25 Nov
1998
25 Nov
'98
6:12 a.m.
Mark[SMTP:mark_k@iname.com] sez:
I have many old computer cassettes, and have been
thinking of
recording them onto a computer in order to preserve their
contents. The signal from computer tapes oscillates between
two levels, right? This being the case, it should be possible
to record them using 1-bit sampling. Perhaps record with 8- or
16-bitsampling and then convert down to single bit.
Are there any programs to do this conversion? I imagine the
equivalent of a Schmitt trigger (in software) would work. What
about playing back a 1-bit audio signal? Are there any standard
audio file formats that can be used to store 1-bit data?
Well, there were/are many formats to put data onto tape, the only
one I'm famalier with is as you said a FSK or frequency shift
keying, using one tone for a mark or '1' and another for a space
or '0'. See http://www.threedee.com/jcm/audio/index.html
for some work in this area.
Actually recording tapes to audio CDs is quite wasteful
since
you can only get 70 minutes or so on a CD (an issue if you have
Yeah 44100Hz/16/stereo eats up space perdy quick, which is why
I'd like to try or hear from someone whose tried the various
levels of RealAudio or open std. MP3 compression - using those
one can get hundreds of hours of 'not bad' audio on a single CD.
(e.g., one 30 minute radio program = about 5Mb of MP3).
Chuck
cswiger(a)widomaker.com
P.S. Nerds 2.0.1 on PBS tonight