This is a free simulation dealing with frequency analysis. You can download and run this on your computer. Below is a screen shot of the simulation demonstrating signal generation and analysis. If you decide to download and install the simulation program you will be able to run this simulation on your computer and change the settings shown below.
This simulation allows you to "generate" your own input waveforms on channels 1 or 2. You can may select a sine, square, or triangle wave form as well as it's corresponding frequency. It's a fantastic visual effect with the waveforms running across the screen like a real oscilloscope!
The signal processing section allows you to select either a Hanning or Hamming window. Then you can specify a Chebyshev or Butterworth filter.
This simulation published with permission from its author, national instruments..