Uniden Corporation

Hideo Hikuma

Hiroyuki Ishida

Takahiro Kudo

Yoshihiro Konishi

Masayasu Fujino

Katsuhiko Otsuji

Yuzo Ishida

Kunihiro Takahashi

Min Zhao

Kiyoshi Tanaka

Hideki Fujiwara

Masaru Akiyama

Hiroki Ohno

Kenichi Konno

Toshiaki Yuasa

Makoto Ehara

Ikuo Awai

Koichi Tomono

Masahisa Fukuchi

The diversity antenna circuit comprises a first antenna for receiving a vertical plane of polarization of an electric wave, a second antenna for receiving a horizontal plane of polarization thereof, a receiving means for detecting the electric field strength of a received signal, a first matching means for matching the first antenna to the receiving means, a second matching means for matching the second antenna to the receiving means, a first transfer means, a second transfer means, a first switching means, a second switching means, and a switching control means for connecting one of the first and second antennas to the receiving means and separating another one from the receiving means according to ON/OFF control of the first and second switching means based on received electric field strength.

Diversity antenna circuit

A cordless telephone set having a base unit and handset units and enabling communications using a channel selected from a plurality of channels. The cordless telephone set comprises apparatus for storing a specified number of channels selected by the telephone apparatus and storing historical channel use data. Whether or not a channel is unused is determined and channels used with high frequency with the data stored in the first storage are changed to those used with low frequency according to the historical use data. Channels that are stored are progressively specified prior to a start of call and a specified channel is selected, if it is determined that the channel is an unused one.

Adaptive channel selection method for a cordless telephone

Communication method, communication apparatus, and cordless telephone

A cordless telephone consisting of base and handset units is disclosed wherein a control circuit incorporated in the base unit comprises first and second D/A converters, first and second A/D converters, and first and second sync. signal generation circuits. The first and second D/A converters respectively convert digital signals from the handset unit and a PBX. The first and second A/D converters convert the analog signals provided from the first and second D/A converters to transmit them to the PBX and handset unit, respectively. The first sync. signal generation circuit regenerates a first clock signal synchronously with a sync. signal provided from the PBX to render the first A/D and second D/A converters to operate in synchronism with the sync. signal from the PBX. The second sync. signal generation circuit generates a second clock signal which is independent of the sync. signal from the PBX to render the first D/A and second A/D converters to operate in synchronism with the second clock signal. Accordingly, the synchronization between the base and handset units is effected independently of the synchronization signal from the PBX.

Cordless telephone

A parent telephone set comprises a transformer, a sidetone level reducing circuit, and a first secret talk processing circuit for executing digital secret talk processing, a counterpart slave telephone set comprises a second secret talk processing circuit for executing digital secret talk processing, a delaying circuit for delaying an aural signal from the slave telephone set microphone by a specified delay time, and a level reducing circuit for reducing the level of output from the second secret talk processing circuit according to the output from the delaying circuit. The specified delay time in the delaying circuit is set according to the time required for digital secret talk processing in the first secret talk processing circuit as well as in the second secret talk processing circuit.

Cordless parent/slave telephone set with improved sidetone handling

An antenna device for a radio transmission-reception apparatus is disclosed which comprises an antenna element which is to be electrically and mechanically connected to a printed-circuit board fixed in a housing of the radio transmission-reception apparatus, an inverted U-shaped hollow reinforcement spacer, an antenna cover and a retaining portion formed on the housing. The reinforcement spacer has a hole formed in the top portion thereof a diameter of which is substantially equal to that of the antenna element to slide therethrough, a slit formed continuously from the hole to a base end thereof through which said antenna element can be entered in the reinforcement spacer, and a flange formed around the outer circumference of the base end. The antenna cover is constituted to accommodate therein the antenna element with the reinforcement spacer, and has a flange formed around the circumference of a base end thereof. The flanges of the antenna cover and the reinforcement spacer are fixedly supported in the retaining portion provided on the housing in a state that said flanges are stacked upon each other. Since the most of forces caused by vibration and/or impact supplied to the antenna element are absorbed by the reinforcement spacer, a mechanically and electrically connected portion between the antenna element and the printed-circuit board will be effected by the forces and thus damage to the portion will be eliminated.

Antenna device for radio transmission-reception apparatus

A cordless telephone apparatus detects the received field strength in a receive channel, as viewed from the base unit side, and if the field strength is below a prescribed level outputs an out-of-range signal on a receive channel, as viewed from the base unit side. The remote unit is provided with a volatile memory area for storing channel connection state data indicating whether or not two-way radio communication was established between the remote unit and the base unit. A backup power source enables the contents of the volatile memory area to be maintained even if there is an interruption in the supply of power from the battery in the remote unit. A call resumption control circuit to resume transmission of call information from the remote unit when internal power in the remote unit is supplied from the battery. The data in the volatile memory area indicating the channel connection state indicates whether two-way radio communication was established, and also detects an out-of-range signal transmitted from the base unit side.

Cordless telephone apparatus which restores radio channels after power

For removing the variation of resonant frequency of the 1/4 .lambda.g coaxial resonator, which is caused by the external connection as a result of conventional capacitive coupling, a 1/4 .lambda.g line having both ends opened is coupled to the 1/4 .lambda.g resonant line having one end shorted through distributed inductive coupling, so as to provide a basic structure of the dielectric resonator of the invention, which can be arranged in usual various types of circuits such as filters, multiplexers and the like with excellent and stable performances.

Dielectric multi-line resonator including a coupling conductor line

A dielectric waveguide-type filter is fabricated by vapor depositing or coating all but one of the four sides extending in the axial direction of a six-sided dielectric block that is long in its axial direction lying perpendicular to its width and height with a conductive material and either leaving the fourth side surface open or forming it with a conductive pattern depending on whether the filter characteristics to be obtained are high-pass characteristics, band-pass characteristics or band-rejection characteristics, the conductive pattern, if formed, being formed in a configuration and distribution depending on the filter characteristics to be obtained. A pair of electrode patterns for electrical connection with an exterior circuit are provided by patterning of conductive material on the opposite axial end surfaces of the dielectric block or on the open surface at positions near the opposite axial end surfaces.

Dielectric waveguide-type filter

An antenna has a main vertical planar part which is connected at its one end to the ground, and a main horizontal planar part which are both arranged in an L-shape. It has a secondary vertical linear part which is arranged in parallel with the main vertical planar part and connected at its one end to the feeding point. It also has a conductive secondary horizontal linear part which is connected between the main horizontal planar part and the secondary vertical linear part and is arranged in parallel with the main horizontal planar part, while being separated from the main horizontal planar part by a definite distance. This makes it possible to incorporate the antenna in the circuit board of wireless communication equipment, and the antenna is particularly suitable for miniaturizing the equipment.

Growing community of inventors

Chiba, Japan

Hideo Hikuma