发明名称 |
Reciprocal index lookup for BTSC compatible coefficients |
摘要 |
An algorithm calculates spectral compression/expansion filter coefficients using a value proportional to a reciprocal of a feedback/feedforward signal and stores the coefficients to a lookup table. The lookup table is indexed by a pre-selected set of coefficient bits to generate a filter coefficient function. A first portion of the lookup table stores a plurality of discrete values at index points of a line segment corresponding to a filter coefficient function approximation, so as to generate an initial discrete value corresponding to the filter coefficient function at a value of the high order bits and a second portion stores a plurality of slope values, which indicates a slope of the filter coefficient function. A linear circuit interpolates/decimates an approximation of the compression/expansion filter coefficient function based on the slope value, the initial discrete value and a preselected set of low order bits of the reciprocal value.
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申请公布号 |
US7397850(B2) |
申请公布日期 |
2008.07.08 |
申请号 |
US20030407041 |
申请日期 |
2003.04.04 |
申请人 |
EASLEY MATHEW F;DARR ROGER;BARNHILL MATTHEW |
发明人 |
EASLEY MATHEW F.;DARR ROGER;BARNHILL MATTHEW |
分类号 |
H04B1/66;H03G5/00;H04S3/00 |
主分类号 |
H04B1/66 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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