[App_rpt-users] RTCM txprelim?

[KJ6KO]

AH!  Besides answering another question I had about the "audio standard" on Asterisk being "line level" spkr/mic audio, you are sying the txprelim=yes is not what does it in a RTCM?  Does that still need to be set?

Sounds like  you are basically "fooling" it by telling it to generate a PL, which makes it think it is connected directly to a modulator, hence it will pre-emphasize the audio automatically? Setting the txctcsslevel=0 just kills the tone.

Do I have it correct now?

ALSO,
  Since chan_simpleusb will not pre-emph, will a DMK URI do it if you use the chan_usbradio to drive it?

Lets see how many other questions I can cram in here.....

  I assume since I do not have an RTCM yet, that the chan_voter is what is used for the RTCM?  Even if it is NOT being used as a voter system, just a radio interface?

Thakns for the help Tim!!

I'm learnin'

73 de Greg
  ----- Original Message ----- 
  From: Tim Sawyer 
  To: KJ6KO 
  Cc: App_rpt-users at ohnosec.org 
  Sent: Wednesday, August 28, 2013 12:46 PM
  Subject: Re: [App_rpt-users] RTCM txprelim?


  Sorry, this deserves a better expansion. Sometimes I get in a hurry.


  Asterisk ships audio around (on the links, etc) as line-level audio (not pre-emphasized and needs no de-epmhasis). This works out great for telephones, computer clients, voice announcements, etc because Asterisk doesn't have to do any filtering. After all Asterisk is a telephone PBX where you would expect audio to be line-level (speaker/mic) audio. This leaves the pre/de-emphasis up to app_rpt channel drivers. Chan_usbradio and chan_voter can add pre-emphasis. Chan_simpleusb cannot pre-emphasise. 


  With chan_voter the DSP pre-emphasis is turned on by setting txctcss = xxx.x in voter.conf. If you want pre-emphasis but no TX P/L set txctcss =  to some (any) tone and set txctcsslevel = 0.


  Hope that helps.
  --
  Tim
  :wq


  On Aug 28, 2013, at 10:26 AM, Tim Sawyer <tim.sawyer at me.com> wrote:


    Absolutely, yes. That is it's normal mode. 

    --
    Tim
    :wq


    On Aug 28, 2013, at 9:42 AM, KJ6KO <kj6ko at innercite.com> wrote:


      I am looking into an RTCM.  Does it have the capability of driving a modulator directly?  May have to use it with an old Palomar controller which is set up for direct modulator input style TX audio (pre-emphasized)

      txprelim=yes?

      I know it has the ability to de-emphasize the DISC audio from the Palomar.

      Thanks..


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