[sdiy] converting data to audio... (WAY OT, sorry)

[Jaco Sloof]

actually, the standard NAG with all MD-recorders is that if you
record a sound using the digital In, you cannot play it back thru a
<optional> digital out, due to copyright infrigment or something...
to prevent an album from being copied lossless all the time, so
eventually the audio will have so much breakdown it is not
interesting anymore to copy it...

(workaround, use goldplated connectors on analog out with VERY short
wire, run it thru toslink module and voila, almost zero audio-quality
loss... hehe, lets see if sony/sharp/whatevercompany likes that...)

but to get back on the story... actually, i put a scope on my NOT
hacked Sharp MD-MT15 analog out, and measured fft and it was the same
as the inputwave... a squarewave is hard to screw up....
(just the ramps are a little bit off, but frequency keeps intact...)

more specs:
MD input is square wave, 1v + to 1v -, straight from the pc-speaker
with about 1/2 foot of wire attacked in between, gold plated 3.5 mm
stereo connector (internal mono)
Spacing frequency on "bleeps" generated by qbasic = 1234 Hz...
(i used the funny spacing freq to prevent fft from seeing
harmonics as the actuall wave, just in case...
(do square waves actually HAVE harmonics?))

now the real task is to get something usefull out of the recorded
bleeps... 
ok, anybody know of any fft-routine for qbasic v1.1 and adding a nice
soundblaster routine for mic in/line in?

or should i step off the whole idea and use a different method of
using the md as data storage device, like some sort of morse code, or
even worse, phase modulation? (soundblaster drivers needed 4 qbasic
1.1?)

i hope this mail clears things up...

 
--- James Husted <james at ersatzplanet.com> wrote:
> All my MD recorders have an optical in. I would imagine that it
> would be the
> easier input to use. No need to convert to audio at all. Now I must
> admit
> that most portable MD players don't have the optical outs needed to
> playback
> the data, but the console units do. The new Sony Viao MX series of
> desktops
> has a MD recorder (a 32X version at that) built in. Maybe it will
> be offered
> as an add on later (can't find it as one on their site now).
> -J
> 
> -- 
> James Husted                        The ErsatZ Planet
> james at ersatzplanet.com           www.ersatzplanet.com
> 
> "Welcome to the first day of the rest of your money."
> 
> 
> > ""-----Original Message-----
> > ""From: Jaco Sloof [mailto:jacosloof at yahoo.com]
> > ""Sent: Wednesday, January 02, 2002 9:43 PM
> > ""To: SynthDIYmailinglist
> > ""Cc: jacosloof at yahoo.com
> > ""Subject: [sdiy] converting data to audio... (WAY OT, sorry)
> > ""
> > ""
> > ""Greetings DIYers,
> > ""
> > ""JUst in case you're the fast "check-ot-and-delete-if"-mail
> reader,
> > ""then click delete now...
> > ""
> > ""else? here's the lineup of the problem at hand...
> > ""
> > ""I have an MD-player (minidisk) and i heard that a 80 minute MD
> > ""can hold up to 180 MB of uncompressed data (that is, NOT
> screwed up b
> > ""the atrac3-algorythm).
> > ""
> > ""I also have LOTSA stuff on my computer (ea: e-mail, and
> > ""musicprograms)
> > ""that i want to save to this MD using ehh, i dunno...
> > ""
> > ""What i have done so far:
> > ""1.0 --> made nifty little program (qbasic.exe v1.1 , the 1 that
> came
> > ""with dos 6.22) that takes file (zip/ace/arj/rar/whatever)
> > ""and converts/saves this into a ASCII7-file (that is, 1
> character in
> > ""file is 7bit,thus readeable)
> > ""2.0 --> made routine to convert "any" 0-127 bitvalue (ea ascii7
> > ""character) to a frequency, and beep it thru the PC-speaker
> using
> > ""SOUND freq%, durationinclockticks%: SOUND fixedbeep%,
> halfsecond%
> > ""(any basicker (spell check?) knows what im talking about now)
> > ""
> > ""so the sound sequence consists of:
> > ""2.1 a frequency containing 1 character out of the file...
> > ""2.2 short pause...
> > ""2.3 a fixed frequency (beep) as a separator, to indicate that a
> new
> > ""character is coming, or has came...
> > ""
> > ""ok, so i put the bleeps of whatever.zip) on MD...
> > ""
> > ""how can i retrieve the data that is on MD?
> > ""(yes i have a soundcard, with a good line-in)
> > ""
> > ""i am willing to deviate from the basic, just as long as i wont
> be
> > ""needing to learn an entire new programming language to do so...
> > ""Tbasic is as far as i go (thats no big deviance right...,
> sorry)
> > ""
> > ""any help is appreciated, so thanx in advance...
> > ""
> > 
> > 
> > ---------------------------------------------------------
> > This message has been scanned for viruses by MIMESweeper.
> > 
> > Wiadomosc zostala sprawdzona pod katem wirusow przez
> > oprogramowanie MIMESweeper.
> > 
> > 
> 


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