Abstract: A small, lightweight radio wave lens antenna device is proposed in which freedom of selection of the installation place is high, which can be compactly installed e.g. on a wall surface, and in which restriction of installation space is relaxed. A hemispherical Luneberg lens 2 is mounted on a reflecting plate 1, antenna elements 4 are supported by a retainer 3, they are integrally combined, and a mounting portion 5 is provided for mounting the reflecting plate 1 to a installation portion such as a wall surface with the reflecting plate 1 substantially vertical. The reflecting plate 1 may have such a shape that an area other than the area for reflecting radio waves from directions in a predetermined range is removed, preferably in the shape of a fan. The hemispherical Luneberg lens 2 is mounted on the reflecting plate 1, offset toward the small arcuate edge 1b of the fan.

Abstract: A small, lightweight radio wave lens antenna device is proposed in which freedom of selection of the installation place is high, which can be compactly installed e.g. on a wall surface, and in which restriction of installation space is relaxed. A hemispherical Luneberg lens 2 is mounted on a reflecting plate 1, antenna elements 4 are supported by a retainer 3, they are integrally combined, and a mounting portion 5 is provided for mounting the reflecting plate 1 to a installation portion such as a wall surface with the reflecting plate 1 substantially vertical. The reflecting plate 1 may have such a shape that an area other than the area for reflecting radio waves from directions in a predetermined range is removed, preferably in the shape of a fan. The hemispherical Luneberg lens 2 is mounted on the reflecting plate 1, offset toward the small arcuate edge 1b of the fan.

Abstract: A diversity antenna communication system for mounting on and use with a mobile body. The system includes at least two receiving systems having different propagation paths from one another. During the transmission, a radio wave including receiving system change-over timing signals therein is radiated. Upon reception, the change-over timing signals are extracted to control reception.

Abstract: A roadside beacon system in which a plurality of roadside antennas transmit data to vehicles passing closely adjacent. The transmitting antennas are mounted high above the sides of the roads and have a gain pattern directed obliquely downward. The mobile antennas on the cars have gain patterns directed upwardly.

Abstract: In a roadside beacon system for transmitting to vehicles moving along roads, signals on position and direction, linearly polarizing antennas mounted to be stationarey either beside or above the roads and other linearly polarizing antennas mounted to be mobile on the vehicles. The downwardly transmitting stationary and the upwardly receiving mobile antennas have matching linear polarizations when the vehicle is traveling on the road adjacent to the antenna but a mobile antenna will have reduced sensitivity when moving on a road at a different angle.

Abstract: A mobile station receives radio waves from all signposts through the positioning channels while making communications using the voice channels. The signal levels of the radio waves thus received are subjected to comparison, so that a zone switching request is made to a signpost with the highest signal level, whereby a mobile station can make communication through that signpost which covers the zone where the mobile station is located, even while traveling. The positioning channels are so set that the frequencies assigned to the signposts are switched every frame in a time series mode, and none of the signposts transmit one and the same frequency at the same time. Therefore, the mobile station can receive radio waves from all the signposts without signal interference (which may be caused when a plurality of stations transmit signals equal in frequency). In the system of the invention, the transmission zones of adjacent signposts overlap each other.

Abstract: A mobile communication system is provided wherein a plurality of signposts enable communications among mobile stations and a switching system in a predetermined communicating area, and are connected through a transmission network connected to a fixed network according to the invention, each of the signposts has dual zone communications ability including a communicating area which overlaps the communicating areas or adjacent signposts, and a zone switching signal area which does not overlap the zone switching signal areas of adjacent signposts. The signpost and mobile stations, jointly detect on-going signal levels of the mobile station, and communication area switching operation are carried out as needed. In the mobile communication system of the invention, a transmitting and receiving equipment can be a single transceiver which switches over the frequencies to communicating channel frequencies and to zone switching controlling frequencies.

Abstract: A navigator system for providing in a moving vehicle a display of the position of the vehicle on a map. This position is recalibrated by a roadside antenna that transmits a split beam so that the signal is a minimum directly in front of the antenna. The on-board navigator recalibrates the position from data transmitted immediately before when the received signal is abruptly decreased as the vehicle passes directly in front of the antenna.

Abstract: An antenna for vehicle mounting in a roadside beacon system comprising a ground plane, a shorting board transverse to the grounding plane and two antenna boards attached to the top of the shorting boards in parallel to the ground plane. Two signal feeding points are symmetrically placed in the ground plane on either side of the shorting board. Depending on whether the two signals are phase shifted with respect to each other the antenna gain pattern is directed sidewardly with high gain or upwardly with low gain.

