移動電話に用いられるROMに準拠した有限長インパルス応答フィルタ

Japanese Patent JP5118234

B2

The finite impulse response (FIR) filter is implemented as a table using read-only memory (ROM). The FIR filter table stores a pre-calculated output filter value for each permissible combination of input values to be filtered. Streams of input values are successively shifted into the table and corresponding output values are successively output. In an exemplary implementation, the FIR filter is employed within a digital cellular telephone for use in smoothing a digital signal to be transmitted. The size of the required FIR filter table is minimized by exploiting constraints imposed upon the signal to be filtered and by exploiting linearity and symmetry within the filter itself. More specifically, the telephone employs a data burst randomizer to provide a data signal composed of sequences of null or 0 values and sequences of antipodal values (+1's and -1's). Hence, the permissible input combinations for the FIR filter include only patterns containing either all antipodal signals, all null signals, leading antipodal signals followed by trailing null signals, or leading null signals followed by trailing antipodal signals. The FIR filter look up is configured to exploit these limitations on the input streams yielding a look up table having relatively few entries. Method and apparatus implementations are disclosed.

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Kenny dee easton
Peter Jay Black

JP2011132557A

January 16, 2013

June 14, 2011

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QUALCOMM INCORPORATED

H03H17/06; H03H17/02

Kurata Masatoshi
Takakura Shigeo
Satoshi Kono
Makoto Nakamura
Yoshihiro Fukuhara
Takashi Mine
Toshio Shirane
Sadao Muramatsu
Nobuhisa Nogawa
Kocho Chojiro
Naoki Kono
Katsu Sunagawa
Morisezo Iseki
Tatsushi Sato
Takashi Okada
Mihoko Horiuchi
Takenori Masanori

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