[op25-dev] Why can't I hear fire tones?
Andrew Porrett firstname.lastname@example.org [op25-dev]
op25-dev at yahoogroups.com
Sat Jun 16 22:20:26 UTC 2018
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 at gmail.com [op25-dev] wrote:
>What exactly are you trying to determine about the tones?Â Â They
>appear to be âAlertâ tones sent by the dispatch operator ahead
>of the voice message.Â 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.Â 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.
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