Hi Samual, --
thank you for giving us a window setting we can have confidence in.
David and Demian.... do you have ability to use Flat Top or rectangle or 'none' ??If so, would you repeat your tests with Flat Top?
THx-
Drums had too short a range David, so they had to use smoke signals.
I guess you then, for arguments sake say the father of modern
digital communications are Samuel F. B. Morse, along with
Joseph Henry and Alfred Vail. Morse profited heavily from
it, I don't know aobut Henry and Vial. The Morse family used
to own Pebble Beach, CA.
Any of us could have purchased it all right after Pearl Harbor as nothing
would have, could have stopped the invasion of Japaneese forces.
There were sightings off the coast then. Rumors of a sub breaking up
south of there and bombers crashing in the Los Padres National Forest.
It is so desolate they still find WWII lost planes in there.
The answer is "42". Please bring your towel.
Somewhere in there is a lost gold mine and I think a silver mind
that has never been rediscovered.
I guess you then, for arguments sake say the father of modern
digital communications are Samuel F. B. Morse, along with
Joseph Henry and Alfred Vail. Morse profited heavily from
it, I don't know aobut Henry and Vial. The Morse family used
to own Pebble Beach, CA.
Any of us could have purchased it all right after Pearl Harbor as nothing
would have, could have stopped the invasion of Japaneese forces.
There were sightings off the coast then. Rumors of a sub breaking up
south of there and bombers crashing in the Los Padres National Forest.
It is so desolate they still find WWII lost planes in there.
The answer is "42". Please bring your towel.
Somewhere in there is a lost gold mine and I think a silver mind
that has never been rediscovered.
Well I looked around but my oscillator seems to be missing.
Yes ARTA has FlatTop.
I also have SpectraPlus and see no disagreement there.
I posted a demonstration of that yesterday of the 339A
Noticeable but not much difference. Agrees with the table I linked to.
Richard here us info from Bruce himself.
AP High Performance Audio Analyzer & Audio Test Instruments : Service & Support
http://www.ap.com/kb/show/170
You may have to add the correction factors in manually according to this. However this is for a different model.
AP High Performance Audio Analyzer & Audio Test Instruments : Service & Support
http://www.ap.com/kb/show/170
You may have to add the correction factors in manually according to this. However this is for a different model.
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Read it carefully. Measuring random noise is the discussion. Measuring discrete tones is what its normally targeted at. The correction factors are for noise.
I have a Wavetek FFT that has a noise measurement mode (in rtHz) that I use. Anything else has too many ways for confusion and mistakes.
I have a Wavetek FFT that has a noise measurement mode (in rtHz) that I use. Anything else has too many ways for confusion and mistakes.
Yes I know it for noise measurements. Richard is getting change on both. If a noise correction factor changes the tone as well something is wrong with the AP.
Some of the choices.... wider filtering would increase noise level on data display:
Click on these and blow them up to read.
View attachment WINdows1.pdf
View attachment Windos2.pdf
View attachment Windows3.pdf
View attachment Windows4.pdf
View attachment Windows5.pdf
THx-RNMarsh
Click on these and blow them up to read.
View attachment WINdows1.pdf
View attachment Windos2.pdf
View attachment Windows3.pdf
View attachment Windows4.pdf
View attachment Windows5.pdf
THx-RNMarsh
And then there is this possibility ---
View attachment Windows6.pdf
THx-RNMarsh
PS -- The ShibaSoku AD725D has put its accuracy of harmonic level measurement at a guaranteed Spec of +/- 1dB If the harmonics are not too low to be read, then it will be accurate numbers.
View attachment Windows6.pdf
THx-RNMarsh
PS -- The ShibaSoku AD725D has put its accuracy of harmonic level measurement at a guaranteed Spec of +/- 1dB If the harmonics are not too low to be read, then it will be accurate numbers.
I don't get what your pointing to. You stated in an earlier post you are seeing 6 to 9dB difference between flattop and hann. That's way too much and what you have above supports that. Therefore something is wrong.
I said also that the average level difference is 4-5dB. Thats after tweeking the sample rates and steps et al. That seems realistic from what I read.
However, which is the most accurate one for measuring single sine wave for harmonic level.... Hann? As you and Demian are using? Or, A-P's Flat Top as I was suggested to use by A-P and is stated in their literature I showed above. and as Samuel seems to suggest using as well for amplitude accuracy. I think I will stick to using what A-P says to use. So there will be data difference between us if you dont want to use Flat Top Windowing.
I would need the 725D to be very different from the A-P before spending money to see if there is a problem with the A-P. When I had the 725D with me and compared, they agreed.
THx-RNMarsh
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I've read this before. Interesting.. however, I dont really care about the noise level shifts with Windowing and A-P's approach to measuring. I accept it and would only need to get into it if I wanted to know the real noise level. But there are easier ways to measure wide band noise than deriving it from FFT/windowing etc. A more direct measure is useful. This only leaves the 'true' level of the harmonics to know and be certain of. After this, all will go smoothly.
THx-RNMarsh