Author Topic: My Philips PM3050 Oscilloscope is giving wrong frequency from cal output. Why?  (Read 363 times)

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Offline TulparTopic starter

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My Philips / Fluke PM3050 Oscilloscope is giving the wrong frequency value from the Cal output. Does anyone know why?
The user manual says that the calibration output should be 1.2V (p-p) 2kHz. When I measure, I see a value of approximately 0.57 ms = 1.75 kHz. I also tested with another oscillator and the oscilloscope can measure 2 kHz as it should. Does anyone have any ideas on how to fix the calibration output or what the problem is?
 

Offline Wallace Gasiewicz

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The Cal output is really just to use as probe calibration.  They are used to calibrate the probes for best square wave. Yours is off more than I would hope for but most of them are not accurate as freq standard, they are usually off quite a bit.  The voltage is usually pretty good but although scopes are good volt meters they are not excellent volt meters,
 
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Offline TulparTopic starter

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I thought that the calibration output would give an output at the frequency written in the user manual. The square form of the wave seems to be correct, I guess there is no problem then. Thank you for your help.
 

Online tggzzz

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The cal out signal would be just as effective at 1kHz or 5kHz. Its sole purpose is to enable you to tweak the LF response of *10 "high" impedance probes.
There are lies, damned lies, statistics - and ADC/DAC specs.
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