All right, here Dragon thing. Oh, hold on, hold on. So this helps, but I would still have, if you take this out, your grid, I have no idea what's going on. And especially here, like, are we looking, this seems to be where we're on the same level and now we're tilting down to see a top view. But if you take all the grid out, it's gonna be a bit tougher to see. So I would highly recommend you have, like actual volumetric, do you put some spheres for clouds or something? Or even if you, maybe it's like on a hillside with really tall trees and things can go fly by, so that when you do wrong, you have a clear perspective change with things coming at us to show what's going on. That'd be my main concern. As you go up, I mean, this is still pretty rough. Your wing poses are right. Just chest involvement, leg drag, stuff like that. But as a general idea, that's cool, yeah. I mean, here it seems like he doesn't care anymore that this is flying by. So you can do this and then he might do like a, and then bring up his legs and tuck in his legs, right? And then do this. And then I will probably wait since this ball, this is almost hitting him, right? It looks like it's hitting him. You could wait a bit and maybe at this point, maybe lower the camera a bit sooner. My point is that when he goes down, it's all very simple. So what you can do is he goes like this and then on this, this turn, this flap, the making go down, he actually spirals. And that spiral, as he goes away, might also help that he, you know, like this, all this whole thing turns this way and then the next rock comes through. So it's just kind of spiraling away from that, that guy. That way it's not as simple. This is cool, but you're really hugging the lower right frame. I would bring this over here, this guy over here, so that his head is here. It's a bit more balanced. And a tricky thing is I would then, okay, I would do it differently actually because he's so huge, he drops them, which is cool. So what I would do is, compositionally, I'm gonna reuse this here. And that should be better. So your guy, all right, so now I'm gonna draw over this where your head is here. So a little bit higher, still around there, but keep this size, right? And then that way the legs, the feet are here. So we see what's going on right now, the stuff is hidden. So I would actually, sorry, that's actually wrong. Keep your head here. But since this is the middle, I will bring in your other dude around here, catapult here, and then you can kind of keep the dragon ish where it is. But that way, you definitely have a clear view of the feet so that you can come out, bring out those claws and really grab them. We get to see what is going on. Right, and then even as you go off-screen, you would still have enough of the head in there. So that way you get a nicer, cleaner composition. And it's not so forming tangents here and clipping that with the legs, you don't know what's going on. I don't think you would see enough and it also cuts the dragon off, whoops. Where is it? Cuts the dragon off, like right there. So you would, damn it, you would by zooming out, you would give this a lot more room. Again, head will be here. And then you would see more of the wings, just be a lot cleaner. And then as you move forward, that'll be all okay. Now probably you can always swing it and chuck him over it its way. So you have head here, dragon here, little guy, ah, it's always like here.  But compositionally, I think this will be better because otherwise you're very right heavy. Like everything's going on in here, which, I mean, you might argue well, but if the head is here and looking, that nose is gonna point nicely at the dragon and this falls, he could drop here. You could, you could try it. I mean, I'm not opposed. You can also, if you do all this and drop him, start panning the camera over. So at the end, there's a slight camera move that motivates the audience to go and move with us to the right and follow these guys. And you know, it can also take a little step at the end so that maybe the guys at the end is here looking this way, dragon's here and then the guy goes this way, which could also be really cool. Because if you look at the dragon, flap, flap. You know, like during all this flapping, it's not as interesting because it's basically just flapping. So you could easily have this guy change. You'd be like, whoa, he turns around and does a little bit of a move over to the right. And then you can do like a big, a big, maybe he stops a little bit and yells and then drops. So when the dragon goes this way, we're looking here. The human moves over here, the bigger human moves over here. So the audience is not looking here. How do you get the audience back to the dragon? You stop the dragon a bit to like a crazy move or something like, whoa, what's going on? And then he does a very deliberate throw away. And then it gets out. Something like that. I don't know, food for thought. Let me know what you think. All right, there's an email. You can sign up. You can start whenever you want. You can submit whatever you want. You get 16 submissions. Either way, a like and subscribe would be awesome. All right? Thank you.


In this video I will describe the location and structure of DNA, list the steps involved in DNA replication including the enzymes involved in their functions, and compare the replication of the leading strand versus the lagging strand. DNA, or deoxyribonucleic acid, is the chemical that functions as the genetic instructions for cells. DNA is found inside of the nucleus. During interphase of the cell cycle, DNA is loosely wrapped around histone proteins, forming the structure known as chromatin, which is uncondensed and spread out through the nucleus. However, during m-phase of the cell cycle, the chromatin will condense to form linear strands known as chromosomes. This figure shows us the structure of DNA. DNA is double-stranded. There are two nucleic acid polymers that are held together by complementary base pairing. The complementary base pairing always pairs thymine with adenine, and thyminess held together to adenine by two hydrogen bonds. The complementary base pairing will always pair guanine with cytosine, and guanine is held to cytosine with three hydrogen bonds. While the hydrogen bonding between base pairs holds two strands together to form a double-stranded, double helix molecule of DNA, within each nucleic acid polymer, the single strand is formed from nucleotides that are held together by a sugar phosphate backbone. The sugar phosphate backbone is a phosphodiester bond formed between the phosphate group of one nucleotide and the five-carbon sugar of an adjacent nucleotide. The free end of a nucleic acid polymer that has a phosphate group unbound is known as the five prime end. The opposite end of that polymer, where there is a free five-carbon sugar that is unbound, is known as the three prime end. The two strands of DNA are anti-parallel to each other, so that the five prime end of one strand is forming hydrogen bonding to create the complementary base pairing with the nucleotide at the three prime end of the other strand. This structure of DNA as a double helix with complementary base pairing enables the semi-conservative mechanism of DNA replication, where two-parent strands serve as a template for the synthesis of the new complementary strands. When DNA replication occurs, there will be a replication bubble formed, and that replication bubble has two replication forks at either end, where DNA replication can proceed in two opposite directions, producing both a leading and a lagging strand. DNA replication will always proceed in the five prime to three prime direction, adding nucleotides onto the three prime end. Therefore, the leading strand will be the strand where nucleotides will continuously be added at the three prime end to form one continuous copy. In contrast, the lagging strand will have to be initiated multiple times, and then the fragments produced from replicating smaller pieces of DNA, known as okazaki fragments, will be joined together. Multiple replication bubbles will form simultaneously in one double helix DNA molecule, so there can be hundreds or thousands of replication forks copying DNA simultaneously. The first step of DNA replication is known as initiation. During initiation, the two complementary strands of DNA are separated, and this creates what's known as a replication bubble. There are thousands of origins of replication throughout the chromosome, and at each of these origins, a DNA replication bubble is formed, and on either end of the replication bubble is a replication fork. The illustration here shows us a replication fork at one end of a replication bubble. At the end of DNA replication, all of the replication bubbles will have joined together, and then the chromosome will have been completely replicated. So in the beginning of initiation, the first step of DNA replication, an enzyme known as helicase, breaks the hydrogen bonds that hold together complementary base pairs. Following helicase, the enzyme primase constructs an RNA primer complementary to the DNA template. The second step of DNA replication is called elongation. During elongation, the enzyme DNA polymerase adds new DNA nucleotides on to the 3'n, creating a longer DNA polymer that grows from the 3'n of the RNA primer. DNA polymerase can only move in the 5'-3' direction, but there are two template strands of the DNA that are simultaneously being replicated. On the leading strand, DNA polymerase can follow along in the 5'-3' direction right behind helicase as the replication fork continues to open up. However, on the lagging strand, a new RNA primer will have to be formed after helicase opens up a new segment of the DNA. Then DNA polymerase can move in the 5'-3' direction, adding new DNA nucleotides on to the 3'n of that RNA primer, creating a nucleic acid sequence that's a short fragment known as an Okazaki fragment. During DNA replication of both the lagging strand and the leading strand, the RNA primers will have to be removed and replaced with DNA nucleotides. This process is carried out by an enzyme known as RNAase H. RNAase H is the enzyme that replaces the RNA primer with DNA. Then finally, the enzyme DNA ligase joins the fragments together, forming a single DNA strand. There are numerous fragments of DNA formed during the elongation step of DNA replication. At the end of the elongation step in DNA replication, DNA ligase catalyzes the formation of phosphodiester bonds, uniting a long sugar phosphate backbone through the entire chromosome as one long DNA molecule. As all of the replication bubbles are joining together at the end of DNA replication, this is the third and final step of DNA replication known as termination. During termination, the enzymes, the DNA polymerase, primase, and finally DNA ligase are released from the DNA, and the process of DNA replication is completed with the creation of two identical DNA molecules that are continuously sealed with a sugar phosphate backbone connecting throughout from the 5' to the 3' end of the entire chromosome.


