[App_rpt-users] Resistor divider

[Bryan D. Boyle]

if you use pins 21 and 22 on the URI,they are already AC Coupled based on examining the schematic on the dmk website. there are already 47pF caps in the circuit to decouple the source from the URI in/out feeds.  

If you are taking discriminator RX audio, the dsp is more than capable of stripping not only the PL but also can determine and derive a pseudo-COS signal, eliminating 2 wires in the interconnect.  In fact, if you use dsp to carrier (and/or ctcss) detect, i don't believe (jim?) that it even matters what the state of those two leads are.

so, minimal connections are needed: flat rx audio, flat tx audio, ptt, and ground to give you full control over the rf side of the house, assuming you have all the app configs set right.  simple is good.  but if you want to have active low, active high, pull up resistors, and all that, the URI will let you get as creative as you want, with the added complexity of wiring and config changes necessary to make it work.

simple is good, and ultimately, less trouble to debug.
--
Bryan
Sent from my iPad

> On Oct 30, 2013, at 11:48 PM, Johnny Keeker <cypresstower at yahoo.com> wrote:
> 
> I use the capacitor it good design practice to isolates the circuits
> although it will not strip the pl or dpl.  If I want to strip pl or dpl,
> use a Communication Specialists Board. You can try removes their
> audio cap and add jumpers.  "Just kidding".  Another consideration,
> take a look at, pin 16, connector P904, on the IF/Audio Squelch Board;
> RX PA. The audio is clean and de-emphasized. 
> JK   
> 
> 
> From: Robert Newberry <N1XBM at amsat.org>
> To: Johnny Keeker <cypresstower at yahoo.com> 
> Sent: Wednesday, October 30, 2013 8:08 PM
> Subject: Re: [App_rpt-users] Resistor divider
> 
> I just realized that the DSP should be able to strip PL off. At least I think it can.
> Apparare Scientior 
> Paratus Communicare
> -N1XBM
> On Oct 30, 2013 6:44 PM, "Johnny Keeker" <cypresstower at yahoo.com> wrote:
> Robert;
> You need to remove the sub audible tone when using vol hi,
> but if your not concerned with hearing your ctcss tones, 
> use a 10uf cap off the vol hi through a series 10k to a 3.3k
> to ground. Tap the audio where the 10k meets the 3.3k resistor. 
> Use a variable 5k pot in place of the 3.3k if you want to change
> the levels or just change the 3.3k value.... 
> JK
> 
> From: Robert Newberry <N1XBM at amsat.org>
> To: "app_rpt-users at ohnosec.org" <app_rpt-users at ohnosec.org> 
> Sent: Wednesday, October 30, 2013 12:45 PM
> Subject: [App_rpt-users] Resistor divider
> 
> I need help, I am using a Mastr II and a URI. I want to use the vol/sql hi for my discriminator audio. I was going to use a resistor divider to pad down the audio.
> Has anyone ever done this? Could you explain it in more detail to me. I've read you take the two resistors and put them in series. I would tap my URI in the middle where those two resistors meet. I assume one end goes to vol/sql hi, but where does the far end go?
> Thanks for your help
> Apparare Scientior 
> Paratus Communicare
> -N1XBM
> 
> _______________________________________________
> App_rpt-users mailing list
> App_rpt-users at ohnosec.org
> http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
> 
> 
> 
> 
> _______________________________________________
> App_rpt-users mailing list
> App_rpt-users at ohnosec.org
> http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.keekles.org/pipermail/app_rpt-users/attachments/20131031/c10542e3/attachment.html>