my constellation point, once my constellation point is chosen corresponding to that I transmit this signal, like I said this signal will occupy a large bandwidth around f0, so I'm assuming it is possible like have a lot of bandwidth around f0, so I have that okay, so I want you to write down the complex envelope for this okay, assuming you're taking a large but finite bandwidth around f0, so that this approximately comes through without much help, what is the complex envelope okay, in other words what am I saying you should do, you should come up with some signal here so that xab of t becomes real part of that complex envelope multiplied by e part j 2 pi f0 t okay, so that's your xab tilde, what will that work out to, a minus jb times root 2 by t, so root 2 by t will always come and then you have a minus j, so you can do that okay, so if you want a strict correspondence, if you want a plus jb to correspond to an a plus jb complex envelope, what should you do? Yeah, so you should think of sine as minus, you should pick your basis as minus okay, it doesn't change anything as far as power and bandwidth and nothing changes, everything is the same except mathematically it will be neater, it will be cleaner, so you pick one basis to be cos 2 pi f0 t, pick the other basis to be minus sine 2 pi f0 t okay, so once you do that you will get a very clean nice complex envelope correspondence okay, but it's okay, I mean we can live with this a plus jb a minus jb makes no difference okay, right, so I am going to remind you once again about this i channel q channel business okay, so how would you actually implement this in practice, so you would have in base band two signals right, what would those two signals be, in fact that would be this right xab tilde equals root 2 by t a minus jb for what time? 0 and t okay, so spend some time and find the exact Fourier transform for this okay, I want you to spend some time and do this okay, I think this is a good lesson you might have forgotten, anyway we have a lot of about 10 minutes left and I don't want to do anything else this class, so I want you to spend some time and find the exact Fourier transform for this, yeah it is base band right, it's constant between 0 and t, but it's a complex number between 0 and t, what is the expression? So you are saying this is what xab tilde f is what, root 2 by t a minus jb okay, e power minus j, ft by 2, t sync, ft okay, so are you convinced, is everybody happy with this answer, okay, so this is how it has to look okay, is it symmetric about f equals 0, does it satisfy your real and imaginary symmetry, so is the real part and the imaginary part right, I shouldn't say symmetric about f equals 0, what I want is are the real part and imaginary part right, so if xab tilde of t was real what would you expect, real part will satisfy even symmetry, imaginary part will have odd symmetry, so my question is check that xab tilde of f does not have those properties, clearly it cannot have those properties right, unless you have b equals 0 okay, so can you check that, what will go wrong, check very carefully, yeah the a minus jb will kill you right, so once you have that it will kill you, you will see everything else will be fine, if you didn't have that a minus jb it will be fine okay, once you have the a minus jb you will see the, it will give you a phase shift which will shift the things around and you won't have that real and imaginary part, so that's good enough, so having just, I mean it has to work right, that's the property of Fourier transforms, you must have known this for a long time, so it works that way, so check all those things just to be comfortable, a minus j, there is a pi okay, there's a pi f t, oh I missed a 2 pi okay, I'm sorry, so that will cause no problem, that pi f t will cause no problem, if it is there you will still have a real signal only right, so real signal shifted, it's no problem it's still real, but this a minus jb will kill you, you will get a real and imaginary part being okay, so hopefully you also know how to compute xab f okay, right from this part you can easily do it, from the, it will also occupy a lot of bandwidth around f naught, but it's okay, so this can also be computed, these are important exercises, don't turn in your answer script saying it's infinite bandwidth, so I won't do it okay, so if I ask question you do, in practice something will happen right, when you do this, so is it all interesting questions, people in interviews ask these questions and most of our students give such answers, they say this is a, so for instance I think the question was something like, it was a capacitor being charged, there was no resistor in the picture, the question was what will happen if I close the circuit, something like some such answer, some infinite answer was given okay, something has to happen in practice right, so as engineers you have to figure out what will happen, you have to make some approximation and say something will happen okay, so always here also assume such things are given to you, don't make, don't give me answers in terms of the other thing okay, so the last thing I want to point out with this QAM, you should draw a picture of how the transmitter will look okay, so you have two times log M base two bits coming in right, this is the bits that are coming in okay, what are you doing, you're first doing what's called a mapper okay, so people call it a bit mapper, bit to symbol mapper okay, you're mapping from bit to symbol, so what comes out here, some A plus JB okay right, so this is just one signal at your point, so what people typically think of is from here you have to convert this into XAB tilde of T okay, so this process is typically not given any name okay, so you have to think of it as XAB tilde of T, what is this XAB tilde of T you know, it will actually have two components, the I channel and the Q channel, what will the I channel have, simply A Q channel will have B okay, so this I and Q will now go into what, go into your up