Phase synchronization

[wbarnha]

Looks like the phase synchronization block for the horizontal and vertical channels we developed won't do the job. Can we figure out what's going on through trial and error?

[wbarnha]

Did a lab test at 915 MHz with BPSK. This looks quite promising!

We'll move forward to retesting our RF front-end.

[wbarnha]

Reassigned tasks. This is going to get quite difficult.

[wbarnha]

It seems that the phase offset is so significant, we need to take an empirical approach.


There appears to be a phase difference of 269.1093 microseconds for this demodulated 333 Hz signal. The carrier is not included since this is in baseband. I have developed an equation that can help us estimate the necessary number of samples to achieve reasonable synchronization.

[wbarnha]

Ran a test at 145 MHz and it works pretty well. However, we need to delay by 223 samples for a sampling rate of 2 MHz and downsampling factor of 10 for our saved IQ data. The time delay between these peaks are normally 111 microseconds and at 146 MHz the delay is 269 microseconds. If there's a difference this pronounced, then we need to factor in the delay related to the difference in lengths for the transmission line.

[wbarnha]

Adaptive synchronization is not possible unless we utilize a message being sent to a variable. Regarding the architecture of GNU Radio, we cannot create feedback looks, which this would require. We have interpolated approximated delay times between 145 and 146 MHz, which should suffice for creating symbol synchronization. Regardless, this feature may never see use since the signal strength received by a single polarity is drastically different from the opposite polarity.