[App_rpt-users] Fwd: COR signal getting confused

[Mike M]

Resending since my initial post has been pending moderation for 2 days now
and got no reply from the list owner email.

I have modified an HT to bring out the receive LED signal and use it
as the COR input to a DMK URI. It is a digital signal as viewed on a
scope (i.e. very short slope in the transitions)  This seems like it
would work well and it does on strong signals. But on marginal signals
where the LED may blink on and off quickly (like during picket
fencing), it seems to confuse the URI (or the software) were it will
start off good, but then a quick dropout of the COR signal will cause
the software to no longer detect carrier, even though the signal on
the COR input has been restored.  Even if the input is solid high (or
low in my case, I'm using usbinvert) it will not detect a carrier
until there is another dropout of adequate time to "reset" it.

I've tried putting a simple RC on the input but it didn't really help
much.  Seems the URI (or software) needs a significant minimum time
between transitions to properly detect them, long enough that it would
delay the carrier detection too much without a circuit more complex
than an RC (i.e. something that would allow instant keyup, but delay
the key down.)

Linked is a scope image.

https://lh5.googleusercontent.com/-CsJ9autUTAE/VCWK-uNJJpI/AAAAAAAAPSM/VsVvbPVvuEA/s800/20140923_184107.jpg

Carrier was detected until this signal
dropout event.  Ch A is my RC filtered signal sent to the URI, Ch B is
the signal out of the radio.  Carrier was not detected after the 5th
dropout even though the signal remained low.

Anyone ever experience this and/or have ideas on how to fix it?

Thanks.

Mike
KF7MBK
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