conversion circuitry to take it to whatever band of interest that is to you okay, so typically like I said what what goes into this question mark, I gave you a brief some two minutes lecture of how this typically is done, how is it done in today's systems, what would sit in here okay, like I said it's some processor okay, so XAB tilde of T is just a sample and hold type thing for some processor here, so what will this processor do, in this case it's very very easy, nothing to do, simply keep sending A at lots of A's okay in that particular time interval, lot of B's in that particular time okay, so imagine some sample and hold sitting on the other side and it works, in this case it's even ideal right, it's all constant, so it's ideal, so everything will work out okay, in future we'll see, we might have to put some filters here to make things work out properly, because you don't want infinite bandwidth, at that time you'll have to do something okay, so you'll have to do something, at there I'll talk more about it okay, so hopefully all these stages are clear, you have bits coming in, you map them into a complex number typically, which is a symbol okay, and those symbols are mapped into the complex envelope signal itself okay, which typically is done in baseband okay, it is baseband, what's typically it's, it is baseband and like I said usually people use digital processors and sample and hold type digital to analog converters to do that okay, and then you have the up conversion which is truly RF right, it's some oscillator, fair shifter all these things sitting inside, some RF goes on, XAB of T goes on okay, at the receiver what do you do, okay of course some noise is getting added here, I'm not showing it, the receiver what do you do, what do you do, you do down conversion first okay, so what all do you need for down conversion, what should you know for down conversion, the center frequency, the accurate version of the center frequency, the reason I'm saying accurate is, oscillators are notorious for being inaccurate and they also drift with temperature etc etc, so you need a lot of stuff there okay, so in most cases what's done is people derive the center frequency from the signal okay, it's possible to do that, then in that case everything will be accurate, if the signal drifts your center frequency will also drift, all those things are done, so you do that okay, then you get the INQ back okay, which is hopefully an accurate representation of your XAB tilde of T okay, like I said in practice today all this is done digital, so you down convert and you sample at a very high rate, so that you can think of this as a nice digital signal and then what do you do, even in the base, the regular PAM case what should you do here next, what's the operation, you have to do the correlation right, you have to do the correlation with your fee, so in baseband what is my fee, it's just averaging it's a constant right, remember the cost 2 pi of not T, sine 2 pi of not T is gone okay, that's a crucial difference okay, so far I've been talking about the signal in passband and I've been talking about fee 1 and fee 2 as cost 2 pi of not T, the reason is what, what's the advantage in talking about the signal in passband okay, I know the accurate bandwidth and the frequency and everything I know okay, but I can get rid of that and deal with everything in baseband and I'll be fairly accurate, I'll know the power, I'll also know the bandwidth right, I'll know the bandwidth also, the complex baseband bandwidth, it's just shifted when I go to up conversion and down conversion, so everything is captured nicely in baseband itself from XAB tilde of T2, that's the XAB tilde of T at the receiver okay, I don't have to worry about this up conversion and down conversion and I can think of my fee 1 and fee 2 completely in baseband okay, in the QAM case right now, it's just constant 1 by root 1 by T between 0 and T that's my fee 1 okay, so I'm going to just do integrate and dump in this case and I'll get my INQ back okay, so this is A hat, this is B hat, so I'll have to then estimate, then comes my detector right, so I'll have to do detector, I'll get back my actual bits okay, so this is how the whole system looks and what goes here is the correlator okay, I want you to be particularly comfortable with this complex baseband and the shift to the real passband picture and back and forth and why it's all the same okay, so why complex baseband is good enough, you don't have to deal with anything in passband as far as your detector and correlator is concerned, so even these correlations are done in baseband, you can imagine doing it in baseband, there may be some advantage to doing it in passband, I don't know maybe in some cases it's good, but typically you imagine doing it in baseband itself okay, all right, so that's where we'll stop today, you'll have to do your attendance


Everybody forced here case number eight our last daytime Immaculate basketball break today 21 22 full case Number eight five box case Alvin s has the Pacers Anthony C Kings Bob H heat bohia B Clippers Chang s wizards Kristen s has the Bulls Harper B Grizzlies and Timberwolves and magic Hang Y with the Nets the Warriors Hilton Thunder hero s sons E and K Hornets Jason F Rockets Joey Y 76ers and Nick's Kenneth G Celtics Kenny T Pelicans Lee Juan Y with the Spurs Mark T Lakers or NW Mavericks Ramin with the Cavaliers Nuggets Sean M Piston Sheldon J Raptors Tatsuya Blazers Tommy L Bucks waming H Hawks and jazz. Good luck everybody. Let's get started here This is seven or not this eight is eight.  