发明公开
- 专利标题: COMPONENT TIMING RECOVERY SYSTEM FOR QAM
- 专利标题(中): 组件行程回收系统QAM
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申请号: EP97940933.0申请日: 1997-09-08
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公开(公告)号: EP0927472A1公开(公告)日: 1999-07-07
- 发明人: KNUTSON, Paul, Gothard , RAMASWAMY, Kumar , McNEELY, David, Lowell
- 申请人: THOMSON CONSUMER ELECTRONICS, INC.
- 申请人地址: 10330 North Meridian St Indianapolis, IN 46290-1024 US
- 专利权人: THOMSON CONSUMER ELECTRONICS, INC.
- 当前专利权人: THOMSON CONSUMER ELECTRONICS, INC.
- 当前专利权人地址: 10330 North Meridian St Indianapolis, IN 46290-1024 US
- 代理机构: Ruellan-Lemonnier, Brigitte
- 优先权: GB19960019712 19960920; US19970835915 19970410
- 国际公布: WO1998012836 19980326
- 主分类号: H04L7
- IPC分类号: H04L7 ; H04L27
摘要:
A receiver for a transmitted quadrature amplitude modulated (QAM) signal representing successive symbols, and including an in-phase (I) component and a quadrature (Q) component. A timing recovery system includes a source of samples (102) representing the QAM signal produced at a fixed frequency. Processing circuitry for the I component includes a first demodulator (104), coupled to the sample source, for demodulating the I component of the QAM signal to baseband; and a first interpolator (108), responsive to a control signal, for producing I component samples taken at times synchronized to the transmitted symbols. Processing circuitry for the Q component includes a second demodulator (114), also coupled to the sample source, for demodulating the Q component of the QAM signal to baseband; and a second interpolator (118), responsive to a control signal, for producing Q component samples taken at times synchronized to the transmitted symbols. A phase error detector (126) detects the phase error between the sample times of the I and Q component samples from the first and second interpolators and times of the successive transmitter symbols. A summer (130) is coupled to the phase error detector and a source of a nominal delay signal. A numerically controlled delay circuit (132), is coupled to the summer, for producing the respective control signals for the first and second interpolators.
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