Abstract: A branching filter in which an input/output port, a first dielectric filter for use in transmission and a second dielectric filter for use in reception are coupled with each other through a branching filter circuit. The branching filter circuit includes a first line provided between the input/output port and an input port of the second dielectric filter, a second line provided between the input/output port and an output port of the first dielectric filter, and a third line provided between the input/output port and the ground. In the filter, conductor lines for use in connection between ports are used for the first and second lines.

Abstract: In a dielectric filter according to the present invention, a depressed part is formed by removing a portion of an outer peripheral conductor on the open face side of each of a plurality of one-end face short-circuited type coaxial resonators or a portion of the outer peripheral conductor including a dielectric member. A dielectric substrate having a plurality of capacitance forming electrodes for forming antiresonance capacitances between the electrodes and inner peripheral conductors of the coaxial resonators formed thereon is mounted on the depressed part, and a reactance element for coupling the capacitance forming electrodes is provided on the dielectric substrate.

Abstract: An antenna sharing device having a transmission filter connectable between a branch node of an antenna and a transmitter and a reception filter connectable between the branch node and a receiver. At least one of the transmission filter and the reception filter includes: a first parallel resonance circuit having a capacitor and a coil connected in parallel; a second parallel resonance circuit magnetically coupled to the first parallel resonance circuit; and a capacitor serially connected to the first parallel resonance circuit. One of the first and second parallel resonance circuits has a first resonance frequency, the other of the first and second parallel resonance circuits has one of the first resonance frequency and a second resonance frequency, and a combination of the first and second parallel resonance circuits and the capacitor forms an equivalent circuit providing a small insertion impedance at a third resonance frequency.

Abstract: A radio frequency switching device package having improved isolation is described. The present invention allows for a radio frequency device packages such as PIN diodes to improve their isolation characteristics by adding an extra wire bond between the anode of the PIN diode and an extra leadframe that is added to the device package.

Abstract: A single-block ceramic filter (102) is coupled to two antennas (142 and 144) for providing both antenna duplexing and antenna-switched diversity in a duplex radio transceiver (100). One antenna (142) is coupled by the filter (102) to a transmitter (132), and both antennas (142 and 144) are switchably coupled by the filter (102) to a receiver (130) by diversity control circuitry (101) in response to a diversity control signal (137). A microcomputer (134) in the transceiver (100) is coupled to the receiver (130) for monitoring the received signal strength (135). When the received signal strength (135) drops in level indicating that the signal being received on one of the antennas (142 or 144) has become degraded due to fading or other interference, the microcomputer (134) changes the binary state of the diversity control signal (137) for switching the receiver (130) to the other one of the antennas (142 or 144 ).

Abstract: Previously it was not possible to realize a ceramic duplex filter using a single monolithic ceramic block, because the isolation between the transmitter branch and the receiver branch could not be made sufficiently high. A duplex filter (1) can be realized in a single ceramic block by making, between its filters (A and B), a strip-like area (9) on the non-coated surface (5) of the ceramic block, due to which the electric and magnetic coupling between the resonators (R.sub.4, T.sub.1) of filters (A and B) on each side of the area can be adjusted to almost zero. This "electric partition" (9) provides a sufficient isolation between the filters of each branch.

Abstract: Transmission-Reception Separating Filter with a PIN diode. A PIN diode is arranged in the transmission channel of the transmission-reception separating filter that has the transmission channel for forwarding a high-frequency current from a transmitter to an antenna. A rectifier is provided that generates a control current for the PIN diode from the high-frequency current flowing in the transmission channel. As a result, a separate power supply is not required for controlling the PIN diode in the transmission channel.

Abstract: In a transmitting-receiving diplexer having a transmitting channel for forwarding a radio-frequency transmission signal to an antenna connectible to an antenna terminal and having a receiving channel for forwarding a signal received from the antenna to a receiver, at least one diode is provided in the receiving channel as an RF switch. A rectifier is connected to the transmitting channel and to the diode or diodes of the RF switch, the rectifier generating a blocking voltage required for blocking the receiving channel during transmission of the transmission signal. Further, a control switch is provided that disconnects the blocking voltage from the diode or diodes of the RF switch during reception.

