1. Software version
quartusii12.1，matlab2017b
2. Theoretical knowledge of this algorithm
First: segmented update of loop filter coefficients to achieve stable frequency tracking effect. When the phase-locked loop starts to work, the fast tracking of the frequency is realized by a group of larger loop filter coefficients, and then the stable tracking of the frequency is realized by a group of smaller loop coefficients.
Second: loop smoothing.
Third: Perform frequency and phase discrimination at the same time
The above two are improvements in performance, and then for the design of FPGA, we adopt the following improved design framework.
First: The pipeline-based design process enables the carrier synchronization algorithm to perform feedback work in the form of streams;
Second: NCO based on Cordic algorithm generates corresponding SIN and COS.
QAM modulation:
Here, we mainly modulate through the mapping table of QAM64, and the mapping table is as follows: