Just got a new Keysight DSOX1102G oscilloscope which has a built in signal generator. By applying a few Hertz of frequency modulation to the sine wave and switching on the scope's display persistence, I can create a pseudo bode plot!
ETI Vocoder constructional project reproduced with permission from Wimborne Publishing Ltd. http://www.epemag.com
ETI Vocoder constructional project reproduced with permission from Wimborne Publishing Ltd. http://www.epemag.com
Thanks for that, Julian. I bought the same scope when I retired after teaching college in Toronto for 25 years since I could no longer borrow stuff from the lab for the weekend! My need for a bode plot is to help local 2m repeater owners flatten their response, and for that I plan to hook the scope up to a Motorola Service Monitor. I knew about the FRA but the idea of viewing it live as one adjusts the circuit is new to me, kudos! I remember you from the ETI days, when I used to be a contributing editor for the Canadian Edition! Your write-up on LCDs helped my students for many years – thanks for that!
Procedure too complicated!
Bloody hell I had an interview with Keysight a few years back, they were going to offer me a job but I chose to work for another company instead
Nice scope, but heaven help you if you ever need to get it fixed…
I think the reason why the phase angle jumps up, is that the oscilloscope cannot distinguish between phases smaller than -180° and the corresponding +1xx° phase. E.g. -190° and +170° are basically the same. So the plot is correct, just keep in mind that a jump is just a phase that lags more than 180°.
I'll bet that scope has the "New Walkie Talkies for Christmas @ 8~10 Years Old" smell.
Very cool! Thanks for posting. I have the 50Mhz version coming next week, with the function generator. I found out thanks to another vblogger here that it is really a 3 channel scope for my purposes because the external trigger is displayed – it is referred to as a digital input on the data sheet.
Yes i will scrap the toys and get a real one hahahaha
how did u come up with 100khz at 10msec.?
I'm glad Keysight haven't sent one of these to me, as their mislabelling of the triangle waveforms as "ramp" (which should indicate a purely rising or falling sawtooth) gives my pedantry a right old jiggle! 🙂
The phase response jumps up 360 degrees. It's equivalent. Good phase plots have limits of +-180 degrees. It's like how there are infinite phaser values for any point of the plane because the angle can go around 360 degrees n times.
Have you seen Daves video on this scope, very interesting. Thats eevblog of course.
wow startup 21 sec that long and way too expensive
Ugh, I hate controls that change step like that.
Wouldn't the FFT function come in handy for this, feeding the circuit with white noise (or is it pink, can never remember).