Okay. These scopes have actually three trigger modes as determined by the "Trig Mode" push buttons: Auto - sweep with or without trigger signal. (results similar to the old recurrent-sweep scopes like the EICO 460! and old Heaths) Norm - the scope -only- sweeps with tgiggering signal criteria being met Sngl Swp - Single sweep Also, you can choose your trigger to be DC or AC - and the AC mode has like a 20 Hz or so low freq cutoff. So, I would choose DC. By careful adjustment of the "A Trigger" "Slope" and "Level" control you should be able to trigger off a slow-moving waveform as it crosses the trigger threshold. Also, be sure to choose "DC" coupling on the switch located below the rotary "Volts/Div" switch on the channel you're working with! Next question - is this just a one-axis gyro (I've not played with the recent crop of piezo gyros, my expereince was with the mechanical stuff a few years back). RF Jim ----- Original Message ----- From: "Bob Japundza" To: Sent: Thursday, August 22, 2002 11:26 AM Subject: Re: [EE]: measuring jitter on a scope Jim, I have set it as you describe and have no idea why it isn't triggering. The dc output of the gyro is proportional to rate acceleration, approx 20mv/deg/sec. I do get some sine waves on the display, but when I rotate the gyro I don't see any change in amplitude. Bob > -----Original Message----- > From: Jim [mailto:jvpoll@DALLAS.NET] > Sent: Thursday, August 22, 2002 11:01 AM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: [EE]: measuring jitter on a scope > > > Bob, > > Can you explain why it is you have nothing to > trigger off? > > I am assuming you can simply set the scope's trigger > Source for CH 1, set for AC, adjust the level and get > triggering ... > > What is the output of the piezo gyro supposed to be? > > Is it DC proportional to something? > > I've got a 475 too, and the Horz scale is shrunk ... > > RF Jim > > > ----- Original Message ----- > From: "Bob Japundza" > To: > Sent: Thursday, August 22, 2002 10:25 AM > Subject: [EE]: measuring jitter on a scope > > > I am working with a piezo gyro that puts out a bit of > noise/jitter in its > output. I have a couple of different op-amp filter circuits > I've thrown > together to see how well they clean up the output of the > gyro, but at the > same time not screw with the bandwidth of the gyro's output. > The gyro puts > out approximately 2.5v at a steady state, and goes up/down from there > depending on the direction of rotation. I have been trying > to measure the > noise level of the output with my scope without success; I > assume it is > because I don't have anything to trigger off of. My guess is > that I need a > function generator (which I don't have at the moment, but one > is on the way) > tied into the external trigger input of the scope and > "sample" that way. > Can anyone tell me that I'm correct in my thinking? What > frequency should I > use to sample the output? > > Also, it seems my scope is a bit out of calibration (Tek > 475). I have just > located some manuals on ebay; is it difficult for one to > calibrate this > scope, or should I be looking to send the scope off somewhere to be > calibrated? > > thanks, > > Bob > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.