This is a spectrum analyser which runs in the audio range dc-20kHz though you can run it higher if you have a powerful enough ADC and PC.
It needs an NI adc for tghe input. Gives an output that is the time-domain waveform and the spectrum. The spectrum has windowing for the FFT and also averaging as an option.
For the time-domain it has triggering like an oscilloscope. (taken from an NI VI - not mine). Of course with no anti-aliasing filter you will see aliasing appearing and this is quite good if you are learning about sampling etc. For example, sampling at 40kHz, if you insert a sine-wave greater than 20kHz the spectrum will start reading 'backwards" towards zero as you increase the fruequency ie for 21kHz you will see 19kHz and for 41kHz you will see 1kHz. (starts reading up again).
