Abstract: A cellular radio system has a plurality of base stations (BS) each for communicating with mobile stations (MS) in its vicinity, and each base station (BS) determines that voice or data communication between the base station and the mobile station has temporarily ceased, and initiates required signalling with the mobile station during that temporary cessation.

Abstract: Off-premises cable television pay per view apparatus is coupled between first and second diplexers of off-premises subscriber service providing equipment. The diplexers separate the transmission path between a headend and a subscriber into downstream or forward and upstream or reverse transmission paths. A radio frequency transmitter is coupled between a controller and the upstream diplexer which may actuate a selected one of a plurality of data channels in the notoriously noisy subsplit 5-30 megahertz transmission spectrum for reporting billable events. On-premises equipment is minimized to comprise only a unidirectional data transmitter. The data transmission is sent repetitively over a predetermined period of time before the data transmitter, comprising a microprocessor, turns itself off to conserve power.

Abstract: A location monitoring system is provided having a radio frequency transmitter for a person or object and radio frequency receiver for someone to monitor movement of the person or object, the receiver sounding an alarm at a predetermined time after failure to receive a signal. The transmitter is made having an intermittent transmitted signal and the receiver is made having an off-timer to coordinate with the intermittent signal, the off times saving battery power. The radio frequency receiver has an electronic switching device controlled by the radio frequency transmitter for sounding an alarm. An antenna is located in part of the carrying strap of the transmitter. The radio frequency transmitter can have various devices for sounding the alarm.

Abstract: An arrangement for duplex transmission in a radio or similar device with a transmitter and receiver comprises a transmitter filter, receiver filter and preferably a transmitter/receiver device. The receiver filter may be a surface acoustic wave filter, and the transmitter filter and receiver filter are connected via a circulator. The arrangement also comprises a power detecting device for detecting the power into the receiver filter, and the power detecting device provides a feed-back signal to an arrangement for controlling the power out from a power amplifier arranged in front of the transmitter filter.

Abstract: The invention relates to a hands-free module (2) for a mobile telephone (1). The hands-free module comprises a housing (11) and a cord (13) extending therefrom. Connected to the end of the cable distal from the housing is an external phone unit (14) and an external microphone (15). Mounted on the module is a connector (12) which connects the module housing (11) mechanically to the telephone housing (3) and which also connects the external phone unit (14) and the external microphone (15) electrically to the respective circuits of the internal loudspeaker and the internal microphone of the mobile telephone. The choice between the external and internal microphones is effected by a switch.

Abstract: In a radio receiver with an input circuit which can be supplied with received signals, with a mixer for deriving an IF signal, and with an IF filter, the passband range corresponds to a usable signal range of the received signal, the received signals are amplitude-modified with an auxiliary signal for detecting intermodulation, in the course of which sidebands are generated outside of the useful signal range. The amplitudes of at least one sideband generated by modulation with the auxiliary signal and of the received carrier are compared in the IF signal. In case of deviations from a ratio based on the modulation factor during modulation with the auxiliary signal, a signal indicating the presence of intermodulation is derived.

Abstract: A transmitter-receiver comprises a transmitter, a transmitter circuit, a receiver circuit, a receiver, a jack, and a switch. The transmitter circuit converts a first audio signal to a transmit signal and transmits the transmit signal. The receiver circuit extracts a second audio signal from a received signal. The jack is adapted to be connected with a plug of an external transmitter-receiver. The switch is on/off controlled dependent on whether or not the jack of the external transmitter-receiver is connected with the plug. The switch, when the jack is not connected with the plug, supplies the first audio signal from the transmitter to the transmitter circuit and also supplies the second audio signal from the receiver circuit selectively to the receiver.

Abstract: To prevent variation of a transmission band characteristic which is caused by variation of operational conditions (e.g., temperature in the rectification feedback amplification) in a system with large extraband attenuation for sharply cutting off the transmission band in each channel of the communication system including plural narrow band channels allotted close to each other, rectification feedback is effected through through an adaptive filter. A band characteristic of the adaptive filter is varied in response to the variation of operational conditions including temperature, while data processing is rapidly effected through digital signal processing. Consequently, even if the communications in each channels are intermittently repeated, each time the communication is reopened, the desired transmission band characteristic can be instantly fixed, so as to prevent the disturbance of stable operation by adjudicating the interference through data correlation.

Abstract: A digital radio receiver avoids overshoot or undershoot of an AGC control loop by isolating a carrier signal using an adaptive narrow bandpass filter. The carrier strength signal is used to control either a full AGC loop or an AGC overshoot limiter to avoid sudden changes in the audio output level.

Abstract: A communication system (20) is provided with multiple purpose personal communication devices (50 and 150). Each communication device (50 and 150) includes a touch-sensitive visual display (60 and 160) to communicate text and graphic information to and from the user and for operating the communication device (50 and 150). Voice activation (78) and voice control capabilities (76) are included within communication devices (50 and 150) to perform the same functions as the touch-sensitive visual display (60 and 160). The communication device includes a built-in modem (82), audio input and output (52 and 53), telephone jacks (86), and wireless communication (90). A plurality of application modules (100) are used with personal communication devices (50 and 150) to perform a wide variety of communication functions such as information retrievable, on-line data base services, electronic and voice mail.

