Abstract: Shown, herein, is a method of allowing use of small, low-power communication systems within the service coverage area of larger trunked systems. The small, low-power systems are constructed to reuse at least some of the inbound frequencies of communication resources, also used by the larger system. The large system measures signal strength values of large cell communication units and transfers such values to the small systems. A small system also measures the signal strength and compares the measured and transferred values with thresholds and when the thresholds are exceeded, reuses the communication resources under a TDM format within the small system.

Abstract: An electronic device (100) includes electrical circuits (208) and a power source (101) having at least one terminal for providing power to the electrical circuits (208). A housing has first and second members (302,304) constructed to cooperatively interconnect to substantially enclose the electrical circuits (208), the housing further being adapted to receive and mechanically couple with the power source (101). An electrical contact strip (220) electrically couples the electrical circuits (208) and the power source (101), and fastens the first and second members (302,304) of the housing together. The electrical contact strip (220) includes a spring indentation (314) mechanically coupled to the at least one terminal of the power source (101) to provide mechanical securing force between the power source (101) and the housing. The electrical contact strip (220) also includes a first opening. The first and second members (302,304) of the housing include second and third openings.

Abstract: A system, and associated method, for measuring a signal level of a signal received by a receiver, such as a radio telephone. The signal received by the receiver is applied to a variable amplifier. The amplification of the variable amplifier is adjusted such that an amplified signal generated therefrom is within the dynamic range of an intermediate frequency circuit. The level of amplification required to position the signal level of the amplified signal within the dynamic range of the intermediate frequency circuit is measured, and the signal level of the signal received by a receiver is calculated.

Abstract: A frequency setting system for a radio transmission apparatus of the type transmitting a signal in the form of bursts and changing transmission frequency burst by burst. A frequency division data signal representative of a frequency division number and a strobe signal representative of frequency setting are fed to a frequency synthesizer. The timings for generating the frequency division data signal and strobe signal are determined with no regard to the locking time of the frequency synthesizer which is dependent on the kind of the synthesizer, frequency, etc.

Abstract: A mobile radio programmed to analyze idle channel assignments issued by a repeater station and select different channels, if appropriate, which are especially adapted for communicating with other communication facilities, such as a telephone interconnect. Programmed into the mobile radio with each communication channel is an indication of whether or not such channel can be utilized to communicate with the other communication facility. If communications are desired with the other communication facility, and if the present idle channel assigned by the repeater station does not permit such communication, then a processor in the mobile radio consults a data list of appropriate channels, selects one such channel, and then establishes communications to the other communication facility on such channel.

Abstract: A radio-telephone system employing a manner of changing a channel and a privacy digital code and interstoring them between by wireless and a method of changing the privacy digital code. The radio-telephone system comprises a stationary apparatus 100 and a portable apparatus 200. The stationary apparatus 100 includes a base MPU 410 containing a ROM, a charging power supply and sensing circuit 450, a transmitting and receiving PLL circuit 420, a duplex radio transmitting and receiving unit 430, a line connecting circuit 460 and an antenna A. The portable apparatus 200 includes a hand MPU 610 containing a RAM, a transmitting and receiving PLL circuit 620, a duplex radio transmitting and receiving unit 630, a charging circuit 680 and an antenna A'. The method of changing the privacy digital code is performed by using the radio-telephone system. Therefore, in accordance with the present invention, the selection of the talk channel having no crosstalk by the system software is enabled.

Abstract: A regenerative RF bi-directional communications system is provided for establishing RF coverage within a RF block tunnel area. The system uses a plurality of cascaded amplifier stages for periodically regenerating signals which are transmitted and received along a series of radiating cable length which link base station transceivers to hand-held or like mobile communication units. An intermediate frequency distribution system is used so that the required level of amplification is achieved through the several cascaded amplifier stages at the level of low-power IF signals generated from the original RF signals in conjunction with the appropriate oscillator and pilot signals. The IF distribution system restricts the cascading effect occurring due to the plurality of cascaded amplifier stages on the relatively low-power IF signals, thereby producing a negligible amount of intermodulation.

Abstract: A scanning-superhetrodyne ESM receiver having a VCO for a local oscillator which is linearized and temperature compensated. A stable combline oscillator is used to generate known frequency signals which are frequency converted to an intermediate frequency (IF) using the local oscillator and frequency converter(mixer). The frequency of each combline signal is measured and a table of known voltage/frequency points is generated. The table is input to a Cubic Spline program which computes the coefficients for the best-fit third order polynomial for each pair of data points. When a particular local oscillator frequency is desired, the corresponding tune voltage is computed by solving the polynomial equation for the given frequency range. By repeating the calibration on a periodic, or an "as needed" basis, temperature compensation is achieved.

