Method of synchronizing precise timing of DVB-T2 (Digital Video Broadcasting-Terrestrial 2) system

Abstract

The invention discloses a method of synchronizing precise timing of a DVB-T2 (Digital Video Broadcasting-Terrestrial 2) system. The method comprises the steps: extracting the pilot frequency of a first P2 symbol in the received T2 frame, performing pseudo random sequence correction, and carrying out IFFT (Inverse Fast Fourier Transform) to obtain channel impulse response; according to the average power and envelope of the channel impulse response, separating the effective path in the channel impulse response; making relation with a time domain P2 signal by using the time domain signal of the locally generated P2 pilot frequency according to the position of the effective path in the channel impulse response and the imaging position of the effective path, analyzing and judging the true position of the path in the channel impulse response; judging the characteristic of a channel by judging whether a path exists before a main path of a CIR, thus regulating the window of FFT (Fast Fourier Transform) in time domain by utilizing the minimal intersymbol interference principle. By utilizing the method, the computation amount and locking time can be greatly reduced, the synchronization accuracy of the precise timing can be improved, and the power consumption of the DVT-T2 system can be decreased.

Description

technical field [0001] The invention relates to a method for fine timing synchronization and FFT window adjustment in a DVB-T2 system. Background technique [0002] In a multi-carrier system, in order to maintain the orthogonality of OFDM symbols and minimize the mutual interference (ISI) between OFDM symbols, a guard interval (GI) is usually inserted between two OFDM symbols to achieve the above the goal of. That is, a certain proportion of the tail of the current OFDM symbol is copied to the start position of the current OFDM symbol. [0003] In a multi-carrier system, in order to adapt to different channel environment conditions, there are usually a variety of guard interval ratio modes to choose from. In the receiver, the length of the guard interval selected by the current system must be determined in order to correctly determine the start of the OFDM symbol. Location. In a multi-carrier system, in order to receive signals correctly, the receiver must determine the s...

AI Technical Summary

Problems solved by technology

Since each FFT / IFFT operation will consume a large amount of computing time, when the number of paths in the channel is large (greater than 5), the system locking time will become very slow, which will lead to very complicated system control on the one hand, On the other hand, it will cause the overall locking time of the receiver to become longer, which is manifested in the long time of searching and changing channels

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