What's up everybody and Merry Driftmas it's time for another Tork Drift update video here on the channel. What's up everybody I'm EvilRabbit. Merry Driftmas update is up and running here on Tork Drift with some new content. We have Nitrous, we have an R32, we have friends list, we have a new pro car, and we have Christmas crates and some new body kits. So we're gonna go hop right into the challenge that is out here. But Nitrous, very excited about it. We're gonna go take a look and see like what kind of Nitrous is available and how much it is. If it's even, where is it? Nitrous, there it is. Oh my. So Nitrous systems capacity one. So this is gonna make for some very interesting drifting but that is gonna be for another episode. So like I said we're gonna hop into this challenge try to get ourselves some Christmas crates and see what we can do. Gingerman full track. Let's go. Hopefully you guys are enjoying all this snowy tracks and everything like that. 239,900 to get that gold tier Christmas crate as well as 199 for a Christmas crate. In that 900 horsepower amazing Kisa Awan. I know I butchered that name. Let's get it. Hopefully we can do this right away. I have not tried this little snowy gingerman track for us right here today. I'm not sure what gear I need to be in. Throw it in in third. Looks like third is probably where we need to be. There we go. Gonna do a double little flick. Oh no. Okay well it's our first run out. We weren't gonna probably get it on the first try. I never get these challenges on the first try but I do like the little snow additive because it is winter and snowing outside of my house as well. So driving in the snow is something I'm very familiar with. So I'm almost 100% positive that we would need to stay full commitment on this track and not miss anything because all right there we missed that and we missed that. I haven't driven gingerman in a minute so I'm trying to remember the track but this car handles very very well so probably nowhere near the high enough but a first shakedown run not too bad. 114,000 and a lot to go. So let me know down in the comments how you guys did on this challenge yourself and make sure you guys follow me on Instagram and Twitter all of which are also found in the description box below. Getting in the holiday spirit with Christmas right around the corner. If you guys don't celebrate Christmas well I do apologize. Happy holidays to you if you don't celebrate Christmas in the new coming year. Oh that's a rip. Force gear where we need to be? Let me force gear. Force gear looks good. Yep force gear looks good. Oh not there though and then we lost drift there. So I know we definitely need to stay 100% in drift and get all of these clips if we're gonna want a shot at actually getting that 230 some thousand yeah force gears where we need to be too soon so we're gonna retry this so fourth gear is what we need to do so let's do fourth gear and see if we can't bang this challenge out here on the channel torque drift big things coming for torque drift did getting okay to do something from the devs themselves so uh look for some different torque drift content coming here to the channel very very soon so definitely oh my gosh definitely excited to be bringing other content to you guys with the torque drift stuff and getting more and more involved with torque drift here coming very soon teasing a lot a lot of you guys like torque drift but it's coming I know a lot of you guys keep asking we need more torque drift we need more torque drift I agree so you guys are going to get some more torque drift as well as a set of course of content modeling content and all that kind of stuff coming here in the next few weeks as well as the coming year that's much better now I think we're uh now I think we're pretty pretty solid start very solid start there we go reach out and touch that clip just a smidge quick transition off the gas stay where we need to stay I am surprised we got that clip I'm gonna have to double initiate that which ran us a little bit wide on that clip but we're going to be able to stay this way need to stay in drift there we go clip the grass a little bit don't oh well unfortunately we were unable to finish this run off completely wall tap oh my lord so that was almost very bad we almost lost everything but we still did not get up there we need to make sure we link the entire track 168 getting better but not good enough we need to get some of those Christmas crates we need to see what we can get in those Christmas crates probably going to be buying some as well and do a little lot Christmas crate opening for you guys here since like I said Christmas right around the corner torque drift bringing us an banger update getting us all in the holiday spirit oh that was a very aggressive clutch kick somehow we managed to keep that on that out wide oh no no not what I wanted to do man you definitely need to be on point with this challenge recent challenges the torque drift bringing out to us definitely uh definitely a strong challenges and uh definitely take some focus here we go I'm gonna quick flip that oh how did we nope we can't do that we need to link the whole track so like I said let me know down the comments how you guys did and what you guys did to complete this challenge I probably could stay in third gear for the beginning of the course and then switch into fourth through the ladder section where returns get a little bit more intense too much clutch kick said no drifter ever I'll throw it in fourth stay out of the grass what am I doing oh rip this is not gonna work out because we missed all those cliffs this challenge is tough I've been struggling recently with torque drift challenges but then again I complete them after uh I stopped recording once I kind of run a couple more times and you know focus myself out so if you guys got it on the first try kudos to you you guys got it on a couple tries after that you know right there with you guys I'm sure a bunch of you guys got it on the first try and a bunch of you guys have driven gingerman so much in this game that you know every little trick to get all the good gravy points in this thing and I'm just trying here to uh stay solid hit all my clips and not lose drift that is kind of what I'm trying to do and I feel like that is a very good idea to complete this challenge no not enough clutch kick oh rough times so like I said we're going to be doing some great openings we're going to be doing episodes on the nitrous express systems and all the knots in the game because that's going to make for a very interesting change to uh how we drive so not sure how the nitrous systems are going to work I'm curious if you have to buy them every single time or how all of that is going to work so we will do a full rundown on the nitrous systems in another episode that was a very greasy greasy way to get that clip and we did miss that one but maybe we can still somewhat come out of this this is a very uh very dirty run and not the smoothest run at all but if it works it works it doesn't work when you do that I thought it was all the points by hitting that wall so torque drift all these challenges geez man they're rough but definitely fun challenging me to increase my driving skills in some new cars that have never driven before so that is another aspect of this challenge but this car does handle pretty good big old drift taxi no coming out of drift should have been clutch kicking or hitting that clutch button that's right there we're gonna try and start in first so I think I'm gonna give this one or two more tries here for today now if I can't complete it well rip on me no Christmas presents for me but if I do complete it I will save those Christmas crates for a crate opening video so let's see what we can do this probably our final attempt maybe one or two more I always say one more time and then I go like six more times because I'm determined to actually get this and I don't want to fail but I seem to recently have failed on mostly all of these challenges recently whoo kick it in the third kick it in no good initiation points so that's right there is uh I'm leaving some points on the board get off the gas transition that helps a little bit stay all kinds of sideways there a little bit of handbrake a little bit more a little left foot brake that was almost very bad but we managed to come out of that one alive and I don't know how but we're gonna have to double flick this one so we are gonna miss that clip but one missed clip is better than three missed clips but that's two missed clips and a loss of drift all right this is gonna be the last try here for today for this episode and if I don't complete it we're gonna come back to this and definitely try and get this challenge completed final flick entry in still no good initiation point so right there's probably a good 8,000 points to the left on the board that's a much smoother run through that section oh boy all right I know I said that was the last one but I can't end on that we gotta try and get a good initiation because I feel like that sets the precedent sets the bar for the entire run we just gotta do a hard flick there we go that's the initiation I wanted we did miss that clip and over angled there but we're not gonna salvage that run all right all right this is the last time I definitely promise all right here we go final attempt here at gingerman here on this torque drift challenge kick it in I feel like I should probably just stay in third gear I feel like fourth is good but I tend to lose drift a lot snow kind of just helped me stay alive but then we wrecked it so I think that'll do it here for this episode here on torque drift gonna be coming back some more torque drift episodes for you guys big things happening on the channel here with torque drift so as always I thank you guys for watching I'm evil rabbit I'll see you guys on the track


Hello, and welcome into the Tracy Johnson show. I'm Joe Wamba, joined with Tracy Johnson, head coach of the women's ice hockey team. And coach, after that weekend off, you guys continued to fill the net no different when you guys come home and play Morrisville for a set of two. Yeah, it was exciting to put that many goals in the net in that first game. And we knew it was going to be a little bit of a closer one the second game. But again, we found the back of the net when we needed to. It's been a point of emphasis for us since we went through a little bit of a dry spell. And I'm glad to see that it's paying off. And that first game was pretty tight. And then Chelsea Blackburn just let her rip. Yeah, four goals in one game is an exciting thing for her. But I think the whole team did their job this weekend. We had some players play some incredible defense. And I think that that's a huge testament to the hardworking players on our team and the pride that we take in playing D-Zone too. So we tried to hammer away at the fact that hockey's played at both ends of the ice. And certainly, you need to get it done in the offensive zone. So I'm glad that we found a way to start doing that as well. And talking about that defensive play, Annie Smith-Hammond having a solid performance for you between the pipes. Yeah, she stepped up and came up big in some key moments for us in that game. And just like you said, she was just solid between the pipes. And that's what we asked our goaltenders to do. And she did just that. And you're going to need those types of performances defensively, offensively, and between the pipes. As you guys travel up to SUNY Canton playing the kangaroos at their place. Yes, we are. It's the hard work that we put in to get ourselves in this position where we could still potentially earn a buy is going to be wasted if we don't focus in this week on what we need to do to put forth the same type of effort going into this weekend. And anything can happen. And we just have to be ready to control our own destiny. So that's what we're preparing for. Right. Just get yourself in the position that you can. Control the things that you can control and good things will happen. Exactly. Well, Coach, we wish you the best of luck and safe travels up to SUNY Canton. And continuing, that's all at play. Thanks so much. She's Tracy Johnson. I'm Joe Wamba. This has been the Tracy Johnson Show.


