Definition of a frequency counter: A frequency counter is a digital circuit that measures and displays the frequency of an input signal by counting cycles over a known time base. Evaluate this definition for correctness.

Difficulty: Easy

Correct Answer: Correct

Explanation:

Introduction / Context:Frequency counters are ubiquitous test instruments in labs and embedded systems. They rely on precise time bases to translate counts of periodic events into a frequency value that can be displayed numerically.

Given Data / Assumptions:

  • The input signal is periodic with a frequency in the counter’s operating range.
  • A stable reference oscillator defines the measurement gate time.
  • Input conditioning circuitry shapes the signal to logic levels so edges can be counted reliably.

Concept / Approach:By counting the number of input cycles N within a gate interval T_gate, the instrument computes f ≈ N / T_gate. Alternatively, some counters measure the period and invert it, which improves resolution at low frequencies (reciprocal counting). Both approaches fulfill the stated definition.

Step-by-Step Solution:

Shape the input signal to clean digital transitions.Open the measurement gate for a precise interval T_gate.Count the input edges during this interval to obtain N.Compute frequency as f_meas = N / T_gate and display the result.

Verification / Alternative check:Datasheets for bench frequency counters and MCU-based counters outline exactly this method, sometimes adding averaging, prescalers, or reciprocal techniques for improved resolution.

Why Other Options Are Wrong:

Incorrect: Denies standard instrument operation.Only correct for sine waves / duty-cycle-dependent: Frequency counting works for any periodic waveform with clean edges.

Common Pitfalls:Measuring noisy or non-periodic signals; inadequate input conditioning causing false counts; relying on short gate times that magnify quantization error.

Final Answer:Correct

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