Abstract: In a circuit arrangement for matching the resonant frequency of an antenna resonant circuit (18) to the output circuit of a transmitter output stage (10), the antenna resonant circuit (18) is coupled via a reactance to the transmitter output stage (10). By means of a current sensor (16), the supply direct current of the transmitter output stage (10) is detected. The value of a tuning component (26), lying in the antenna resonant circuit (18), can be changed by a control signal; the tuning component is a governing factor for the resonance frequency of the antenna resonant circuit (18). A comparator and control unit (36)repeatedly samples the value of the supply direct current detected by the current sensor (16). In dependence upon the result of a comparison with a sequential previously sampled value, it applies th control signal to the tuning component (26) to obtain a maximization of the supply direct current detected.

Abstract: A diversity control circuit which selects an optimum receiving signal in a diversity receiver and which corrects receiving signal levels in such a manner that characteristics in measuring systems for a plurality of receiving signal levels can be regarded as homogeneous. The circuit includes memory means which stores correction data and which responds to receiving signal levels to provide corrected signals conforming to a preselected characteristic.

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 method of generating a first signal (115) in a radiotelephone (101) representing the detection of speech on a second signal having background noise, a magnitude, a zero crossing rate and divided in time by frames having a predetermined time period. In absence of speech, the method characterizes the background noise (209) and computes background noise thresholds (211). The method computes an average of the magnitude of the second signal and a zero crossing rate of the second signal for a given frame (215). Then, compares said average of the magnitude (217) and said zero crossing rate (221) of the second signal to said background noise threshold. Upon one of said average of the magnitude and said zero crossing rate consecutively exceeding said background noise thresholds for a first predetermined number of frames, the transceiver(107) is turned on.

Abstract: A radio receiver having a narrow effective beamwidth includes a receiver antenna, a receiver and a receiver transmission line interconnecting the two, and an interference cancellation system having an auxiliary antenna, a first directional coupler connected to the auxiliary antenna, a second directional coupler connected to the receiver transmission line, a synchronous detector connected to the first and second directional couplers, a signal controller and a subtractor connected to the signal controller and to the receiver transmission line. The receiver antenna is selected to exhibit an omni-directional antenna pattern, while the auxiliary antenna is selected to exhibit a null in its antenna pattern.

Abstract: A wireless RF communication system that shares frequency assignment with existing RF systems scans a set of possible operating frequencies for signals transmitted by the other systems. This data is sent to a frequency management center where a safe operating frequency is assigned. The new RF system periodically scans the set of frequencies and will automatically inhibit transmissions if a signal from another system is detected which exceeds a threshold, thereby indicating that a possibility exists for interference.

Abstract: An interference cancellation system for cancelling at least two interfering signals received simultaneously and which is adapted to be connected to a radio receiver system having a receiver antenna, a receiver and a receiver transmission line interconnecting the receiver antenna and the receiver includes an auxiliary antenna, a first directional coupler connected to the auxiliary antenna, a second directional coupler connected to the receiver transmission line, a synchronous detector connected to the first and second directional couplers, a signal controller connected the synchronous detector and a subtractor connected to the receiver transmission line and to the signal controller. The auxiliary antenna has a non-zero phase relationship for the two interferring signals relative to the receiver antenna.

Abstract: In a cellular radiotelephone system, the data base of a visitor location register is protected from saturation by releasing n-tuplets from the data base corresponding to those temporary mobile identity words corresponding to mobiles which announced their presence more than some predetermined time earlier, and by changing the predetermined time when the register nears saturation.

Abstract: In a method of connecting channels of a plurality of decentralized radio systems which perform independent channel connections, each of the plurality of radio systems sets a given channel and monitors a reception signal level of the given channel. Each radio system detects that the given channel is busy and sets a next channel when the reception signal level of the given channel is higher than a level corresponding to a threshold value. Each radio system rejects a connection if all channels are busy. Each radio system detects the given channel as an empty channel and starts communication through the given channel if the reception signal channel is lower than the level corresponding to the threshold value. Each radio system increases the threshold value when the channel connection is rejected. Each radio system decreases the threshold value when the communication is started.

Abstract: A trunked communication system wherein less than all of the communication units may transmit an identifying data word thereby registering their location to a system controller every time they enter a different coverage area, while the remainder of the communication units do not. The identity of the communication units which operate in each mode is known to the system resource controller in advance. Pre-registration allows the system controller to know the locale of target units in advance when communications to those units is requested. The locale of units that do no pre-register their location are identified through system wide paging. Coordinating the identification of locales of units in both modes permits greater optimization of spectral resources.