General exam question G4B07
Subelement G4, AMATEUR RADIO PRACTICES· Group G4B
What signals are used to conduct a two-tone test?
- A.Two audio signals of the same frequency shifted 90 degrees
- B.Two non-harmonically related audio signals (correct answer)
- C.Two swept frequency tones
- D.Two audio frequency range square wave signals of equal amplitude
WhyA two-tone test uses two non-harmonically related audio signals. A two-tone test feeds the transmitter two audio tones that are deliberately not harmonically related, so that any nonlinearity in the transmitter creates new, easily identified intermodulation products distinct from the original two tones, answer B. Same-frequency phase-shifted tones, swept tones, and square waves wouldn't isolate intermodulation distortion the same clean way two independent sine tones do.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2023-2027 NCVEC Element 3 pool (public domain); the explanation above is original writing, see our methodology.
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