We have added a new tool to the Autonerdz Sample Rate Calculator page.  

http://www.autonerdz.com/java/SampleRateCalculator.html

Of course, the calculator is still there and available for everyone to use to help compare the true sample rate of various digital storage oscilloscopes.  The new tool is a demonstrator of The Nyquist Limit.  

The upper window is a representation of the actual analog signal input.  You can control the frequency of this with the frequency slider.  You can vary the scope sample rate with the sample rate slider.  The results are below the sliders showing the samples taken and then the reconstructed signal.

A few minutes playing with this tool will really help with the concepts of digital scope sampling and signal reconstruction.  You can clearly see the effects of not having enough sample rate for the signal.  The image below shows the effect of aliasing.  You must sample a signal at least 2x signal frequency to avoid aliasing.  The more samples, the better your signal reconstruction.  A DSOs TRUE sample rate is the single most important thing to consider when choosing an instrument.  The calculator will assist you in determining the true sample rate for a given instrument.  

PicoScope will outperform all other automotive DSO alternatives when it comes to true sample rate.

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Tom

That is the easiest way to understand aliasing
Also it shows how aliasing can actually look like a good waveform when it is actually bad.

Wilf

Just a note this does not work with the firefox browser even after downloading java from the supplied link.  It does seem to work OK with IE

Sam

I had to go here to make it work.

http://www.cs.brown.edu/exploratories/freeSoftware/repository/edu/brown/cs/exploratories/applets/nyquist/nyquist_limit_java_browser.html

Hey guys,

Try this with firefox and tell me if it works

http://www.flatrater.com/Free/Autonerdz/test3/nyquist.htm

Just another way to display applets with html

Works Great with Firefox.

Dave

I snagged Jim's code.  Thanks Jim   ;)  

So, the calculator page should work with Firefox now.

Tried it with both version of firefox that I am running and it works good :)

Thanks Jim, Tom