Universal drive

From: Eric Smith <eric_at_brouhaha.com>
Date: Fri Oct 2 18:43:22 1998

Tony Duell wrote:
> The advantage of the hardware PLL and clock synthesiser is that it's also
> possible to write the disks with the pulses in the right places. I've
> been thinking about making a 'universal' controller that can not only
> read obscure disks, but can also produce them.

No, if you oversample at a sufficient rate, writing disks is no problem
either. My suggested 8x the channel code rate should work fine; 16x or
more would obviously work fine but would be overkill.

Software PLLs are much easier to muck about with even than DPLLs in FPGAs.

If you're going to use a clock synthesizer (even though it is unnecessary),
you might as well simply use it for the sample clock at a multiple of
the channel code rate, and still do the data decode (or encode) in software.

Eric
Received on Fri Oct 02 1998 - 18:43:22 BST