Taiyo Yuden Co., Ltd.

Kenji Kamitani

Mamoru Sakamoto

Junichi Shimamura

Fumitaka Iizuka

Chikahiro Tomita

An adaptive array antenna is disclosed which permits the circuit scale to be reduced by omitting a down-converter, an AD converter, and interconnects for them while controlling the directivity well. In one aspect, the array antenna comprises phase shift-amplitude control modules which accept signals received by antenna elements via an analog-to-digital converter. The value of any one of phase-amplitude change modules is set to 1. The values of the other phase-amplitude change modules are set to 0. Thus, the signal from any one antenna element is accepted. This sequence of operations is repeated as many times as there are antenna elements, whereby signals received by all the antenna elements can be accepted.

Adaptive array antenna system and method of controlling directivity thereof

A bidirectional optical communication apparatus is composed of a set of a first device ( ) and a second device ( ). Using linear-polarization plates ( A, B, A, and B) and quarter wavelength plates ( A, B, A, and B), a transmission section (TX ) of the first device ( ) radiates a first signal (Ls ) consisting of circular polarization in one of the rotational directions, while a reception section (RX ) of the second device ( ) receives only these circular polarization components. In addition, a transmission section (TX ) of the second device ( ) radiates a second signal (Ls ) consisting of circular polarization in the other rotational direction, while a reception section (RX ) of the first device ( ) receives only these circular polarization components. This configuration enables bidirectional optical communication without complicated communication control and accurate optical-axis alignment.

Bidirectional optical communication apparatus and optical remote control apparatus

It is an object of the present invention to provide a method and an apparatus for driving a piezoelectric transformer capable of always driving with maximum conversion efficiency regardless of changes in the input voltage level, load and temperature, etc. The method and apparatus for driving a piezoelectric transformer of the present invention generate a time-varying sweep voltage through a sweep circuit at predetermined regular intervals, thereby changing the frequency of a drive signal output from a voltage control oscillator, at this time detect a phase difference between the voltage and current generated on the primary side of the piezoelectric transformer by a phase difference detector, and hold the sweep voltage corresponding to the timing at which a maximum value detector detects the maximum value by a sample-and-hold circuit, thereby controlling the frequency of the drive signal so that the phase difference between the voltage and current on the primary side of the piezoelectric transformer always becomes a maximum value.

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Tokyo, Japan

Kenji Kamitani