Re: [Discuss-gnuradio] XM on GR

[Chris Kuethe]

Yep, I'm aware of that. On that note, their FCC and SEC filings are
pretty interesting.

https://www.google.com/search?num=20&safe=off&q=sirius+%22FM-3%22+%22TT%26C%22&oq=sirius+%22FM-3%22+%22TT%26C%22&gs_l=serp.3...466273.468341.0.468752.7.7.0.0.0.0.287.1073.2j4j1.7.0.ckpsrh...0...1.1.64.serp..7.0.0.2rZ6gnDtP7M

https://www.google.com/search?num=20&safe=off&q=siriusxm+right+hand+circular+polarization&oq=siriusxm+right+hand+circular+pol&gs_l=serp.3.0.33i21.9261.17199.0.19298.18.18.0.0.0.0.114.1520.16j1.17.0....0...1.1.64.serp..1.12.1070.uCsnuHPRz8Y

On Sun, Apr 10, 2016 at 3:03 PM, Andy Walls <address@hidden> wrote:
> Just to be clear, Sirius is different than XM (even though they merged).  The 
> lower edge of the 12.5 MHz XM allocation is at 2332.5 MHz, IIRC.  The upper 
> edge of the 12.5 MHZ Sirius allocation is there as well.
>
> Sirius does have patents on hierarchical modulation, which I'm guessing they 
> would use in the Sirius band.
>
> Regards,
> Andy
>
> On April 10, 2016 5:36:08 PM EDT, Chris Kuethe <address@hidden> wrote:
>>Thanks to Steve for hitting me with a clue-stick. For anyone else
>>playing along at home, the Sirius patch antenna has an integrated amp
>>and takes inline power - a fact that I did not see anywhere.
>>
>>This test was done with a hackrf tuned to 2.3265GHz, 20Msps, 8MHz
>>analog filter - there is clearly something interesting going on when
>>inline power is enabled with the "bias=1" argument.
>>
>>On Sat, Apr 9, 2016 at 6:32 AM, Andy Walls
>><address@hidden> wrote:
>>>
>>>
>>> On Fri, Apr 8, 2016 at 10:48 AM, Andy Walls
>><address@hidden>
>>> wrote:
>>>>
>>>>
>>>> >         The audio codec is proprietary and not documented anywhere
>>AFAIK
>>>> > so
>>>> >         even if you demod the bitstream, you won't be able to do
>>much
>>>> > with it.
>>>>
>>>> > Thank you all for the conversation, it is pretty interesting.
>>That
>>>> > makes sense
>>>> > that they have a proprietary protocol, it's a shame though.  Is
>>the text
>>>> > that
>>>> > comes through encoded in a proprietary way?
>>>> >
>>>> > Does anyone know what the frequency of channel 1 is on (I'd like
>>to see
>>>> > if I
>>>> > can even see the signal popping up above the noise)?
>>>> >
>>>> > ~Jason
>>>>
>>>> The XM center freqs are shown here:
>>>>
>>>>
>>>>
>>https://www.rohde-schwarz.com/us/technologies/satellite-broadcast/xm-satellite/xm-satellite-technology/xm-satellite-technology_55613.html
>>>>
>>>> The Sats are QPSK, the terrestrial is COFDM.
>>>>
>>>> That page also states the audio codec for voice programming is AMBE,
>>and
>>>> AAC+ for all other programming.
>>>>
>>>>
>>>> The XM radio patents give you a lot of clues:
>>>>
>>>>
>>https://www.google.com/search?tbo=p&tbm=pts&hl=en&q=inassignee:%22Xm+Satellite+Radio+Inc.%22
>>>>
>>>> Images 4 and 6 of this one:
>>>>
>>>>
>>https://www.google.com/patents/US7020217?dq=inassignee:%22Xm+Satellite+Radio+Inc.%22&hl=en&sa=X&ved=0ahUKEwj5ycbeoP_LAhXEXh4KHWSdDeA4HhDoAQgwMAM
>>>> Image 4 of this one:
>>>>
>>>>
>>https://www.google.com/patents/US6510317?dq=inassignee:%22Xm+Satellite+Radio+Inc.%22&hl=en&sa=X&ved=0ahUKEwikn4Ogof_LAhVIJx4KHYaYCt44KBDoAQhTMAg
>>>>
>>>> And maybe the most useful I've skimmed:
>>>>
>>>>
>>https://www.google.com/patents/US7123875?dq=inassignee:%22Xm+Satellite+Radio+Inc.%22+MCM&hl=en&sa=X&ved=0ahUKEwidqpT1of_LAhUFXh4KHXqIDuEQ6AEIKjAC
>>>> Images 1, 5, and 6.
>>>>
>>>> This particular patent also indicates that after the demod, RS
>>decoder,
>>>> viterbi decoder, and deinterleaver, that an MPEG TS *might* be the
>>>> transport multiplex.
>>>>
>>>> The images show that the decryption happens after all the FEC and
>>>> deinterleaving is handled and also after SL (service layer)
>>decoding.
>>>> The I2C connected external NVRAM is likely where the program
>>decryption
>>>> key is stored (inside of a tamper boundary), according to other
>>internet
>>>> pages from 7 years ago.
>>>>
>>>> So I'm guessing you have to totally demodulate and decode one of the
>>SAT
>>>> or terrestrial channels, and then dig around in a (hopefully MPEG)
>>>> transport stream to find your unencrypted "Channel 1"
>>>>
>>>
>>> The STA400A datasheet gives a lot of good information about the XM
>>signal
>>> characteristics, bit rate, RCC filter bandwidth, code rates and
>>puncturing,
>>> proper order of FEC blocks, etc.:
>>>
>>> http://www.chipfind.net/datasheet/pdf/stmicroelectronics/sta400a.pdf
>>>
>>> Enough info to give one half a chance of getting the demodulation
>>correct.
>>> It also talks a little bit about the frame structure.
>>>
>>> This MAXIM 2140 App Note has a yet another picture of the spectrum
>>> allocation, that also shows Sirius' and WCS' allocations in context:
>>>
>>> http://pdfserv.maximintegrated.com/en/an/AN3851.pdf
>>>
>>> I also found a Sirius patent that talks about an overlay modulation,
>>but it
>>> wasn't clear to me if it was being applied to the XM satellite
>>signals.
>>>
>>> Regards,
>>> Andy
>>>
>>> _______________________________________________
>>> Discuss-gnuradio mailing list
>>> address@hidden
>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>
>



-- 
GDB has a 'break' feature; why doesn't it have 'fix' too?