High-frequency offset carrier recovery system and method for cable digital television
A cable digital TV and carrier recovery technology, applied in the field of digital signal transmission, can solve the problems of long time consumption and small frequency offset range, and achieve the effect of overcoming the long time consumption
Active Publication Date: 2013-05-08
SHENZHEN STATE MICRO TECH CO LTD
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Problems solved by technology
[0006] In order to overcome the shortcomings of the time-consuming method of sweeping frequency plus guiding judgment method and the shortcoming that the polarity judgment method plus guiding judgment method can correct the small frequency deviation range, the purpose of the present invention is to propose an easy-to-implement large frequency deviation carrier recovery for cable digital TV system
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[0021] Below, the technical solution of the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.
[0022] The large frequency offset carrier recovery method used in the cable digital TV of the present invention is a carrier recovery method for rapid correction of large frequency offset by using three methods of frequency sweep, polarity judgment and guidance judgment at the same time.
[0023] The frequency sweeping method starts from an initial frequency and increases with the frequency sweep step. The judgment module works in each adjustment period (sweep frequency interval), and then calculates the mean square error (MSE) according to the signals before and after the constellation judgment. When the carrier frequency deviates, the MSE will drop significantly, so it can be determined whether the carrier frequency is scanned by comparing the MSE with the threshold value. In addition, when the carrier is captured,...
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The invention discloses a high-frequency offset carrier recovery system and a high-frequency offset carrier recovery method for a cable digital television. The recovery system comprises a sweep-frequency module, a polarity determining module, and a guide determining module which are used in a carrier recovery module and connected with one other. After sweep-frequency points are subjected to frequency sweeping, signals are subjected to polarity determination; and after the polarity determination, the signals subjected to error correction are subjected to guide determination. The rapid high-frequency offset carrier recovery method with a drifted correction center overcomes the defect that the traditional sweep-frequency and guide determining methods are time-consuming, and overcomes the defect that the polarity determining and guide determining methods correct too small frequency offset. Therefore, the carrier recovery method has the advantages of rapid correction and high-frequency offset correction.
Description
technical field [0001] The invention belongs to the field of digital signal transmission, and in particular relates to a large frequency offset carrier recovery system and method for cable digital television. Background technique [0002] Digital cable TV is a kind of broadcast service based on cable TV network transmission, and it is also the development trend of cable TV broadcast in the world today. The system is a cable TV system that converts analog TV signals into digital signals and processes and transmits them digitally. [0003] So far, several different standards have been formed in the world; taking Europe as an example, since 1995, Europe has successively released digital TV terrestrial broadcasting (DVB-T), digital satellite broadcasting (DVB-S), digital TV Cable broadcasting (DVB-C) standard. In 2001, China also started the trial broadcasting of digital cable TV. [0004] In the cable digital television (DVB-C) standard, since all parameters of the signal tr...
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IPC IPC(8): H04L25/03H04L27/38H04N7/10
Inventor 吴建兵陈燕生
Owner SHENZHEN STATE MICRO TECH CO LTD