[App_rpt-users] Fwd: COR signal getting confused

[Jon Rorke]

The URI wants to see a signal that goes hi to low or open collector to 
ground. It also has a diode on the input to block incoming voltage. So 
if your COR line sources a voltage then removes it but doesn't go all 
the way to ground when it goes low, then the URI will not see a transition.

So perhaps you can put a resistor to the base of a NPN transistor and 
connect the collector to the URI I/P. Change the carrier from to "USB" 
in usbradio.conf and you should be good to go.

On 9/26/2014 11:50 AM, Mike M wrote:
> 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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