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Carrier track loop adaptive for digital television terrestrial broadcasting

A digital TV terrestrial and carrier tracking loop technology, applied in the direction of AM carrier system, high-definition television system, electrical components, etc., can solve problems such as signal damage, and achieve the effect of removing frequency jitter

Inactive Publication Date: 2006-12-13
SHANGHAI JIAO TONG UNIV
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  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

The technical problem to be solved in the present invention is that the damage and distortion of the signal in the wireless transmission process of the high-speed digital signal require carrier recovery processing in the receiver to restore the correct data at the starting point, the purpose of the present invention In the ADTB-T OQAM system receiver, a carrier tracking loop is added after the equalizer to remove the remaining carrier frequency jitter

Method used

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  • Carrier track loop adaptive for digital television terrestrial broadcasting
  • Carrier track loop adaptive for digital television terrestrial broadcasting
  • Carrier track loop adaptive for digital television terrestrial broadcasting

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Embodiment Construction

[0025] The embodiments are further described below in conjunction with the accompanying drawings.

[0026] image 3 The basic structure of the carrier tracking loop of the present invention and the block diagram of NCO driving information generation are shown. The carrier tracking loop includes an FIR of an equalizer, a DFE of an equalizer, a complex multiplier, an adder, a decision device, a subtractor, a real multiplier, an accumulator, and a loop low-pass filter.

[0027] Among them, the loop low-pass filter can generally be replaced by an active proportional-integral filter.

[0028]Its main workflow is: the complex signal obtained after OQAM demodulation is composed of I and Q signals (I+jQ); the output after the complex equalization FIR is still a complex signal (I′+jQ′), (I'+jQ') and the total phase difference  complex multiplication (equivalent to phase derotation), remove the frequency and phase jitter, and take out the real baseband signal; the above real baseban...

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Abstract

The invention discloses a carrier tracing loop of digital TV ground broadcast in the digital signal transmission domain, which comprises the following parts: equalizer FIR, DFE, complex multiplier, adder, judger, subtracter, real multiplier, accumulator and loop low-pass filter, wherein the demodulated complex signals is composed of I and Q paths, which is output as complex signal through equalizer FIR; the complex signal is multiplied by total phase difference phi with real baseband signal being fetched out in the adder with DFE output, which obtains the output of equalizer; the judger disposes the signal, which enters into subtracter after DFE; the signal and imaginary part Q' output by equalizer FIR are sent in the real multiplier; the signal is sent in the accumulator to eliminate phase-detector noise, which outputs driving frequency error signal delta f of digital control oscillator.

Description

technical field [0001] The invention relates to a carrier tracking loop in the technical field of digital signal transmission, in particular to a carrier tracking loop suitable for digital television terrestrial broadcasting. Background technique [0002] In a high-speed digital signal wireless transmission system such as digital high-definition television (HDTV), the signal undergoes linear and nonlinear fading of the channel during wireless transmission, and non-optimization of the sampling interval and carrier phase in the receiver, etc. The damage caused by the signal changes the state of the original digital signal. These distortion changes need to be processed in the receiver to restore the correct data at the starting end. [0003] In single-carrier modulation transmission VSB (Vestigial Sideband), QAM (Quadrature Amplitude Modulation), OQAM (Offset Quadrature Amplitude Modulation) systems, the received signal is usually subjected to 4 steps: carrier recovery, Timing...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B7/185H04L27/01H04L27/02H04N7/015H04N7/20
Inventor 管云峰归琳孙军
Owner SHANGHAI JIAO TONG UNIV
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