I have installed an additional sound card in a minimal Win98se computer. My
goal was to run two copies of MMTTY simultaneously to compare various
filter mode/parameter combinations.
I have read on the newsgroups that it is difficult to get two sound cards
running simultaneously, so approached this with a bit of fear. But the
sound card was inexpensive, so not much to lose if it didn't work.
It works! After some initially confusing results, all seems to work now. I
am running two independent copies of MMTTY on the (150PR Cyrix 6x86)
machine right now, using different demodulator parameters, from the two
independent soundcards, and each copy is getting its input audio stream
from the proper input line jack. I don't see any performance degradation of
any kind yet, with one copy running FIR and the other IIR, both with
"normal" parameters.
Yippee!
The new sound card was a $20 (regular price) cheapie from CompUSA with
ALS-4000 guts. The install was the automatic PnP install under Win98se, and
followed an automatic install of the original (also a cheapie, but
different) card. All interrupts were already in use on this machine, so
some are being shared now. I may have to change interrupts manually later
if conflicts arise in use.
I set the volume on each card independently - calling up the "master
volume" panel allows me to select which card to adjust. This is a little
cumbersome, but is not needed often.
One copy of MMTTY is using sound device 0, the other is using 1.
This computer will be dedicated as a receive-only dumb terminal
demodulator. It will eventually pass the decoded outputs through the serial
ports to a second computer running WriteLog. I hope to use the second
decoded RTTY stream initially to run a routine RTTY filter and a flutter
filter simultaneously and later provide both demods for two-radio contesting.
Jerry W4UK
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