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From: Mahen K on 29 Jan 2010 08:21
I am trying to build a USB sound card and trying to finalize the
specs. It will have USB to I2S converter (part of PCM2706) connected
to DAC. Since PCM2706 is only doing USB to I2S format conversion,
samples (WAV) and sample rate (16 bit, 48Khz) remain unchanged. Shall
I safely take that PCM2706 USB-I2S conversion will not alter the
following parameters before passing the digital audio to the DAC.
(assuming no jitter)

THD+N
Noise Floor
Dynamic Range
SNR

Thanks
-m
From: Jeroen Belleman on 29 Jan 2010 09:01
Mahen K wrote:
> I am trying to build a USB sound card and trying to finalize the
> specs. It will have USB to I2S converter (part of PCM2706) connected
> to DAC. Since PCM2706 is only doing USB to I2S format conversion,
> samples (WAV) and sample rate (16 bit, 48Khz) remain unchanged. Shall
> I safely take that PCM2706 USB-I2S conversion will not alter the
> following parameters before passing the digital audio to the DAC.
> (assuming no jitter)

Of course. That's the beauty of digital. As long as you don't change
the numbers, signal quality is preserved perfectly. Aren't you in
over your head a little if you need to ask such questions?

Jeroen Belleman
From: Ban on 29 Jan 2010 09:13

"Mahen K" <mahen.jnk(a)gmail.com> schrieb im Newsbeitrag
news:794465ef-9a02-4379-a6b1-3a0060bbcf0d(a)t34g2000prm.googlegroups.com...
>I am trying to build a USB sound card and trying to finalize the
> specs. It will have USB to I2S converter (part of PCM2706) connected
> to DAC. Since PCM2706 is only doing USB to I2S format conversion,
> samples (WAV) and sample rate (16 bit, 48Khz) remain unchanged. Shall
> I safely take that PCM2706 USB-I2S conversion will not alter the
> following parameters before passing the digital audio to the DAC.
> (assuming no jitter)
>
> THD+N
> Noise Floor
> Dynamic Range
> SNR
>

A bit is a bit is a bit. You can degrade the quality by bad layout, which is
the analogue part of the task, but if you just migrate the hardware to the
dongle or whatever it should do a decent job. Of course the supply has to be
well decoupled and filtert.
ciao Ban


From: MooseFET on 29 Jan 2010 09:23
On Jan 29, 5:21 am, Mahen K <mahen....(a)gmail.com> wrote:
> I am trying to build  a USB sound card and trying to finalize the
> specs. It will have USB to I2S converter (part of PCM2706) connected
> to DAC. Since PCM2706 is only doing USB to I2S format conversion,
> samples (WAV) and sample rate (16 bit, 48Khz) remain unchanged. Shall
> I safely take that PCM2706 USB-I2S conversion will not alter the
> following parameters before passing the digital audio to the DAC.
> (assuming no jitter)

The "assuming no jitter" could turn out to be the place where your
design fails.
You need to make that "making sure to keep the jitter within the
specs"
The jitter of the timing is the one place where noise etc can sneak
into your
design. The digital signals cn be considered perfect except for this
issue.

The noise floor can be lost if you let the digital bits leak into the
audio
part of the design.

>
> THD+N
> Noise Floor
> Dynamic Range
> SNR
>
> Thanks
> -m

From: JosephKK on 31 Jan 2010 15:44
On Fri, 29 Jan 2010 05:21:19 -0800 (PST), Mahen K <mahen.jnk(a)gmail.com> wrote:

>I am trying to build a USB sound card and trying to finalize the
>specs. It will have USB to I2S converter (part of PCM2706) connected
>to DAC. Since PCM2706 is only doing USB to I2S format conversion,
>samples (WAV) and sample rate (16 bit, 48Khz) remain unchanged. Shall
>I safely take that PCM2706 USB-I2S conversion will not alter the
>following parameters before passing the digital audio to the DAC.
>(assuming no jitter)
>
>THD+N
>Noise Floor
>Dynamic Range
>SNR
>
>Thanks
>-m

That should be OK, however, you will need data buffering to deal
with the bursty, discontinuous nature of USB.
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