It's flying now Is this the logo man case everybody? You guys are in central, Florida come to the apopka show this weekend. We will be there Think we're sponsoring again we sponsored last few times It's a good show. It's good. It's definitely a good regional show. I'd say it's the best in central Florida area Once a month, too, which is awesome. They have JSA to authenticate stuff there Like every other month, which is cool Here we go, everybody. Last daytime case some random styles tonight with Sam Be a little more PYT's tomorrow morning as well We got a bucks drew holiday 17 of 99 Miami Heat Jersey card is Jimmy Butler 81 of 99 Subdark from Mario Jersey card for the Nuggets Aaron Gordon 27 out of 50 prime Jersey number. I think is what this is called PJ N It is to 50 Prime patch auto going to the Pacers. You've got Dwayne Washington, Jr. Rookie 10 of 25 Three color patch there for the Pacers Prime patch rookie auto Raptors is Dallin O'Banson 9 of 25 Let's hit Raptors and a shadow box signature Bob Coosie Celtics. That's pretty cool 12 out of 49 second Coosie auto of the day He's not in a lot of stuff either in the past few years Who's got the C's Kenneth G. There you go And again guys impeccable football random team styles tonight as well as some more random divisions I think we have PYT's tomorrow for impeccable football There's more follows baseball right now on the channel with on the baseball channel with Matt and more tomorrow as well Man breaking all these new releases all the next few days Kessler Edwards rookie net story of 399 and we also have tops finest baseball release day Friday. Those breaks are on sale now Roger on tiktok link is in the bio The standard jumbo jersey for the heat Jimmy Butler at 39 out of 99. Yeah, I'm actually it's gorgeous My favorite high-end product like card designs that noir Chris or Greg Brown the third rookie jersey number patch six out of 50 Blazers JJ Hope hopefully logo man this case my last my last chance today I'll leave it up to Sam if I don't Harold and signatures Nuggets David Thompson 23 of 99 LSE baseball. It's only on YouTube LSE baseball I'll get you a link for that stream right here That's where we got all our flawless daytime over there Drop in Lincoln chat right now that stream Three-color patch out over the Hawks Danilo Galanari 48 or 49 Sam is not a Danilo Galanari fan Who pulled one of these tonight and he'll get upset pretty mean Mike. Not sure what happens Think anything happens Harold and signatures spurs Manu Ginobli 27 is 75 Here we go spurs a lot of nice vet hits for the spurs so far today Some Parker some Robinson some monos I think he's there now right he's out the whole year with a knee injury Vaughn is doing it as Danilo on the Celtics right now Yep, there it is Vaughn. Yep, never mind. I see your chat now Vaughn. You're already answered You're right. Yeah, there was some really nice Robinson. I forget though. Was it like it's not modern marks I forget the name of the Robinson we pulled Bulls act Levine parallel one of ten It was like inoculate marks, maybe I don't remember the it was a really nice on at on-card acetate auto 1299 Jersey card Darius Garland Cavaliers next dual Jersey 75th anniversary Pat Ewing 23 of 75 Magic legend Pat Ewing one of the greatest the flat tops in sports history Past and present signatures for Sacramento Mitch Richmond 11 of 99 Modern marks Steven Adams Grizzlies 19 of 99 It wasn't modern marks the Robins and I forget I forget what it was. I also forget which case This is hobby Whoa Three of ten Jersey numbered rookie inaugural ain't got a Josh giddy giddy up monster for okc Hilton again Hilton's had him all day. He's hit some pretty nice ones Jersey numbered inaugural ain't Wow Yeah, there's four there's first offline immaculate. That's nasty. That's going right in a mag. Congrats. Okay. See congrats Hilton appreciate you buying teams all day be immaculate 2k 1999 at 99 Link is in the buy if you want to buy a box or rip personal is later on tonight and we have We free shipping worldwide as well. I think we also have some for a ship sealed option Could be mistaken though Chris Milton bucks numbered six out of 99 But again tiktok link is in the bio Chris Middleton there a lot of bucks cards today Patch card heat hero ball 35 and 99 the standard Lakers and other LeBron James game use Jersey 64 of 99 Lake show a lot of LeBron patches today, too Yeah, I like five or four five Yeah, I haven't seen any Scotty today outside of like a base parallel and a Jersey card Rookie inaugural ink Sixers Charles Bassie 40 of 99 past the present signatures Pacers TJ Warren 9 of 25. Oh Now this this is gorgeous My man Vin Sanity Local legend here Raptors Scores Club auto Vince Carter 9 of 10. Oh my god. I Love that.   Love and scores club love the photo too Yeah central Florida legend Vince Carter God, that's nice He went to mainland in Daytona really mainland high school. Yep. I didn't know that goodness gracious, dude That's an outrageous card Those are some of the best unions in in history those those old purple alternates. Yeah Like unmet like some of those late 90s like grizzlies magic Raptors So glad the magic went to their current jerseys like the one that I'm wearing right now Kind of like an homage to that era. Love it. God clean signature. That card is just something right there, man One of my favorite cards we pulled today Come on. Let's see a logo man last box here It's a five rookie Kessler Edwards nets green parallel rookie to five Jumbo Jersey Chris Paul Suns six out of 99. That's a game worn all that should be game worn in this Rookie team logo jumbo patch grand theft Alvarado We are all over Alvarado today Yeah, there you go. That's awesome, man. I like the big frames in the mag Modern marks going to the Cavs. Isaac O'Coro five out of 99 You know I don't know how to say him Prime patch rookie Otto Isaiah livers 13 to 25 pistons Alvarado a Alvarado. It's hard. It's hard to not like Alvarado guy that just hustles and he was an older rookie and he you know, he had Tough for him most of the way to you need to stick on the roster. So always got a root for guys like that And a scorers club auto again. Love this design Pelicans CJ McCollum 40 of 49 Big key for them pelicans pelicans are dangerous you guys I think we all know that by now, but They are dangerous Do you expect any less on first take? Let's do a quick recap if you're watching on youtube or sorry if you're watching on