Question
When using a transceiver that displays the carrier frequency of phone signals, which of the following displayed frequencies represents the lowest frequency at which a properly adjusted LSB emission will be totally within the band?
Answer Options
- A) The exact lower band edge
- B) 300 Hz above the lower band edge
- C) 1 kHz above the lower band edge
- D) 3 kHz above the lower band edge
Correct Answer: D
Explanation
Lower Sideband (LSB) emissions have their main signal energy below the displayed carrier frequency. A typical voice (phone) signal occupies a bandwidth of approximately 3 kHz. To ensure the entire signal is within the legal band, the lowest frequency component of the signal must not fall below the lower band edge.
Therefore, if your LSB signal is 3 kHz wide, the lowest legal carrier frequency (the one displayed on the transceiver) must be at least 3 kHz above the lower band edge. Selecting a displayed frequency of 3 kHz above the band edge ensures the entire 3 kHz of the signal (extending downward from the displayed carrier) stays within the authorized segment. The other options would result in the lower portion of your signal extending illegally outside the band.
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