At 22.03 23/02/2006, you wrote:
...[snip]
>Relatively inexpensive portable high sampling rate consumer Ato D interfac=
es
>or digital recorders suggest this sort of investigation is now more
>affordable
>(assuming a suitable microphone), but, as Gianni and Raimund have shown he=
re,
>the antialiasing in the devices they've tested is, unfortunately,
>designed for
>audio range input.
This is not completely true. Some devices running at 96 and 192 kHz
have sharp a-a filters at both frequencies, but others have good
filters at 96 kHz and very smooth (bad) filters at 192 kHz. In some
192 kHz devices I also found a frequency response smoothly falling
above 40-50 kHz.
Thus it is important to carefully test the devices before completely
trusting in their specifications.
I'll try to publish some tests soon.
Gianni
--------------------------------------------------------------
Gianni Pavan
Email
Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
Universita' degli Studi di Pavia
Via Taramelli 24, 27100 PAVIA, ITALIA
Tel +39-0382-987874
Fax +39-02-700-32921
Web http://www.unipv.it/cibra
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