Around Dark City and at the territory on West there's just one way to handle the killers and the spoilers And that's with a US Marshal and the smell of gun smoke Gun smoke Starring William Conrad the story of the violence that moved West with young America The story of a man who moved with it Matt Dillon United States Marshal You want to see the prettiest side north of the Pekas Sight come over here to the window and look what's are coming down the street Out of it's anything besides trouble a little surprise me she must have come in on the side of feet from the east Wow Say I think she's coming here Yeah, it looks that way Why I should have shaved this morning or even yesterday morning now What could a lady like that be doing in Dodge City? Say maybe she's gonna work in one of the saloons mr. Dillon. I hope not Chester. Good morning, ma'am How do you do? I'm looking for the United States Marshal. Well, I'm the My name's Dylan Matt Dillon I'm Catherine Blair, mr. Dillon. Oh, it's a pleasure miss Blair may I introduce my deputy? This is Chester propfoot. How do you do? I? Yeah, just got in on the train from Boston mr. Dillon. Oh the station master said that You might be able to help me. Well, I'd be glad to I'm looking for my brother Martin Blair. Why say mr. Dillon Chester. Well, will you punch up that fire? It seems a little chilly in here? chilly Yeah, sure Right away mr. Dillon. Do you happen to know my brother mr. Dillon? Yes, yes, I know him. Oh good then You can tell me where to find him. Well, I I'm not too sure that I can you see he He moves around a lot. Yes, I know He left home and came out West two years ago and every time he's written this it's been from a different address He's always been that way Restless, I guess you might call it Yes, yes, I guess you might Mothers always thinking he might get into trouble out here by himself But I tell her not to worry He's young yet He'll grow out of it. I see Meanwhile though, you'll you'll need some place to stay I imagine Yes, I suppose there's a Hotel I think the wood of Markham may have an extra room. You'll be better off there than at the hotel Your baggage at the station. Yes, Chester Will you go to the station with miss Blair and then take her over to with a Markham's and get her settled in a room sure thing mr. Dillon This is awfully nice of you not at all and Chester, will you explain the situation to miss Markham? I mean that? We don't know where miss Blair's brother is at the moment Chester Yes, sir I'll explain it to her mr. Dillon After you ma'am. Oh, thank you You're very kind mr. Dillon Goodbye. Goodbye Jack Wake up Jack I'm not asleep Martin What do you want? The jail cell usually softens a man up Not this one Dylan Not now or 20 years from now. Yeah. Yeah, I know You want something or are you just making conversation? Your sister's in town Martin Kathy Kathy's here in Dodge. She just left the office. She's looking for you What'd you tell her? Nothing yet. It seems like a fine girl You got to get her out of here Dylan Don't let her find out You're on a train and get her out of here. No, why? Maybe I'm no good, but there's no reason why Kathy should pay for it It's got nothing to do with me Then you won't help You won't keep her from finding out. I don't know if I can Martin.  No, sir. It's been the quietest night in weeks. Yeah, no trail herds in town. I guess that's the reason Miss Blair's all right, I suppose. Yeah. Yeah, she's all right Chester Have you told her about her brother mr. Dylan? Well, I I told her that he's out of town and we're trying to get word to him The truth is bound to get to her somehow sooner or later. Yeah, I know Only reason it hasn't already is because everybody in town knows him as Boston Jack Yes, but his real name will come out at the trial next week.  Yes, sir. I Don't rightly see how you can keep her from finding out mr. Dylan. Come on Chester. Let's have a talk with Martin Nice night, mr. Dylan. Yeah, it's fine Great night for taking a walk Don't you think so Martin? Anything's better than rotting in that cell Well, where did you expect to end up? All you got is old man Hawks word against mine He's lying Jury will believe him If he could see me so plain how come he couldn't tell you who was with me It was dark. He saw your face in the gun flash When you shot his foreman in the back, that's a lie As far as that's concerned, I know who was with you, but I haven't got a case against him read polly Wasn't it? I wouldn't know I Wasn't there Well, suppose we leave it to the jury here's a way to mark his place, mr. Dylan.  You understand Sure, I understand All right, let's go. I'll be there at the first one to mr. Dylan's Parlor's on the left. All right, Chester. It's up Chester. Yes. Good evening, miss Blair Why mr. Dylan? I uh, I've brought you a visitor a visit. Hi, Cathy You're now take it easy Martin why didn't you write you know how it is sis?  Oh, of course Come on in coming in. I couldn't imagine who was knocking. Mrs. Markham is going to bed and oh Here sit down Thank you, miss Blair. Oh, mr. Dylan Where on earth did you find him? Well, I uh, I guess I better confess to you miss Blair I uh, I knew all along where he was What the only trouble was I just couldn't produce him I'm afraid I don't understand you. Uh, well, you see Martin's been doing some work for me Sort of secret work you might say We're trying to dig up evidence on a gang of cattle rustlers around Just wait a mother hears about that. Oh And she was so worried about you Yeah, it's Quite a job It's pretty hard for your brother to get away from the gang without stirring up suspicion. In fact, he He's only got about an hour this evening. Oh But you will manage more time in the next day or so I'm afraid not sis. I May not be able to get away again for a month. In fact I've been thinking it over and I think the best thing you can do is to take a train back home right away But I just got here Martin. It's no place for you Kathy. Uh, he's right, miss Blair That city's no time for a girl alone, but I came all this way to see Martin. It's like I told you though sis it may be a month before I can Manage to get away again I Tell you what? After this job is finished Maybe I can get back east for a week or so. Oh Martin if you only could We'd all be so happy. I can't guarantee it, but I'll sure try I'll admit. I'm a little nervous here But the very first thing Mrs. Markham showed me was a revolver. She keeps hanging out there in the hall In case of intruder she said good heavens. Well, this is the frontier miss Blair the law is still pretty much for the man who shoots first Except sometimes Yeah That sounds awful Martin you will be careful, won't you? I'm always careful I suppose I had better take your advice in a range to leave in the next day or two But meanwhile we have an hour at least Tell me about yourself Martin Tell me everything you've been doing It's cold in here mr. Dillon.  