71. Design 4-bit SISO shift register

SISO Data Transmission: A mechanism where binary data is transferred over a single physical channel one bit at a time. It requires n clock cycles to completely load an n-bit word into the register, and another n-1 cycles to completely unload it serially.

Core Shift Features:

• Single Line Gating: Minimizes physical wiring by utilizing only one entry and one exit terminal regardless of bit depth.
• Synchronous Delay: Naturally introduces a predictable time delay proportional to the number of stages and the clock frequency.

Applications: Primarily used to construct digital time-delay lines, isolate processing speeds between different subsystems, and serve as temporary buffer memory in long-distance bit-stream communication networks.