Furuno Electric Company Limited

Katsuhisa Yamamoto

Hiroyuki Toda

Satoshi Misonoo

Yuriko Onishi

Osamu Kubota

Masahiro Yokoyama

Youhei Kinoshita

Yoshihiro Tada

Takanori Satoh

A quantitative echo sounder includes delay circuits, phase correction circuits, an incidence angle calculator and a directivity correction unit. The delay circuits adjust transmission start timing or phases of acoustic waves radiated by individual vibrating elements based on pitch and roll angles measured by a motion sensing device so that the direction of an acoustic axis of a transmitting beam matches a sounding direction. The phase correction circuits adjust phases of received echo signals based on the pitch and roll angles so that the direction of an acoustic axis of a receiving beam matches the sounding direction. The incidence angle calculator calculates echo signal incidence angle with respect to the sounding direction from phase differences among receiving beam signals obtained by four vibrating element groups. The directivity correction unit corrects a measured target strength by using the echo signal incidence angle calculated by the incidence angle calculator.

Quantitative echo sounder and method of quantitative sounding of fish

The invention provides a trackball unit featuring good water resistance and user maintenance capabilities. A case ( ) of the trackball unit has a drain pipe ( ) connecting a cavity ( ) formed inside the case ( ) for accommodating a ball ( ) to the exterior of the case ( ). A case cover ( ) has a ring-shaped projecting part ( ) while a ball cover ( ) has a pair of locking tabs ( ) which engage with the projecting part ( ) of the case cover ( ), so that the ball cover ( ) can be detachably fitted to the case cover ( ).

Trackball units

Growing community of inventors

Nishinomiya, Japan

Katsuhisa Yamamoto