A comb generator is a signal generator that produces multiple harmonics of its input signal. The appearance of the output at the spectrum analyzer screen, resembling teeth of a comb, gave the device its name. 

Comb generators find wide range of uses in microwave technology. E.g., synchronous signals in wide frequency bandwidth can be produced by a comb generator. The most common use is in broadband frequency synthesizers, where the high frequency signals act as stable references correlated to the lower energy references; the outputs can be used directly, or to synchronize phase-locked loop oscillators. It may be also used to generate a complete set of substitution channels for testing, each of which carries the same baseband audio and video signal. 

Comb generators are also used in RFI testing of consumer electronics, where their output is used as a simulated RF emissions, as it is a stable broadband noise source with repeatable output. It is also used during compliance testing to various government requirements for products such as medical devices (FDA), military electronics (MIL-STD-461), commercial avionics (Federal Aviation Administration), and digital electronics (Federal Communications Commission), in the USA.