Abstract: A roadside antenna system permitting the transmission of data to a vehicular navigation system and providing for the recalibration of positional data carried by the navigation system includes an antenna structure and transmitter system which permits the data transmission signal to be broadcast in a wide pattern. Meanwhile, the signal that provides for positional recalibration is broadcast in a high directivity signal or split beam. The positional accuracy of the navigator system is improved by performing the positional calibration only when intercepting the narrow beam pattern. Data transmission and reception can be carried out within a larger effective reception area without affecting the positional accuracy.

Abstract: A modem system is disclosed which has improved reliability of detection of transmitted PSK data using a simple signal delay detection scheme. A transmission signal is produced in which repetitive digital time slots each contain phase encoded "mark" or "space" data. Each time slot includes a reference phase portion at at least one of a front and rear portion of the tome slot. The phase of the transmitted signal changes in the remaining portion of each time slot in accordance with applied digital data. For a "mark" data signal the phase changes from a reference phase in a first direction to predetermined phase in a first half of the remaining portion of the time slot, and then back to the reference phase before the end of the time slot. For a "space" data signal the phase changes from the reference value in a second direction opposite the first to another predetermined value in a first half of the remaining portion of the time slot, and then back to the reference phase before the end of the time slot.

Abstract: A demodulator is disclosed for a PSK-modulated transmission signal in which the time average value of the frequencies thereof ar equal to the carrier frequency. A mixer receives and mixes the PSK-modulated transmission signal with a signal from a local variable frequency oscillator and the output thereof is converted to a square wave which is used to reconstruct the original digital modulation data. A pulse counter receives and counts the square wave signal for every period of time which is n times a time slot of a digital signal and a subtractor provides a difference between the count value from the pulse counter and a reference count number. The subtractor output is converted to an analog signal which controls the local oscillator frequency.

Abstract: A roadside beacon system having improved reliability in the face of multi-path fading and the presence of large vehicles or the like which shield or scatter the received signal. The roadside antenna is of the split beam type. In the navigation system on the vehicle, the received signal is divided into two parts. The first part is smoothed and its level detected to determine when the vehicle is approaching an antenna. The remaining signal is then employed directly to detect the null in the transmitted beam when the vehicle passes directly in front of the antenna.

Abstract: A modem system is disclosed which has an improved reliability of detection of PSK data using a simple signal delay detection scheme. A transmission signal is produced which has a phase reference portion provided at at least one of the front and rear portions of a time slot. In a first half of the remaining portion of the time slot the phase of the transmission signal changes stepwise in a first predetermined direction for a "mark" state while in a second half of the remaining portion it changes stepwise back to the reference value. For a "space" state the phase changes stepwise in a second predetermined direction, opposite the first, in the first half of the remaining portion and then in the second half it changes stepwise back to the reference value. In a second aspect of the invention only one of the two digital states causes a corresponding phase change while for the other state the transmission signal retains the phase reference value throughout the time slot.

Abstract: A map plate for adjusting the angle of elevation of an antenna for use with an artificial satellite communication system is composed of a map in polar coordinates of the area of signal receiving points, a group of equi-angle elevation lines which are drawn on the map, a scale of the angle of elevation which covers the whole area of the signal receiving points, which is given on the circumference of the map, a pointer which is provided on the origin of the polar coordinates and a device connected to said pointer which interconnects the revolution of the pointer to the revolution of the antenna for adjusting the angle of elevation such that the angle of elevation of the antenna will reach a designated value by driving the antenna until the pointer reaches the designated value on the scale.

Abstract: A disc antenna which consists of a conductor ground plate and a conductor disc provided in parallel to it, signals of a desired frequency being fed between one point on the conductor disc and the point opposite to it on the conductor ground plate and a point on said conductor disc other than said feeding point on the conductor disc being grounded, so as to radiate non-directional electric waves from the space between said conductor disc and conductor ground plate.

Abstract: An antenna having a helically formed conductor positioned closely adjacent and in parallel relation with a conductor image means such as a conductive surface or the ground or another helix to provide an "image" of the helical conductor when the same is energized and thereby effectively cancel the vertically or axially polarized wave component and intensify the horizontally or transversely polarized wave component of the energized helical conductor.

Abstract: A method of forming an antenna reflector having a predetermined curved surface by forcing a plate of metal or plastic upon an array of die members of different heights protruding from a die base, for example, coaxially arranged cylinders of proper height with proper spacing on the die base. This process makes the manufacture of the antenna reflector extremely rapid and easy.