Digital frequency counter — which is NOT a typical control/timing signal? In a standard frequency counter block diagram, the control and timing section produces signals such as Gate/Enable, Reset/Clear, and Store/Latch. Which of the following is NOT generally issued as a distinct control signal by that block?

Difficulty: Easy

Correct Answer: Clear

Explanation:


Introduction / Context:
A basic frequency counter counts input pulses during a precise time window. A control and timing block (often driven by a time base) generates key control signals: open/close the counting gate, reset the counters, and store the measured count for display. Understanding these signals clarifies how accuracy and display stability are achieved.


Given Data / Assumptions:

  • Common control names: Gate (Enable), Reset, and Store (Latch).
  • Naming conventions vary, but functions are consistent.
  • “Clear” and “Reset” are often synonyms; designs usually choose one.


Concept / Approach:
The control and timing section opens the counting interval (Gate/Enable), then closes it, commands a Store/Latch so the display updates without disturbing the next count, and asserts Reset to zero the counters before the next measurement window. Because “Clear” duplicates the meaning of “Reset,” designs typically implement only one of those as a distinct signal, not both.


Step-by-Step Solution:

Time base defines a window (for example, 1 second).Gate/Enable goes HIGH to allow pulses into the counter chain.At the end of the window, Gate goes LOW and Store captures the count into a display register.Reset clears counters to zero for the next cycle.


Verification / Alternative check:
Block diagrams in textbooks typically show three lines from control: Gate (or Enable), Reset, and Store/Latch. “Clear” is either the same as Reset or unused; rarely is it provided as an extra, separate control in minimal counters.


Why Other Options Are Wrong:

  • Enable/Gate: always required to define the counting interval.
  • Reset: needed to zero counters between measurements.
  • Store: used to transfer count to the display register.


Common Pitfalls:

  • Not separating Store from Reset; storing before resetting avoids display flicker and race conditions.


Final Answer:
Clear

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