Additional Notes
An important application of the shift register is a delay circuit for a bit string. The time that the but takes to propagate through the shift register is a function of both the clock frequency and the number of flip-flops in the register. If a clock signal of 10 usec is used to clock an 8-bit shift register than it will take a total of 80 usec (8 × 10 usec) for a bit at the input of the register to appear on the output. In addition, the shift register can be tapped at each ! output as a function of multiples of the clock frequency. The first Q output will be delayed by 10 usec, the second by 20 usec, the third by 30 usec, and etc. A series of data bits applied to the input of a shift register can then be delayed in the shift register by multiples of the clock frequency.
