[GreenKeys] Looking for Alternative Method of Receiving Internet Broadcast of TTY Modem Tones

[Paul Newland, ad7i]

I want to thank everyone who has shared their comments with me on this
topic.  I have to admit that I'm driving way beyond my headlights with this.

Bill, KE3BK, mentioned that he already has an app that will do this, so
that's great.  I will check in with him in the next few days to get more
info on that.

Harold, W6IWI told how to just download a PCM wave file with the latest
info from his news servers.  I'm guessing it would be possible to also post
the text file for the content that was used to generate the WAV file, and
bypass the modem part, although the modem tones playing softly in the shack
as the printer runs is part of the ambiance of RTTY.

Johannes suggested having the EPS32 not only get the audio data from the
internet, but also have the ESP32 do the demodulation of the AFSK to binary
UART format.  And that led me to a conversation with Claude (which is kinda
still weird for me).....

Starting from scratch with Claude and not assuming the answer was yes, I
asked Claude if it would be possible to have the ESP32 demodulate a typical
narrow shift RTTY AFSK signal.  Claude not only said yes, but that it
should consume no more than 1% of one core of computational time, and it
gave me the code to do that (I don't know if it works, but I'll find out
over the next few weeks).  I pointed out to Claude that the code it
generated used Trig functions as well as floating point math, and wouldn't
that make the process very slow.  Claude responded by (gently) telling me
that my concerns were reasonable, but only if it was about 10 years ago.
Claude pointed out that the trig functions were in another file and done
via lookup table, not calculation, and that the ESP32-S3 had a hardware
floating point unit.  I had no idea.

I'm always interested in low cost solutions, so I asked Claude if the AFSK
demodulator could run on a PIC32CM3204GV ( 63 cents in singles  32bit ARM
processor, 48 MHz, 12bit ADC).  Answer:  difficult because of low RAM (4 k
bytes) and no DMA.  I then asked if it could run on a $1.06 in singles
PIC32CM1216GV (32bit ARM processor, 5V, 16 K bytes of ram, 12 channels of
DMA, 12 bit ADC).  Answer: easy, it would take about 5% of the one core
(it's single core MCU running at 48 MHz) and the code Claude offered for
that MCU dropped the floating point and used only 32bit integer math.  It
would be interesting to see how well Claude's AFSK demodulator running on a
$1.06 MCU did next to an XR2211 AFSK demod.

Again, I would like to thank everyone for their comments. I appreciate the
community support that this group offers.  I'm not sure where I will start
on this project, but it looks like it will be something that can keep me
busy for a few months.

73, Paul, ad7i
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