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Andy, LF,
some time ago, Wolf DL4YHF wrote a pair of sound
utilities, SndInput and SndOutpt, which create or consume a continuous stream of
raw audio files:
I have found
these extremely useful, as they have allowed me to implement quasi-realtime
audio processing in QuickBasic, my favourite but super-ancient programming
language. There is an option for downconversion and decimation into / from
complex IQ data, which greatly enhances efficiency for narrowband applications
(eg. slow Hell). SndOutpt can also generate a sinusoidal test tone, which can be
frequency shifted in a phase-continuous manner by DOS commands
Best 73,
Markus (DF6NM)
Sent: Sunday, May 06, 2012 6:14 PM
Subject: Re: LF: Generating 8970 Hz carrier with Spectrum Lab
?
...
A custom A/D could send its data in its own format via
USB, or serial
COM port or whatever, to software that saves blocks in the
format of a
.WAV file. Then the decoding software works on the
resulting .WAV
files. It won't be real time any more, but none of
these slow data
modes actually are that real time. The speed of reading
and switching
(using a pair of ping-pong files if necessary) can make the
whole
system pseudo real time - in the same way as WSJT appears to
run
continuously.
Now, any A/D design can be used provided the results
are written to a
.WAV file. Wav files can have any sample rate
(so long as it is an
integer number of Hz) and do not have to be restricted
to 48000, 11025
or whatever, so custom LF receivers using quite slow A/D
converters
and low sample rates are now valid.
Just throwing that idea
into the ring..
Andy
www.g4jnt.com
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