Hello!

With a proper calibration of the oscilloscope probes, you have to measure the right magnitude of the signal no matter what. Foe example here, you know that the probe is set up to 10 times, so when you adjust the measurement scale  (V/div or mV/div), this must reflect your signal magnitude.

Here, in your measurements, the voltage probe amplifies the signal 10 times: if your Tektronix scope is set for 1X and your probe is 10X, then your real signal is in the range of 4mV; if is set for 10X, with a probe of 10X, the real signal is in the range of 40mV.

So, when you change the voltage probe setting, you have to look at the oscilloscope for a proper set-up as well.

Here, if you set-up your probe to 1X, without following an oscilloscope calibration, your signal will be in the range of 4mV.

Cheers

Hi Sorin,

Sorry for replying so late.

Yes, I figured out that we had to control the multiplication factor on the CRO to adjust for the attenuation provided by the CRO probes. 

The correct measurements showed that the amplitude was 400mV and not 40mV.

Thanks.