Trying to lock onto an MSK signal. I don't think any of these is the right constellation...pic.twitter.com/I0Op6OdIhf
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I use a sampling rate of 4 times the symbol rate, because the DSP library (liquid) wants an integer ratio. There's no MSK synchronizer available so I tried to lock it using common QPSK constellations, resulting in this funniness. Perhaps there's a better way to synchronize MSK.
The third image *could* be okay? If you're sampling at 4x (and plotting those extra samples too) then that would explain the extra points between the four corners. AIUI MSK is supposed to look like a square (like OQPSK). Not sure why it would turn out rectangular though.