Abstract: The process and apparatus of the present invention limits the output power of a radiotelephone, operating in a cellular system in the preferred embodiment. This ensures the transmitted sidebands and synthesizer phase noise remains within a certain specification. This is accomplished by power detection and a correction accumulator that together generate a gain control signal by limiting the gain adjustment to a maximum value, even when the cell site communicating with the radiotelephone is sending power turn-up commands to the radiotelephone. This process includes dynamically correcting the output level of the transmitter due to gain variations in the transmitter stages or gain control elements.

Abstract: A communication unit is improved to comprise a volume/mode selection switch, mode detector, volume level setting detector, and a processor. The mode detector and the volume level setting detector monitor the volume/mode selection switch to determine, respectively, the selected mode of operation and the volume level setting. The processor, which is operably coupled to the mode detector and the volume level setting detector, processes the mode of operation and the volume level setting based on the mode of operation selected.

Abstract: A new and improved arrow tracking apparatus includes a radio transmitter assembly, attached to an arrow, for transmitting radio waves associated with the arrow. The radio transmitter assembly is in the form of a jacket that jackets a shaft of the arrow. A battery-powered hand-held receiver assembly is carried by a person for receiving radio waves from the radio transmitter assembly. The components of the radio transmitter assembly are distributed along the jacket, such that the arrow, equipped with the radio transmitter assembly, is well balanced so that the arrow does not wobble in its flight path. The jacket includes a substantially smooth surface, such that the arrow has both good dynamic flight characteristics and good aerodynamic characteristics. The radio transmitter assembly includes a transmitter unit and an antenna assembly, and the antenna assembly may include antennas in the form of barbs. The jacket includes a first jacket sub-unit and a second jacket sub-unit.

Abstract: A stacked double balanced mixer (220) includes a double balanced mixer (320) and a first cross coupled differential mixer (330). The double balanced mixer (320) includes two input transistors (321, 322) and four cross coupled output transistors (323-326). The first cross coupled differential mixer (330) includes four cross coupled input/output transistors (331-334) and a second mixer output (227, 228). The four cross coupled input/output transistors (331-334) have first output terminal pairs DC coupled in series to second output terminal pairs of the four cross coupled output transistors (323-326). The stacked double balanced mixer (220) generates, at the second mixer output (227,228), a second IF differential output signal having a second IF frequency at a difference of a radio frequency of a differential input signal and the sum of first and second LO frequencies, respectively, of first and second LO signals.

Abstract: There is provided a method and an apparatus for assigning a radio channel between base and mobile stations in a mobile communication system, which provide advantages of first available and reuse partitioning systems and do not cause as great a proportional increase in a processing amount as an ARP system. A radio zone is divided into a number of regions having the same area which is equal to channel number N, usable in an entire system by concentric circles centering on a base station 12. Channels 1 to N.sub.s are allotted to the respective regions. Upon the issuance of a channel assignment request, a channel corresponding to the region where the mobile station is located or its neighboring channels is assigned preferentially.

Abstract: An automatic level control circuit for cellular telephone transmitters which is compatible with both existing analog cellular service and expected next generation digital TDMA service. The circuit automatically and dynamically changes modes to maintain communication when a mobile subscriber moves from one type of service to another. In a first mode of operation, which is compatible with existing analog cellular service, the circuit provides a closed loop negative feedback circuit which produces a control signal for continuously controlling the output power level of the transmitter amplifier. In a second mode of operation, which is compatible with proposed digital TDMA service, the circuit operates to alternately close the negative feedback loop during the periods when the transmitter is permitted to transmit (assigned TDMA frames) and open the loop during other periods when the transmitter is turned off. When the loop is opened, the invention temporarily stores the magnitude of the control signal.

Abstract: Traffic Condition information is settled by actuating a key (15, 16, 17, 18) of a four-way toggle switch (8) of a radio receiver in order to specify a directional quadrant. The position (34) of the radio receiver is established by the computer (5), using program comparison and identification methods, and traffic conditions information relating to the selected directional quadrants (30, 31, 32, 33) is issued via an output device (11), for example visually by a display or acoustically via loudspeakers (10) with the aid of a voice synthesizer (7).

Abstract: A method to implement multiple talk-around communication links using the communication resources of one repeater. A system resource controller determines whether talk-around is possible for any two communication units intending to engage in a point-to-point communication link. Assignment of a talk-around repeater depends on the geographic locations of the two communication units, and a predetermined range criterion between them. In addition, the talk-around communication must not interfere with any existing talk-around communication already in the system. When talk-around communication is possible, an enabling communication grant is issued to the units, and the talk-around repeater's communication resources are assigned to support the link. Otherwise, a repeater for normal trunking is assigned.

Abstract: A transmitter that includes an amplifying element, an antenna, a gain stage, and a closed loop feedback may compensate for varying antenna loads without an isolator. This may be accomplished by determining the effects of the varying loading on overall loop gain. Knowing the effects, the transmitter adjusts the gain of the gain stage to maintain a constant overall loop gain, thus eliminating the need for an isolator.

Abstract: A power amplifier used in a portable, radio frequency transmitter is switched between different modes of operation when transmitting differently modulated carriers. The first mode of operation corresponds to amplitude modulation (AM), while a second mode corresponds to angle modulation techniques such as frequency modulation (FM). A switching network alters the impedance of the power amplifier to match network for matching the impedance of the transmitter antenna in order to achieve maximum efficiency in each mode of operation. Various switching methods and impedance matching circuits are disclosed.