That is that is the scientific requirement isn't it. Repeatably.
So what do we do? Send all our stuff to Samuel I guess.
I only use that example because we have worked to together, there are too many results flying around now to make perfect sense of.
@ Richard,
When you get the chance, can you stop by over here?
I've got a question and there is another DIY guy who had a
question about the vp7723 that you once owned. Maybe you
can help clear it up?
http://www.diyaudio.com/forums/equipment-tools/257223-panasonic-vp-7723a-help.html#post4986241
When you get the chance, can you stop by over here?
I've got a question and there is another DIY guy who had a
question about the vp7723 that you once owned. Maybe you
can help clear it up?
http://www.diyaudio.com/forums/equipment-tools/257223-panasonic-vp-7723a-help.html#post4986241
What's missing here is a standard.
When in doubt use a standard to compare to.
What standard?
I agree with you about Samuel Groner. Don't know how he finds the time in his busy schedule.
Maybe he doesn't sleep.
I want to know where the discrepancies are coming from. Let's keep working on this.
I ordered some of Victor's oscillators and he is getting me two of the 1kHz ones. I will see what I find, I have access if need be to the latest AP and plenty of other stuff. I still dream of finding our Shibasoku under someone's bench.
I know you would love to prove the generator not be this good. But it is. And, no there really is no issue now with a repeat-ability red herring.
The answers are VERY repeatable and very stable over long periods of time.
What ever David sets it for is what it does forever. I have to fiddle with things when i see pots..... so I changed his settings. My unit is as I said. And, it does not change. I can change it back to his original setting.
If David made the unit with fixed R values, As Vic does with his gen/osc, my results and all other units would be the same as what he measured. As mine was when i received it.
For those who may wonder about the ShibaSoku 725D:
Short of a standards lab type environment and measurement standards, the latest ShibaSoku 725 (D) is about as good as we can get. It is the same physical size as the AP2722A I have. The AP has the IM option, does MLSSA, multi-tone, and a huge array of tests... even jitter. Both weight about the same. The 725D is crammed packed with electronics on many seperate pcb plugged into a mother board. It does not do IM tests. it does not provide an internal generator. It does not do any other tests -- just THD. And, does it exceedingly well.
THx-RNMarsh
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I ordered some of Victor's oscillators and he is getting me two of the 1kHz ones. I will see what I find, I have access if need be to the latest AP and plenty of other stuff. I still dream of finding our Shibasoku under someone's bench.
And what happened to your Shibasoku?
If it's just matter of building a better notch filter and gain chain then this doable.
I've been been playing around with the software Victor uses. Spectra Lab. It's got so many bells and whistles in it, I having trouble setting it up. I can see a lot room for error with this package. Lot's DSP included. Filters etc.
There is mention of SDR (software defined radio) in the setup menus. I think this was put together by hams.
I have SG's geber files for his low THD notch filter. Maybe I'll send it off to the board house.
Oh, now you tell us. How long have you been keeping this from us
David? It might just be the "peaste de resistance" Maybe one of you
French Canuck's can spell it correctly--so we can all get on the same page.
Book one for me please. We should ask Samuel, ja?
We should also ask if he's got v2 or an update?
Or
a, I forget what you call them...but it's like a trap
or a snare that makes it not work unless you find out
from the guy who designed it...which part to leave out
or which trace to cut, etc. to keep it from self destructing.
And for that gentlemen....
This round is on me,
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Richard, we might also want to mention what David described to me and when
I started using mine a bit more I found the same thing.
I love it. It is fast! it does it thing and then you are done.
There is nothing to fooling around with, wasting time, setting
up measurements, tests, etc, etc. etc.
You just set up your DUT, switch on the 725D, press the analyze
button...Bang your done, finished, write down the meter reading.
In fact it takes longer to type this up than it is to use....really.
Once I realized what David was telling me...it was like...
well you know...like the very first time!
Madonna and Me = Very good buds.
LOL
Cheers,
Maybe useful.....
Low distortion oscillator tests measurement circuits | EDN
See Performance Verification.
THx-Richard
Low distortion oscillator tests measurement circuits | EDN
See Performance Verification.
THx-Richard
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The JanasCard design does work very well. It was the one discussed almost 4 years ago:
http://www.diyaudio.com/forums/equipment-tools/205304-low-distortion-audio-range-oscillator-258.html#post3478061
The link I provided back then doesn't seem to work anymore.
http://www.diyaudio.com/forums/equipment-tools/205304-low-distortion-audio-range-oscillator-258.html#post3478061
The link I provided back then doesn't seem to work anymore.
Yes, this design must work very well. The NSL32SR3 optocoupler has less distortions than the FET in the same conditions, and good polystyrene caps seems the best.
State variable oscillator configuration is also very good, but needs three perfect opamps.
Also interesting may be one opamp oscillator design with the twin T notch in the feedback.
Victor.
Yes
Gee what a coincidence, the noise floor agrees again. Ref 2 is my oscillator Jeff was my tech and I wanted him to get the company publishing award (as small as it was). You see why I feel some ownership of this. We also were required to use our parts and get the caps from the stockroom. Subsequent fiddling got down to -130db with 1998 parts. I did do an unpublishable version that took several minutes to to settle even at 1K that was probably better.
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It is the Verification part that might be useful for testing this and other generators.
-RNM
Yes, it is useful. Together with the oscillator, I also built the twin-T notch filter and amplifier. I used that to verify the performance of the oscillator.
I have also made a fully balanced passive twin-T filter with XLR in and out. I use this to test the Audio Analyzer generator distortion.
I have also made a fully balanced passive twin-T filter with XLR in and out. I use this to test the Audio Analyzer generator distortion.