[amsat-bb] Re: ARISSat 1 & Funcube Telemetry Question: DBPSK vs BPSK

[Alexandru Csete]

On Sun, Feb 6, 2011 at 12:36 PM, Iain Young, G7III <g7iii at g7iii.net> wrote:
> Hi All,
>
> Just a quick clarification needed by me on the Telemetry format that is
> going to be used by ARISSat-1 and Funcube (& I guess the Funcube boards
> onboard UKube-1...)
>
> Lots of places are referring to it as BPSK1000, but I have seen
> references claiming it is DBPSK. Can someone clarify if it is
> Differential BPSK, or "just" plain old BPSK as used before, but at 1000
> BPS, rather than 400 ?
>
> Reason for asking is that I have a USRP, and use gnuradio, along with
> the gnuradio-companion. That has DBPSK blocks built in, but pure BPSK
> would take a little more work (possibly just routing the output to a
> loopback soundcard, and then running decoding software)
>

Hi Iain,

It is differentially encoded. You can find the specification on Phil
KA9Q's website:
http://www.ka9q.net/bpsk1000.html
He has also made his reference modem available under GPL:
http://www.ka9q.net/demod2.tar.bz2

The package contains functional application that can send and receive
BPSK1000. What I am still missing is description of the telemetry
format, i.e. how to translate the decoded data stream into engineering
values. Is there such a document available?

73
Alex OZ9AEC