On Sat, 11 Sep 2004, Tom Jennings wrote:
On Sat, 2004-09-11 at 14:42, John Lawson wrote:
I was assuming PC audio cards would not be fast enough. I am an analog
person too, but not to your extent of expertise.
What can the actual drum clock be... I dunno... another reason to slow
the drum; see below further...
The disk has one (or a few) timing tracks. I assumed I would record the
timing track plus a data track; hence all recordings would have a
reference. A stereo sound card would do this. There's no physical index
pulse, it's derived from disk data. I haven't looked at the timing data
for over a year, I need to RTFM before I open my mouth any more.
If you could trigger a simple pulse to SMPTE converter, and if the data
rate of the "index" pulse is slow enough, then your synce problems get
solved... SMPTE can resolve 30/100 of a second, BTW - 100 'subframes'
per video frame at 30fps - the highest video rate SMPTE was designed for.
And yes, the FM needs to be consulted.
[Aside: I always wanted to have a manual entitles: "The Book of
Armaments"]
if you
could get a 'whole drum after this pulse' (sort of like capturing one
video frame) sync set up, then you could record each track onto a similar
parallel track in the DAW....
1) I figured I could capture N seconds, to get N * 1/RPM copies of data,
and pick the timing::data out.
2) What's "DAW"?
Sorry. Digital Audio Workstation. I lapsed into AudioSpeak by habit.
Another choice is to simply disable writing electrically, and use the
computer itself. The biggest worry (at this point) is head/platter
issues. THe heads contact at rest, then lift. The mechanical issues
exist no matter the data-recovery method.
Yeah. I'd intercept the 'lift' line and do that manually. before spin-up,
if this is at all possible.
Well the problem as I see it is deterioration of the magnetic
surface/circuit, and changing motor speed won't improve that (probably).
Lost data is secondary to a lost timing track! That would be ruinous, I
have no idea how I'd re-create that. Certainly, I need a copy of that.
On a system this old, with (relatively) large data tracks, I think that
there would probably be recognizable pulses at slower speeds...
Anyway, just Thoughts...
Cheerz
John