Re: [Discuss-gnuradio] The PLL for the burst signal

[Vitt Benv]

Hello!

About frequencies pay attention that there are more than a single (406.025 MHz) frequency.

In my direct experience there's also 406.028 / 406.039 MHZ in use. So also tuning has to be on the right frequency.

Take a look also at https://www.ntia.doc.gov/files/ntia/publications/compendium/0406.00-0406.10_01MAR14.pdf , but I suppose that also this document isn't up-to-date...

2017-04-23 17:07 GMT+02:00 Marcus Müller <address@hidden>:

Had to google that; for the others: http://www.epirb.com/

Emergency Position Indicating Radio Beacon ; 406 MHz, bursty, wikipedia
says:

> The digital distress message generated by the beacon varies according
to the above factors and is encoded in 30 hexadecimal characters. The
unique 15-character digital identity (the 15-hex ID) is hard-coded in
the firmware of the beacon. The 406.025 MHz carrier signal is modulated
plus or minus 1.1 radians with the data encoded using Manchester
encoding, which ensures a net zero phase shift aiding Doppler location

So, a PSK that can only take values of +1.1 and -1.1, relative to the
"idle" carrier. Bit rate is 400b/s, so that makes it a 800 S/s PSK
symbol rate (manchester-encoding happening in between).

Cheers,
Marcus

[1]
http://www.cospas-sarsat.int/images/stories/SystemDocs/Current/cs_t.001_oct_2013.pdf

On 04/23/2017 04:48 PM, Vicfield Medici wrote:
> Hi,
>
> When trying to decode the signal, I always use the PLL Carrier Tracking to
> solve the error
> about phase shifting, and it’s always doing a good job.
>
> But I start trying to decode the EPIRB signal, I just got a sample with only
> one burst,
>  and PLL seems not work anymore even I tuned the parameter in many ways.
>
> Does the PLL Carrier Tracking can’t handle the discontinuous signal somehow?
> Or it’s my misunderstanding?
>
> I really want to know how to take that, thanks for any help.
>
> Regards,
>
> Vicfield
>
>
>
>
> --
> View this message in context: http://gnuradio.4.n7.nabble.com/The-PLL-for-the-burst-signal-tp63604.html
> Sent from the GnuRadio mailing list archive at Nabble.com.
>
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> Discuss-gnuradio mailing list
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