Shift-register counter types — identification Which of the following is a type of shift-register-based counter?

Introduction / Context:
Shift registers can be used not only for data movement but also to implement counters by circulating specific patterns. Recognizing these counter types helps in selecting the right topology for timing, sequencing, or state machine applications where one-hot patterns or specific code sequences are desirable.

Given Data / Assumptions:

• A “shift-register counter” refers to a counter realized by shifting bits rather than by incrementing binary numbers.
• Examples include ring counters and Johnson (twisted ring) counters.
• Options include other familiar counter families for contrast.

Concept / Approach:

A ring counter is a shift register configured with feedback so that a single HIGH circulates around the stages, producing a one-hot sequence. This is the quintessential shift-register counter. Johnson counters similarly use feedback of the inverted output to generate a 2n-state sequence. By contrast, “binary,” “BCD,” or “decade” refer to modulus or code families, usually implemented with standard binary add-one logic rather than pure shifting of a one-hot token.

Step-by-Step Solution:

Verification / Alternative check:

Inspect example circuits: a 4-stage ring counter produces 1000→0100→0010→0001→repeat, purely by shifting.

Why Other Options Are Wrong:

Decade and BCD describe 10-state sequences typically formed with binary counters plus reset decoding, not shift-register circulation.

Binary refers to a general counting scheme based on adders/toggles, not a shift-register structure.

Common Pitfalls:

Equating “decade/BCD” with any implementation technology; although one could create a decade sequence with a shift register, the canonical “type of shift register counter” is the ring (and Johnson), not the code family items.

Final Answer:

Ring