Nihon Musen Kabushiki Kaisha

Kabushiki Kaisha Toshiba

Japan Radio Co., Ltd.

Yoshihiko Takeuchi

Masahiro Watanabe

Kazuo Yamashita

Hiromi Yatsuda

Yasuhiro Ishibashi

Shokichiro Yoshikawa

Toichi Kohda

There is provided a time-division duplex transmit-receive apparatus in which the respective amplitude and phase characteristics of N sets of transmitting unit-receiving unit pair connected with N antenna elements are corrected all together and at the same time. At the time of reception, the reference signal from reference signal generator is branched into N reference signals. The branched reference signal is applied to the reception system through the transmit-receive switching switch. The reception-side error detector detects the error between the output signal of the reception-side amplitude-phase correction circuit and the reference signal to control the reception-side amplitude-phase correction circuit so that the error becomes zero. At the time of transmission, a part of transmitting signal is applied to the reception system through the antenna path. The transmission-side error detector detects the error between the output signal of the reception-side amplitude-phase correction circuit and the transmitting signal to control the transmission-side error detector so that the error becomes zero.

Time-division duplex transmit-receive apparatus

When a digitally compressed and encoded video data stream contains line data, a line data detection circuit in a DVD decoder detects the presence of that line data, and informs a CPU of it using an interrupt signal. When the CPU receives the line data from a data register in the DVD decoder, it converts it into character information and writes the information in an image memory, or converts the line data into an on-screen display command for controlling the OSD function of the DVD decoder and issues that command.

Computer system and closed caption display method

A composite longitudinal vibration mechanical filter for delivering out a supplied high-frequency signal in a predetermined frequency range includes a plurality of vibratable bodies including input and output longitudinal vibratable tuning bars with piezoelectric members superposed thereon, coupling elements by which the longitudinally vibratable tuning bars are coupled to each other, supporting elements projecting respectively from the input and output longitudinally vibratable tuning bars, and a holder to which the supporting elements are attached. At least one resonant frequency adjusting finger is disposed on at least one of the vibrational bodies. Grooves are defined in the longitudinally vibratable tuning bars at the same time that they are fabricated. The grooves extend in the direction in which the longitudinally vibratable tuning bars are longitudinally vibratable, and are shorter than the length of the longitudinally vibratable tuning bars. Through holes may instead be defined in the longitudinally vibratable tuning bars, the through holes having an opening size smaller than the wavelength of the longitudinal vibration of the longitudinally vibratable tuning bars. Piezoelectric members are fixedly superposed on the input and output longitudinally vibratable tuning bars in sandwiching relation thereto.

Composite longitudinal vibration mechanical filter having undesired

A method of manufacturing a composite longitudinal vibration mechanical filter that vibrates at a preselected central frequency in a high frequency range. The filter includes a plurality of vibratable bodies including input and output vibratable bodies each having respective piezoelectric members superposed thereon. Coupling elements couple the vibratable bodies to each other. Supporting elements project respectively from the input and output vibratable bodies. A holder is provided to which the supporting elements are attached. The method includes forming an integral body including the plurality of vibratable bodies, the coupling elements, the supporting elements, the holder and a vibration absorbing body holder for eliminating unnecessary vibrations. The vibration absorbing body holder is disposed between at least one of the vibratable bodies and the holder, and is disposed so as to absorb unnecessary vibrations which are transmitted to the output vibratable body, and to reduce unnecessary spurious responses occurring outside of a bandpass region of the filter. The piezoelectric members are fixedly superposed on the input and output vibratable bodies in sandwiching relation thereto, and respective electrodes are connected to the piezoelectric members.

