16 Jun
2018
16 Jun
'18
10:20 p.m.
I don't see how anything in your replies is helpful.
- They are definitely tone frames. Tones run through the vocoder
are irrelevant and OP25 would handle them just fine anyway.
- Why should the user seek other solutions? The system is sending
IMBE tone frames and any decoder thrown at it should handle it.
- And how does simulcast have anything to do with this? It doesn't.
To the OP: You need to record the raw signal (I/Q data or FM
demodulated audio) so someone can analyze it. Then the decoder logic
can be updated to accommodate tone frames and you'll get your audible alerts.
At 04:19 PM 16-06-2018, 'William Becks' wllmbecks(a)gmail.com [op25-dev] wrote:
What exactly are you trying to determine about the tones?  They
appear to be âAlertâ tones sent by the dispatch operator ahead
of the voice message. I donât think they actually serve as a
signaling function as would commonly be found in analog paging systems.Â
I believe that someone has already stated that there are only a
handful of specific tones or tone combinations that are provided for
in the P25 vocoder. Any other tones or tone combinations
transmitted into the speech input of the vocoder quote likely will
not reproduce and exact replica as the source tone(s) primarily
because the vocoder is designed to encode and compress speech.
Bill, WA8WG