In a single-sideband phone signal, what determines the PEP-to-average power ratio?

The PEP-to-average power ratio in a single-sideband (SSB) phone signal is primarily determined by the speech characteristics of the audio being transmitted. In SSB modulation, speech signals exhibit varying levels of intensity and frequency content, which influences the power output of the transmitter.

The PEP (Peak Envelope Power) represents the maximum power of the signal when it reaches its peak level, while average power is the mean power over time. Human speech is not a constant signal; it consists of varying dynamics, with certain phonemes or syllables producing higher peak levels and thus higher PEP. In practice, the characteristics of the speech, such as loudness, pitch, and the way it is articulated, directly affect how high the signal peaks can become compared to the average power of the transmitted signal.

Although factors like modulation technique, frequency, and transmitter power play roles in the overall system, they do not directly dictate the ratio of PEP to average power in the context of SSB signals as much as the speech characteristics do. Therefore, the speech characteristics are crucial in determining how efficiently the modulation can transmit the information and how it impacts the power levels involved.