Research On The Key Technology Of Telemetering Intermediate Digital Reaceiver

With the rapid development of wireless communication technology, softwareradio technology, digital receiver has become an important part in moderncommunication systems for the characteristics of generality,openness andprogrammable. Therefore, it is significant to research into and develop digital IFreceiver. With the wide development of telemetry system, the distance of telemetrysystem becomes more longer. So the telemetry digital IF receiver should have goodperformance at low SNR(Signal Noise Ratio).In the dissertation Digtal Down Converter and bit synchronization technique isanalyzed based on the digital IF receiver. The Digtal Down Converter technique isrealized by Multirate Signal Processing method, and a bit synchronization algorithmat low SNR is proposed.What’s more, a novel bit synchronization method for low SNR is suggested inthis dissertation. Bit synchronization is known as symbol synchronization which isthe special technique in communication system. Bit synchronization is needed inboth baseband transmission and RF transmission system. A non-optimal bitsynchronization algorithm will effect the performance of the communication system,Even caused the communication system invalid. So bit synchronization is thecrucial technique of the communication system.As the SNR is lower than othercommon communication system, And traditional bit synchronization algorithmcan’t meet the requirement.So by means of mean filtering,A bit synchronization forlow SNR algorithm based on FPGA is proposed and applied to Telemetry digital IFReceiver in this dissertation. And it is shown that this algorithm has a goodperformance for low SNRFinally, Via the simulation with MATLAB and programming with VHDLlanguage， and then it is compiled in the Quartus II software，running timingsimulation testing and debugging with SignalTap II software. The Digtal DownConverter and bit synchronization technique is implemented on FPGA.