Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-004-008
What audio frequencies are used in a two-tone test of the linearity of a single-sideband phone transmitter?
- A Any two audio tones may be used, but they must be within the transmitter audio passband, and must be harmonically
- B Any two audio tones may be used, but they must be within the transmitter audio passband, and should not be
- C 20 Hz and 20 kHz tones must be used
- D 1200 Hz and 2400 Hz tones must be used
Correct answer: B — Any two audio tones may be used, but they must be within the transmitter audio passband, and should not be. From the official ISED question bank, verified word for word.
Why
A two-tone test checks if a single-sideband transmitter distorts your voice by mixing signals together. The full explanation — and one for every question — is in Pro.
Practise this section
Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.