tiktok the link is in the bio Let's start with the relics. So we had Chris Paul LeBron James Tyler hero pat ewing. I like uh 75th anniversary game used dual jersey for the nicks there jarius garland calves Greg brown the third jersey number rookie patch for the blazers relics jimmy butler heat twice Aaron erin gordon nuggets autos now pacers tj warren sixers charles bassie grizzly steven adams kings mitch richman's hawks denillo gallinari patch auto three color Manu for these furs david thompson nuggets bob coosy celtics 12 by 99 nice coosy uh prime patch rookie auto pacers dwayne washington jr and raptors dalin obantan and pistons isaela livers a lot of prime patches calves isaacau coro McCollum on the scores club for the pelicans very nice card there. Love those uh vet auto design there Had the alvarado team logo rookie patch to 25 for the pelicans Scores club Vin sanity nine of ten Just so awesome So awesome in three of ten jersey numbers ignogrel ink rookie auto josh giddy Now we'll do it. Thanks again everybody impeccable football is up next


Welcome to the field here I dodged your stadium as you can see we got special guest galore our usual crew with the big hurt Hall of Famer Frank Thomas big poppy his protege Mookie Betts is here miss morel into hit one to the moon is here a rod Alex Rodriguez and I'm Kevin Burkhard Red Sox What a win it and let's let's start here Mitch you guys you know this was a marathon last night, right? I mean here you are it's four nothing tweak. It's a home run That's a tough spot and I want to know what you guys are thinking they're coming up and that anything when you got this thing going Yeah, obviously You know we went a few innings there didn't have a whole lot going for us You know everybody was fighting it's just one of those grinds. You you know you could feel it But you know we kept our heads in the right place You know kept trying to create that that havoc on the bases get some opportunity out there We've got a couple base runners and you know able to capitalize. Hey, I had a question for y'all How do you guys feel about Richard coming out of the game? I mean, you know, he was He was pitching great, you know, but Just tried to grind through a bats and kind of wear him down and get him out of the game Maybe get to somebody else where we can put some runs on the board But you know he pitched a great game. Hey, we talked about Dave Dombrovsky and he doesn't get enough credit for bringing guys like Nathan of Aldi and obviously Steve Pierce who's like all world, right? How big have guys like that? Obviously Nunez guys like that been for you guys I mean they've been they've been great for us, you know, obviously a new knee came over last year and You know hadn't quit doing what he did, you know As soon as he got here last year, he's done that all year for us Obviously, uh You know piercey Nate kins all those guys have stepped up and helped us get to where uh, where we are As far as acquisitions in the middle of the season these guys have been huge for us for sure I saw chris sell yelling and screaming in the middle of that dugout. Did that have an effect in that seventh inning? Oh, absolutely. You know, he was uh, he was letting us have it for sure You know, we were we were slow, but you know, once he started yelling I think everybody kind of knew we need to pick it up, you know, because uh, he's not gonna yell for no reason I mean guys, you know, just give me a sense for the ability to hit with two outs, right? I mean, this has been a state all year. You guys were better than anyone in the league But in the playoffs, it's been a stable. How have you been able to consistently do that, Mitch? Um, I don't think we changed a whole lot. Um, I was telling somebody the other day that I asked that I feel like we've been pretty consistent with it across the board and uh, in every part of it, but uh, You know, we we approach all of them the same. We're grinding out at bats trying to win the pitch That's something AC preaches a lot just go up and win the pitch And uh, you know, I think we don't take we don't take it bats off We don't take pitches off whether it's no outs one out two outs bases loaded It doesn't matter we go up there and you know, we're trying to win that win that pitch in that situation Can somebody talk to me about steep ears, please preach I mean For some reason everybody thinks he's this serious guy, you know, I guess the way he looks or whatever, but he man He's he's hilarious He's one of those people you got to have with the team just because he brings laughs brings joy But he also brings that intensity that everybody needs and then obviously he's a he's a great player And you know swings it plays defense does everything you need him to do And he's just one of those guys that kind of flies under the radar But it definitely carries the team Hey fellas, you're one win away from the world series tonight. What are you sleeping? What are you thinking about when you wake up just one win away? I don't even know if I want to go home right now I'm ready to get back out there and uh, let's do it again tomorrow. Let's play right now There you go. Well, you got Chris cello tomorrow. So, you know get a few runs And hopefully the rest of people to say him all season long a big victory for the socks Yeah, I mean like you said just try and get a few runs and uh, let him do his thing Unbelievable night for the red socks and I got out. Hey poppy have one one question Why are you holding mookie like he's your son? My son right here boy. You can go in the charter. He's going to the hotel with me now And you can get a ring if you want to We went to the hotel man. Can I ask a serious question mookie? We got poppy. We saw poppy's first journalistic sit-down interview the other day with you right So we got his take. How did he do? Well, tell me about his reporting skills and his sit-down interviewing skills He did all right, you know, it wasn't uh, it wasn't You know fantastic All right, but he did all right.  Just yeah, you need to do one more and then I got you. I got it All right, there you have it the true the true scoop poppy. Hey, you gotta be I like it


