[EMAIL PROTECTED] wrote:
>
> currently i am involved in a research project in my computer engineering
> studies to allow a home audio md unit (je510 initially... same process for
> others) to store data and audio on the same disc.. if this conversion was
> patented and fairly cheap, do you all feel there is a market for this? it
> would use the audio discs and pass data through the serial port at
> 150Kbps. single speed cd... there is also the possibility of speeding up
> the drive itself... like with using the new quad speed ones.... sound
> good?
1) Sony already did it... It's called MD-Data. MD-Data uses a slightly
different disc than MD-Audio. A necessity since storing data on a
disc requires a diffent TOC structure than storing audio.
But the unit didn't catch on. It was limited to 150kB/s transfer speed,
used the expensive SCSI interface and it came to late on the market,
(around the same time as the inexpensive ZIP-drive!).
2) I think it would be possible to store data on a audio disc using the
analog interface.. Use two frequencies, one for '0' and one for '1'. Or
use four frequecies, one for '00', '01', '10' and '11'. You should be
able to build a device that converts bits into frequencies and store these
frequencies. But I don't think you'll be able to use the disk-space on
an MD very efficiently.
Here's an example of a storage algorithm (using harmonics since they:
'0000' == 1 kHz
'0001' == 2 kHz
'0010' == 3 kHz
'0011' == 4 kHz
'0100' == 5 kHz
'0101' == 6 kHz
'0110' == 7 kHz
'0111' == 8 kHz
'1000' == 9 kHz
'1001' == 10 kHz
'1010' == 11 kHz
'1011' == 12 kHz
'1100' == 13 kHz
'1101' == 14 kHz
'1110' == 15 kHz
'1111' == 16 kHz
maximum transfer rate equals 4 bits * 1 kHz == 4kbits/second = 500
bytes/second...
or combining it with a key frequency:
'00000' == 1 kHz
'00001' == 2 kHz
'00010' == 3 kHz
'00011' == 4 kHz
'00100' == 5 kHz
'00101' == 6 kHz
'00110' == 7 kHz
'00111' == 8 kHz
'01000' == 9 kHz
'01001' == 10 kHz
'01010' == 11 kHz
'01011' == 12 kHz
'01100' == 13 kHz
'01101' == 14 kHz
'01110' == 15 kHz
'01111' == 16 kHz
'10000' == 1 kHz + 17 kHZ
'10001' == 2 kHz + 17 kHZ
'10010' == 3 kHz + 17 kHZ
'10011' == 4 kHz + 17 kHZ
'10100' == 5 kHz + 17 kHZ
'10101' == 6 kHz + 17 kHZ
'10110' == 7 kHz + 17 kHZ
'10111' == 8 kHz + 17 kHZ
'11000' == 9 kHz + 17 kHZ
'11001' == 10 kHz + 17 kHZ
'11010' == 11 kHz + 17 kHZ
'11011' == 12 kHz + 17 kHZ
'11100' == 13 kHz + 17 kHZ
'11101' == 14 kHz + 17 kHZ
'11110' == 15 kHz + 17 kHZ
'11111' == 16 kHz + 17 kHZ
maximum transfer rate equals 5 bits * 1 kHz == 5kbits/second = 625
bytes/second...
You could use an even better schema, (including 18kHz as another frequecy,
Ie, 1 extra frequency, gives two more bits, ie 7kbits/second = 875
bytes/second..
, include 19 kHz, gives three more bits, ie 8kbits/second == 1 kbytes /second.)
Ie,
it's possible, but I don't think you'll reach higher than modem speeds. And it
will
take quite some DPS power.
I don't really believe that the ATRAC algorithm will destroy the data. Hell,
I bet you could even use the schema above usign two, three or even four
different
amplitudes for your data. This would give you even more bits...
Cheers,
Ralph -> good luck. (I think you need it!)
--
=======================================================================
Ralph Smeets Functional Verification Centre Of Competence - CMG
Voice: (+33) (0)4 76 58 44 46 STMicroelectronics
Fax: (+33) (0)4 76 58 40 11 5, chem de la Dhuy
Mobile: (+33) (0)6 82 66 62 70 38240 MEYLAN
E-Mail: [EMAIL PROTECTED] FRANCE
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"For many years, mankind lived just like the animals. And then some-
thing happened that unleashed the powers of our imagination: We learned
to talk."
-- Stephen Hawking, later used by Pink Floyd --
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