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Method for empty symbol and pattern discrimination and frame synchronization of DAB system

A pattern discrimination and empty symbol technology, applied in the field of electronic communication, can solve problems such as reducing algorithm multiplexing, prolonging signal recovery time, and occurrence of deviation, so as to avoid multiplication operations, facilitate popularization and application, and improve accuracy

Inactive Publication Date: 2009-10-14
威望科技(苏州)有限公司
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Problems solved by technology

And the algorithm based on the DAB empty symbol often has deviations in the calculation when the signal-to-noise ratio is low, which affects the quality of signal processing
[0004] Therefore, the frame synchronization of the DAB signal cannot be quickly performed using these traditional algorithms, which will inevitably prolong the signal recovery time, so it is impossible to quickly recapture the signal when the signal is lost
And the design of these traditional algorithms depends on the structure of the DAB signal, so it cannot be applied to the synchronization calculation of the general OFDM signal, which will greatly reduce the multiplexing of the algorithm, thereby reducing the competitiveness of related products in the market

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  • Method for empty symbol and pattern discrimination and frame synchronization of DAB system
  • Method for empty symbol and pattern discrimination and frame synchronization of DAB system
  • Method for empty symbol and pattern discrimination and frame synchronization of DAB system

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[0029] In the following, the DAB signal of mode 1 and mode 2 under different signal-to-noise ratios is taken as an example to further describe the technical solution of the present invention in detail.

[0030] For digital audio broadcast signals, the signal obtained by the receiving end after de-carrier and down-conversion processing is an OFDM signal with a sampling rate of 2.048MHz, and its OFDM symbol is as figure 2 Shown. From figure 2 It can be seen that each OFDM symbol A includes two parts, namely guard interval B and FFT length C. The guard interval B is a copy of the sequence B'at the end of the FFT length C. In particular, for the mode 1 signal, the guard interval B is 504 samples, and the FFT length C is 2048 samples. For the mode 2 signal, the guard interval B is 126 samples and the FFT length C is 512 samples.

[0031] Further combining the test results in Table 1 to Table 5, the test results show that even when the signal-to-noise ratio is reduced, starting synchron...

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Abstract

The invention relates to a method for empty symbol and pattern discrimination and frame synchronization of a DAB system, which comprises the following steps: firstly, performing the correlation calculation of variable step size according to the length of OFDM signals under different patterns of DAB signals; secondly, respectively calculating the maximums from the results of the correlation calculation according to a certain length, and differentiating adjacent elements of a vector Mk; thirdly, calculating the absolution of the Dk, then summarizing the Dk to obtain Sk, and collecting the number of zero elements in the Dk to obtain Zk; fourthly, respectively calculating the maximum from the Sk and calculating the minimum from the Zk, therefore, determining the transmission pattern of the DAN system according to the subscripts of the maximum and the minimum. The invention is suitable to a plurality of OFDM signals such as DAB, DVB-T / H, STIMI, and the like, reaches the shortest time required by the pattern discrimination and frame synchronization of the DAB signals, improves the accuracy of empty symbol detection and frame synchronization, and is convenient for being implemented in an integrated circuit design.

Description

Technical field [0001] The present invention relates to Orthogonal Frequency Division Multiplexing (OFDM) signals, in particular to Digital Audio Broadcasting (DAB) signals, and particularly to methods for identifying null symbols and modes and frame synchronization in DAB signals, which belong to the technical field of electronic communication. Background technique [0002] In the DAB system, data is transmitted in a frame structure. The frame is composed of a null symbol (Null Symbol) at the beginning and a number of Orthogonal Frequency Division Multiplexing Symbols (OFDM Symbol). According to different null symbol lengths and different orthogonal frequency division multiplexing symbols, the structure of the DAB frame is divided into four transmission modes. When doing system synchronization, the DAB transmission mode must first be detected. After the transmission mode is determined, the position of the orthogonal frequency division multiplexing symbol can be determined. Subse...

Claims

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Application Information

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IPC IPC(8): H04L27/26
Inventor 刘一京
Owner 威望科技(苏州)有限公司
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