Hi!


I started to work with the following oscilloscope: Multicomp pro Digital Storage Oscilloscope 100MHz MP720665
I used a function generator: PM 5127 PHILIPS to generate functions. (Yes, it is pretty old.)
I executed the self calibration and also the factory reset.
I gave a 2000 Hz sinusoidal wave and the result is around 1366 Hz.

How can I solve this issue?

Thanks a lot.

 

You cannot perform a proper calibration on either instruments without a known frequency standard.

A simple solution is to get a quartz crystal oscillator module that generates an accurate frequency.

 

Hi Slan,
I would say looking at the very poor form factor of the Sine wave, it's a low grade sine wave generator.
I would suspect the calibration of the generator scale.
E

 

Also it would be better to use a square wave signal because the rise and fall times are shorter.

 

How can I solve this issue?

I always thought that you used a time mark generator for calibrating the time base.

I bought one of these on eBay to calibrate my scopes:

 

Measure the output of a mains transformer. What frequency does it read? and what frequency should it be?

 

You can easily check digital oscilloscope by measure
very accurate period (2 sec) of pulses from ordinary wall clock:

 

IF this is your scope,

and this is your generator

Then the analog generator is off, and the digital scope is right on.

 

Hi!


I started to work with the following oscilloscope: Multicomp pro Digital Storage Oscilloscope 100MHz MP720665
I used a function generator: PM 5127 PHILIPS to generate functions. (Yes, it is pretty old.)
I executed the self calibration and also the factory reset.
I gave a 2000 Hz sinusoidal wave and the result is around 1366 Hz.

How can I solve this issue?

Thanks a lot.

 

Hi!


I started to work with the following oscilloscope: Multicomp pro Digital Storage Oscilloscope 100MHz MP720665
I used a function generator: PM 5127 PHILIPS to generate functions. (Yes, it is pretty old.)
I executed the self calibration and also the factory reset.
I gave a 2000 Hz sinusoidal wave and the result is around 1366 Hz.

How can I solve this issue?

Thanks a lot.

 

Thank You for the answers. I attached the measured square wave as well.
Unfortunately, my hands are tied, I cannot buy another oscilloscope.

 

Hi!


I started to work with the following oscilloscope: Multicomp pro Digital Storage Oscilloscope 100MHz MP720665
I used a function generator: PM 5127 PHILIPS to generate functions. (Yes, it is pretty old.)
I executed the self calibration and also the factory reset.
I gave a 2000 Hz sinusoidal wave and the result is around 1366 Hz.

How can I solve this issue?

Thanks a lot.

What is the problem?

 

... that the 2000 Hz signal is processed as 1366 Hz by the oscilloscope.. ?

 

Of course I can see that. So which unit is in error, the oscilloscope or the signal generator or both?
...waiting for TS to respond.

 

When I touch tip of oscilloscope probe by finger,
I am seeing on oscillogram distorted sine.
Frequency of sine is 50 Hz, exactly as in mains.
It means oscilloscope is good.

 

... that the 2000 Hz signal is processed as 1366 Hz by the oscilloscope.. ?

Not at all surprising from one of these:

For more precise frequencies you require a digital AWG that can provide Sine, Square and Pulse that you can adjust to be a defacto Mark Space generator.
Back in the days when I used to fix scopes I had a PM5131 FG and it was a horrible unstable and inaccurate bit of kit totally unsuitable for checking/adjusting scopes.
A SDG805 would be vastly superior but frequencies will never perfectly match unless both the AWG and scope can be externally referenced.

 

Of course I can see that. So which unit is in error, the oscilloscope or the signal generator or both?
...waiting for TS to respond.

I connected the Output 1 on the rear of the oscilloscope. It looks fine.

 

Do the test suggested in post #15.

 

Hello,

The test in #15 will give an 50 or 60 Hz signal on the scope dependent on your countries mains voltage frequency.

Bertus

 

Frequency measurement with an oscilloscope, if it is done by measuring the time between zero crossings, is often subject to setup and operation errors. What is the scheme that your scope uses???