Design And Implementation Of Vector Signal Analyzer For Cable Tv

DTV has been popular in China, especially the cable DTV technology.With the development of DTV, kinds of measurement instruments about DTV are emerging in recent years, which vector signal analyzer most widely used in cable TV.The analyzer can test and measure the signals from the time domain, frequency domain and modulation domain, which is all-round and multi-angle.The analyzer can provide a comprehensive solution for the measurement of DTV transmitters, the test of the receivers and the cable channel assessment test.This paper successfully designs and implements the vector signal analyzer for cable DTV based on FPGA, using the idea of the software radio, the all-digital receiver design and the PLL theory.The paper first introduces QAM demodulation and basic principles of PLL.It proposes the design programs of analyzer, and then details IF digital signal processing algorithm of analyzer, including DDC, MF, timing recovery and carrier recovery.To understand the performance of the algorithms and complexity of the FPGA implementation, the algorithms have been simulated in MATLAB. Based on this, the circuit design and function simulation have been implemented and taken on the ALTERA FPGA platform. Finally, the timing simulation of the design has been taken in the third-party software - ModelSim. The design system has achieved the desired targets and requirements from the shows of simulation results. Finally, this paper designs the board-leve verification platform for the cable analyzer, and gives a brief introduction to design the system testing.After the timing and resource optimization for the FPGA system design, this design can be transformed to QAM demodulation chip to reduce the size and cost, also enhance the reliability of the circuit for the system, so the design of this paper also has good practical value.