An acquisition method of frame head pseudorandom noise(PN) mode in digital terrestrial television multimedia broadcast(DTMB) system based on fast fourier transforms(FFT) was proposed according as the analysis of the character of frame head PN in Chinese national standard on DTMB. In this method, firstly, three kinds of local sequence are chosen based on the frame head-s character and the difficulty in hardware design to correlate with signal frame received, in which FFT correlation method was used. Then, correlation peak of each channel was compared with the relevant threshold to judge whether the acquisition succeed in a certain channel or not. At last, frame head mode corresponding to the channel which has acquired PN successfully was chosen as the final frame head PN mode for the output. Compared with the acquisition method based on time-domain correlation, the proposed method needs less computation overhead and acquisition time. Simulation results show that the method can acquire and identify all kinds of frame head PN mode accurately and the feasibility of the method is validated.
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