Ring counter definition – is it a register that “continuously outputs” a fixed bit pattern in parallel rather than circulating a single 1 (or pattern) through its stages?

Introduction / Context:
Ring counters are a classic example of counters implemented using shift registers. A clear definition avoids confusion between “parallel outputs” (which all registers have) and the behavior of a ring counter, which is about circulating a token through stages over time.

Given Data / Assumptions:

• A ring counter feeds the last stage's output back to the first input.
• It is initialized with a single 1 (or a known pattern) and clocked.
• All stage outputs are available in parallel as pins, as with any register.

Concept / Approach:
What makes a ring counter special is not parallel outputting of a fixed word but the sequential circulation of a 1 (or encoded pattern) through N flip-flops, yielding N distinct one-hot states over N clocks. A Johnson (twisted-ring) counter similarly circulates a complementary pattern, creating 2N distinct states. The phrase “continuously outputted in parallel” mischaracterizes the dynamic nature: the state vector seen at the parallel outputs changes each clock as the token moves; it is not a single, unchanging word continuously driven in parallel.

Step-by-Step Solution:

Verification / Alternative check:
Timing diagrams show a walking 1 across Q0…Q(N−1). Datasheets for ring/Johnson counters present state tables cycling through positions, not a constant parallel word.

Why Other Options Are Wrong:
Calling the statement “Correct” confuses static parallel output with dynamic state progression. Johnson counters are related but still circulate patterns; asynchronous clocks would break deterministic sequencing and are not part of the definition; reset polarity is an implementation detail.

Common Pitfalls:
Equating “has parallel outputs” with “outputs in parallel as a definition.” All registers expose parallel outputs; the special behavior is the rotating one-hot or pattern sequence.

Final Answer:
Incorrect