25Mhz, 100Mhz wave representation on different bandwidth scope

[glatocha]

After the Rigol teardown and excellent follow-up I have an interesting idea for a blog episode.

Please show us, how the 25Mhz wave sine and square will look on the 25Mhz bandwidth scope and on the 50 or 100MHz scope.
Saying it different way. What does the bandwidth really tell us and what limitation it produce!

I think it takes some equipment to do that test: a generator, different scopes etc. and, Dave, you have them all.

[tggzzz]

After the Rigol teardown and excellent follow-up I have an interesting idea for a blog episode.

Please show us, how the 25Mhz wave sine and square will look on the 25Mhz bandwidth scope and on the 50 or 100MHz scope.
Saying it different way. What does the bandwidth really tell us and what limitation it produce!

I think it takes some equipment to do that test: a generator, different scopes etc. and, Dave, you have them all.

This is such a simple and fundamentally important topic that you will gain major benefits from understanding it on a general theoretical level - not just with one or two experiments. Once the theory is understood you will be able to predict what will happen with any digital waveform of any frequency with a scope with any bandwidth.

That will be immensely useful to you multiple times in the future.

It best understood by finding out:

• what frequency components are present in a square wave - or, more usefully, a trapezoidal wave with finite rise/falltimes
• what a square/trapezoidal wave with higher frequency components removed looks like
• which of those components would be removed by the scope's front end - or, more usefully, by the various filters that are invariably present in practical circuits

There are many many many web pages on this subject, and they will give you a far better description than anything hacked together in this thread. Keywords: FFT, fourier series, trapezoid power spectral density

[awallin]

FWIW: 100MHz Rigol vs. 500 MHz Tek.

http://www.anderswallin.net/wp-content/uploads/2014/07/pulse_stretcher_test_keithley3390.png
and
http://www.anderswallin.net/wp-content/uploads/2014/07/pulse_stretcher_test_PMT.png