Mitsubishi Denki Kabushiki Kaisha

Minori Kawano

Fumiaki Komatsu

Kohji Ogawa

Yasuhiro Ishizaki

Sadayuki Tsukagoshi

Masato Sato

Eiichi Kuroda

Hiroyuki Kuroiwa

Nobuhiro Kimura

Hideyo Ono

Yasushi Ozu

Koji Mihashi

Kohji Mihashi

Nagayasu Harada

Masaharu Hirooka

Kazuo Mitsui

A radio relay system including a water-proof conductor housing on which is located a pair of antennas, one antenna being used for transmitting and receiving radio carrier wave signals of a first and a second frequency, respectively, while the other antenna is used for transmitting and receiving radio carrier wave signals of a third and a fourth frequency, respectively. A skirt for each of the antennas is located adjacent the antennas on the housing, one skirt has a length equal to a quarter of the wavelength of the first frequency while the other skirt has a length equal to a quarter wavelength of the third frequency. A relay circuit is located in the housing which includes circuitry for extracting and combining a portion of the radio carrier wave signals of the first and the third frequencies respectively radiated from the two antennas with the radio carrier wave signals of the first and third frequencies respectively received by the opposite antenna of the pair of antennas for cancelling unwanted local interference therebetween.

Radio relay system, including interference signal cancellation

A radio relay system which comprising an external conductor, a first antenna installed on the externals conductor for transmitting and receiving a first radio carrier wave, a second antenna installed on the external conductor for transmitting and receiving a second radio carrier wave, a skirt provided around the second antenna, the skirt having a length equal to a quarter of the wavelength of the second radio carrier signal, and a relay device which includes a branching filter for extracting a part of the second radio carrier wave as a carrier wave, an adjusting unit for adjusting the amplitude and phase of the carrier wave extracted by the branching filter, and a combining unit for combining the carrier wave extracted by the branching filter with the second radio carrier wave received through the first antenna, and the relay device transmitting as the second radio carrier through the second antenna the first radio carrier wave received through the first antenna.

Radio relay system with a multiplex separation circuit and control for

A base station for a mobile communications system including an antenna for transmitting a radio carrier wave to a mobile communications device and receiving signals therefrom, a coaxial external conductor including a skirt in the form of a sun shade having a length equal to a quarter wavelength of the radio carrier wave, a radio section located inside the coaxial external conductor for providing radio communication with the mobile communication device via the antenna, and a connecting section connecting the radio section to a telephone line and where the antenna is configured in the form of an upper disk of a discone antenna and where the skirt is a lower conical member of the discone antenna.

Base station for a radio communication system

A method and apparatus for a hand-off of a call-in-progress according to the present invention is arranged such that both a first ratio of a length of time, in which a measured value of SNR is below a predetermined 'threshold' to a total length of the measuring time, and a second ratio of a length of time, in which a measured value of RSSI is below a predetermined 'threshold', to a total length of the measuring time are detected and that the first ratio functions mainly when the 'threshold' of RSSI is predetermined to a relatively low value; and the second ratio functions mainly when the 'threshold' of RSSI is predetermined to a relatively high value, thereby optimizing the hand-off timing.

Method and apparatus for hand-off of call in progress

A pocket transceiver can be, for example a portable wireless telephone apparatus small enough to be put into a pocket of a user. The apparatus operates at a low power level. The pocket transceiver as an independent unit only handles signals at a low power level and is suitable for communication over close range. The pocket transceiver can also be used as a telephone apparatus for communication over long range, such as a mobile transceiver in a vehicle, by being connected to an adapter, which includes a power amplifier and a power controller for selecting an output power level out of multiple levels in response to an instruction from a transmitting-receiving unit of the pocket transceiver.

Pocket transceiver

A high-frequency signal booster which has at least one channel unit including a down-converter for converting input signals into intermediate-frequency signals and an up-converter for converting time into output signals. The respective up- and down-converters are separately equipped with station-originating signal oscillators. Further, the station-originating signal oscillator provided for the up-converter has a function of effecting the modulation with out-of-voice-band signals.

High-frequency signal booster

In a mobile radio telephone system having multiple base stations controlled by a single line control unit, all base stations use a single common control channel in addition to their voice channels to communicate with a mobile station. If a calling signal from a mobile station is received by two or more base stations at once on the common control channel, the base station with the highest received signal level is selected. If voice signal quality becomes degraded during a call, the call is handed off to the base station with the highest received signal level.

Mobile radio telephone system

A mobile radio communication system has base stations 1a, 1b, 1c at the centers of major service areas A, B, C defined by a contiguous array of hexagons or partially overlapping circles, and repeater or one way relay stations 3a-3m at each vertex or intersection point. The repeater stations have directional receiving antennas subtending successive 120.degree. arcs of surrounding minor service areas similarly defined by a ring array of hexagons or circles, amplifiers for imparting a high gain to signals received from mobile units in the minor service areas, and narrow width transmitting antennas for relaying the amplified signals to the base station closest each mobile unit. Such an arrangement enables a substantial reduction in the transmitter output capacity of the mobile units.

Mobile radio communication system with repeater station grid

A high dielectric constant element suitable for making a coaxial line shape resonator comprises a number of sheets, for instance, of mica or plastic, each having plural pieces of conductive film or electrodes provided on one face with appropriate small gaps inbetween, the sheets being assembled in a pile to form a high dielectric constant element body that has high equivalent .epsilon. value without using a conventional high dielectric constant ceramic body. Fine adjustment of the resonance frequency of the coaxial line shape resonator is easily made by adjusting number of sheets per length.

Growing community of inventors

Hyogo, Japan

Minori Kawano