I'll take Martin back and lock him up I could use a little heat back in that cell you got plenty of blankets Well, come on, let's go now you walk ahead of me Dillon Suppose the jury brings in a conviction What's the Senate's gonna be that's not up to me. I'm just asking for information. It means hanging Right probably all right stand right there while I open the cell. I don't want much to hang Marshall. Nobody does All right, Martin get in slow and easy Dillon Put your hands up slow good Now keep them that way Where'd you get the gun in the hall of Mrs. Markham? I slipped it under my coat when I was kissing Kathy. Goodbye. I'll take your gun now Dillon It feels good to be holding a pair of guns again. You won't be holding them long. Maybe One thing though If you take me again, you'll have to take me dead any way you want it In the cell Dillon Come on move tell Chester. Goodbye for me. Will you I? Think I'll just go on out the back way. What about your sister? I Guess she wouldn't want to see me hang either When you come right down to it so long don't he will return for the second act of gun smoke in just a moment But first if you've ever had delusions of grandeur or a particularly soul satisfying daydream You'll understand the predicament of my little Margie tomorrow night on CBS radio Convents that she's a princess my little Margie played by Gale storm gives her father He's Charles Farrell a royal pain in the neck. It's another comedy episode of CBS radio's news Sunday night Laugh program my little Margie tomorrow night on most of these same stations Now for the second act of gun smoke. It's just girl. I've got to say is it a better fit. Yes, you know, that's not it It would be a fine how to do we had to call in a blacksmith to get you out of your own jail Yes, sir, it'd be started like the time never mind Chester. Just get the door open. Yes, sir. Oh I know how you feel all right, mr. Well, I declare There you are mr. Dillon come on I'll get the other gun out of the office safe fine. Thanks. You get for trying to help people man gets careless And he winds up in a jam like this. Let's see now Right 27 69 You sure gonna be hard to explain why you took Martin out of jail, mr. Dillon. Yeah, I know If he gets clean away, we're gonna look pretty foolish He's not gonna get away Chester. Yes, sir Ten to one Martin will try to team up with his sidekick pulley before he heads out of town Let's try the saloons first see if we can pick up his trail. Yes, mr. Dillon Martin said we'd never bring him in alive So don't take any chances. Oh Sign of him in here, mr. Dillon not unless he's in the back room Let's walk over toward the bar bad business Chester Martin's already shot one man in the back We'll never catch him in the open if he's got anything to say about it. Yes, sir. I've been thinking about that Kind of makes a man spine crawl. Hi, you boy.  I've always suspected Chester of having a shady past Have a drink man. No, no, we haven't got time. We can't stay we're looking for a fellow by the way Who went bail for Boston Jack? What do you mean? Well, he was in here about ten minutes. He was in there Yeah, he talked to red poli and the two of them left together. I thought he must you know where they went kitty No, man. I haven't got any idea, but they sure left here in a hurry He broke out of jail. There's 40 ways. I'm standing. They could have ridden mr. Dillon. Yeah, I know But if they're not in dodge, there's only one way they'd hit the circle be yeah Martin knows Hawks is the only witness. I've got against him. Come on Chester We've been making time maybe we out wrote them if they're even headed this way now they better be Somebody standing there at the side of the house. Yeah, I see It's the Marshall Matt Dillon Is that you Ezra?  What are you talking about Boston Jack? How to jail Matt, how'd that happen? Well, I doubt it could serve any good purpose to go into that right now He hasn't been here I take it no Matt he's a mad dog got to be shot long time ago.  Dillon and You may as well stay there Chester and cover the yard What about us Matt? What are we gonna do go inside the house and put the lights out and wait? That's all just wait. I think you're on a cold trail Yeah He's had enough time to get here Maybe not enough courage, so they figured the odd to two to one in their favor Shouldn't take much courage People who've never killed anybody don't understand The killer's worst enemies his own nerve. Yeah, I Take your word for it Matt. I Guess you've sat waited like this plenty of times.  Do you ever get to wondering wait a minute our is room where Matt over there by the corral you see They're walking the horses into the yard Yeah Yeah, I see him. What are you gonna do Matt?  Oh, they'll fire from the dark without no warning. Yeah, I know I'm getting off their horses Gonna walk up here. I guess All right, Ezra stay in the house and keep out of this chest, and I can handle them. Yeah, Matt. Good luck. Thanks Martin Paulie you're under arrest Drop Paulie Martin's running into the corral Martin I climb out of that corral. He didn't shoot you back. No He fell off right in front of the stampede They went right over him. I hope she believes me. Don't worry, Mr. Dillon She will I'll be out in a couple of minutes. Evening miss Blair. Why mr. Dillon? This is a surprise. Do you mind if I step in? Of course, I don't mind. Thank you Friend of Martin's is welcome any mr. Dillon There's something wrong I'm afraid so miss Blair I've got bad news for you It's Martin Something's happened to Martin. Yes, ma'am He's hurt. It's worse than hurt ma'am No Martin was killed in a fight If it's any consolation miss Blair he He died hard with all the odds against him Martin never asked for faith. He fought a good fight That's something to remember Martin has always been fine and clean He was just restless People didn't understand No, I suppose they didn't miss Blair But he died on his feet fighting I Guess that's the way Martin wanted it Yes, I think so ma'am. I suppose miss Markham's here. I Wouldn't want to leave you alone. Yes. She's here I'll be all right mr. Dillon. Well, I'll come by and see you in the morning Um If there's anything at all I can do you've been very kind mr. Dillon. I'm grateful to you I'm sorry about this miss Blair Marshall. I'll be leaving tomorrow Yes, goodbye Goodbye miss Blair Dillon. I think so Chester. Did she believe what you told her how what I told her was true Well, there's no harm in letting her think the best of it Martin paid his debt. No reason his sister should suffer. That's right. Mr. Dillon Chester if I remember correctly kitty offered us a drink earlier this evening. That's right. Well, let's go Gun smoke under the direction of Norman McDonald stars William Conrad as Matt Dillon US Marshal Tonight's story was specially written for gun smoke by Les Crutchfield with music composed and conducted by Rex Corey Featured in the cast were Gene Bates Sam Edwards and Ralph Moody Parley Bear is Chester and Georgia Ellis is Kitty Gun smoke a sir bar troops overseas through the worldwide facilities of the armed forces radio service Join us again next week as Matt Dillon US Marshal fights to bring law and order out of the wild Islands of the West in Gun smoke plays the wisecracking English teacher Connie Brooks of Madison High Sunday nights on CBS radio And when our miss Brooks calls the roll-on comedy, there's laughter enough for all takers Sunday nights and most of these same stations join Eve Arden is our miss Brooks for high-class classroom comedy This is Roy Rowan speaking America now listens to 105 million radio sets and listens most to the CBS radio network


The study found that head orientation is more variable when it comes to pitch compared to roll, and that there is an overrepresentation of downward head pitch. This suggests that people tend to look downwards while walking or running, which could have implications for models of vestibular processing. Additionally, the study showed that gravitational and inertial acceleration are similar, but differ in terms of their relative power at different frequencies. This provides insight into how vestibular processing works, and could help inform future research. This article was authored by Christian B. Sinott, Peter A. Hausman, and Paul R. McNeillidge.


