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Old 16th January 2014, 03:35 AM   #21
1audio is offline 1audio  United States
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Richard-
I'm not sure what you are driving towards. I have posted a way to confirm level accuracy at these low levels while making distortion measurements. Verifying ultra low distortion is extremely difficult. If you know your source is clean you can then verify the harmonics using the above techniques. I would use a CLT-1 and see what I get at the higher harmonics since its the only device I know if that is essentially free of HD3 and up. But its really clumsy to use.
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Old 16th January 2014, 05:11 AM   #22
RNMarsh is offline RNMarsh  United States
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Its easy question --- how good/accurate is the data at or near and below -100dB being shown by anyone here?

After looking at QA400, all are now suspect to me. [Unless they use a notch filter, I dont trust any of them down there]

Thx-RNMarsh

PS -- hope the CES was fun and good for you. Glad you are back. :-)

A-P 2722 internal source-analyzer loop:

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Old 16th January 2014, 09:13 AM   #23
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Just a thought: has anyone here ever used a lock-in amplifier to verify these low level harmonics?

Jan
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Old 16th January 2014, 01:15 PM   #24
davada is offline davada  Canada
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Quote:
Originally Posted by jan.didden View Post
Just a thought: has anyone here ever used a lock-in amplifier to verify these low level harmonics?

Jan
Can you describe a procedure using a lock in amp?

David.
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Old 16th January 2014, 01:36 PM   #25
Shinja is offline Shinja  Japan
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I am planning to make 3stage cascaded twin-T notch filter...
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Old 16th January 2014, 01:53 PM   #26
davada is offline davada  Canada
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Very cool. Let us know how it works out.



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I am planning to make 3stage cascaded twin-T notch filter...
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Old 16th January 2014, 02:09 PM   #27
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by jan.didden View Post
..... has anyone here ever used a lock-in amplifier to verify these low level harmonics?.....
Quote:
Originally Posted by davada View Post
Can you describe a procedure using a lock in amp?
...................
What is a "lock-in amplifier"
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Old 16th January 2014, 04:36 PM   #28
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Sorry, I didn't realise you guys were internet-challenged
Lock-in amplifier - Wikipedia, the free encyclopedia

Jan
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Old 16th January 2014, 05:17 PM   #29
davada is offline davada  Canada
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Quote:
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Sorry, I didn't realise you guys were internet-challenged
Lock-in amplifier - Wikipedia, the free encyclopedia

Jan

No just lazy.

I know what a lock in amplifier is just not sure what you have in mind for test.
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Old 16th January 2014, 05:32 PM   #30
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Quote:
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No just lazy.

I know what a lock in amplifier is just not sure what you have in mind for test.
Ehhh? EMU 1212M for measurements

Jan
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