Decoding Flux Information
#8
That information is not very accurate.  The bitcell time base is different for every disk format.  A 1.44MB disk uses 2us/3us/4us for the bitcell times.  However, the bitcell times for a 720K disk are 4us/6us/8us.  A FM disk (like your TI/99-4A) is 4us/8us, with only two zones - not 3 like MFM or GCR have.  Every single flux transition is known as a "bitcell", which represents the duration of the flux transition.  If you look at the DISPLAY FLUX option in SuperCard Pro's editor/analyzer, you will see the number of bitcells for the track, and the index to index time.  These numbers should be extremely close, and vary only by the amount of drive speed fluctuation.

There is source code available for decoding FM disks for SuperCard Pro image format, and even for driving the hardware directly.  "a8rawconv" will convert Atari 400/800 FM  disks, which use the same format as TI/99-4A disks.  You can download the executable and source code here:

http://atariage.com/forums/index.php?app..._id=411198
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Messages In This Thread
Decoding Flux Information - by Relayer - 02-15-2016, 07:12 PM
RE: Decoding Flux Information - by admin - 02-15-2016, 09:10 PM
RE: Decoding Flux Information - by Relayer - 02-16-2016, 08:27 AM
RE: Decoding Flux Information - by admin - 02-16-2016, 10:30 AM
RE: Decoding Flux Information - by Relayer - 02-16-2016, 12:37 PM
RE: Decoding Flux Information - by admin - 02-16-2016, 02:49 PM
RE: Decoding Flux Information - by Relayer - 02-17-2016, 01:43 PM
RE: Decoding Flux Information - by admin - 02-18-2016, 08:43 AM



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