Kokusai Denshin Denwa Co., Ltd.

Michitoshi Tamori, Deceased

Hideo Kobayashi

Kazuo Hashimoto

Kazuo Kawai

A smear-desmear filter having the frequency depending group delay characteristics is implemented by a transversal filter having a plurality of delay elements each having the delay time 1/(2f.sub.2), where f.sub.2 is the highest frequency component of an input signal, tap weight coefficient means for providing the product of the output of the tap and the predetermined coefficient which is supplied from a digital memory, and an adder for summing up all the outputs of the tap weight coefficient means. A tap and/or a tap weight coefficient means is provided for every m number of delay elements, where m is an integer larger than 2, thus, the number of tap weight coefficient means is merely 1/m of the number of the delay elements. The tap weight stored in said the digital memory is determined by the position (n) of a tap, a delay time (.tau.) of each delay element, the required delay expansion width (a), and the value of said integer (m). The obtained delay characteristics is sinusoidal in the given frequency band.

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Tokyo, Japan

Michitoshi Tamori, Deceased