Abstract: This device is intended for the coupling to a same antenna of at least two devices for transmitting and/or receiving microwave frequency signals operating in a same frequency range but having separated working bands. It is constituted by a circuit (M) comprising four passive filters (F.sub.1 -F.sub.4) and two circulators (C.sub.1, C.sub.2) defining four channels for respectively coupling each of the transmitters (E.sub.A, E.sub.B) and receivers (R.sub.A, R.sub.B) of the two devices (A, B) to the antenna. Each circulator (C.sub.1 ; C.sub.2) is connected by the intermediary of a filter to the transmitter of one of the devices and to the receiver of the other device in order to couple them to the antenna, while isolating them from each other. The invention has an application for coupling transmitting and/or receiving devices installed in aircrafts.

Abstract: A single antenna, dual frequency transponder is provided. The transponder includes the antenna, first and second capacitors, a microprocessor/coder for generating a first and second control signals, and a logic circuit which uses the two control signals as inputs and depending on the state of the second control signal either provides an open circuit or a frequency signal at its output node. When the second control signal is a dormant (inhibit) signal, an open circuit is provided. As a result, the capacitors and the antenna provide a first tuned LC circuit which will receive an incoming signal at a desired first frequency. The incoming signal thereby resonates the LC circuit which provides a wake-up signal to the microprocessor/coder. In turn, the microprocessor/coder generates the first control signal of a desired second frequency. In turn, the logic circuit provides a related signal of the same second frequency as an output.

Abstract: An auxiliary frame to be detachably fastened inside a hand-held telephone for mounting at least some of the components of the hand telephone, has a lower edge with separate indentations for receiving power supply contacts and for securing them between the auxiliary frame and the attachment base of the hand-held telephone, e.g., a circuit board. Another indentation is provided at the lower edge for receiving the signal conductor of the external antenna of the telephone and for securing the signal conductor between the auxiliary frame and the attachment base. The upper surface of the auxiliary frame is designated for supporting the internal disc antenna of the telephone, which antenna is secured to the upper surface in abutting relationship therewith.

Abstract: A signal switching apparatus for switching between a 1/4 wavelength transmission line, which transmits a transmission signal, and a 1/4 wavelength reception line, which receives a reception signal, which share a common antenna. The apparatus sets the characteristic impedance of one of the 1/4 wavelength lines to be zero while the other 1/4 wavelength lines is set to infinity so that the switching operation can be effected without passing the transmission and reception signals through semiconductor switches.

Abstract: A dual function antenna system and method. A system is provided for using a single antenna for both the reception of low frequency navigational signals, such as LORAN-C, and high frequency communications signals in the VHF region. The antenna is at a remote location from a low frequency receiver and a high frequency transceiver. Both the low frequency and the high frequency signals are coupled to the receiver and transceiver, respectively, over the same transmission line at one end thereof. A preamplifier is provided at the location of the antenna to increase the strength of the low frequency signal applied to the transmission line. A high pass filter is provided to couple the antenna and the transmission line and prevent feedback from the output of the preamplifier from reaching its input. The other end of the transmission line is coupled to the high frequency transceiver by a high pass filter, and to the low frequency receiver by a low pass filter.

Abstract: A reciprocal transceiver to radiator coupling circuit uses both microstrip and waveguide modes of RF signal transmission (including a pair of nonreciprocal hybrid mode phase shifters) to gain size and weight advantages useful in feeding large scale phase arrays. At the same time, the radar cross section of such array apertures is reduced by arranging separate nonreciprocal receive and transmit branches of the circuit to route spurious intra-circuit reflections of incoming RF signals to a matched termination.

Abstract: A single-block ceramic filter (102) is coupled to two antennas (142 and 144) for providing both antenna duplexing and antenna-summed diversity in a duplex radio transceiver (100). One antenna (142) is coupled by the filter (102) to a transmitter (132) and to a receiver (130), and a second antenna (144) is switchably coupled by the filter (102) to the receiver (130) by diversity control circuitry (101) in response to a diversity control signal (137). A microcomputer (134) in the transceiver (100) is coupled to the receiver (130) for monitoring the received signal strength (135). When the received signal strength (135) drops in level indicating that the signal being received on the antennas (142 to 144) has become degraded due to fading or other interference, the microcomputer (134) changes the binary state of the diversity control signal (137) for switching the receiver (130) between antenna (142) and both antennas (142 and 144).

Abstract: A toy including headgear mounted thereon a simulated weapon system, a visor, apparatus for indicating on the visor a sighting reference and non-hand actuated apparatus for producing simulated firing on a target. Preferably the headgear and the non-hand actuated apparatus are operative for producing simulated firing on a target which appears on a television screen in an interactive television game.

