Title:
【発明の名称】固定小数点演算子または浮動小数点演算子およびブロックスケール浮動小数点演算子を組み合わせた適応フィルタシステム
Document Type and Number:
Japanese Patent JP2002509672
Kind Code:
A
Abstract:
An adaptive filter is provided which has fixed point or floating point data stored in a data RAM (74) and block scale floating point coefficients stored in a coefficient RAM (84). The data and coefficients are utilized in a filter algorithm which utilizes a multiplier and an accumulator to provide a convolution result. Coefficients are updated by adding the multiplied result of the data RAM value and the error value to the old value of the coefficient. This is done for all the coefficient values in the coefficient RAM. The error value indicates the difference between the filter output and the sampled near-end signal that is the echo. These new coefficients are examined and if any have a value above or all have a value below a predetermined threshold, then the mantissas of all the coefficients are shifted and the exponent adjusted in the next filter cycle.
Inventors:
Chadda, Mandeep
McCaslin, Shaun
Kamana, John
Hemm Kumar, Narian Kadu Datatreya
McCaslin, Shaun
Kamana, John
Hemm Kumar, Narian Kadu Datatreya
Application Number:
JP51093499A
Publication Date:
March 26, 2002
Filing Date:
July 02, 1998
Export Citation:
Assignee:
Cirrus Logic, Incorporated
International Classes:
H03H17/02; H03H17/06; H03H21/00; H04B3/23; (IPC1-7): H03H21/00; H03H17/06; H04B3/23
Attorney, Agent or Firm:
Shusaku Yamamoto