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I'm thinking watching this tonight so your third leading scores been out for a while now Nick does not have a huge impact in this game But what is when you win a game like that with all of these contributions how much does it help you down the road? Do you think I don't know what helps us because I thought offensively you know without Nick and without those other two guys We were just I mean Kyle played a little bit, but we didn't look very good offensively You know we're playing cash is a little bit too many more minutes, but I think it talks a lot about our defense I think defensively boy. We did a heck of a job And that's what I was gonna point out coach the defensive side of the ball for you now It seems like your guys are really connected somebody dribble drive somebody's there Is that all about taking pride in supporting each other on the court? Well, I really thought you know McQuade started it, but but the other guys Xavier Tillman's really good And I was proud of cash is because I was disappointed in my challenge them and boy that last five six seven minutes I thought he did a heck of a job and fairness to him We just playing him to death. So we got to figure something out there. How would you best describe your point card? I mean, he's just so smooth that everything he does Special I mean, he's a special kid, you know, he is smooth That was a heck of a move at the end a lot of coaching to get Again, it's the whole thing is I gotta get him some rest So a lot of it falls on me well coach, but I think the depth of this team I show tonight Nick Ward not really a scoring threat, but Xavier Tillman play well High guys like that really stepping up. How much does that help you moving forward with that death? Well, you know Jimmy, I thought the first half Kenny coins was a monster He got his hands on a lot of stuff. He made a couple shots. He tipped a couple balls loose But you're right We have a lot of weapons that can do something but our offense doesn't look as smooth right now Because we got to get a little bit more done. We got to have Nick inside. They did a good job on them I thought a couple calls were close, but we need Nick in there for sure Please though with with you coach on the fast break dominated that aspect of the game Yeah, we can go I mean, you know that we can go and and if we we're going without you know Josh is that runner? So we're gonna get better here I think but if we can keep the defense going the defense travels We've won some road games. You got to win games on the road Coach, I'm gonna say there's it's a lot of butts in there, but you still got a chance to get that big W Congratulations, I love you Jimmy Thanks so much coach. We appreciate it. All right, we're gonna bring in catch us with suitors hanging out waiting patiently as we say goodbye to Tom Izzo cast us. How are you man? Good? How you doing? Congrats on the win and all right? So first we you know your coaches as heck of a coaching job on that move that he did it that you did at the Take us through that that was pretty smooth though behind the back and then the reverse Oh, yeah, I mean it was in transition You know we had a break ahead just you know take what they give me Cut me off just put him on my back real quick saw the lane. I know Jimmy like he was smiling I like the move and this game is all about challenges Anthony Cowan coming in, you know Four plus games a 20-foot plus points How did you take that not in regards to just going at him? But as a challenge to one of the premier point guards in the Big Ten conference Like I said, you know our program is big on taking that one-on-one challenge You know just that that competitiveness, you know, I knew he was having a great year I knew he's doing a lot things well and at the end of the day I want to be the better guard on the floor and that's just miles approach to the game How about overall defense with a steam look you've been great all year So it's no surprise what you did to them defensively, but tell me about the collective mindset What helps you in that department? We just we trust each other, you know, we got you know, I couldn't do it by myself It's times he blew by me times my teammates cover my back plenty of times And that's just that's the faith we got in each other, you know We close up on a three-point line because we know somebody's our gap So it make defense a lot easier. Well cash is speaking about trust Nick Ward not effective really because of foul trouble But can he go on? Okay play with Zevier Tillman play well Aaron Henry play walk the trust that you guys have in each other That somebody can step in it's just amazing. Talk a little bit about that. Yeah, you know any given night We feel like anybody can step up and that's just you know, we share the ball We keep the ball movement and like I said, we got trust in each and every one of these guys Each and every guys are you know high division one basketball players and cable playing on this level in high ways So if the guys open we don't give them the ball and we have every faith They're gonna hit the shot. All right. Give us that last thing We had a great shot at the end give a little hug dear could best thing about playing for time is always what cash is Just his passion and his love for the game You know it rubs off on everyone rubs off on the fans and the whole crowd Hey, you've been wonderful to watch progress to that other way to keep it going. Okay. Thank you appreciate that


The study conducted in Putna, Bihar, India found that children living near battery recycling facilities have elevated levels of lead in their blood and environment. This suggests that lead from battery recycling activities may be a major source of lead exposure for children in this region. This article was authored by MJ Brown, Pee Patel, Enash, and others.


