dave@onfcanim.UUCP (08/16/87)
I'm looking for information on how to extract the data from the
signal that is fed to the "digital output" jack of my Philips (Magnavox)
CDB 650 CD player.
Looking at the signal on an oscilloscope, it appears to consist of a framing
pulse, and then a block of bits transmitted using a simple modulation
technique. I want to know:
1) how to build a circuit that will find the framing signal and then
demodulate the data into an N-bit parallel word plus strobe ready
to be connected to a computer parallel interface
2) how to interpret the various bits that I get from this. Most of them,
of course, are audio data, but there should also be an "uncorrected
error" flag, and maybe subcode information.
3) how to build a simple FIFO buffer to sit between the decoder
circuitry and the "host" computer, since the computer
will accept data in bursts.
The idea is to obtain high-quality digital audio to experiment with
(e.g. using the Fourier transform to look at the frequency spectrum)
without the cost of analog-to-digital conversion hardware.
I'd appreciate pointers to code standards, circuitry, or anything else
that seems relevant.
Dave Martindale
{watmath,musocs,micomvax}!onfcanim!daveczei@osupyr.UUCP (Michael S Czeiszperger) (08/18/87)
In article <15368@onfcanim.UUCP> dave@onfcanim.UUCP (Dave Martindale) writes: >I'm looking for information on how to extract the data from the >signal that is fed to the "digital output" jack of my Philips (Magnavox) >CDB 650 CD player. > >Looking at the signal on an oscilloscope, it appears to consist of a framing >pulse, and then a block of bits transmitted using a simple modulation >technique. I want to know: > >I'd appreciate pointers to code standards, circuitry, or anything else >that seems relevant. > Try looking up the AES/EBU digital audio standard. Your CD player probably is using that format, and it can be found at your closest Audio Engineering Society reference source. Michael S. Czeiszperger | Disclaimer: "Sorry, I'm all out of pith" Sound Synthesis Studios | Snail: Room 406 Baker Phone: (614) College of the Arts Computer Lab | 1971 Neil Avenue 292- The Ohio State University | Columbus, OH 43210 0895 UUCP : {decvax,ucbvax}!cbosgd!osupyr!czei