5 Jul
2000
5 Jul
'00
3:39 a.m.
True, but if he's only reading, the present frequency is plenty. The
assumption is that the write precomp on the already-written media is
sufficient. If it's not the data might never have been readable.
Dick
----- Original Message -----
From: <allisonp(a)world.std.com>
To: <classiccmp(a)classiccmp.org>
Sent: Wednesday, July 05, 2000 6:59 AM
Subject: Re: Tim's own version of the Catweasel/Compaticard/whatever
<snip>
> I will admit, MFM *does* require at least twice
the timing resolution of
FM.
> I once got in a small argument with some other
members of this list
about
> AC circuit design of MFM vs FM data recovery
circuits. IIRC, they were
> insisting that MFM did come "for free" if you had the frequency response
> necessary for FM at half the data rate. My point was that it
> wasn't the max pulse frequency which made life difficult, it was the
phase
> response (finding where the pulse occured in the
window) that was the
tough
point.
Also since precomp ranges from .0625uS to as long as .375uS the ability
to slice a bit finer is a desireable thing.
Allison