Abstract: A radio apparatus having a unit for receiving a first signal from a first transceiver compressed in time by a predetermined rate, a unit for reproducing a first original signal from the first signal, a unit for receiving a second signal from a second transceiver compressed by the predetermined rate during the reception period of the first transceiver, a unit for reproducing a second original signal from the second signal, and a unit for adding the first and second original signals and outputting the added signal.

Abstract: A communication device (100) includes three levels and at least one feature and at least one protocol for communicating with other communication devices. The three levels are high level or user ergonomics (302), common level or feature/protocol (310), and low level or hardware platform (318). The feature/protocol level (310) is adapted for controlling the at least one feature and the at least one protocol. The user ergonomics (302) includes a first interface (304) coupled to the feature/protocol level (310) for allowing the user ergonomics level (302) to change without affecting the feature/protocol level (310). The, hardware platform (318) includes a second interface coupled to the feature/protocol level (310) for allowing the hardware platform (318) to change without affecting the feature/protocol level (310) or the user ergonomics level (302).

Abstract: A radio having two architectural platforms integrated in one integrated circuit (IC). A synthesizer controller (312) selects between an offset local oscillator (LO) synthesizer (318) and a second LO synthesizer (316) to provide a common architecture for either an Frequency Division Duplex (FDD) or Time Division Duplex (TDD) system design while providing isolation between the two frequency sources. An offset LO signal (319) is translated to an isolated LO signal 310 and combined with a main LO signal (322) to provide the FDD platform. A second LO signal (314) is translated into the isolated LO signal 310 and combined with the main LO signal (322) to provide the TDD platform. The second LO synthesizer signal (314) is common to both systems in the receive mode.

Abstract: There is provided a radio communication apparatus wherein a band-pass filter and a variable attenuator of a radio high-frequency circuit are designed such that these can be commonly used by transmitter and receiver systems. In a base-band circuit system, analog low-pass filters for smoothing a base-band signal and roll-off filters for removing unnecessary frequency components by digital filtering processing are designed such that these can be commonly used by the transmitter system and receiver system. In the demodulation system adopted in the orthogonal circuit system, orthogonal detection is followed by delay detection, and multipliers for orthogonal modulation are also used as multipliers for orthogonal demodulation. Further, for common use of the circuit elements by the transmitter system and receiver system, switches for connecting the signal line to the transmitter system or the receiver system in the transmission/reception mode are provided at one end or both ends of each of these circuits.

Abstract: A method and apparatus system for cancelling a leak-through signal component generated by an interfering transmitter from a received/leak-through signal comprising a multiplier for multiplying the received/leak-through signal by a reference signal provided from the interfering transmitter. The system further includes an integrator for integrating the output of the multiplier to generate an estimate of the gain and phase of the leak-through signal component. A gain and phase adjustor, responsive to the generated gain and phase estimates, is also included for adjusting the gain and phase of the reference signal to generate a cancellation signal that is a substantially gain and phase matched estimate of the leak-through signal. The generated cancellation signal is then subtracted from the received/leak-through signal to substantially cancel the leak-through signal component.

Abstract: A loop testable radio transmitter/receiver includes a transmission system which includes a transmission frequency converting unit and a transmission signal filter unit. A receiving system is provided, including a receiving signal filter and a receiving frequency converter. The transmitter/receiver further includes a transmitter/receive sharing unit, a transmission signal looping unit for attenuating the transmission signal of the transmission system and for looping back it to the receiving system, and a shifter arranged to the output side of the receiving frequency converting unit in the receiving system for converting an intermediate frequency of a signal converted by the receiving frequency converting unit into the receiving input frequency of a modulator/demodulator.

Abstract: A method for compensating for time mismatch between an interference signal path and a cancellation signal path in an interference cancellation system involves two cross correlation steps. The first cross correlation establishes a baseline by correlating a reference signal at a synchronous detector of the interference cancellation system with a reference signal through a signal controller and error signal path of the system, which is the signal route from a sample coupler of the interference cancellation system to the synchronous detector by which the residual cancellation signal is measured. When this process is taking place, external signals from the air path are eliminated by using an isolation switch in the receive signal path of a radio receiver system to which the interference cancellation system is coupled. The second correlation is performed between the reference signal at the synchronous detector and the external interference through the error signal path.

Abstract: A voice transmission method and apparatus in a duplex radio system are disclosed in which a voice signal to be transmitted in a constant period of time is subjected to 1/N time compression, N being a numeral not smaller than 2.0. The time-compressed voice signal is supplied to a transmitter as a modulating signal and a transmitting operation is performed by the transmitter in synchronism with a period of time when the modulating signal is inputted to the transmitter. A receiving operation of receiving a time-compressed and modulated signal transmitted from the transmitter to demodulate it is performed by a receiver in a period of time other than the period of time when the transmitting operation is performed. A demodulated signal is subjected to N-ple time expansion to obtain a reproduced receive voice signal, and both the transmitting operation and the receiving operation are repeated at the constant period of time.

