[sci.electronics] Modem chips for 9600 baud over good-quality audio channel

jbn@glacier.STANFORD.EDU (John B. Nagle) (06/21/88)

     I'd like to transmit 9600 baud, simplex, (one-way) over a good-quality
audio channel that can handle at least 10KHz.  The transmit end must be
small and consume modest power; this is a telemetry application.  Telephone
oriented modems assume a much narrower audio bandwidth (about 3-4KHz) and
thus must use very elaborate techniques to cram 9600 baud into that narrow
a bandwidth.  I'm looking for something simpler, with about 1 baud/Hz
channel utilization.  This should be about as complex as a 2400 baud modem,
for which there exist single-chip versions such as the Fairchild
F2224.  But that chip can't be turned up to 9600 baud, as far as I know.
Any better ideas?

    The guys who want to push more bits through VHF FM repeaters might
have some ideas on this.

					John Nagle

bill@videovax.Tek.COM (William K. McFadden) (06/25/88)

In article <17506@glacier.STANFORD.EDU> jbn@glacier.STANFORD.EDU (John B. Nagle) writes:

>     I'd like to transmit 9600 baud, simplex, (one-way) over a good-quality
>audio channel that can handle at least 10KHz.

I posted a reply to this in comp.dcom.modems if anyone is interested.
-- 
Bill McFadden    Tektronix, Inc.  P.O. Box 500  MS 58-639  Beaverton, OR  97077
UUCP: bill@videovax.Tek.COM,  {hplabs,uw-beaver,decvax}!tektronix!videovax!bill
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