In an SDRAM block, one of these devices takes as input the refresh counter and the row address latch.  One common way to implement a 8 bit barrel shifter is to use five stages of these devices. The 74157 is one of  these devices. One can implement A XOR B using this device by using B, not B as the inputs and A as a special  type of line. A minimal one of these can be created from two tristate buffers and a not gate, which corresponds to the  equation Y equals D sub 0 S or D sub one not S. They act as the opposite of a n
In an SDRAM block, one of these devices takes as input the refresh counter and the row address latch.  One common way to implement a 8 bit barrel shifter is to use five stages of these devices. The 74157 is one of  these devices. One can implement A XOR B using this device by using B, not B as the inputs and A as a special  type of line. A minimal one of these can be created from two tristate buffers and a not gate, which corresponds to the  equation Y equals D sub 0 S or D sub one not S. They act as the opposite of a n to 2^n decoder. These are depicted  as trapezoids on digital circuit diagrams. They take in a set of input lines along with control or select lines. For 10  points, name these digital logic devices that are used to choose from a set of inputs, thus combining multiple inputs  into a single output.
In an SDRAM block, one of these devices takes as input the refresh counter and the row address latch.  
multiplexer [or mux; prompt on encoder; prompt on selector]