So, welcome to the third lecture of digital system design with PLDs and FPGAs. The last class we had a brief revision of the basic subjects. So, let us quickly run through those slides before today's lecture. So, let us move on, essentially we talked about the major constituents of the digital design. To start with we will look at the function and there are two parts. One is a combination logic, higher level blocks we said. All those blocks which you have studied in the basic course. Then we have the sequential elements like flip-flops, registers, memories and all that. This is constitute the function part which you have to learn thoroughly and we have looked at the minimization using some algorithms. Single output minimization like Karnoff maps, Koin-McLoosky, Espresso and for there are multiple output multi-level minimization which is based on this algorithm but then it involves many other steps. We had a brief look at it. Then we looked at differentiating between the gates and the functions. The gates are able to implement. Then we had basically it is bringing the de Morgan's theorem into our concept and we have seen that the NAND and NOR are universal gate and we have seen some example of AND OR is getting implemented using NAND-NAND gates. And also we have seen how advantages is to conceptually think like that then you will not waste gates if you bring this into concept while designing some simple logic circuits. And we have looked at the encoder, the decoder, the multiplexers, the tri-state gates and we have seen what is a tri-state gate and some care need to be taken when you are busing or multiplexing using the tri-state gate. You have to pull up or pull down. Then we have looked at the multiplexer and demultiplexer and real life that it may not be like a textbook picture. Then we have looked at the difference between latch and flip-flop. Latch is transparent, flip-flop is edge-triggered. We have looked at the timing that is the second important constituent of the design. And for combinational circuit what is the timing, it is a propagation delay and for sequential circuit flip-flop there is a propagation delay called TCO and at the input you have to meet some time called setup and hold time for the flip-flop to transfer the input to the output properly. Then we have looked at something called hazards where in unexpected outputs you will get glitches which I said there is static 0 hazard and static 1 hazard in a sequential circuit is not a problem because we latch the output after settling. But this is just a model in real life and there is an unbalance path delay at the input of an AND gate or an OR gate this glitches can happen. So one has to wait for it to settle before latching on to a flip-flop or a register. You can have dynamic hazard for a single change in the input there could be multiple glitches at the output instead of one pulses. Then you have electrical characteristics basically voltages and current we have seen output voltage, output currents, how it is the voltage is related to the current. Then we have seen the noise margin, the fan out how to calculate the fan out, the power dissipation for a switching power dissipation not the leakage power dissipation, expression for the power dissipation in a CMOS output stage. So that is where we have dissipation of the whole circuit. So we can attack at a lower level at the transistor level at the power dissipation at the circuit level we can reduce the power dissipation. The third level is that when you have a system complete embedded system say with the processor with lot of peripherals and all that and a particular circuit particular system may not use all the peripheral at the same time. So it is possible to power down the peripherals or the modules which are not working or you can freeze the clock of some registers or memory so that it reduces the power dissipation or you can reduce the clock frequency of the unused blocks so that the power can be brought down. It does not stop there maybe when you are designing the whole architecture you can take care that the architecture is designed such that the power dissipation in the system is reduced. So that can be handled at the architecture level ultimately one might think it stops here but does not stop there. When you choose the algorithm for some computation you can choose an algorithm which reduces the power dissipation. There could be like you have a multiplication there are different algorithms you can use for multiplication but there may be algorithms which reduces the power dissipation but it may be slow. But if our primary aim is to reduce the power dissipation then you can choose an algorithm which reduces the power dissipation. So the low power design can attack at all these fronts you know these transistor level circuit level, the system level, architecture level and at algorithmic level the power can be reduced. And this is a very major focus in the current VLSI design even in devices like FPGA one would like to have low power dissipation but this is not the focus of our course. So I will give a I mean I have given a taste of it and if you want low power to know about low power VLSI design you have to go and credit a course which talks about it or read a book in the low power design domain. So let us move on what is the next issue in design. So that is the high frequency design. You know that in high frequency the tracks or the lines or the wires within on a PCB or a chip can act like transmission lines. So there could be reflections so unless we take care maybe your logic is correct the timing is correct everything else is taken care but because of the high frequency the wires can act like transmission line if there is impedance matching problem there can be reflections which can corrupt the signals. So this has to be taken care in high frequency design. Similarly there can be crosstalk like when you have two wires running parallel for long distance then one signal in the wire can be coupled to the next signal. So you can imagine what can happen if the clock line is running close to the interrupt line of a processor then that is disaster. So this has to be taken care the crosstalk. Similarly there is in the noise analysis there are ground loops the ground currents say there is an analog component and there is a digital component in the chip the switching current of the ground can pass through the digital ground can pass through the analog that can create problem in the analog circuit. All these has to be taken care and that is done in the back end tool in the back end design there are special tools for it. And this is also an important area one need to know in VLSI. So let us move on to the next technology that is the device technology. So our course is about PLDs and FPGAs so it is let us have a look at what are the device technology available. One thing is the application specific integrated circuit or ASIC and this is normally supposed to be full custom. So that means it is designed from scratch you know almost everything is designed at the gate or flip flop level maybe they will use some library cell but most of it is designed from the scratch. The problem is that it has a very huge cost because one has to set up the EDA tools for design tools for it people have to work on it and the foundry has to set up and the chip has to be fabricated. So it has a huge non recurring engineering cost that means it is a one time cost is huge and that has to be amortized over the number of the chips produced. So if the chip is produced only 10,000 you cannot possibly make an ASIC and get money out of it because each chip will cost so high. So the ASICs are designed only where there is high volume like you have the desktop CPU or the mobile phone SOC chips and so on. And this also take a large turnaround time from the you know finalization of specification to the first chip it may take one year, one and half year, two years and so on. So this ASIC is a huge costly affair but once it is designed it can be made to work at very high frequency like you have three guards, processor chips that is because it is ASIC it is custom designed. Many times people do not have such luxury they do not have the number to justify such a cost then one can go for semi custom design that is a mask programmable or standard cell that means the foundry will give you some standard design and you make your system based on that standard design and the foundry has all the layout for those blocks. So it is quick when you send out the interconnection of the standard cell or the array of gates it is quickly interconnected at the foundry. So this works for the medium volume it has medium NRE cause medium turnaround time the field programmable gate arrays. So this is the device technology so the next I want to touch on the current state of the VLSI technology you must have learnt that the PMOS is slower than the NMOS because the whole mobility in PMOS is less than the electron mobility in NMOS. But you know that with the current technology like strain silicon the PMOS is getting faster strain silicon means the silicon lattice structure is strained by some deposit on top of silicon so the lattice structure you kind of stretches so that the electrons and the holes can pass faster. So the PMOS is getting faster and the current feature size is the technology wise is 22 nanometer and if you look at the indel core I3, core I5, core I7 is fabricated in this 22 nanometer and the next technology which is coming which people are working the manufacturers are working is 14 nanometer where the inverter delay is of the order of 5 to 7 picosecond. So you know how fast this technology is going to be. But now the present trend is not to make things faster you know that we are reaching the limit so one cannot expect this to go down considerably in the same scale as before. But people are using parallel multiple core for computation you know that the indel current chips as the quad core and you know 8 cores and things like that. The present trend is not on the row speed but to have multiple computational units parallely working whenever possible ok. So which is many a times possible because there are in a processor or even in a mobile phone there is multitasking. So it will be good if you can you know listen to the music on a cell phone at the same time you are going for a walk and you want to capture the picture. So if both can work parallely it is very good you know it is very bad you are listening to music then you click a picture if the music stops yes nothing catastrophic happens but the user experience might get interrupted. So I am not greatly talking about the social implication of the technology but the good things can happen with the multiple core parallel computing and things like that. So let us move on next is the design methodology we will have a look at it we have already touched upon it but then let us have a look at the design methodology of the VLSI and FPGA. So as I said there is something called front end design and which goes basically from specification to the gate and flip flop level circuit or the net list or we can say from algorithm we design an architecture and we go to the logic circuit in terms