What is the term for the sum or difference frequencies generated when a local oscillator and input signal are mixed?

The correct term for the sum or difference frequencies generated when a local oscillator and an input signal are mixed is Intermediate Frequency (IF). In the context of signal processing, particularly in radio communications and modulation schemes, mixing involves combining two frequencies to produce new frequency components. The resulting intermediate frequencies provide a manageable range for further processing, such as amplification and filtering.

When the local oscillator frequency is combined with the input signal frequency, the mixing process yields two frequencies: the sum (local oscillator frequency plus the input signal frequency) and the difference (local oscillator frequency minus the input signal frequency). The intermediate frequency is specifically chosen to be lower than the carrier frequency, allowing for easier and more effective signal processing in devices such as superheterodyne receivers.

The other terms mentioned do not specifically relate to the mixing process of oscillators and input signals. Baseband frequency refers to the original frequency range of the signal before modulation; signal frequency generally refers to any frequency the signal may occupy; and carrier frequency denotes the main frequency of a radio wave that is modulated with information. These terms do not encompass the specific frequencies resulting from the mixing process in the same way that intermediate frequency does.