Abstract: A Q multiplier circuit which is automatically feedback stabilized through the use of phase and gain control loops and thereby adapted for use as an amplifier and filter. In a typical embodiment, a variable gain amplifier and band pass filter are provided in a forward signal path while a phase shifter is provided in a feedback signal path. The output of the circuit is sampled and compared to a fixed reference in order to generate a gain control signal for application to the variable gain amplifier. The input signal on the forward signal path is sampled along with the signal on the feedback signal path and the phases of these samples are compared in order to generate a phase control signal for application to the phase shifter. The variable gain amplifier is controlled to maintain a predetermined power output level while the phase shifter is controlled to maintain positive feed back.

Abstract: A bidirectional amplifier apparatus comprising a plurality of diodes located in a ring structure around an amplifier device to be switched. Each pair of diodes are spaced approximately one quarter wavelength, at the frequency to be passed, in order to maximize isolation across the "off" diode pairs. Use of transmission line devices of approximately one quarter wavelength, at a desired frequency, provide a high impedance at the desired frequency while attenuating higher frequencies where the transmission line devices length approach one half wavelength. The use of the transmission line devices also provide a ground bias for the paired diodes.

Abstract: This active antenna is incorporated in the terminal station of a system for data exchange with a central station, by the modulation of a microwave carrier. The terminal station is of the chip card type. The modem of the active antenna is constituted by a transistor, the bias current of which is switched over from a low value at demodulation to a high value at modulation. The switch-over is obtained by a circuit with three resistors (R.sub.d, R.sub.gd, R.sub.g), which themselves have their values switched over by two transistors parallel connected with the resistors, these transistors being controlled by two signals emitted by the control circuit of the terminal station. The active antenna can be applied to long-distance data exchange, for example in the remote management of toll-charge systems, remote cash dispensing, localization of moving bodies etc.

Abstract: A radio communication apparatus used for both digital communications and analog communications is disclosed which comprises a digital signal processor DSP (4) which processes many kinds of digital signals according to a plurality of signal procedures (55,56,57,58) stored in the ROM (5). In the present invention, since the radio communication apparatus processes many kinds of procedures (55,56,57,58) stored in the ROM (5), the size of the apparatus becomes small and weight becomes light.

Abstract: A radiotelephone data transfer apparatus connects peripheral devices external to the radiotelephone and other user information inputting devices, such as a handset for a cellular mobile radiotelephone, to the radiotelephone's central processor and speech processor. The data bus apparatus generates frame formats in which the information is sent over the data bus. The frame formats are further subdivided into time slots, the time intervals in which individual messages are sent. The data transfer apparatus is configured so that messages sent to the cellular radiotelephone's speech processor are not flow controlled, while messages sent to the radiotelephone's central processor are flow controlled. Further, the radiotelephone's central processor controls operation of peripheral devices attached to the radiotelephone.

Abstract: A radio transceiver for use in data communications uses a single phase-locked loop to control the frequency of the receiver portion while simultaneously providing coarse control of the frequency of the transmitter portion. The output of the receiver portion is also used to provide an error signal for fine tuning the transmitter frequency after the component of the error signal caused by modulation of the transmitter portion has been removed.

Abstract: A digital transmitter/transceiver accommodates multiple simultaneous receiver and transmitter channels by time division multiplexing the tuning and modulation hardware. Only a single digital-to-analog converter is required for multiple channel transmission, and time multiplexing permits the use of only a single set of digital hardware.

Abstract: A communication unit (10), capable of operating in either cellular or trunked communication modes, comprises a receiver (14), a transmitter (16), and a dual synthesizer (18), coupled to the receiver and to the transmitter. The dual synthesizer comprises a main synthesizer (124) and an offset synthesizer (132). The offset synthesizer comprises a phase modulator (131) and an offset voltage-controlled oscillator (134). A protocol controller (20) comprises modulator circuitry for modulating only the offset voltage-controlled oscillator when communication unit operates in the cellular mode, and for modulating both the phase modulator and the offset voltage-controlled oscillator when the communication unit operates in the trunked mode.

Abstract: A method of voice communication is provided to avoid disruption in the received voice signal. A compressed voice signal is received occupying 100% of the audio time during a lesser percentage (352) of the radio frequency (RF) time (302). An informational signal is also received during at least a portion of a remainder (354) of the RF time. Scanning for another channel, receiving data or embedded control signals may occur during at least a portion of the remainder (354) of the RF time saved.

