[GreenKeys] ITTY comments and demodulator

[Dale Hughes]

Hello folk,

Greetings from VK1 (Canberra, Australia). I've been printing some of the
ITTY streaming news which has been fun and interesting. Many thanks to
those people who provide the excellent and useful service.

Previously I printed the 45 baud version of the news using my old RTTY
modem with a Kleinschmidt TT4C machine, however I have now updated the
system so I can use my Teletype Model 28RO which otherwise wasn't getting a
lot of use.

The new demodulator uses a PLL device and includes a UART to regenerate and
upconvert the baud rate of the demodulated characters, so I can now easily
print the 45, 50 and 75 baud services to a single machine running at 75
baud. The PLL can be easily tuned to the various tones that are used using
a front panel control. Attached is the schematic of the new unit, it is
easy to build and it works very well. I have written up the design which
includes the various source documents like application notes and datasheets
and I am happy to send the file to anyone who is interested. It's about 12
Megabytes so I haven't attached it to this post.

Regards
Dale VK1DSH
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