Does someone have that series of articles from Electronics World 2003 where Baterman is measuring some caps? What kind of like oscillator/measurement setup he uses for measurements?
Local university didnt have EW and closests library subscribing EW is beyond polar circle. Had to wait untill summer so that library is digged out of snow again and even then one has to run so fast to get rid of polar bears.
Local university didnt have EW and closests library subscribing EW is beyond polar circle. Had to wait untill summer so that library is digged out of snow again and even then one has to run so fast to get rid of polar bears.
Here is something related to capacitor distortions measurement:
http://www.ec.ss.titech.ac.jp/~hajime/uec/distortion/cap/
But in japanese
http://www.ec.ss.titech.ac.jp/~hajime/uec/distortion/cap/
But in japanese
Actually both circuitry and results as I am building low-distortion osc. Unless i manage to order photocopies I had to drive 500km to that libraryphase_accurate said:I think he is much more interested in the equipment than the outcomes.
CB did indeed build his own measuring equipment. This can be used for very accurate THD measurements of amps also. But it is fixed frequency only unfortunately.
Regards
Charles
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Vidalgo, thanks for link, at least i can guess from text and pics.
...at least i can guess from text and pics.
Goddammit, he has PCB-layouts but no schematics. And what worries me is the level of distortion what he measures from vima MKP. I tought that polypropylene is nearly as good as you can get. Maybe something to do with metallized vs. foil polyprop?
Goddammit, he has PCB-layouts but no schematics. And what worries me is the level of distortion what he measures from vima MKP. I tought that polypropylene is nearly as good as you can get. Maybe something to do with metallized vs. foil polyprop?
Cyril Bateman has made a full cd-rom with all his articles and more
The better would be to contact him directly, however his email has changed and I have been unable to write to him since one year.
Making copy of the whole of his writings or of his Cd-rom would be author's rights infringement. I think it is worth to spend a little money for such a serious work. Does anyone know how to contact Cyril ?
~~~~~~~~~ Forr
§§§
The better would be to contact him directly, however his email has changed and I have been unable to write to him since one year.
Making copy of the whole of his writings or of his Cd-rom would be author's rights infringement. I think it is worth to spend a little money for such a serious work. Does anyone know how to contact Cyril ?
~~~~~~~~~ Forr
§§§
Vidalgo said:Here is something related to capacitor distortions measurement:
http://www.ec.ss.titech.ac.jp/~hajime/uec/distortion/cap/
But in japanese
No big deal, traces and numbers speak a universal language: in this case click on the appropriate capacitor to see all you need to know. Just like ordering at a Chinese restaurant.
Cheers,
Francois.
forr said:Cyril Bateman has made a full cd-rom with all his articles and more
The better would be to contact him directly, however his email has changed and I have been unable to write to him since one year.
Making copy of the whole of his writings or of his Cd-rom would be author's rights infringement. I think it is worth to spend a little money for such a serious work. Does anyone know how to contact Cyril ?
~~~~~~~~~ Forr
§§§
Coudnt find anything related about ordering that cd, but luckily local polytech has EW subscription so I am going to head there for some reading. No need to go lapland then
Maybe something to do with metallized vs. foil polyprop?
AFAIR that was indeed one of his conclusions.
Regards
Charles
The better would be to contact him directly, however his email has changed and I have been unable to write to him since one year. Does anyone know how to contact Cyril ?
- send me a note via the addr from my web site
Coudnt find anything related about ordering that cd
- the cd exists, as I have all versions, but yes, "it is worth to spend a little money for such a serious work"
Skimmed trought that article series at library, tough measurement hardware was a bit disappointment. Linear's 180db feedback osc might be the way to go but I have been trying to avoid it as it is more than complex. At 1Khz you can get even more than 200db of feedback from that circuitry, so opamps are not the limiting factor in this.
Cap test results were easy to interpret, metal-foil polyprop is going to be my choice.
Cap test results were easy to interpret, metal-foil polyprop is going to be my choice.
with some trickery you can get a lot more than the basic specs suggest from a sound card
direct distortion meas is limited by source but nonlinearities may be "probed" by looking for intermod products from 2 simultaneous sine inputs of differing frequency but only modest quality
a low distortion narrow band amp can pick out the IM diffrence F while rejecting the 2 fundamentals and their harmonics - the narrow band filter can be fixed while you can sweep the probe frequencies as long as their IM difference falls in your filter's passband
as long as you can combine the 2 sines without IM - say generate them from seperate DAC channels, buffer and add resistively or in inverting summer
you could easily add 20-30 dB resolution by indirect methods, start with a LynxStudio card and your'e beating AP
direct distortion meas is limited by source but nonlinearities may be "probed" by looking for intermod products from 2 simultaneous sine inputs of differing frequency but only modest quality
a low distortion narrow band amp can pick out the IM diffrence F while rejecting the 2 fundamentals and their harmonics - the narrow band filter can be fixed while you can sweep the probe frequencies as long as their IM difference falls in your filter's passband
as long as you can combine the 2 sines without IM - say generate them from seperate DAC channels, buffer and add resistively or in inverting summer
you could easily add 20-30 dB resolution by indirect methods, start with a LynxStudio card and your'e beating AP
jcx said:
.... and your'e beating AP
Thats not so difficult as long as fixed frequency is enough. Wien bridge, 1khz -135db THD 1Vrms out with opa637. maybe even couple of db lower if i try hard enough
Yeah, your method has edge over "normal" thd measurement. Had to try it next to get below -160db
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