Matsushita Electric Industrial Co., Ltd.

Mitsuru Asanuma

Nobuaki Furuya

Yoshihiro Kino

A ghost signal erasing system for television receivers in which a variable delay element utilizing the propagation of an elastic surface wave is used. The variable delay element includes a piezoelectric substrate, a plurality of first interdigitated electrode pairs formed on the substrate and a plurality of second interdigitated electrode pairs also formed on the substrate. An elastic surface wave produced by applying a video i-f signal to the first interdigitated electrode pairs is propagated along the surface of the piezoelectric substrate and taken up at the second interdigitated electrode pairs as a delayed a-c signal. By switching the first and second interdigitated electrode pairs to change the combination thereof, various delay times are obtained.

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Machida, Japan

Mitsuru Asanuma