of the gates and the flip flops and this is many a times called logic synthesis this step of going from an architecture to the logic level circuit is called logic level synthesis. Then the moment you have it the circuit here that the front end design is over then we go for the back end design. In the back end design this gate and flip flop level net list is converted to the chip mask not in one step first the logic circuit is converted to the transistor level circuit and this is called physical synthesis that is the physical transistors are synthesized out of the logic circuit. And thereafter the each transistor and the interconnection is designed in detail in terms of the mask which is required for the fabrication. So that is the back end design as far as the VLSI integrated circuits are concerned but if you take the FPGA we do not go for this step the FPGA has already the logic circuit built in as logic resources with the wires laid out with switches in between. So you literally you know go in one step from the logic circuit to the configuring the FPGA. So for FPGA this physical synthesis and chip mask is not there we directly go from this circuit level to the configuration of the FPGA directly with of course there is a step involved in translating this circuit mapping it to the resources of FPGA interconnecting it and so on. So that is the back end design for FPGA so we talked about the front end design and the back end design. So let us continue as I said in a digital design there is a data path where the computation happens it is made of registers and combinational circuit registers holding the value combinational circuit computing it. And there are controllers or finite state machine which control the data movement in the data path there could be multiple controllers or a single controller depending on the need and in VLSI design we have metric or we have constraints these are the constraints the area normally one would like to have a smaller area. So that the chip is smaller you can make more chips and reduce the cost and when the chip is small it will be compact and the delay will be less the wire delays will be less and the power dissipation will be less. So these are conflicting requirement it is not that you can have small area small delay and small power. So where one go for small area some block you may get a larger delay and when you go for a very fast circuit you may end up with a large area and large power dissipation and if you have looked at even very simple example like an adder say you have studied ripple adder you know that suppose we have an 8 bit ripple adder it use 8 full adders cascaded. So the area is very less you know what is in a full adder full adder use 2 exclusive or gate and 3 AND gates and an OR gate ok at the maximum. So such 8 stages but it is you know that it repulse through 8 stages in the worst case one state delay is say 1 nanosecond the worst case delay of addition will be 8 nanosecond. But you can go for a carry look at adder which has only 2 step delay so you anything you add you will get in 2 steps may be 2 nanosecond. But you know that when you go to as you go from the 0th bit to the 7th bit the whole circuit gets exponentially larger and larger and it occupies lot of area the carry look at adder is not very seriously used because of this problem it occupies huge area. So just an example saying that these are conflicting requirements you do not get everything low it is very difficult you have to make a trade off between the area and delay. So let us move on so the next thing I want to talk is this thing called system on chip which is or SOC and many a times you have a word called intellectual property or IP. So you know that earlier may be 10 years back a system was designed in a on number of boards you have a box or you have a rack based system where are the multiple boards like earlier if you looked at the computers there are motherboards there are daughter boards. But now it is shrunk to a single motherboard everything is built on the board and if you look nowadays on to the motherboard there are very few chips you have a processor chip and a peripheral chip which is also getting kind of integrated into a single chip. So the complete system of the desktop CPU can go as a single chip may be the DRAMs DDR3 memories will be outside but things are shrinking. So the complete system will be on a chip it will reduce the power dissipation it will reduce the area the cost will be reduced the delays will be less and the power dissipation will be less. And same thing is happening in the FPGA domain also in the ASIC domain you have system on board in the FPGA domain you have programmable system on chip ok. That means you have in FPGA domain also you have lot of processors peripherals are built into FPGA and you design your custom design on the FPGA put it together for a system which is called programmable system on chip and some manufacturers called system on programmable chip and so on ok. So if you take a system on chip it has lot of things typical you know I am taking an example it may have one or more processor cores. So it will have a communication maybe there is a processor for basic communication there is a processor for control there is some DSP for computation there could be multiple cores of DSP or control processors and so on. There are lot of peripheral devices like memory controller, UR, USP, the timer and so on IOS and so on. There will be one on chip bus architecture because lot of peripherals need to be interconnected. So there will be some kind of bus architecture on the chip like if you have an ARM you have an AXI bus in an ARM based system maybe like in a PC you have the PC chips of the local bus within for connecting the memories and you have network interfaces maybe you have Ethernet interface or a Wi-Fi interface and Bluetooth interface and so on. Then there could be custom hardware for packet processing, signal processing like Kodak you know you have a TV setup box which has an H.264 or Mbeck for decoder that is required and ultimately you have the software, the real time OS or the OS, the network protocols stack, application software everything in a flash memory in the chip within the chip. So that is an SOC so do not get you know if you do not know what is system on chip typical system on chip is like this and let us move on to the next key word which is many a times called intellectual property which is related to smart related to system on chip because when you have a complete embedded system it is very difficult to design from the scratch and you know that the way the short time duration in which the cell phones are coming into the market with newer and newer chips and it is very difficult to design a complete system in 6 months. So most manufacturers when they design a system on chip they use already design components of CPUs, of peripherals, of Kodaks and so on and they buy it from somebody who have already designed it and just put it together for as they require. So that is called intellectual property these are this designs which is already done is called the intellectual property there are different type of soft you know intellectual property one is a soft IP, soft IP would mean suppose you have a suppose a memory controller win VHDL or verilog you can buy and use it, it is very flexible because you can change it depending on the license but then you have to synthesize it you have to do the front end design, back end design maybe it may not be depending on your tool and your the way you design it may not end up in an optimised design and it may not give the desired delays it can be slow. So soft IP is very flexible but it may not give the performance. The next is a firm IP which is nothing but a synthesized IP that means the logic circuit is synthesized. So it may be optimally synthesized with the minimal logic circuit. So it can work faster but the changes are difficult now because earlier it was a hardware description language you could easily change the design. Now you have to change in the synthesized design in terms of the gates and flip flops it is cumbersome it is a better option than soft IP in terms of performance but flexibility is less. The last category is a hard IP where this is literally not the synthesized circuit literally plays and routed IP. So you can directly place it in the silicon the mask is ready for that circuit. So you integrate this hard IP with the other hard IP at the back and to level. So the advantage with this hard IP is it is already tightly integrated very optimally placed and routed. So it can be very fast but you know that any change in this hard IP is very difficult because it is already kind of physical synthesis is over the transistors are over chip masks are ready to change it is quite tough. So these are the IPs but the present the design friend goes for the IP design and people make IPs and sell it to other people you know the ARM chip the ARM processor this is an IP this is not a chip mostly you buy from the manufacturers the ARM consortium give it to whoever wants it they license it and they ask for some royalty and people are very happy with it because there are lot of peripherals and the processor along with the peripherals can be integrated and there are lot of standard IPs available standard OS available for ARM processor. So let us move on this is the next technologies that is something called dynamic or run time reconfiguration which is very much talked about researched pretty much. So this can work in FPGA and as ASIC level and the basic idea is that a part of a device is reprogrammed to implement a different functionality that means take an example say you have a SOC which is used in a mobile phone and suppose you are working with a Bluetooth okay then that Bluetooth part of the hardware is programmed into the chip okay. Now suppose after some time instead of Bluetooth you are connected to the Wi-Fi okay the wireless network not the Bluetooth and you are not using the Bluetooth at the same time. Then what is done is that at the run time dynamically this Bluetooth part of the hardware is removed and the Wi-Fi part of the hardware is put. So you can save lot of area and reduce the power dissipation and the cost and things like that this can happen this is supported in FPGA but you can even do this cleverly in ASIC which saves area which allows reconfiguration maybe you can even think of a system level reconfiguration like you have a general purpose device maybe it can act as a cell phone after some time it can act as a general computing device like a tab or a pad like that. So it is quite advantageous here the important thing is that the reconfiguration time is important you should be able to reconfigure very fast suppose you turned off the Bluetooth and you switched on the Wi-Fi then if it takes some 10 second for the hardware reconfiguration then this may not you know satisfy the user. So the reconfiguration has to be faster and very important is the granularity is important what part of the circuit can be reprogrammed is very important suppose the manufacturers restrict saying that only half the part of the chip can be reconfigured and all of the half part has to be