Composite longitudinal vibration mechanical filter's method of

A composite longitudinal vibration mechanical filter for delivering out a supplied high-frequency signal in a predetermined frequency range includes a plurality of vibratable bodies including input and output longitudinal vibratable tuning bars with piezoelectric members superposed thereon, coupling elements by which the longitudinally vibratable tuning bars are coupled to each other, supporting elements projecting respectively from the input and output longitudinally vibratable tuning bars, and a holder to which the supporting elements are attached. At least one resonant frequency adjusting finger is disposed on at least one of the vibratable bodies. Grooves are defined in the longitudinally vibratable tuning bars at the same time that they are fabricated. The grooves extend in the direction in which the longitudinally vibratable tuning bars are longitudinally vibratable, and are shorter than the length of the longitudinally vibratable tuning bars. Through holes may instead be defined in the longitudinally vibratable tuning bars, the through holes having an opening size smaller than the wavelength of the longitudinal vibration of the longitudinally vibratable tuning bars. Piezoelectric members are fixedly superposed on the input and output longitudinally vibratable tuning bars in sandwiching relation thereto.

Tunable composite longitudinal vibration mechanical filter manufacturing

A surface acoustic wave device has a package and a surface acoustic wave element mounted therein face down. The package includes a side wall comprising linear inner side surfaces close to respective outer side surfaces of the surface acoustic wave element and recesses defined where the inner side surfaces of the side wall intersect at respective inner corners. When the surface acoustic wave element is inserted into the side wall along the inner side surfaces thereof, the corners of the surface acoustic wave element do not engage the side wall because of the recesses. Therefore, the outer side surfaces of the surface acoustic wave element may be positioned very closely to the inner side surfaces of the side wall. The surface acoustic wave device may be reduced in size, and the surface acoustic wave element may have input and output electrode pads and ground pads positioned highly accurately with respect to electrode pads on the bottom plate of the package.

Surface acoustic wave device

A composite longitudinal vibration mechanical filter for delivering out a supplied high-frequency signal in a predetermined frequency range includes a plurality of vibratable bodies including input and output longitudinal vibratable tuning bars with piezoelectric members superposed thereon, coupling elements by which the longitudinally vibratable tuning bars are coupled to each other, supporting elements projecting respectively from the input and output longitudinally vibratable tuning bars, and a holder to which the supporting elements are attached. Grooves are defined in the longitudinally vibratable tuning bars at the same time that they are fabricated. The grooves extend in the direction in which the longitudinally vibratable tuning bars are longitudinally vibratable, and are shorter than the length of the longitudinally vibratable tuning bars. Through holes may instead be defined in the longitudinally vibratable tuning bars, the through holes having an opening size smaller than the wavelength of the longitudinal vibration of the longitudinally vibratable tuning bars. Piezoelectric members are fixedly superposed on the input and output longitudinally vibratable tuning bars in sandwiching relation thereto.

Composite longitudinal vibration mechanical filter having central

A surface elastic wave filter includes a plurality of input interdigital transducers for receiving a high-frequency input signal, and a plurality of output inter-digital transducers for producing an output signal derived from the input signal and having predetermined frequency characteristics. Each of the input and output interdigital transducers having a pair of confronting connectors for receiving the input signal and extracting the output signal, respectively, and a pair of groups of interdigitating electrode fingers extending from the connectors. The input and/or output interdigital transducers include finger-withdrawn interdigital transducers with electrode fingers selectively withdrawn in different positions. With such withdrawal weighting, the interdigital transducers have different sidelobe characteristics, i.e., frequency blocking characteristics, so that the surface elastic wave filter operates with a greater sidelobe suppression.

Surface elastic wave filter having finger omitted transducers to

A surface elastic wave filter has a pair of electrodes on a surface of a piezoelectric body, and at least one of the electrodes is constructed as electrode fingers in the form of comb teeth which are progressively spread away from each other along a direction normal to the direction in which a surface elastic wave is propagated on the surface of the piezoelectric body. A grating or dot structure as a scattering reflector for scattering and reflecting a portion of the surface elastic wave is disposed in a desired position between the electrodes. Alternatively, some of electrode fingers of a surface elastic wave filter are dropped or removed, or divided voltages are applied to electrode fingers, or a scattering reflector is added to a filter with some of its electrode fingers removed or with divided voltages applied to electrode fingers. With such an arrangement, a filter having good selectivity and desired frequency characteristics can be achieved.

Growing community of inventors

Mitaka, Japan

Yoshihiko Takeuchi