PCSU200 waveform generator distortion - is this normal?

Instruments PC Oscilloscopes and Recorders
1

Hello All, new user here.

I have a PCSU200 and when I look at the waveform generator output on a spectrum analyzer, I see a lot of distortion.

Can anyone tell me if this is normal?

The image below is the spectrum from 0Hz to 1.25MHz - the fundamental frequency is 410kHz

The fundamental peak amplitude is 1.37dB - the worst harmonic is -10.9dB @

The remainder of the harmonics are ~ -29dB

The quality of the output is quite poor compared to an AD9850 DDS generator and also a Picoscope 2204A

This does not seem right to me.

Thanks. :slight_smile:

2

I made a test with the FFT spectrum analyzer of the PCSU200 and got following result:

Fundamental 410kHz, 1.31dBV
Worst harmonic (3rd) -51.5dBV

So the distortion factor is about 0.2%

3

So there must be a fault with my unit then.

I note that this morning, after I left it powered up all night, the waveform is a lot cleaner.

That suggests there is something wrong. I’m going to unplug it fo a while and try it again from cold, and see how long it takes to produce a clean waveform.