Sampling Explorer
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Introduction

This is a visual demonstration of sampling analog signals, including time sampling, quantization, and interpolation of the samples.

The tool

The original analog signal is the blue line in the top plot. Its samples are denoted by the stems, or lollypops. The dark blue line in the bottom plot is the interpolation of the samples back to a continuous signal. You can choose different analog signals from the waveform menu at the bottom.

Things to investigate

1. For a sampling rate of 1000 Hz, what is the highest frequency sinewave that can be sampled accurately?
2. Set the number of periods to plot to 5. Set the sinewave frequency to 500 Hz, and the sampling rate to 1000 Hz. What happened? Now click on the phase slider arrow until it reaches 90 degrees. Interesting...
3. Set the number of periods to plot to 2, the sinewave frequency to 200, the amplitude to 1, phase to 0, and the sampling rate to 1000. What is happening at the edges? Change the number of periods to 3, 4, 5. Explain by aid of the interpolation button.

Further reading

Credits

Produced by Bob L. Sturm and Dr. Jerry Gibson.
Release date: January 20, 2004
Copyright 2003 University of California, Santa Barbara