Firstly, thanks for the prompt assistance.
"The modulator expect /packed/ bytes, so what you are providing it with is a lot of 0's."
But I have an Unpacked -> Packed block set to MSB before the modulator. So with the Vector Source generating a sequence of (1,0,1,1,0,0) it should be packing bytes as follows:
1xxxxxxx 10xxxxxx 101xxxxx 1011xxxx 10110xxx 101100xx 1011001x 10110010 <--so that 1st byte received by the modulator is 50% 1's, then...
1xxxxxxx 11xxxxxx 110xxxxx 1100xxxx 11001xxx 110010xx 11001011 11001011 <--2nd byte is 62%% 1's....
0xxxxxxx 00xxxxxx 001xxxxx 0010xxxx 00101xxx 001011xx 0010110x 00101100 <--3rd byte is 37% 1's... and then the sequence repeats. Correct?
"Set the random source to produce values of [0, 256)."
That's how it is currently configured, and produces a messy output.
"Most likely, we'll be using the Constellation Modulator block and remove both DPSK and PSK Mode blocks."
Ok, good to know. I've updated my flowgraph with the Constellation Modulator block.
"Which block exactly? There's the "BER" block from the Error Coding category that comes with GNU Radio"
I was using the "Error Rate" block from the Misc category. I've switched to the BER block you mentioned and I get an error rate of roughly 50% with the default settings and then flowgraph still freezes after a few seconds.
"You really want to reduce this value (< 10, usually 2 to 4 is good enough) and handle the upconversion for the FHSS in a different way down the line. Basically, keep your sample rate as small as possible for as long as possible."
Hmmmm, looks like I've got some reading to do....
At any rate, I've attached an updated GRC. In its current configuration, I have constellation sinks showing the output at each block in the receiver. Everything seems to work correctly and you can see the constellation clear up. If I simply disable the Vector Source and Unpacked->Packed blocks and enable the Random Source.....the constellation becomes a cloud after the CMA Equalizer. I've fiddled with the sample rates and it seems the constellation significantly worsens somewhere around 6e5-7e5 samples....roughly 10x2^16....I'm not sure what to make of that.
-Jason