Abstract: A DC offset compensation circuit for use with a detector of an interference cancellation system or the like includes an RF switch. The interference cancellation system has a reference signal path on which a reference signal representative of an interfering signal is provided to the detector, and an error signal path on which an error signal representative of a received signal of a radio receiver system to which the interference cancellation system is connected is provided to the detector. The RF switch is positioned in the error signal path of the interference cancellation system and is switchable between an open position in which the detector is disconnected from the error signal path, and a closed position in which the detector is connected to the error signal path. A switch controller is coupled to the RF switch, and controls the positioning of the RF switch in the open and closed positions. The detector provides a first DC signal when the RF switch is in the open position.

Abstract: A bi-directional amplifier having two symmetrical and versatile impedance matching circuits with a JFET therebetween, and a method for bi-directional amplification using a JFET. Each junction of the JFET may be a drain or a source depending on the direction of amplification. Each impedance matching circuit provides a low impedance for the junction that is a source and a high impedance for the junction that is a drain. The impedance is varied by adding a first capacitor parallel to a resonating inductor and a second capacitor, which is removed or inserted in series with the load, responsive to the direction of amplification. The frequency of the signal being amplified may be different for each direction.

Abstract: A mobile radio is disclosed which includes an integrated circuit audio processor which operates under the control of at least one microprocessor. The audio processor provides basic transmit/receive audio filters, tone signaling filters, squelch filters, an RF power level control circuit, a DC voltage measuring circuit, a volume level adjusting circuit, and a transmit level adjusting circuit. In the audio processor, audio bandwidth, tone filter response, squelch filter response and other operating characteristics are adjusted by an incoming data bit stream from the controlling microprocessor. In addition, in response to data received from a microprocessor, the audio processor is controlled, for example, to have its receive audio path closed and its transmit audio path opened to switch from the receive to transmit mode.

Abstract: A connecting structure for connecting two oscillator circuits to an amplifier. The oscillator circuits are provided on one surface of a printed circuit board and include two dielectric resonators. The amplifier circuit is provided on the other surface of the printed circuit board for selectively amplifying oscillatory outputs from the oscillator circuits. The dielectric resonators are fixed to a metal plate mounted on the printed circuit board, and the amplifier circuit is located at a position opposite to the metal plate.

Abstract: A method for operating a transmitting/receiving circuit for ultrasonic signals includes the steps of producing a carrier frequency by a voltage-controlled oscillator having an output frequency controlled in accordance with a temperature dependency of an inherent frequency of the transducer, modulating the carrier frequency, applying the modulated carrier frequency in a transmitting mode to energize an ultrasonic transducer to produce ultrasonic transmission signals, switching from the transmitting mode to a receiving mode, applying output signals from the transducer representative of received ultrasonic signals to a phase-locked-loop circuit using the voltage-controlled oscillator whereby the phase-lock-loop circuit is automatically matched to a frequency of the received signals.

Abstract: A multi-mode radio transceiver comprising a sequence of bi-directional circuit modules including a radio frequency input/output amplifier module (1), a radio frequency/baseband I and Q quadrature channel conversion module (2), an analogue/digital conversion module (3), a digital signal processor (4,5), and a digital signal input/output interface (6), with a control means (7) whereby for transmission a radio frequency signal is formed from analogue quadrature I and Q channel components of a digitized signal at baseband and translated to the radio transmission frequency and for reception the radio frequency signals are transformed into I and Q quadrature analogue components at baseband and subsequently digitized.

Abstract: An improved encoder/decoder circuit which utilizes a phase locked loop frequency synthesizer configuration to permit both encoder and decoder operation. In addition, a sampling filter detector is employed to permit monolithic integration of the circuit and minimize sensitivity to vibration. The sampling filter detector has digitally controlled bandwidth which permits rapid response to reverse burst turn-off. In addition, the circuit includes a pulse adder to implement an energy limited reverse burst turn-off mode.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Both base and remote units each include a radio transmitter and a radio receiver. Also included in the base unit is bimodal tuned circuit operable as a filter and as an oscillator.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Included in both the base and extension units are a radio receiver and a radio transmitter. Also included in the remote unit is a bimodal tuned circuit operable as both a filter and as an oscillator.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Both base and remote units including a radio receiver and a radio transmitter. Also included in both base and remote units is a bimodal tuned circuit operable as a filter and operable as an oscillator.

Abstract: A method and apparatus is disclosed for automatically and exactly tuning a boradband filter. Upon the detection of a tuning change, the filter is automatically switched end to end so that the output terminal of the filter is connected to the radio frequency power source. Radio frequency in this application refers to any signals whose frequency facilitates propagation of data via electromagnetic waves. The input terminal is terminated into a known load such as 50 ohms and C1, an input variable reactance is adjusted until a 90.degree. phase relationship exists between the input resonator and the output resonator's node voltages. These actions set the exact tune condition for the broadband filter.