According to the characteristic of synchronizer signal, multi-channel synchronizer signal generator is designed based on USB and C8051F340. Software implementation is given using Aitken interpolation algorithm. It greatly reduces the cost of development and effectively improves the precision. Meanwhile, using the USBXPress development kit for PC and firmware development shortens the development cycle. Compared with the special numeric synchronizer converter, the price of designed Synchronizer signal generator cheap 100 times, the full range error less than 0.04º and the accuracy improved 25 times. At the same time, it has work stability, strong anti-interference and high practical value.

The paper briefly introduces the structure principle and excellent characteristics of protograph LDPC codes and designs the serial encoding circuit based on FPGA. On the basis of the further study of Belief Propagation (BP) algorithm, λ-min algorithm and A - min algorithm, decoder is designed adopting the complexity and performance eclectic mixed decoding algorithm. Meanwhile, it is verified by the simulation. The result shows that coding gain can be up to about 6 to 8 db, if it meets the requirements of 10-5bit error rate.