[sdiy] BLIT/BLEP virtual analogue synthesis

[ASSI]

On Wednesday 04 August 2010, Olivier Gillet wrote:
> Would it be a stupid idea to get away with the downsampling, put
> instead a sigma-delta loop and just output a bit at, say, 8 Mhz, so we
> could also get away with the DAC and just put a simple analog low-pass
> on this bitstream?

Sampling rate is not the same as the bit rate of a single bit delta-sigma 
modulator, which necessarily oversamples the signal to achieve resolution.  
SACD/DSD uses 2.8MHz bit rate, as you probably know.

> Am I wrong to suspect that the very first thing a
> modern audio DAC would do with the signal you have carefully
> downsampled to 48 kHz, is to upsample it back to several MHz for
> sigma-delta conversion?

No, it certainly needs to do that, see above.


Achim.
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