A two channel sine wave generator is used to generate a combination of signals at two slightly different frequencies. The output is made audible to the class with a loud-speaker. The signals, along with a Fourier spectrum, may be viewed using a projection oscilloscope.

For a simple beats demonstration, simply select the frequency range for both channels, select the waveform, tune the frequency, amplitude and phase and then look at and/or hear the output through the output jacks. The mixer will mix the signals appropriately. When connecting to a speaker, use low impedance, while for the scope, I found that higher impedance gives a better signal. You can also look at the individual waveforms by connecting the immediate outputs to the scope.

L3, scope by workbench or D3

PIRA DCS 3B60.20