24 bit 192kHz is a real misnomer. I can't think of any affordable 24bit A/D
that goes anywhere near that speed. "Real" converters that can put out a
real 24bits are only good for a few kHz (the last time I looked)
Audio "type" converters have a 24bit output word, but typically about 5 of
those bits are marketing bits. Look at the SNR and DR of the ADC for the
real story.
I don't think you'll have any luck VCing (by varying the clock) a
delta-sigma converter anyway. They almost all have internal PLLs that
wouldn't like a radically changing clock and many of them have async timing
inside that is very dependant on specific external frequencies. They figure
out what the external freq is and make timing adjustments.
If you want to use variable clocks, you're better off doing it the old
fashioned way (think Deltalab gear)
Tony
> -----Original Message-----
> From: paulhaneberg [mailto:phaneber@...]
> Sent: Tuesday, February 26, 2002 6:42 PM
> To: motm@yahoogroups.com
> Subject: [motm] Re: Delay Module
>
>
> 24 bit would certainly have improved sonic quality over 16 bit, but I
> think you could probably get a bigger variation in clock speeds with a
> 16 bit. If the converter is less complex the actual conversion would
> be quicker assuming a succesive-approximation type converter. I don't
> know what the highest number of bits available in a flash converter
> is, but presumably this could be clocked at higher speeds (up into the
> MHz range) There are 24 bit converters available that can convert at
> 192 kHz, but cost is an issue. Another possibility is to use a
> one-bit converter at even higher clock speeds.
> I would definitely use a filter at a low fixed frequency like 20kHz.
> One of the pitfalls of this module ideas is that in order to be truly
> musically useful the voltage to frequency conversion for the clock
> must be very accurate over a wide range. I'm not sure how possible
> that is in the MHz region.
> Multiple taps are easily implemented. A range of delay times from
> very short to reasonably long could be available. This is simply a
> function of the amount of RAM.
> Even 12 bits would probably be an improvement over an analog delay.
> I think a module of this sort would be very useful and popular as long
> as the cost was not too high.
> At some point I will probably try to build this thing and find out.
>
>
>
>
>
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