Explanation: When transmitter power is measured over a period of time, it refers to **Average power**. **Average power** represents the total power delivered or radiated over an extended duration, taking into account the fluctuations inherent in modulated signals like voice (SSB or AM). While the instantaneous power of a voice signal can vary dramatically from milliwatts to many watts, the average power provides a stable and consistent metric for regulatory limits, power consumption, and the overall heating effect on components. This is particularly important for signals with varying envelopes. **Peak power** (specifically Peak Envelope Power, PEP) is the maximum power reached during the highest point of the modulation envelope. It's an instantaneous measurement, not one taken "over a period of time." **Reciprocal power** is not a standard term used to describe transmitter output power. **Return power** refers to the power reflected back from the antenna system to the transmitter due to an impedance mismatch (measured by SWR), not the power transmitted out.