PowerSpectrumDemo, Version 2 Digital signal generator (sumulator) with power spectrum display and sliders for "real time" control, useful for teaching and demonstrating the power spectra of different types of signals and the effect of signal duration and sampling rate. The signal slider selects from 10 different signals (you can change these in RedrawSpectrum.m). The Time slider controls the total duration of signal, the Rate slider controls the sample rate, and the F1 and F2 sliders control the global variables f1 and f2 which are used in different ways in the different signals. The Sound slider has only two settings: OFF (down) and ON (up). When Sound is ON, each time a slider is moved, the signal (y) is sent to the Windows WAVE audio device. When Sound is OFF, no sound is played when a slider is moved. However, even when Sound is OFF, clicking on the Sound slider plays the signal once for each click. Version 1.2 fixes a problem with the sawtooth waveform and displays the number of cycles of the signal waveform that fit in the signal window. T. C. O'Haver (email@example.com), version 2, Sept.2000 Function rtslid.m modified by commenting out lines 337 and 373 prevent crash on Matlab 20078 and 2009.