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Re: Re: [Discuss-gnuradio] FSK with TX-RX in ISM-band 433 Mhz

From: Luis Simoes
Subject: Re: Re: [Discuss-gnuradio] FSK with TX-RX in ISM-band 433 Mhz
Date: Fri, 24 Mar 2006 14:01:29 +0100
User-agent: KMail/1.8

Hi Thomas,

nice to see someone in the gnuradio world treating with the same problems.
In my case the cc1k send 5 preamble bytes (0x6666) followed by a
synchronisation sequence of 0x9999. After this comes the header and my data.
The synchronisation sequence of 0x9999 is the chip pattern of transmition
 what represents a bit pattern of 0x33.
Could you sent me some of your code to see how you realised the
synchronisation detection and the manchester decoding? Did you use bit
padding as in gmsk2?

Thank you in advance,

Luis Simoes
Department of Wireless Networks
RWTH Aachen

On Wednesday 22 March 2006 20:44, you wrote:
> Hi Luis,
> I have the code to decode mica2 motes. It is not perfect yet since I
> still use the correlator and I would like to move over to the gmsk way
> with proper synchronisation. But it works ;)
> In my case, the cc1k sends a synchronisation sequence of 0x999999 to
> which I synchronize the correlator. Then, I feed the found softsymbols
> into the sos_packet_sink. You have to note that I use SOS as an
> operating system on the mica2s. SOS adds a sync sequence just before
> the message starts (tinyos does the same). The sos_packet_sink then
> finds that sequence in the soft symbols which allows us to get byte
> synchronisation. Then, we can look at the packet header and read the
> whole message. Once parsed, the messages get added to a msg_queue.
> >From the message queue, they get to the registered callback.
> Thomas


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