Extra exam question E7E02
Subelement E7, PRACTICAL CIRCUITS· Group E7E
What is the function of a reactance modulator?
- A.Produce PM or FM signals by varying a resistance
- B.Produce AM signals by varying an inductance
- C.Produce AM signals by varying a resistance
- D.Produce PM or FM signals by varying a capacitance (correct answer)
WhyA reactance modulator produces PM or FM signals by varying a capacitance. A reactance modulator produces phase or frequency modulation by varying a capacitance (or sometimes inductance) that's part of an oscillator's tuned circuit, directly shifting the oscillator's instantaneous frequency in step with the modulating audio, answer D. It doesn't work by varying resistance, and it produces PM or FM, not AM, those are fundamentally different modulation types produced by different circuit techniques.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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