Several different types of signal generators exist with no single device capable of every output signal desired. Audio or tone generators, RF generators and waveform generators are some of the types commonly used.
Accurate tone generators may assist in electronically tuning traditional musical instruments. Electronic keyboard instruments depend upon signal generation rather than mechanical vibration to produce musical tones.
To troubleshoot faulty electronic systems such as radio or television, a clean input signal from the signal generator is fed to the input of the device. Stage by stage the processing of the signal is observed until the problem area of the circuit is pinpointed.
Signal generators produce different types of waveforms as well as different frequencies. Electronic filters are designed to react differently with the various signal patterns, passing some and blocking others.
Although older signal generators were stand-alone devices, their functions are easily mimicked by modern computers. Software for reproducing many signal forms and frequencies is readily available, even as freeware, but special equipment for interfacing is still needed.