Test and Measurement Forum

I'm using an adc 212-100 an a pIII winXP with PicoScope sofware 5.09.4

I'm looking at very fast pulse events (50-100nsec) in duration. I set the trigger to 100mV. My understanding is that the scope should trigger only if the voltage exceeds the 100 mV. However, trigger events occur, even though the displayed samples never exceed 100mV for the said trigger events. This seems like a probelm. I am runing the scope in the 'unfiltered mode,' with max samples/trace of 25000, and the time/div of 100nsec/div.

I read the help pages, and saw the note on max oversample, but this wasn't available to me under advanced options. Where can this be set?

Thanks,
Derek

The only reason the scope should trigger if the trigger levels are not met is if the trigger mode is set to Auto. In this mode, the scope waits for a trigger for a period of 1 second and if the trigger is not met will trigger anyway.

Try using repeat trigger, if you are already doing this, probably the best course of action is to e-mail a .psd scope file to tech@picotech.com so that we can check your settings.

Alan
Pico