发明授权
- 专利标题: Equalization and decision-directed loops with trellis demodulation in high definition TV
- 专利标题(中): 均衡和决策导向循环与高分辨率电视网格解调
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申请号: US12330064申请日: 2008-12-08
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公开(公告)号: US08098725B2公开(公告)日: 2012-01-17
- 发明人: Tian-Min Liu , Loke Kun Tan , Steven T. Jaffe
- 申请人: Tian-Min Liu , Loke Kun Tan , Steven T. Jaffe
- 申请人地址: US CA Irvine
- 专利权人: Broadcom Corporation
- 当前专利权人: Broadcom Corporation
- 当前专利权人地址: US CA Irvine
- 代理机构: Sterne, Kessler, Goldstein & Fox P.L.L.C.
- 主分类号: H03H7/30
- IPC分类号: H03H7/30 ; H03H7/40 ; H03K5/159
摘要:
Improved decision feedback equalizer and decision directed timing recovery systems and methods suitable for use in connection with a dual mode QAM/VSB receiver system are disclosed. A trellis decoder operates in conjunction with a decision feedback equalizer circuit on trellis coded 8-VSB modulated signals. The trellis decoder includes a 4-state traceback memory circuit outputting a maximum likelihood decision as well as a number of intermediate decisions based upon the maximum likelihood sequence path. Any number of decisions, along the sequence, may be provided as an input signal to timing recovery system loops, with the particular decision along the sequence chosen on the basis of its delay through the trellis decoder. Variable delay circuitry is coupled to the other input of the timing recovery system loops in order to ensure that both input signals bear the same timestamp. Final decisions are output from the trellis decoder to a DFE in order to enhance the DFE's ability to operate in low SNR environments. A decision sequence estimation error signal is also generated and used to drive the tap updates of both the DFE and an FFE portion of the equalizer.
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