Hi, Nino!

If you dont need high density of information,
perhaps you can use a modem in a chip, like 74HC942
or MC145442/3 and attach it at the serial port of the PIC.

I think that you can record the 1200/2200 Hz in the tape
without problems.

I think that, with a modem like this, your application
not only can record data, but also can send and receive
data in real time using a communication standard (Bell 103
or CCITT). Most of modems today still supporting this
standard in order to mantain compatibility.

Well, these are my ideas...

Regards,
          Alejandro.

At 11:18 23/02/01 +1100, you wrote:
>Can anyone point me to information on building or probably purchasing a
>QPSK Modulator/Demodulator. I'll be using a 16C874 to collect data and
>then dump it to a standard tape recorder. I was considering FSK but QPSK
>offers better data density.
>
>Yes, I know, it can all be done with solid state memories, but consider
>this , the data interface is RS232C, the proposed data format is TAR
>(uncompressed) and the quantity of data is small. Tapes are very cheap
>and tape recorders can be purchased for < $50.00 (AUS). The QPSK
>interface will hopefully be very cheap to put together. This permits
>connection to any PC, Laptop, PDA, UNIX, LINUX, Ultrix, SunOS, IRIX, you
>name it work station and OS.
>
>I welcome all pro's and cons.
>
>Nino.
>--
>------------------------------------------------------
>| Antonio (Nino) L. Benci                            |
>| Professional Officer, Electronic Services          |
>| School of Physics & Materials Engineering          |
>| Monash University                                  |
>| email: nino.benci@spme.monash.edu                  |
>| T: 61 3 9905 3649. F: 61 3 9905 3637               |
>| M: 0414 924 833                                    |
>------------------------------------------------------
>
>Attachment Converted: "c:\eudora\attach\Nino.Benci16.vcf"
>

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.