reconfigured and things like that. The granularity is important and the flexibility how flexibility is like we should be able to reprogram any part of the chip or any area of the chip flexibility. So this dynamic reconfiguration this granularity the reconfiguration time the flexibility is very important. So let us move on this is another area as embedded system is concerned like also when system on chip is considered at a top level you need something called system modeling when you start with the system on chip you are not sure what part should be in hardware and what part should be in software. So there many a times you know that the hardware design is done in HDL and software design is done in C or C++ and it is a very cumbersome thing to like once a partition is made the hardware designer start designing the hardware and the software designer start designing in software and half the way you realize some software part has to be moved to the hardware it is a very tough thing. So it will be good at a system level you can model and study the performance at the cost that means hardware you know that it is concurrent we can make it very fast but it is very less flexible and the cost is higher. But software is sequential it has a lower performance compared to the hardware but it is more flexible you want to change the software you can change it easily. So it will be good to have a system modeling language we can model it together in one language and you know work out on the cost performance paid off and freeze it then go for the you know the hardware design and software design after partitioning. So the languages like system C allow the system modeling and there is a system verilog language which is mainly used for the system verification. So that is all about the system modeling let us move on you have learned you know like suppose you have learned the VLSI design or FPGA design that in itself is not an end. Because if you know how to design a VLSI chip or an FPGA chip but it is of no use but you know that you have to design the chip in some area. So it is very important to know that where these chips are used in which domain it is used ok. So maximum the A6 or FPGAs are used in communication networks. So if you are an VLSI or a FPGA designer you should have some background in communication network. So let us turn to the communication network. So you have learned about the layering of the protocol stack say layer 0 is a physical layer, layer 1 is a data link layer, layer 1 is the physical layer, layer 2 is the data link layer, layer 3 is the network layer and so on. So if you will take the physical layer mostly it is analog and digital mix. If you take the data link layer or many a times it is called MAC layer or media access control layer. It is digital mostly and in the case of a computer it is in hardware but it is controlled by a network driver. The operating system will have a driver to control this data link layer. So whenever a new networking protocol comes like you know you have the Wi-Fi or you have the latest protocol stack then a lot of design has to happen in the data link layer to implement this in a chip. And similarly network layer there is a layer 3 where the packets are switched or routed and that is as far as the end systems are concerned it is done in software. But if you look at the routers and switches on the main network this will be done in hardware. So there is lot of hardware work within the communication network. So it is worthwhile for an VLSI or FPGA designer to learn about communication network, communication protocols because lot of communication network based chips are designed. Similarly lot of things are happening in the signal processing like multimedia, the video encoding, video decoding, H.264, Mbac4 and various other codecs need to be designed, filters need to be designed, lot of compression need to be done all this happen in the signal processing area. So for an VLSI or FPGA designer it is very important to have some basic background the algorithms of signal processing so that you can implement it. And ultimately computer architecture within the like designing a CPU that is a job of VLSI designer many a times it is prototyped in the FPGA then move on to ASIC domain. So your FPGA design can move ultimately to the ASIC design so the computer architecture. So three areas one is communication network or computer networks then signal processing computer architecture. So that you should learn the basics of it so that when you design for a particular domain this knowledge comes handy and you will be a good designer in the field. So better know this so that gives an overview of the field. So we started talking about the various issues like application areas, design methodology, device technology, then the system modeling, then the high frequency design, low power design and so on. Just to give a glimpse of the state of the art or the current technology to be aware before moving into the nitty gritty of the digital design. So we have some time left let us move on to the digital design. So let me put the slide so I call it advanced digital design. So in this advanced digital design we will you know conceptually develop from a lower level to the higher level. We will start with small system then build we will see how the bigger systems are built upon these basic building blocks and what are the standard basic building blocks to understand the structure, timing and so on okay. So let us move on the first thing let us take the synchronous sequential circuit okay. So that is the first thing so I assume as I said before I assume all the background that you have learned the combinational circuit, sequential circuit and now we are coming to the serious design sequential circuit and synchronous sequential circuit and we will learn three things essentially the structure of a synchronous sequential circuit. What is the architecture of it, how to design it say knowing the structure how to design it and do the timing analysis of the synchronous sequential circuit. So that is what is shown in the slide. So we will study the structure of a synchronous sequential circuit design of it and the timing analysis of it and you must have learned we will start with the basic very simple thing you have learned that is the synchronous counter. You must have learned in your undergraduate program something called a ripple counter okay. This is a very crude circuit which has less use so like you know you have a suppose in a ripple counter you have a the least significant bit the output of which will clog the next bit and so on okay. This is not timing wise not a very good circuit. So forget about the ripple counter let us take the synchronous counter. Synchronous counter is the simplest synchronous sequential circuit we can study and the structure is same for all the synchronous sequential circuit or at least we can build on the basic synchronous counter. So let us try to design a very simple counter. So let me ask you how to design a modulo 6 counter okay. So modulo 6 counter has 6 states or 6 count which start with 0 it is a binary counter it start with 0 then it counts 1, 2, 3, 4, 5 and then goes to 0 okay and then it look it continues it loops okay that is a modulo 6 counter. So how to design this counter okay. So let us go step by step so we use binary encoding so that means we will encode the 6 in flip-flops. So we need logarithm to the base 2 number of flip-flops which comes you know some 3 point some numbers. So 2 point some numbers so we have to use 3 flip-flops. So let me put 3 flip-flops okay. Now I am already abstracting in your basic course you would have already put 3 flip-flops separate and try to design. So the first thing to notice is that we cannot go you know to the complex system with you know separate flip-flops you know because if you try to design something 32 bit we cannot put 32 flip-flops and in a paper or anywhere and design and we are also not you know that we are also not going to detail gate level design we are going to use higher level blocks. So we do not need to know all the details which is done by the tool optimization is done by the tool so we go to a higher level. So I have put 3 flip-flops together and you can see there is clocks are tied together in a synchronous circuit all the clocks of the flip-flops are same. So you get a single clock is connected to all 3 flip-flops a reset is connected to all the asynchronous reset. Now there are 3 queues Q2 Q1 Q0 and 3 Ds D2 and D1 D0 okay. Now assume that at the power on we have power on this at the power on this has become 0 0 0 3 0s that means the value is 0 now when the clock comes we should get the 1 here okay. So that is the basic counter design so how to make it 1 okay. So we only have we have initially made the 0 and somehow we have to derive in the next clock we have to get the 1 and you know that when the clock comes whatever as far as the flip-flops or registers are concerned whatever is here is transferred to the queue. So it is worthwhile it is enough if you have 1 ready here so when the clock comes 1 comes here and in the next clock 2 should be ready here. So you get the idea you at the beginning you have 0 here but we want 1 at the input so it is enough if you put a combination circuit here here and feedback this the present count to the input of that circuit. So that then we design that circuit such that given 0 that will give 1 given 1 that will give 2 and so on okay. So what I am saying is that we will put a combination circuit before the flip-flops and the input of that is the output of the flip-flops and the output of that combination circuit goes to the input of the flip-flops okay. The basic idea is that we design this combination circuit such that given 0 it gives 1, given 1 it gives 2 and so on okay in this fashion. Then when the clock comes initially it was 0 in the next clock if the 1 comes here and that 1 gives 2 here, next clock 2 comes here and 2 comes here and so on okay. So you design this circuit then you get a counter which count you know sequentially 0, 1, 2, 3, 4, 5 and you must have learned again in the basic course something like you want a mode 6 counter you have a mode 8 counter then what you do is that which counts up to 8 but then you catch 6 here decode and reset it and then it becomes 0 and so on. But there is a problem if you reset it using an asynchronous reset for a brief duration it might go to the next state and so on okay like you wait for the 7 to come here then you reset it then 7 there is a glitch 7 at the output. So this is a very neat design it works perfectly but next question is so that is the structure of a synchronous counter you have flip-flops and many a times we call this as a present state of the flip-flop and it goes to a combination circuit and the output of the combination circuit is called next state because upon the clock the next state it become present that is why it is called next state and this combination circuit is often called next state logic because it is a logic it is a combination circuit which decode the next state from the present state. Now it is very easy to design we have to design basically we have to design this combination