SD722 frequency response and aliasing @ 192k

Dan Dugan wrote:

>>As I recall they're good to at least 50K.
>found it:
>http://www.sounddevices.com/tech/7series-bandwidth.htm
>Looks like 3 dB down is around 100K.

Dan, I think that the above frequency response plot applies to the analog
preamplifier circuit only. The effective frequency response of a recorder i=
s
determined by the combination of the frequency responses of both the
preamplifier and the A/D converter at a certain sample rate.
I measured the approximate frequency response of the 722 at the 192kHz
sample rate by using a sine signal sweeping from 6 to 128 kHz (fed into the
LINE input):

http://www.avisoft.com/scratch/alias_722.gif

The response I got is very similar to the published response of the Cirrus
Logic A/D converter product family CS53xx at quad speed mode:

http://www.avisoft.com/scratch/alias_CS53xx.jpg
(taken from http://www.cirrus.com/en/pubs/proDatasheet/CS5381_F2.pdf , page
9)

So, I would agree with your initial suggestion that the SD722 is good to at
least 50kHz (at -10dB). However, aliasing can occur above about 60kHz.

Regards,
Raimund Specht
Avisoft Bioacoustics
http://www.avisoft.com

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