On May 28, 2009, at 9:00 PM, Chuck Guzis wrote:
If you don't really need a design that old, you
might be able to
find a TMS99532 or Am7910 FSK modem chip.
An eBay seller has a number of TMS99532s available at $2.75/ea,
item # 110376664450.
I don't recall what the Pennywhistle used. Was it NE567s or am I
thinking of another hobbyist modem design?
I honestly don't recall, but I seem to recall their having been
more components than a TMS99532-based design would require.
-Dave
--
Dave McGuire
Port Charlotte, FL