Thanks, Jim, I'll give it try tonight. Yes, the gyro is a single-axis = unit. Bob > -----Original Message----- > From: Jim [mailto:jvpoll@DALLAS.NET] > Sent: Thursday, August 22, 2002 12:33 PM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: [EE]: measuring jitter on a scope >=20 >=20 > Okay. >=20 > These scopes have actually three trigger modes > as determined by the "Trig Mode" push buttons: >=20 > 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 >=20 > 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. >=20 > 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. >=20 > Also, be sure to choose "DC" coupling on the switch > located below the rotary "Volts/Div" switch on the > channel you're working with! >=20 > 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). >=20 > RF Jim >=20 >=20 > ----- Original Message ----- > From: "Bob Japundza" > To: > Sent: Thursday, August 22, 2002 11:26 AM > Subject: Re: [EE]: measuring jitter on a scope >=20 >=20 > Jim, >=20 > I have set it as you describe and have no idea why it isn't=20 > 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=20 > when I rotate > the gyro I don't see any change in amplitude. >=20 > Bob >=20 > > -----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=20 > 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. > > > > > > >=20 > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. >=20 > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. >=20 >=20 >=20 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.