Tophtoh
Member
Does anyone have any audio clips or anything of what ProVoice sounds like?... worth a shot, thanks.
I wonder what ProVoice sounds like...
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mlevin
Member
I've never heard provoice before, but I wouldn't be surprised if it sounded similar if not exactly the same as Apco 25 IMBE digital. If I'm not mistaken, Provoice is considered IMBE as well.
Tophtoh
Member
Then why is ProVoice not monitorable? I don't understand what the big deal is about monitoring ProVoice. O well, Motorola has any other two way radio company beat hands down anyway, and will prolly continue in the future. Agree?
mlevin said:
ProVoice uses the same vocoder as APCO-25 (IMBE) so it would sound the same.
The reason lies in the digital modulation style used by ProVoice
APCO-25 uses C4FM or CQPSK - C4FM is the most common modulation format for APCO-25.
ProVoice uses GFSK modulation.
nd5y
Member
Pro voice doesn't sound the same as P25
and when the control channel has ESK it sounds different too.
and when the control channel has ESK it sounds different too.
Provoice does sound similar to APCO 25 voice. They both use 4 kbps vocoders. That's pretty low resolution, but that's how they fit it into a 12.5 kHz channel.
By comparison, digital cell phones use an 8kbps or 13 kbps vocoder (at least twice the bandwidth). That's why they sound better and people expect that on a phone.
There are some differences in the way Provoice and APCO 25 sound just because of manufacturer design differences. You can do a lot with DSP chips in terms of programming how they behave.
Also, ESK has nothing to do with the sound on a voice channel (called working channel in the EDACS world). It only affects the programming of the radios and the control channel if it is activated on the system. Maybe you meant the sound of the CCH, sorry if that's true.
And APCO 25 and Provoice are no where near compatible with each other because the modulation schemes are totally different. That's why M/A-Com has taken a lot of heat for Provoice and lack of interoperability. Now they have just started putting out radios that can have both Provoice and full APCO 25 trunking (9600 bps CCH)/voice in the same radio. Now they just need to make a system that is APCO 25 trunking. The reason they don't is they want to lock buyers into their product.
One of the main reasons for APCO 25 is an open standard that more than one manufacturer can make radios and systems for. But the problem is that competition cuts into profit big time.
By comparison, digital cell phones use an 8kbps or 13 kbps vocoder (at least twice the bandwidth). That's why they sound better and people expect that on a phone.
There are some differences in the way Provoice and APCO 25 sound just because of manufacturer design differences. You can do a lot with DSP chips in terms of programming how they behave.
Also, ESK has nothing to do with the sound on a voice channel (called working channel in the EDACS world). It only affects the programming of the radios and the control channel if it is activated on the system. Maybe you meant the sound of the CCH, sorry if that's true.
And APCO 25 and Provoice are no where near compatible with each other because the modulation schemes are totally different. That's why M/A-Com has taken a lot of heat for Provoice and lack of interoperability. Now they have just started putting out radios that can have both Provoice and full APCO 25 trunking (9600 bps CCH)/voice in the same radio. Now they just need to make a system that is APCO 25 trunking. The reason they don't is they want to lock buyers into their product.
One of the main reasons for APCO 25 is an open standard that more than one manufacturer can make radios and systems for. But the problem is that competition cuts into profit big time.
N
N_Jay
Guest
OK, letrs clear this up.
Decoded ProVoice (Listening on a radio, not a scanner) sounds somewhat like decoded P25. There are similar vocoders running at similar rates.
Encoded ProVoice (listening on an analog scanner) sounds very different from encoded P25 (listening on an analog scanner) because the modulation is completely different.
Hope this is clear. :wink:
Decoded ProVoice (Listening on a radio, not a scanner) sounds somewhat like decoded P25. There are similar vocoders running at similar rates.
Encoded ProVoice (listening on an analog scanner) sounds very different from encoded P25 (listening on an analog scanner) because the modulation is completely different.
Hope this is clear. :wink:
N
N_Jay
Guest
logitec said:
BTW, M/A-COM does build P25 systems.
Joseph11 said:
Nice!
BTW N_Jay, I think M/A-Com has built a handfull for the Feds now that you mention it, but I bet you can't go buy one on 800 or 700 Mhz for a local or state system unless they've changed their marketing lately.
re:
Check out the specs on this bad boy. I'd love to have one of my own.
8)
http://www.efjohnson.com/5100.asp
It's both P25 and ProVoice, and then some.
*EDIT: I could have swore it was, but it isn't.
Check out the specs on this bad boy. I'd love to have one of my own.
8)
http://www.efjohnson.com/5100.asp
It's both P25 and ProVoice, and then some.
*EDIT: I could have swore it was, but it isn't.
Tophtoh said:
Are you referring to the raw digital audio or the encoded audio?
I have a wav file of ProVoice digital as it's heard from a scanner.
ProVoice soundbyte
ShawnCowden
Member
what will digital ham radio run on the new icom digital radios ?? i heard GMSK or something like that
Re: re:
Chit..yer right. All this time I was under the impression that radio was APCO-25 and ProVoice capable. I read the spec sheet thru twice and now I'm swallowing it. GULP.
:?
The P7100ip does it all..for a price.
logitec said:
Chit..yer right. All this time I was under the impression that radio was APCO-25 and ProVoice capable. I read the spec sheet thru twice and now I'm swallowing it. GULP.
:?
The P7100ip does it all..for a price.
ShawnCowden said:
It appears the current D-STAR equipment is GMSK
http://www.icomamerica.com/amateur/dstar/
Yet it appears ICOM and Kenwood are working together to
develop it further:
http://www.icomamerica.com/press/?id=20050406
Modulation Method: 4-Level FSK (FDMA)
6.25 kHz very narrow bandwidth
Occupied bandwidth 1/2 of existing analog FM
Data Baud Rate: 4,800 bps
Combined Voice & Slow Speed Data transmit
GPS Location with Voice
No Data Modems Required
Advanced VOCODER DVSI AMBE+2 TM
Half-rate of IMBE TM (P25)
N_Jay said:
Just got done reading a press release from the 6th of this month and you're right they do make P25 systems, but the way I read it, it's only for VHF or UHF. I suspect that's to not lose the Feds (who usually require P25) as a customer. But it sounds like no P25 systems for 700 or 800 yet. They'll probably have to come around on that eventually.
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