Abstract: A broadband PIN diode transmit/receive switch. The switch is used for electrically coupling a single antenna alternately to a transmitter and to a receiver. A first PIN diode for switching is connected between the antenna and an output port of a second order network, an input port of the second order network being connected to an output of the transmitter. A tuned tank circuit has an input port connected to the antenna and has an output port connected to an input of the receiver. A second PIN diode for switching is connected from the output port of the tuned tank circuit to an RF ground. A DC source controls the PIN diodes. When both diodes are forward biased the transmitter is connected to the antenna and is provided a good impedance match over a substantial bandwidth, otherwise the receiver is connected to the antenna.

Abstract: A combined switch and filter comprising coupled first and second quarter-wave transmission line sections and switching elements for providing selective coupling and filtering between ports of the switch coupled to the ends of the quarter-wave sections.

Abstract: A circuit such as a duplexer which isolates a first and second frequency signals respectively directed to and from an antenna terminal. A transmitter filter has a output terminal connected to a connecting point through a first inductor. A receiver filter has an input terminal connected to the connecting point. The connecting point is connected to the antenna terminal, and to ground through a second inductor. In a modified circuit the output terminal of the transmitter filter and the input terminal of the receiver filter are respectively connected to the connecting point through first and second capacitors. In the preferred embodiments the transmitter filter and the receiver filter are mounted to one side of a dielectric plate and the inductor and/or capacitors are formed by electrically conductive step lines and a capacitance patterns formed on the opposite side of the dielectric plate.

Abstract: A ceramic block filter (100) includes coupling pins (101 and 102) disposed in holes (124 and 125) in corresponding electrodes (121 and 122) for interconnecting the filter to radio frequency devices, such as a radio transceiver. During manufacture of the filter (100), the coupling pins (101 and 102) are bonded to conductive material (131) of the holes (124 and 125) and corresponding electrodes (121 and 122) when the rest of the conductive material (160) is fired. To facilitate the electrical bond during the manufacturing process, the coupling pins (101 and 102) may be silver or silver plated and co-fired at the same time. Since the coupling pins (101 and 102) are fired at the same time as the rest of the conductive material, a reliable and inexpensive bond is achieved between the coupling pins (101 and 102) and the conductive material of the holes (124 and 125) and corresponding electrodes ( 121 and 122).

Abstract: An antenna switch using two low-cost relays substantially improves isolation of signals from a transmitter to a receiver by connecting an impedance across the input of a receiver during transmit. During receive, the transmitter is disconnected from the antenna while the receiver is connected.

Abstract: Antenna sharing device used for a communications system such as a land mobile radiotelephone which has a transmitting frequency and a receiving frequency that are different from each other, and which commonly uses the antenna transmission and reception. The bands of transmission and reception of the antenna sharing device are each divided into half and are switched into a pair of sending side low-pass filter and a receiving side low-pass filter and a pair of sending side high-pass filter and a receiving side high-pass filter by a switching device, whereby the band widths of transmission and reception are narrowed and the isolation point is increased between the transmission and reception.

Abstract: The radio transmitter-receiver system for increasing or decreasing communication channels comprises radio transmitter-receivers each including a separated intermediate frequency portion for modulation and demodulation and a separated microwave portion, and having a multiplexer and a divider therebetween. Local oscillators in the intermediate frequency portion have a variable frequency function and the operating frequency of the intermediate frequency portion can be easily changed. The intermediate frequency portions are connected to the microwave portions through the multiplexer or the divider and the frequency of the microwave to be communicated is easily changed. Thus, an increase or decrease of the communication channels is possible at a low cost.

Abstract: A multiresonator dielectric block filter is disclosed in which capacitive coupling between resonators disposed in the dielectric block is controlled by an electrode strip coupled to the conductive material covering the majority of the dielectric block surface. The electrode strip extends at least partially between two adjacent resonators to control the capacitive coupling between the resonators.

Abstract: During a transmit cycle portion, a radio frequency transmitter (C) continuously generates an AC biasing signal and selectively generates a radio frequency signal. The AC biasing signal gates a first switch (10) and a second switch (32) such that the radio frequency signals from the transmitter are conducted to a magnetic resonance probe (E) but are blocked from being conducted to a receiver (F). A first filter (20) prevents the bias signals from being applied to the probe. The second switch includes a pair of crossed diodes (34, 36) which are gated conductive by the AC bias signal. A filter (72) passes the radio frequency signals but not the bias signals to ground to prevent the radio frequency signals from reaching the receiver. A filter (80) allows the bias signals to be applied across a load (88) such that the transmitter sees the load at the bias signal frequency. Another filter (40) prevents the bias signal from reaching the transmitter.

