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I'm attempting to decode a manchester-encoded packet using GNU Radio Companion. I've been following this example where the author decodes packets from a Somfy window blinds remote. From what I've read in that article and this mailing list, the Viterbi Combo block is the way to perform manchester decoding.

The Viterbi Combo block requires the block size (frame size) beforehand. This isn't a problem in the case of the first article because the frame size is fixed and known beforehand. In my case, however, the frame size is variable and conveyed in the first octet of the header. i.e.

[preamble][sync][header][data][crc]

There are several blocks for extracting length information out of a stream, but these assume that the manchester decoding has already been done. Is there a way to do manchester decoding without knowing the block size? Is this a case where I need to make my own custom block?

watkipet
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    I Also don't know how to decode manchester... This guide ( https://nccgroup.github.io/RFTM/fsk_receiver.html ) just says manchester and sort of inexplicably assume that the ClockSync block would decode (for that I don't see no reason); +1 Q. I'm on the verge of writing my own python code for this rather simple process. – HLL Jun 11 '17 at 16:51
  • I ended up writing my own C program that read from a named-pipe. It actually did the clock recovery at the same time. It's not the orthodox way to do things, but it was simple and it worked for me. – watkipet Jun 12 '17 at 05:03
  • I'm also doing just that in python (working on it) can you post? (Here is the start of mine, still WOP https://pastebin.com/cBFgRRiP ) – HLL Jun 18 '17 at 09:17

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