[RTTY] AFSK-to-FSK Circuit

[W5KDJ]

Can I send the chips to you for check out, I used sockets so they will 
unplug.  I will check the wiring for the 20th time.

----- Original Message ----- 
From: "Doug Hall" <k4dsp.doug at gmail.com>
To: "RTTY" <rtty at contesting.com>
Sent: Saturday, March 08, 2008 1:39 AM
Subject: [RTTY] AFSK-to-FSK Circuit


> Hi All,
>
> There has been some discussion in the past about how to generate an
> FSK signal if you don't have a serial port or if your RTTY software
> doesn't support FSK. If you find yourself in this situation and you
> want or need to run FSK I have created a fairly simple circuit for
> creating an FSK signal from the AFSK output of your sound card.
>
> This circuit is a very simple AFSK demodulator, with the demodulated
> output driving the FSK input on the radio.  A PTT signal is also
> generated, so this can also be used as a general purpose sound card
> interface if you are so inclined. But the main purpose is to provide a
> way for those who can't otherwise run FSK to do so.
>
> There are details (schematic, firmware, source code, and
> theory/operation documentation) at
> http://k4dsp.homeip.net/~doug/regenerator/index.html  I have toyed
> with the idea of laying out a little circuit board, but I just don't
> think there is that much demand. If I find out otherwise I'll get some
> boards made.
>
> I hope it's useful for someone. I have been using this circuit for a
> while now and it works very well. If you have questions or comments
> please feel free to drop me a note. And if you're looking at this and
> asking yourself "Why the heck do I need that?" then you probably don't
> need it :-)
>
> 73,
> Doug, K4DSP
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