Rigol DS4014 Strange Waveform

[AlanM]

Hi everyone,

I am hoping someone has seen something like this before. I am looking at the signal output (using a Rigol DS4014 with RP3500 probe) of a step up transformer that is driving a piezo transducer at 175vac p/p, 41Khz, eight pulses every 250mS. I have tried AC and DC coupling combinations on the Channel input and trigger types (amongst many other combinations of source and trigger settings) and I just cannot understand or improve the difference in these two waveforms. The signal appears to be fine at 5v/div and higher but when selecting 2v/div (and lower). a strange sine wave appears. It may well be a characteristic of the electronic circuit but cannot see why the two settings (5v/div and 2v/div) should be so different. I have tried a Tektronics TDS210 and the signals are fine (no sine wave) but the DS4014 may be using it's higher resolution to pick something out? Surely it wouldn't appear just at 2v/div and lower?

Rigol have been far from helpful.

Thanks for any help or suggestions,
Alan

[tinhead]

look for me as distortion (self oscilation of input stage) due too high Vpp voltage. Every DSO will ast here complettly different, some will "overdrive", some clip the wave and others will autoset back to 5V or more DIVs.

[AlanM]

Very pleased to say that Rigol have sorted the problem for me. A change of probe was all that was needed.

I love this scope!!

Thank you Rigol.