On 06/25/2020 12:44 PM, Cameron Matson wrote:
I moved my setup from e312s to n310s so that I could run the
flowgraphs with the gui blocks to help with debugging. It looks like
the phase is off at the RX as the constellation gui from the USRP (the
one before the Packet Rx block) is rotating. I'm able to adjust the
magnitude of the IQ data by playing with the tx and rx gain, but I
can't get the phase to lock.
What are some of the knobs I can turn to help the Packet Rx block
detect the signal given the phase offset?
Thanks,
Cameron
So an independent RX and TX will NOT be operating on exactly the same
frequency. This means that for many types of phase-sensitive
modulation, the RX needs to track the phase rotation caused by the
(small) frequency difference. This is just standard modem
design, and you'll need to look at carrier-tracking with PLLs, etc.
There are a plethora of folks on here more adept than I at suggesting
which PLL approaches to take, but suffice it to say, any modem RX design
that doesn't include some kind of PLL-based tracking is "born flawed".
