Study On Bit Synchronization Technology Of All-digital Receiver

In digital communication system, synchronization is a very important question. Whether communication systems can work validly and reliably or not depends on synchronization technology. In other words, synchronization affects the quality of communication directly. So it is a key technology in communication system. Bit synchronization is the most basic synchronization.It is the foundation of correct judgement, and makes signal recovery the correct data in recevier.This thesis mainly deals with the bit synchronization for all-digital receiver.The main work and achievements of this paper are summarized as follows:1. This paper summarizes timing synchronization in different situations, analyzes the bit timing technology for continuous signal and burst signal, and discusses feedback and feedforward algorithm. Otherwise, for different modulation signals, such as QPSK, BPSK, OQPSK, QAM, MSK signals, studies the difference of bit synchronization algorithm according to their characteristic.2. This paper studies on interpolation which is a special problem in all-digital receiver. In digital modem, if sample rate and data symbol is asynchronous, it should adjust timing according to interpolation.It discusses theory and component of interpolation, and studies its performance. In order to reduce the calculation complexity and resources, this paper designs a kind of interpolation filter based on polynomial, realizes and optimizse its structure. These simulations show: the designed interpolation filter can work reliably.3. Gardner algorithm, which requires only two samples per symbol for its operation, and one of the two samples, is also used for the symbol decision. It is also not decision directed, and is quite independent of carrier phase. This paper designs timing error rate algorithm by adopting Gardner algorithm, studies its influence according to different Square-Root Raised-Cosine roll-off coefficients.This paper study shows: Timing synchronization scheme with designing Gardner algorithm and interpolation can implement correct system data recovery.4. The paper studies on a filtering and squaring algorithm and its improvement algorithm in bit timing estimate application. According to comparing algorithm performance, its performance is improved notably after improving.Then analyzes algorithm performance under different estimate length, and obtains the condition that the best performance can meet.This paper is developed based on all-digital receiver need, its contents and relevant results can be further applied to the software radio system and design for bit timing technology study and design.