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View Full Version : SB2 really doesn't support 96kHz PCM on S/PDIF?



Patrick Dixon
2005-03-16, 03:55
Phil, are you seriously saying that you can design a 'brick-wall'
reconstruction filter at the Nyquist rate (fs/2)?

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com]On Behalf Of Phil Karn
Sent: 16 March 2005 10:19
To: Slim Devices Discussion
Subject: [slim] SB2 really doesn't support 96kHz PCM on S/PDIF?


Kim Rochat wrote:
> I've been waiting for a wireless-G version of the Squeezebox on the
> assumption that it would support PCM sampling rates greater than 48kHz,
> but reading the specs for the SB2 says that the digital outputs only
> support 44.1 and 48. Is this really true? If so, I'll have to wait for
> an SB3.

Do you seriously claim that you can hear sounds above 24 KHz? All the
way up to 48 KHz? Or are you trying to entertain your dog?

--Phil

Phil Karn
2005-03-16, 09:40
Patrick Dixon wrote:
> Phil, are you seriously saying that you can design a 'brick-wall'
> reconstruction filter at the Nyquist rate (fs/2)?

With reasonably modern DSP techniques such as those employed in most
modern DACs, yes. It's not *totally* brick-wall because all such filters
are impossible, but it is a very good approximation.

All it takes to provide an excellent LPF is a FIR filter with enough
taps, and this is again readily doable with modern DSP hardware and
oversampling so that the final analog filter can be trivial.