Large frequency deviation detecting method of DTMB receiving system

A detection method and technology for a receiving system, which are applied in transmission systems, multi-frequency code systems, broadcast transmission systems, etc., can solve problems such as slow speed, and achieve the effects of low complexity, short time, and reliable estimation.

Active Publication Date: 2009-10-14
麦克盛科技(香港)有限公司
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Problems solved by technology

The disadvantage of frequency sweep is that it is slow, an...

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  • Large frequency deviation detecting method of DTMB receiving system
  • Large frequency deviation detecting method of DTMB receiving system
  • Large frequency deviation detecting method of DTMB receiving system

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Embodiment Construction

[0018] Referring to the accompanying drawings, the present invention will be described in further detail below in conjunction with the accompanying drawings.

[0019] In the frame structure of the terrestrial broadcast transmission system signal defined by the Chinese national standard, a complete signal frame consists of a frame header and a frame body, and the frame header is composed of a determined PN sequence modulated in the time domain. After finding the position of the frame header in the baseband sampling signal received by the receiver, the frequency offset can be estimated by fast Fourier transform using the sequence obtained by dot multiplying the local sequence and the frame header part in the received baseband sampling signal. The position of the frame header can be obtained by segmenting the local PN sequence and correlating with the received baseband sampling signal, and then performing peak judgment. Usually, the correlation peak will be affected by the freque...

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Abstract

The invention discloses a large frequency deviation detecting method of a DTMB receiving system. The position of a frame head is found through a relevance to a PN sequence and a subsection of receivedbaseband sampling signals. Point multiplication is carried out onto a data symbol sample point which is received by and corresponds to a local PN sequence so as to obtain a point-multiplied data sequence. The point-multiplied data sequence undergoes fast Fourier transformation, and a greatest peak value is found from transformed values so as to estimate the large-carrier frequency deviation of tens of and even hundreds of kilohertz. The large frequency deviation detecting method has low complexity, can reliably and correctly estimate the carrier frequency deviation and needs shorter time compared with a frequency scanning method. The method is applicable to digital televisions receiving chips which comply with the national standard of digital terrestrial television of People's Republic ofChina, or other receiving chips of wireless transmission systems using a time domain pseudo-random sequence.

Description

technical field [0001] The invention relates to the field of wireless signal transmission, in particular to a method for detecting large frequency deviation in a DTMB (digital terrestrial multimedia broadcasting) receiving system. Background technique [0002] Carrier synchronization is the basis for receiver implementation in communication systems. The reasons for carrier desynchronization are as follows: 1. There is a difference between the local oscillators of the transceivers; 2. The Doppler effect caused by the relative motion between the mobile station, the base station, and the reflector will cause frequency jitter. [0003] The carrier frequency offset between the transmitting end and the receiving end is called carrier frequency offset (hereinafter referred to as frequency offset). A tuner with a relatively stable crystal oscillator is usually used in the receiver, which can reduce the complexity of the receiver, and of course increase the cost of the receiver. Ba...

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Application Information

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IPC IPC(8): H04L27/26H04B1/707H04H20/72
Inventor 蒋朱成杨毅潘国振张帆
Owner 麦克盛科技(香港)有限公司
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