circuit and we know how to design a combination circuit write the truth table in terms of the input present state is the input and the next state. So you write the truth table so we take this combination circuit develop the truth table the present state as 3 inputs Q2 Q1 Q0 the next state as we call it let us call it D2 D1 D0 because it is going to the D2 D1 D0. So the moment you know that you write the truth table we have to look at the D2 separate D1 separate and D0 separate the normal course of time you would have picked all the once in this D2 column and go to the Karnoff map minimize it and you come out with an equation or sum of product equation in terms of Q2 Q1 Q0. So ultimately you will get 3 Boolean equation in terms of D2 D1 and D0. So let us write that I say DI is Fi of Q2 Q1 Q0 so I is nothing but 2 1 and 0 so you have D2 is F2 of Q2 Q1 Q0 D1 is F1 of Q2 Q1 Q0 D0 is F0 of Q2 Q1 Q0 so you get 3 equation that can be implemented. So normally we are not going to do this hand level design it is enough if you describe the truth table in terms of the hardware description language in a high level design then you get the design okay. So many a times this is also called the next state is a function of the present state. So we call it next state is a function of the present state. So mind you the next question I want to ask is that we still take the mod 6 counter but it does not count sequentially like 0, 1, 2, 3, 4, 5, 0 it counts in a crazy way that it starts with 0 then 5, 3, 2, 1, 4, 5 okay. So the question is can we design such a counter you know already the answer is very simple absolutely no worry anybody specify anything you change this next state logic you change the truth table you write start with 0 the next state is 5 you write 5 here the next state is 3 you write 3 here the next state is 2 and so on then you take form the equation or write the truth table in VHDL code then this should be you know perfectly okay it can be designed. And so let us look at the little bit timing how this present state changes with respect to the clock to give you an idea you may already know it but then let us look at the timing the symbol timing of a counter.  So at the positive clock edge the present state changes its state and that cannot happen immediately in many a times in textbook it will be shown that this state change will have you know coincide with this active clock edge it is in practical circuit with delays it does not happen you know that here the flip flop has delay called TCO when the clock comes this D is transferred to Q with the delay called TCO. So after the clock edge it takes TCO time for the present state to change. So when the clock edge comes the state will change the count will change only after the TCO. So similarly here it is 1 then but when the clock edge comes it after a TCO delay changes to 2 and after TCO delay it changes to 3 and so on mind you there are 3 flip flops. So there is Q2, Q1, Q0 so there is TCO1, TCO0, TCO2 so I am showing only one time so there are 3 TCOs we are taking the showing the worst case timing delay ok. So this is one disadvantage when you go for little abstract high level block diagrams it hides lot of details actually you are used to maybe showing the 3 flip flops separate in thinking that clarity comes but you should be very careful when you put higher and higher level blocks more and more abstract you should not forget the details involved. So here you should know that when you say TCO the 3 TCOs we take the maximum for the maximum like 3 outputs are changing we wait for the latest output to settle there will be lot of glitches here I am showing just state change but there can be glitches depending on the state change say like from 1 to 2 there could be glitches ok because there are 2 bits are changing like 1 is 0, 1 and 2 is 1, 0 so there are Q0 and Q1 is changing state there could be transitory state in between so there could be glitches which I am not showing here but this in real life it can happen. So let us look at a picture of a binary counter I just want to show that picture ok so this is a real picture this is what you have used I am showing a mod 8 counter which is count from 0 to 7 so you know that this is a picture we have shown in abstract next level higher level block diagram but here you see D0 is Q0 bar D1 is Q1 exclusive or Q0 and D2 is Q2 exclusive or Q1 and Q0 and so on ok. So when we put it you should not forget that D0 is a function of Q2, Q1, Q0 D1 is a function of Q2, Q1, Q0 and so on. In the case of a binary counter you know that the D2 only depends on you know the Q2, Q1, Q0 and D1 only depends on the Q1 and Q0 it does not depend on Q2 but if you take a counter which count not very sequentially all this can change maybe the D0 can depend on Q2 also. So that is just to say that do not forget when we use such block diagram do not forget the detail picture you should have in your head you should in the mind otherwise you can make mistake in analysis when you analyse some circuit debug some circuit you can forget something and make a you know it can create trouble. So we have looked at the basically at the structure of a synchronous counter how what is the structure it consists of flip flop and combinational circuit and the flip flop output is called present state and combinational circuit is called next state logic. It is basically designing the next state logic all the intelligence is in the combinational circuit the flip flops are used to control it control hold the value at every clock this looks you know this is like a gate which allows you know gate is open then the next count comes in at the precise interval you know it is precisely controlled every clock at the count changes then we have looked at the output waveform. So in real life the output changes after the TCO delay which is the worst case delay of the multiple TCO of the output and finally I have told about you should though we abstract to the next level of the diagram you should not lose sight of the detail diagram because if you forget it then you can make mistake in analysis in understanding and so on. So I stop here in the next lecture we will continue with the timing analysis of this and we will build on this you know we will go on to the real life design system level design very soon. So I suggest you go back to this lecture revise do some simple design of the counters look at the structure of it try to understand the timing details and so on I wish you all the best and thank you.


On the road, on our Wal-Mart to Wal-Mart tours, we don't get much entertainment. And when we do, we're watching Trucker Josh. You should too. Flip that truck and Sam rides. Tell them all about it, Sam. Tell them. They're on your road. Tell them. Tell them, Sam. Tell them how it is. Woof, woof, woof! Ordered at 2 p.m. Eastern time. We have a new trailer behind us with some new stuff in it. And somebody in Canada wants that stuff. They're paying big bucks for it. And we're excited to be moving to Tennessee. The sign said anyway. Welcome. Very friendly people. Thanks for the sign. I feel welcome. We go left. We're not going home, so we're going right. I-24 splits off to the left here, takes us up to Chattanooga. 24 splits off to the left here. And this driver just realized now that he wants to go right, even though there's been signs for like 15 miles. 24 west is what I would take if I was going home to Manitoba. I-75 north. Up to Ontario. So this is where the fork in the road is.  Swift right beside me. You're making me nervous. Dangerous driving beside that truck. Here we go. Okay. Construction, construction. Wonderful. More construction. Just what I was hoping for. I had my fingers crossed hoping. Please, let there be lots of construction today. It's my favorite. Got my windshield here, but nothing compared to what we have up in Canada. Why do we get all the parts? I'd love to share some with you guys. So I'm confused. None of my 70 a little bit. Work overtime. Why is this guy doing 45 in a 70 mile an hour? Gas shifts up and then bogs me down. Of course. Professional driver right there knows what he's doing. You can do two things at once. That makes him a professional. That's how it works, right? I got to start thinking about where I'm going to stop. Diesel. Diesel. You and this whipper of a tail that you got right here. The audience is demanding more of you. More of all of this. And lots of that tail wagging. Lots of that. Yes. Everybody says more diesel or they're going to leave. I don't want them to leave. I want them to keep watching the videos. Say something. Say something clever. A dog? Is that a dog? Don't mess with me man. Don't mess with my emotions. Put me on your spot and then you tease me about other dogs. You really got another dog man? Is he over there? You think he wants to be friends? You asked for it and I delivered. More weasel. Hey guys. How did I do? Not much of a vlogger myself but hey. I'm usually more of a sort of kind of an extra. I'm more of a background kind of guy. Here I have been requested though. This is how I look when I'm relaxed. Very good diesel. Very good. Always relaxed. So I've just done laundry here. This is actually from a different day that I'm finishing this just editing this and putting this together now and wrapping it all up for you. So thanks for watching today. It's been a really fun trip. Since we've got back on van division I've been a lot happier with the work I've been doing. It's been more fulfilling it feels like and it's been better for me. I do miss home a lot though. I'm gone a little bit longer now than I was when I was on Dex and as much as I love being in the truck and I love getting back in the truck after being at home doesn't take long and I'm missing home again.  You miss your husband. That's a perfectly normal feeling. I struggle with that a lot. Maybe I'll do a whole video one day sort of diving into what would I say the emotions of trucking with trucker Josh. I don't like talking about emotions much. So maybe we won't. Maybe we will. I don't know. But it might be beneficial to some people who are thinking of getting into the industry. Thinking of getting into the truck just so that you guys know what the tax is emotionally. It's not easy for me. And I'm a guy who loves this job. I love it. There's nothing else in this world I'd rather do. But being away from home isn't easy for anybody. So I won't go too much further into this. I'll do a separate video one day. But I do miss home a lot when I'm on the road a lot. And it's tough. Especially when I got a beautiful wife waiting for me at home. I miss her a lot. But you got to do what you got to do. It's so hard to balance. Because I love my job. I love trucking. I also love my wife. I can't have the things we have at home without going to work. So you have to go to work. You have to work for what you have. You want a good life. You want to have a home. You want to have a little bit of a property. You want to have a bit of a retirement when you're at that point one day. You got to work. It's just part of life. You got to provide. Anyways. Enough with all that. Thanks for watching today everybody. And I'll see you tomorrow. Don't forget to tune in and subscribe.