Abstract: A burst-mode two-way radio communications system in which a plurality of antennas at a base station share a branched antenna switched dependent on the strength of the signal received from a portable transceiver, wherein a switch controller controls operation of one or more branch selection switches on the basis of an instructing signal received from any one of the base station transceivers.

Abstract: Disclosed is a wireless talking apparatus in which signal transmission is performed by utilizing an antenna and simultaneous talking can be performed. The wireless talking apparatus is constituted by a main communication device and a subsidiary communication device, and when these main and subsidiary devices are used in one-to-one correspondency, talking can be performed in a full-duplex communication mode, and in the case where a plurality of subsidiary communication devices are prepared, mutual talking can be performed also between the subsidiary communication devices and the conversation can be monitored by the main communication device.

Abstract: A radio transceiver, improved in that an antenna switching circuit is so connected between an antenna and the transmitting and receiving sections of the transceiver that a filter for removing spurious emission components from a transmitted wave is connected only to the transmitting section of the transceiver, whereby insertion loss of a received wave is avoided.

Abstract: A power limiter circuit for a radio frequency transceiver of the type having a single input-output antenna port is comprised of an isolator, first and second three port circulators and a pair of PIN diodes. One port of the first circulator is connected to the antenna port and one port of the second circulator is coupled to a transmit/receive antenna. The second ports of the two circulators are connected together through the isolator for passing signal from the transceiver to the antenna and the third ports of the two circulators are connected together for passing signal from the antenna to the transceiver. The PIN diodes, arranged in inverse parallel relationship, are connected between the third ports and circuit ground and operate in connunction with the isolator to limit to a safe value the signal passed from the antenna to the transceiver.

Abstract: A data communications system is described that covers a geographic area divided into a plurality of non-overlapping zones and includes a general communications controller (GCC), a plurality of channel communications modules (CCM) and associated transmitters and receivers, and a plurality of portable radios. Message signals carrying alphanumeric information are communicated between the GCC and the portable radios by way of a radio channel. Each CCM takes a signal strength measurement every time it receives a message signal from a portable radio. The GCC gathers the signal strength measurements from the CCM receivers receiving the same message signal and computes an adjusted signal strength for each zone. The GCC then selects the zone having the largest adjusted signal strength for determining the location of the portable radio that transmitted the message signal.

Abstract: A magnetic-field, noise-cancelling transceiver is provided by a dual-coil antenna circuit. In the receive mode, two identical coils, connected in series opposition, cancel noise signals common to both coils and receive desired signals present at only one coil. Capacitance in parallel with the series-opposed coils establishes the resonant frequency of the receiver, antenna circuit. In the transmit mode, the two coils, connected in series opposition, have their non-adjacent terminals clamped to ground via two pairs of oppositely-poled diodes, one pair on each non-adjacent terminal. The transmitter signal, coupled to the junction of the two coils through a capacitor, generates additive magnetic fields by causing equal currents to flow in each coil from the common junction, to their respective diode junctions, to ground through the respective, oppositely-poled diode pairs. Series resonance is established by the transmitter coupling capacitance and the parallel combination of the two coils.

Abstract: A single channel, or push-to-talk transceiver includes a switch-controlled Gunn oscillator for generating the carrier frequency during transmission and a continuously operating local oscillator for demodulation of a received signal in the receive mode. When the push-to-talk switch is depressed, the transmit oscillator is energized and leakage signals cross the circulator to the receiver portion of the transceiver. An RF AFC loop between the transmitter and receiver portions includes a low-pass filter at the preamplifier output which serves as a simple slope discriminator. This output is detected and used to close an electronic servo loop. Once closed, this servo loop locks the transmit oscillator frequency relative to the local oscillator thereby preventing frequency drift during warm-up.

Abstract: A transmit/receive switch incorporating a latching relay in a feedback circuit so that the relay is energized only when it is commanded into a different mode (transmit or receive) than it is in, and the energization is removed as soon as the relay switches into the correct mode.

Abstract: A transmit-receive switching circuit is provided for switching a transmitter and a receiver to common antenna via a common signal path. A circulator is employed in the common signal path. The flow of transmitter RF energy and received RF energy is controlled through the circulator by a selectively actuable impedance element coupled to the circulator.

Abstract: A microwave combining filter arrangement including circulators for connecting a plurality of transmitters and receivers to a common antenna wherein the circulators are all three-arm circulators which are connected in cascade and the transmitters and the receivers are alternatingly connected to the circulator chain.