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Re: Digital transfer of bird recordings from a MD to a PC ?

Subject: Re: Digital transfer of bird recordings from a MD to a PC ?
From: "Raimund Specht" <>
Date: Thu, 05 Jun 2003 09:13:27 -0000
Po-Jen Chiang wrote:
> I did a little research on these external audio interface. I think 
> Edirol/Roland products like UA-1D, UA-3D, UA-5 resample the 
digital signal
> because it could not sync to external clock of digital signal. 
That is, it
> resamples to 48k and then resample again to your desire sample 
rate such as
> 44.1k into the computer. Even 48k digital signal, it still 
resamples. Thus,
> not bit-perfect.

I just did a quick test with my Edirol/Roland UA-30. I generated a 
synthetic sine signal with a constant frequency of 12 kHz and saved 
it into a .wav file with a sampling rate of 48 kHz. The resulting 
binary pattern of the resulting sound file is very simple and can be 
easily verified (the binary sequence is : 0, +16383, 0, -
16383, ...). I transferred that file onto my SONY TCD-D3 DAT 
recorder (sampling rate 48 kHz) via the SP/DIF optical out of the UA-
30 (sample rate selector set to 48 kHz). I then played that test 
signal back and recorded it via the UA-30 digital interface (with 
the recording software set to 48 kHz). The resulting .wav file 
showed very minor changes only. I  found some deviations in the 
least significant bit of some samples (the binary value changed from 
0 to -1  or from 16383 to 16382). This corresponds to a very small 
attenuation. Both long-term spectra and spectrograms of the re-
recorded test signal did not show any significant distortions. There 
was no phase shift over time, which means, that the clock 
synchronization worked fine. However, there were some strong 
distortions during the first 250 milliseconds after starting the 
recording process on the computer. The synchronization circuit seems 
to require that time until it works properly.

Raimund Specht

Avisoft Bioacoustics


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