Is it possible to use a Logic Analyzer (such as this one), to determine the waveform s.t. on the DATA out pin of an ISM-band ASK/OOK (315/433.92MHz) RF module, in turn to decode it's encoding scheme. I know for sure that it is not Manchester/NRZ. By 'waveform', I mean the highs/lows with the duration of every bit
Note that this questions is an extension of my other thread on choosing a DSO. While I might still go in for a DSO, but I really wanted to thoroughly understand the LA as an option for my purpose.
Now for the other (possibly dumb) question -- will a logic-analyzer work without a clock input ? Say in my case of decoding ASK/OOK encoded data, I have no way to retrieve the clock, as this is asynchronous operation.
Query extension (Nov 9, 2011): My target RF encoder's encoded pattern uses 32 oscillation cycles to encode every bit. So for 9600baud, I have 307200 sample/sec. However, for better accuracy, it might be good to use 3x-5x that many no. of samples (does this concept apply for Logic Analyzers as well) ? If that is true, then for 5x sampling, I'd need 1536000 (~1.5Ms/s), on a single channel. Of course, this reasoning for (kind-of over-)sampling comes from the DSO world, but not sure if it applies for Logic-Analyzers as well ?
Answer
I did exactly that in a previous project, I didn't use the open logic analyzer but the bus pirate which uses the same software.
http://s3cu14r.wordpress.com/2011/06/19/basic-rf-sniffing-with-the-bus-pirate/
I used this to decode the protocol for another project that sniffed RKE data.
http://hackaday.com/2009/10/03/garage-door-packet-sniffer/
Hope this helps.
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