Kyuriko to everyone. OK, so today I've seen a little bit already from mainly museums about the inclusion of a 3D element within this kind of cultural heritage sector. It doesn't necessarily seem like an obvious thing that you would find inside of a library. And I guess within the national library, other libraries, city libraries, we don't hold a huge deal of 3D objects. And so there's also a larger question of whether there would be any reason to even go down that path of looking at 3D technologies and bringing that into our space at all. But as I kind of continue along this, I think I'm going to try and make a case that there is definitely a reason to do it, if not for any other reason that it's such an emerging part of the world that we're living in at the moment. This technology is becoming more widely used with other kind of industries around us. And as we do use it more and more, we are recording information in new ways. We're recording rather than in sort of traditional means of, you know, a text or even video in some cases. This is going to be something that for our own kind of collecting purposes we're going to need to put a little bit more of a focus on. So if I'm just sort of show you a little bit about 3D printing in libraries. So this tends to be the main focus area that a lot of generally public libraries look into when it comes to this technology. There's always a little bit of a debate that's going on around having 3D printers in libraries. Generally, it's seen more as a novelty, I suppose. The quote that I have here is actually from an Australian librarian who kind of sparked a lot of debate on this topic. His name was Hugh Randall. It says here, if 3D printing was a truly useful technology for libraries, there'd be serious articles about the potential for how we can use that to store information, make it discoverable, et cetera. So this has been our first kind of venture as a library into 3D technologies and that is with 3D printing. However, yeah, it often gets kind of given this perspective that it's just something that can be used for novelty for, in this case, printing in chocolate. But I think what it offers, at least from my point of view, is just an immediate way of being able to get your hands on with this new sort of technology, with this new way of dealing with information as more things start moving down this path. It's just an entry point and it provides access to a wider community of people who may not necessarily be able to afford to look into these kind of things. So off the back of getting 3D printers ourselves in our own spaces at the National Library, we started working in partnership with Victoria University's School of Architecture and Design. Every year we run summer scholarship projects with the university and through these summer scholarship projects we're actually able to explore the ways that this technology can be made useful inside of a library and why that may even be, you know, a necessary thing in the future. If we look back kind of over the history of libraries and the kind of materials that we hold or even just the ways that we create knowledge, I guess the earliest sort of times we would have been recording a lot of our stories and our experiences and our understanding of the world through an oral tradition. So in that instance we don't actually have any kind of an artefact in which information is stored. Often it comes down to mnemonic techniques and being able to remember how things work or what things are and what maybe could be poisonous in the world and within that way of trying to maintain some kind of repository, the repositories held within people. In those instances there are methods that people use to be able to try and remember things that would otherwise, you know, be for maybe you or I, easy to forget.  It's a way of being able to kind of take a mental note but out on the physical kind of a landscape. As time went on people started using clay tablets. Clay might be a little bit heavy or you don't want to carry that around with you. Later on industries start moving to paper, you've got the printing press, you start moving into books and once there are more static ways of recording information, things that you can actually pass on to someone else so that they can see this is true, we can look through this, you know, is this verifiable, did this come from this place or other origins, as you say they are, then we actually have an increasing amount of fidelity in the way that we store and record information. I guess as we learn more about how we copy and keep material over longer periods of time we learn other ways that they can be at risk. For instance with microfilm there's plenty of examples that you are probably all aware of where an original item might be recorded on microfilm and then that original was then thrown away only to later on discover that that microfilm is not a good enough copy to be able to refer back to. With digital materials there's more fidelity there you're able to capture at a higher resolution, more details, more kind of accurate representation of what that thing really was, but at the end of the day we're still stuck on a two dimensional screen, we're still stuck generally with photographs to a single point of perspective of what this information can hold. So for instance you may be able to take something like the Treaty of Waitangi which is the first sheet at least is on like parchment which looks like it's probably actually taken from some goat skin. There's sort of a whole story just in the texture and the way that that moves that you can't really capture just through a photograph and I guess those things may not be the main point of why you want to collect those things but as time does move by we are finding if you want to be able to return to a point of origin where something came from some of this extra detail is actually becoming increasingly more necessary as our default means of being able to collect things or to be able to record and copy things has a huge much larger demand on being able to maintain that level of fidelity with your information. So what I have here is just an example of the technologies that may not necessarily be dominant at the moment but within industry in general becoming more and more common and which sort of shaping the way in which we produce products in the first instance but also the ways that new knowledge is being created. So I guess there are always going to be things like books which is like the staple of libraries which are never going to necessarily become obsolete but as we start performing in other ways as we start doing things as a society in other ways in order to be able to retain a record of our cultural heritage we do want to be able to try and find ways that we can store these other things which may not be suitable in the kinds of formats that we have available at the moment. So everyone at the moment tends to have some kind of immobile device so that's been taken up already. Everyone has some form of generally contact with each other through immobile means you don't have to post a letter etc. As we kind of come around the circle we start seeing things like location detection technologies so being able to make your whereabouts discoverable to be able to place a point on a map. These things are kind of taken for granted a little bit now but there's always new information that's being collected from this and the ways that that information can be used to create a sort of a broader picture or deeper sort of