Adaptive equalizing and carrier recovering method suitable for high-order QAM and circuit thereof

An adaptive equalization and carrier recovery technology, which is applied in multi-carrier systems, shaping networks in transmitters/receivers, baseband system components, etc., can solve the problem of signal-to-noise ratio reduction, difficult carrier recovery algorithm carrier frequency offset, Signal distortion and other problems, to achieve the effect of reducing the steady-state phase error, improving the ability to capture frequency offset, and improving system performance

Inactive Publication Date: 2005-10-26
上海微科集成电路有限公司
View PDF0 Cites 26 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] For high-order QAM signals, the distance and phase difference between the constellation points become smaller, so blind equalization and carrier recovery are more difficult
If the carrier recovery is performed directly, the signal will be severely distorted due to bad channels, a

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Adaptive equalizing and carrier recovering method suitable for high-order QAM and circuit thereof
  • Adaptive equalizing and carrier recovering method suitable for high-order QAM and circuit thereof
  • Adaptive equalizing and carrier recovering method suitable for high-order QAM and circuit thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0029] Further describe the present invention below in conjunction with accompanying drawing.

[0030] The self-adaptive equalization and carrier recovery hybrid algorithm and its circuit realization structure proposed by the present invention are applied to the digital TV demodulator. The digital TV demodulator supports the European digital TV broadcast standard (DVB-C), and supports 4, 16, 64, 256QAM. The circuit structure used is figure 1 The architecture shown.

[0031] The signal-to-noise ratio of the input QAM signal I and Q is 36dB, the baud rate is 6.9M, and the carrier frequency deviation is 600KHz. Feedforward equalizers 1 and 9 use 8-tap finite impulse response (FIR) filters, and the structure is transposed; feedback equalizer 3 uses a 16-tap FIR filter; loop filter 7 uses a proportional , Integral filter, its transfer function is H LP ( Z ) = K ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

This invention relates to a digital balance and carrier recover joint algorithm and its circuit structure used in high order quadrature amplitude modulation (QAM). Demodulation becomes difficult since the high-order QAM signal is influenced by the carrier frequency deviation and channel distortion, this invention applies four steps of blind balance, frequency discrimination, phase discrimination and the least square error adaptive balance to obtain the stable balance and carrier recover performance, which can capture the carrier frequency deviation of 9% baud rate. This invention also provides a structure for realizing the circuit.

Description

technical field [0001] The invention belongs to the technical field of digital communication, and specifically relates to an adaptive equalization and carrier recovery method for high-order QAM signals and a circuit structure thereof. Background technique [0002] Under the urgent demand for huge information transmission in the digital information age, various modern modulation and demodulation technologies are pursuing reliable high-speed transmission rates. The development of digital communication technology makes various communication applications show a trend of mutual integration, such as the trend of "three networks in one" of telephone network, cable TV network and Internet. To implement many communication applications in the same wired channel, it is necessary to save limited spectrum resources, improve spectrum utilization, and achieve high-speed data transmission. [0003] Quadrature Amplitude Modulation (QAM) technology has high spectral efficiency and strong ant...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): H04L27/38
Inventor 田骏骅沈泊李铮苏佳宁郭亚炜
Owner 上海微科集成电路有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap