Author Topic: Siglent1104X-E versus Square Waves  (Read 2417 times)

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Offline IAmBack

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Re: Siglent1104X-E versus Square Waves
« Reply #25 on: August 11, 2023, 08:20:23 pm »
If we consider that harmonics of square wave are odd, then 20M square wave has harmonics at 20, 60, 100, 140, 180, 220, 260 ad so on MHz. Se beside Basic 20M a scope with 200M bandwidth can "see" 4 harmonics if these are present in the square wave (remember limits of generator). So imho, everything looks about normal.
 

Online tggzzz

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Re: Siglent1104X-E versus Square Waves
« Reply #26 on: August 11, 2023, 09:50:36 pm »
If we consider that harmonics of square wave are odd, then 20M square wave has harmonics at 20, 60, 100, 140, 180, 220, 260 ad so on MHz. Se beside Basic 20M a scope with 200M bandwidth can "see" 4 harmonics if these are present in the square wave (remember limits of generator). So imho, everything looks about normal.

Ignore the harmonics, and concentrate on something that is
  • constant, whatever the frequency of the square wave
  • directly relevant to what the instrument is designed to observe
in other words, the risetime.

Make sure, of course, that the risetime of the input signal is much less than the published risetime of the instrument.

If you insist on relating that to the frequency domain, start by using the rule of thumb that BW=0.35/trisetime
There are lies, damned lies, statistics - and ADC/DAC specs.
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