understanding of the things that we're collecting today. So just to make kind of more clear what I'm talking about while there is a general focus I guess on exploring the kinds of collections that we already have available there is also a need which may not necessarily be fully explored around how we capture these emerging forms of information which seem to be quite fluid and I guess in some ways not too tangible just because the subject to change and with things being made available online that information can be edited and updated and it doesn't necessarily remain in some static form that we may be used to. As we come back around to 3D printing it completely changes the supply chain so once upon a time you may have probably bought your music in a store you're probably downloading it now in time to come that is a likely scenario for the way that you may be getting products or being able to purchase items rather than actually having them delivered and so doing you're also making much less of a demand on transport logistics etc. So through that it's cutting down costs that we're otherwise including into other things that we do in the broader picture of our lives but what that means for libraries as well is we would then have a reason at least to look into being able to collect the sorts of designs or 3D models that may have some kind of a cultural or I guess historic for the future impact and to be able to retain those maybe in a repository or something so that they can be made available later. One thing that is I guess being looked into quite a lot more often at the moment is big data and augmented reality I guess is kind of here already but I guess if anyone's sort of had a look at it again we're still for the most part trapped behind a two dimensional display. So following on from augmented reality we have light field technologies which are sometimes referred to as mixed reality so this is just a you may have seen this before somewhere else but it's an example of I'll just make that a little larger. So this is a I'll just let you watch through it and then I'll give a brief explanation about it. So in this video what we're seeing is mixed reality and what that involves is as opposed to being able to view extra digital information overlaid onto the world through an iPad which is kind of how we're doing things with augmented reality at the moment what we have is light field signals being projected directly into one's eyes and so what it's doing is it's creating a blend of digital overlays with the physical world in a way which is quite indistinguishable from it looks like it's out there essentially and the sort of projections from the magic leap who have created this is that the uptake of that technology around about the 2020s should be probably about 70% of people will be looking at having that kind of technology available to them and so with that just around the corner that's going to sort of impact on the way that the material that we collect now is made available I guess we're we're looking at things still in very two-dimensional ways and that would still be a way I guess in which you can view that but whether that provides you with the most the highest level of detail that you need to be able to conduct research is just another question and one of our earlier exhibitions that we run at the National Library big data we looked into the use of LiDAR and remote sensing technology to capture sort of landforms and we are looking at it again with our current unfolding the map exhibition but what this shows is the way that sort of point clouds can be generated to create 3D models of an environment so while the sorts of things that we may collect at the moment will be maps or photographs of locations being able to actually capture entire three-dimensional models that just provides another sort of an edge on what later on we will be able to sort of interact with and then what can be done with that in terms of output whether that be 3D printed into a model that can be used for other purposes or whether that model can reveal something about the time that wasn't previously available with other means of capturing information so in terms of open data there's a lot of information that is now made available publicly throughout the internet and the way that information can be used by individuals is quite limited in terms of their understanding around what they can do with it so a huge part of what our role is in the public programs team is to be able to facilitate an understanding around digital technologies and develop digital literacies one form of information with these data sets is geospatial information so what we've got here in this image is some map of sorts of Wellington and it's all just survey data the way this works is it's not really a map designed for people, it's a map more designed for machines so the pixels in this raster image they represent different levels of elevation as that can be examined you can then generate sort of virtual terrains from that which reflect to the human eye a little bit more accurately what that information should look like other sorts of data sets are available out there for instance you have information from the City Council here which shows the entire sort of footprint of the Wellington CBD within that you've got information saying how high each building is if you were to take some of this information and combine it together you can get outputs which will provide a model of the city there of the landscape with the buildings available on the top so this is all just information in spreadsheets or on tables and then from that you are able to visualise in such a way that you are able to interact with it without having to know things like structured query language or other scripting languages you are able to just move in there and just sort of make that visually sorry guys, it's a little bit buggy but while that is something that's available today we have this kind of technology and that sort of data readily available where I'm trying to go with this is this is a new way of recording information there are new ways of being able to put this stuff together but when we want to reach back and take older information that's not as easy to do so with some scholarship projects that we have focused on they've gone back into our collections and they've taken material which may not necessarily be easy to work with and have been able to bring that up to date and be able to pull extra information out of that that wasn't already there so in this instance here we have a model that they have built of the Wellington waterfront with three different puzzle pieces those puzzle pieces can be overlaid on top of the model of Wellington and then through an iPad it's possible to then view the footprint of the city at that point so as each puzzle piece is added onto that model that footprint is then updated for the time with that that's not only the new buildings that have been built since but it's an update to the entire city so other buildings that may have been replaced or have grown up around it those will also be added in as well and this will be available to view once the library reopens as part of our Unfolding the Map program other ways that the Victoria University has been able to sort of reconfigure the information in our collections has been through taking floor plans so in this instance we have Lambton Tower which was a tower that was never actually built and they've been able to use I just guess CAD from this they've also learnt to