First try at prototyping the PLC transmitter using 2x 74LV4046A. It works but the jitter is more than I like, giving a noisy signal. The CD4046, based on an older process technology, is rumored to have a better VCO section, which I'll be testing when I get them. (Digital circuits favor newer processes while analog circuits usually favor older processes.)
I used GNUradio to build a signal analyzer on my PC. In the actual application, the signal processing code will have to be ported to Verilog in order to run it on a FPGA, the sort of stuff Tiffany Yep is good at. Sadly, she's too busy to really help me with that, but she did give me a list of resources she used to learn how to do DSP in Verilog. (Now I get to have a bit of a feel of what it's like to be Tiffany Yep, but I don't think it would make me as good looking as her...)