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Old 18th January 2005, 06:30 AM   #1
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Default how is it measuring?

MINASAN KONNICHIWA

how is it measuring?
my measuring ,play test CD and am measuring a spot with the distortion-analyzer.
It is only 1KHz and 10KHz.

I can not buy the AP and RS.

:bawling:
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Old 18th January 2005, 11:14 AM   #2
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Default Re: how is it measuring?

Quote:
Originally posted by fumihiko
I can not buy the AP and RS.
Ebay spectrum analyzer can find for cheaper.
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Old 18th January 2005, 02:33 PM   #3
banana is offline banana  Hong Kong
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I suggest RMAA and a decent soundcard, such as "ESI Wave Terminal 192X" or "Echo MIA".
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Old 18th January 2005, 03:00 PM   #4
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I am afraid a soundcard is limited to 20kHz ???
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Old 18th January 2005, 03:27 PM   #5
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KONNICHIWA banana SAN
Quote:
I suggest RMAA and a decent soundcard, such as "ESI Wave Terminal 192X" or "Echo MIA".
I tried RMAA wirh Roland UA-30 but,can not measuring DAC
It measured the performance of ADC
To measure surely, the performance of ADC becomes a problem.



thanks
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Old 18th January 2005, 11:27 PM   #6
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If you like to measure 0dB signal you will have big problem because distortion is very low and maybe souncard is worse.
If you use standalone analyzer you need one with 100dB dynamics which cost $$$$$

Better use -60dB signal from Pedja`s website.

I have Nicolet 446B with only 75dB dynamics and works fine.
New DAC measurement
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Old 19th January 2005, 07:23 AM   #7
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A -60 dB test tone will tell you a lot more about your DAC than a 0 dB tone.

Jocko
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Old 19th January 2005, 08:28 AM   #8
banana is offline banana  Hong Kong
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I don't have very good experience with stand alone Dynamic Signal Analyzer, the oldish HP analyzer in my work place seems to have too high noise floor.

But I have good results working with HP8903B analyzer. Though no FFT feature, its low noise preamp allow me to see -90dBFS signal. Below is the -90dBFS signal from my diy AD1853 DAC, 30KHz bandwidth, ignore vertical scale.
Click the image to open in full size.

And I'm planning to build a diy low noise preamp and a 30KHz LPF, so that I can skip the 8903.
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Old 19th January 2005, 12:17 PM   #9
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HI Banana,

this looks like only last two bits are switching.
Measuring such a signal is useless, exept maybe for MSB adjustment, but not to see the result.
-60 dB is better.

Click the image to open in full size.
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Old 19th January 2005, 01:28 PM   #10
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KONNICHIWA Bernhard SAN

I try again measurement with +20dB amplifier and Roland UA-30.

-60dB 997Hz sin-wave 16bit/44.1KHz input,
It is a result of measurement.
The vertical scale,please subtract 20dB.


The result of measurement is very good.

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