[GreenKeys] XR2211 demodulator circuit boards?

[Harold Hallikainen]

> Are there any printed circuit boards for building an XR2211 based RTTY
> demodulator? Â Google shows me all kinds of articles from complex to
> over-simplified but doesn't lead me to any PCB artwork or vendors.
> I'm thinking I might build a demod to run a Model 15 from a laptop running
> MMTTY. The program only outputs tones (no on-off output to key a loop
> directly) so a PLL demod should be fine since noise won't be an issue. Or
> should I look at something even smaller/simpler?
> Thanks!WayneWB4OGM______________________________________________________________

There's an evaluation board at
https://media.digikey.com/pdf/Data%20Sheets/MaxLinear%20PDFs/XR-2206-11-12_Man.pdf
. I'd be tempted to wire wrap it, though.

Several products I did using the XR2211 are at

http://bh.hallikainen.org//wiki/uploads/HaroldHallikainen/20130416125339_Part5.pdf

http://bh.hallikainen.org//wiki/uploads/HaroldHallikainen/Harold_018.pdf

http://bh.hallikainen.org//wiki/uploads/HaroldHallikainen/20130416125339_Part1.pdf

http://bh.hallikainen.org//wiki/uploads/HaroldHallikainen/Harold_011.pdf

http://bh.hallikainen.org//wiki/uploads/HaroldHallikainen/20130416125553.pdf#page=11

The XR2211 is a fun chip. Before that, I used the NE565, but the XR2211
includes the data comparator, a carrier detect, etc. The XR2206 is also a
nice chip. It will generate a square wave, triangle wave, and sine waves.
It can do linear FM, AM (including double sideband suppressed carrier),
and FSK. The FSK circuit has a logic input that switches between two
timing resistors. But, during the transition, the frequency goes to zero
for a very short time. I'd probably use the linear FM circuit and drive it
with the data after running it through a low pass filter to limit
bandwidth. It IS a nice chip, though. I used it as an upconverter (local
oscillator and mixer) to upconvert subcarriers on FM broadcast stations to
455 kHz where the signal then went through ceramic filters, IF amplifier,
and a ceramic discriminator.

Fun stuff!

Harold
https://w6iwi.org


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