How is a single-sideband phone signal generated?

A single-sideband (SSB) phone signal is generated by utilizing a balanced modulator followed by a filter. In this process, the balanced modulator takes an input audio signal and a carrier wave frequency, modulating the carrier with the audio signal to produce two sidebands: the upper and lower sidebands.

The crucial aspect comes next, where a filter is applied to remove one of the sidebands, typically the lower sideband, leaving only the upper sideband (or vice versa). This results in the creation of a signal that occupies less bandwidth than traditional amplitude modulation (AM) signals while retaining voice quality. The use of a balanced modulator is essential because it generates the two sidebands appropriate for SSB modulation effectively.

The other answer choices do not correctly describe the method of generating SSB signals. An unbalanced modulator does not typically provide the necessary performance for SSB and would not lead to the same bandwidth efficiency. A simple bandpass filter by itself does not generate SSB; it merely passes signals within a certain frequency range without the modulation process. Similarly, a notch filter is used to remove a specific frequency component and is not involved in generating a single-sideband signal.