develop the algorithm that was used over aerial photographs, aerial images to develop the buildings on the previous slide as well and here we just have a 3D printed interpretation of that which is taken from our collection materials again we've got an image here of the Wellington waterfront which is a virtual reality experience that had been created using collection materials as well as the basis for being able to see what the waterfront looked at at that particular time and the idea behind this then is that you can actually take some of this material out into the world if you were to look at it through for instance a pair of binoculars with a virtual reality headset in it then that allows you to be able to move back and forth between the physical and the digital interpretation of what Wellington may have looked like at that point just looking at some precedents for other means of being able to take older or limited materials and what do we got here and do things with them so here we have Recre which is also known as Project Mosul in Iraq the Mosul Museum was destroyed by ISIS Project Mosul originally was put in place to crowdsource photographs from just visitors who had been to the Mosul Museum and then to use photogrammetry as a means of being able to just restore, I lost the model there I've got 2 minutes left I think so I'll just try and move through quite quickly so what 3D printing in libraries provides is a means of being able to take some of these objects that have been reconfigured out of collection material and to make them physical with working on other projects with the University through the Summer Scholarship Programme we've explored augmented reality so we've been able to incorporate that into existing exhibitions that we have on display so these are some examples just from last year's programme that we ran so we have World War I Contemporary Conversation which we used augmented reality to enhance that we had a Child's War which was one of the exhibitions that we held in the Alexander Turnbull Gallery as well which was able to then use augmented reality and 3D printing to look at for instance sheet music and things like that and to be able to play back music from sheet music using augmented reality as a means of being able to identify whereabouts in that sheet music that music should be playing from and then we had an interpretation of Paul Gendon's material as well so taking sketches of puppets from those collection materials and then being able to bring those to life using motion capture to be able to move and freeze those models at a particular point where they can then be pushed out for 3D printed birthed into the world from that point kind of just rushed ahead because really coming to the end of the session here now but what this all sort of leads down to is the idea of what has been coined semantic nodes so the use of augmented reality and 3D printed technologies just allows a way of being able to interact with the world which previously wasn't possible so it's just being able to blur the lines between physical and digital and within a library setting what that means is for instance being able to take an original item and be able to get descriptive information out of it just through things like image recognition and then maybe using real items to be able to hyperlink to other items just through looking at those through one medium or another and then there's obviously in our role as learning facilitators, as educators of a much broader range of what is actually possible by using these technologies as an educational tool as well really I've got one minute left I can see which is probably questions and answers but I'm probably not going to get very far with that so thank you guys really had too much to get through but I'll be around tomorrow as well if you guys have any further questions, cheers


The population over the last 50 years has gone from 3 to 8 billion and the next 50 years it's expected to go from 8 to 12 billion. Most of that growth is going to be in the African continent. That's going to show, we're going to have a real boom in Africa because there's going to be a much younger population there and that's going to be great. It's going to be an age of about 18 right now. Yeah and really booming and Nigeria will be the biggest of all of those. I think that that world will rise and so we're going to start and some of the other lesser developed countries are also going to rise around the globe and I think we're not going to feel so different going across borders and so I think that's going to be really interesting. You mentioned a new technology that can do all this great stuff like you can replicate meat without killing an animal but you can also use it for biowearfare. That's always been our choice whenever there's a new technology. That technology first tends to win all the wars but it also tends to move society forward in a magic and imaginative ways and I think that's always going to be the case. There will always be the group that says, hey how can I use this for power and then how can I use this to improve humanity? That would be the other group and the ones I think that are clinging to power right now are I think are sort of a dying breed. I actually think that humanity is winning out and it has to do with social media. With all the communications vehicles we have now, I kind of had the sense that when we had free communication around the world when we did Hotmail and I came up with the viral marketing idea well that was going to really open the world up and it really has. So we're all very interconnected and interrelated through just friendships but also through businesses and through walks of life different ways of operating and so that's when you see one country threatening another. You think, wait a second that's just that guy, that leader so-called leader being mad at that other leader because down at the human level we already have great friends in those countries. I mean I think of all this friction between the US and China. That's friction between the two leaders of those countries. It's not friction between us. We have amazing relationships with all those people in China. I've been working in China for 30, 40 years now and had built some amazing relationships. Now I look at any kind of a war or whatever that kind of danger zone as the equivalent of just shooting off your own leg in order to see if you can hobble a little faster with your remaining leg. It really doesn't make sense except to those leaders who are trying to cling to power. That's going to be the threat, that's going to be we are moving to a new level, society is moving to a new way of thinking. The leaders have to catch up and it's interesting the leaders of these smaller countries are going, yeah, how do I do this? How do I use Bitcoin? What do I do with, how do I get more venture capital here? How do I get more citizens to come to my country? They're also saying things like, wait, how did Estonia do the virtual citizenship thing? How do I do that? Malaysia already has a virtual residency program and Kazakhstan is working on a virtual citizenship program. There are lots of countries that are all kind of going, huh, this is interesting.


I remember the one divorced family in the neighborhood I grew up with was like a big scarlet letter. And now if you went to the street, my kids grew up on. Half of the people are divorced in that geographic area, if you will. But these all leave imprints of how we feel safe with another human being.