Sony Corporation

Fumiharu Hashimoto

Nobuo Yamazaki

Tsutomu Kume

Yoshihiro Yamamoto

Koichi Ohya

A double integration type filter circuit, consisting of a pair of integrators connected in series with each other, has a changeover switch for commutating the filter characteristics to a filter configuration which emphasizes portions proper to the characteristics of the filter circuit to facilitate filter adjustment to reduce filter adjustment time and to realize improved accuracy while providing for automatic adjustment of the filter characteristics.

Filter circuit

A filter adjustment apparatus adjusts the properties of a filter by changing, for example, the circuit constants of a filter connected in series with a signal processing circuit to correspond with desired optimum properties of the filter. The state of the signal processing circuit is changed to a state not affecting the filter adjustment, to thereby eliminate the influence of the signal processing circuit on the filter characteristics, to facilitate and increase precision of the filter adjustment.

Filter adjustment apparatus and method

Filter adjustment apparatus for adjusting cut-off frequencies or dip frequencies, for example, may be adjusted to desired optimum properties, during application of an input signal of a constant frequency. The optimum filter adjustment data are found, based on data manifested when the level detected output of the filter output crosses a prescribed reference level whereby the filter adjustment operation is simplified and accuracy is improved with a simplified structure, and it is possible to achieve automatic adjustment of the filter characteristics.

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Tokyo, Japan

Fumiharu Hashimoto