Fwd: Capturing 2 Level FSK with frequency hopping?

[WarMonkey]

First you should build a packet detector which can determine if there is a packet over the air or not. This can be done by detecting channel power change

Then you can cut out the part of I/Q stream which just includes one packet. After that you can run frequency demod on the packet.

To demod this kind of burst please consider it as an optimizing procedure: you guess the center freq, symbol phase and symbol rate of the FSK burst, making both the freq and symbol timing error minimized.

Peter Lambrechtsen <peter@crypt.nz> 于2022年7月10日周日 18:20写道：

Hello,

Excuse my ignorance as I am fairly new to gnuradio but I am trying to figure out how best to capture a data stream that is in the ISM band that also has frequency hopping. 

Channel spacing of 25kHz 

It has two data bit rates of 62.5bps and 500bps

Starting at 910.5Mhz and going up to 919.975 and in there it has 6 sub bands of 60 channels it hops between sequentially between the frequencies in the sub band every 0.4s

I'm wondering what the best approach would be to capture the data and figure out when the timing frame was to determine which was the initial frame as then it should be able to follow the sequential hopping.

Still trying to work on the blocks to capture all the traffic as I haven't figured that out yet as I am just working off the specification and trying to understand the Frequency Xlating FIR Filter to at least capture one FSK stream to make sure it is sane what I should be receiving, then move to the frequency hopping.

Thanks, Peter