发明授权
US07440521B2 Method of normalization of forward metric (alpha) and reverse metric (beta) in a map decoder
有权
在地图解码器中正向测量(alpha)和反向度量(beta)的归一化方法
- 专利标题: Method of normalization of forward metric (alpha) and reverse metric (beta) in a map decoder
- 专利标题(中): 在地图解码器中正向测量(alpha)和反向度量(beta)的归一化方法
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申请号: US09952212申请日: 2001-09-12
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公开(公告)号: US07440521B2公开(公告)日: 2008-10-21
- 发明人: Hau Thien Tran , Kelly B. Cameron
- 申请人: Hau Thien Tran , Kelly B. Cameron
- 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: Garlick Harrison & Markison
- 代理商 Shayne X. Short
- 主分类号: H03D1/00
- IPC分类号: H03D1/00
摘要:
In a normalization process, overflow occurring in limited size registers, holding the alpha or beta values in a map decoder, may be overcome by subtracting a constant value from all of the alpha or beta values when they reach a limit. Because subtracting a constant value may slow down the computation, detection of a constant value may occur on one decoding cycle and normalization on the succeeding decoding cycle. A multiplexor type circuit can be used to direct either zeros, in the normalization case, or a most significant bit(s), in computations without normalization, into the register holding the alpha or beta values. To minimize the impact on the computation by the normalization process, the multiplexor circuit can be set by the previous decoder cycle so that the computation does not have to wait for the multiplexor to be set to normalization or normal computation.