SigJenny

SigJenny turns your PC into a flexible and powerful signal generator for free! It can create numerous waveshapes; sine, triangular, square, noise, etc, and display them graphically. The square and triangular signals can have their mark/space ratio continuously altered to make sawtooth and pulse waveforms and all signals can be inverted. The output can be a single frequency or swept, or a single or repeating tone burst. The response to a single burst acquired from a microphone can also be displayed.

With most sound boards the range is 10Hz-20kHz but with a 96kHz sampling sound board 40kHz can be achieved and the output can be calibrated in volts.