[GreenKeys] recording rtty

[John Beckman]

Someone recently inquired about recording RTTY pix. Recording the RTTY 
audio tones and playing them back never did work well, because of audio 
tape "wobble." In 1978 I built a coder/decoder which worked amazingly 
well. It converted the tones to pulses and on playback converted the 
pulses back to tones. Because it produced a number of pulses for each 
character, if static or interference took out a few pulses it didn't 
matter because there were plenty left to do the job.
I used this feeding to and from a UT4 which had a Uart and a number of 
Fifos. I don't see why it couldn't be interfaced directly to a loop itself.
If you'd care to see the "ancient" way of doing this, the schematic is at:
http://www.w4btx.com/recorder.html
Good luck and 73
John, W4BTX
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