MOTOTRBO CPS pre & deemphasis settings

[w0en]

I have had the CPS software for a little while now and just today looked at the digital versus analog settings in the codeplug examples provided with it from Motorola, looks like they have one channel analog and one digital. One of the differences seems that analog has pre & deemphasis set on and the digital examples have none as a setting. All my XPR8300s,4550s and 6550s programming were setup by a local shop and have it enabled in both analog and digital. What is the experience of some of you pros out there as to which way works best on digital channels? I understand that in the analog world you want it on but how about in TRBO?

[wavetar]

Where are you seeing emphasis settings in the digital personality? It's not a digital option...the only digital voice setting I'm aware of you can change is AGC on or off in the 'general settings' screen, with corresponding level settings associated with the 'off' setting.

[RF_Burns]

Pre and De-emphasis are an analog only parameter which improves the signal to noise ratio.

Co-incidentally I'm having an issue with the XPR8300 Pre & De settings right now. I want to install an external repeater controller so I need Flat Unfiltered audio to detect the PL on receive. However that turns OFF the pre-emphasis on the Tx side. I'm using a single Tx tone so the XPR will generate that, but I'm having a difficult time making external Preemphasized sound right on Tx. I don't think you can actually use an external repeater controller. There is only one Tx audio input so you would need to pre-emphasize, deviation limit and frequency limit the audio, then mix in the PL tone externally to the repeater.

I'd actually like to use the built-in Pre and De for my audio and get the discriminator audio to the repeater controller as I just want it to only validate a couple PL tones, and not touch the audio. What would be great is if the XPR repeater could do 2 or more PL tones.

However... if anyone has ever looked at the Rx circuits in the Trbo radio, this is impossible!! They digitize the IF and then process it in a DSP. There is no such thing as "Discriminator" audio. You get the choices they give you.

Once again Motorola has severely limited the possibilities of solutions their radios can be used in!!

[w0en]

Pre and De-emphasis are an analog only parameter which improves the signal to noise ratio.

Co-incidentally I'm having an issue with the XPR8300 Pre & De settings right now. I want to install an external repeater controller so I need Flat Unfiltered audio to detect the PL on receive. However that turns OFF the pre-emphasis on the Tx side. I'm using a single Tx tone so the XPR will generate that, but I'm having a difficult time making external Preemphasized sound right on Tx. I don't think you can actually use an external repeater controller. There is only one Tx audio input so you would need to pre-emphasize, deviation limit and frequency limit the audio, then mix in the PL tone externally to the repeater.

I'd actually like to use the built-in Pre and De for my audio and get the discriminator audio to the repeater controller as I just want it to only validate a couple PL tones, and not touch the audio. What would be great is if the XPR repeater could do 2 or more PL tones.

However... if anyone has ever looked at the Rx circuits in the Trbo radio, this is impossible!! They digitize the IF and then process it in a DSP. There is no such thing as "Discriminator" audio. You get the choices they give you.

In my actual code plug from the Moto distributor under Channels - Zone - where you see all channels on one screen under "Voice Emphasis" all my digital channels have De & Pre in the box. you do get an arrow selecting the box but the arrow doesn't pull down and give you any selection like None, the analog boxes pull down and give you the two selections of None & De & Pre. In the examples it is just as you said so I am wondering how the De & Pre show up in the Digital channel box but allow no way to chaange them (no arrow pulldown box) this code plug is for XPR6500 portables. I am wondering if this was "cut and Pasted" in somehow? And is it actually doing anything or is the software ignoring it? Looking at the samples you are correct there is no option on digital but it is set to "None" and can't be changed.

[RF_Burns]

Since there is no "De or Pre" options to choose from in digital, they are locked out. I suppose they could have made the box change to a Greyed-out N/A (Not Applicable), but not allowing the choice gets the job done.

Here is a link that explains how we got pre & de-emphasis in narrowband FM signals.
http://www.repeater-builder.com/tech-in ... audio.html