Abstract: The mobile radio system includes a plurality of power amplifier modules having discrete power levels, a common transceiver module and a plurality of control head modules having different control functions. Selected ones of the power amplifiers and control heads are electrically and mechanically coupled to opposite ends of the transceiver. In one form, the control head may be remotely mounted and electrically coupled to the selected power amplifier. A common bracket is used to mount a radio having selected ones of the power amplifiers coupled to the transceiver with a selected control head. In a further embodiment, a receptacle having electrical fittings at its rear end and an opening at its opposite end receives the radio through its open end with the electrical connections being automatically coupled to one another upon final seating of the radio in the receptacle. The radio includes a handle which forms a latch for releasably securing the radio in the receptacle.

Abstract: The present invention includes a system and method for minimizing interference between two radio stations, e.g., a mobile radio telephone and a fixed base station, at the initiation of a radio communication. A mobile station initiates a random access at the lowest power level and increases the transmission power level until the base station detects the access signal. Once detected, the power level of the message is maintained at the detected level so that the signal interference is avoided. The present invention also provides a mechanism for synchronizing random access communications between mobile stations and the base station despite variation in distances between the mobile and base stations.

Abstract: Transceiver frequency and optionally power level are allocated to a radio personal communications system which includes a base station connected to a wire telephone network and a cellular terminal operating within a region of a wide area cellular network to minimize interference between communications over the wide area cellular network and communications between the base station and the cellular terminal. The same cellular terminal may thus be used to communicate over the lower cost wire network when within range of the base station and over the wide area cellular network otherwise. The frequency for communications between the cellular terminal and the base station are optionally assigned by the operator of the wide area cellular network so appropriate frequencies and power levels can be assigned for base stations, to minimize same channel interference with the wide area cellular network.

Abstract: A communication system having a frequency hopping scheme which provides increased interferer diversity without increased system delay is disclosed. The frequency hopping scheme includes providing a staggered offset period between hops of neighboring or adjacent base stations so as to create additional interference situations (diversity).

Abstract: The present invention relates generally to RF power amplifiers for portable cellular radiotelephones, and more particularly, to dual-mode cellular radiotelephones. A power supply network enables the RF power amplifier in a dual-mode radiotelephone to operate with two separate modes: saturated and unsaturated. Switches in the power supply network, e.g. complementary transistors, are driven to a first set of logic states by a square wave which is synchronized with transmit time slots present in a TDMA frame structure to charge a capacitor from a battery. When the switches are then driven to a second set of logic states, the capacitor is placed in series with the battery to essentially double the supply voltage. When the radiotelephone operates in a digital mode, the increased supply voltage coincides with the transmit time slot and temporarily increases the saturation point of the RF power amplifier to permit linear amplification.

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.

Abstract: A compensation circuit including resistors, capacitors and a varactor diode powered simultaneously by the same voltage source applied to a voltage controlled oscillator for reducing deviation from a desired oscillator output frequency on power-up. When power is applied, an exponentially varying voltage is applied to the varactor diode changing its capacitance in such a manner as to change the oscillator frequency in the opposite direction to its natural drift tendency, thus producing a substantially constant output frequency over the period of interest.

Abstract: An apparatus for upgrading a mobile telephone, the mobile telephone having a main memory the apparatus comprising a module reader provided in the mobile telephone and a software upgrading module card adapted to be temporarily connected to the mobile telephone by insertion into the module reader. The card comprises means for storing upgrading software to be transmitted into the main memory in the mobile telephone. The apparatus further includes means provided in the mobile telephone for transmitting the upgrading software into the main memory.

Abstract: A single channel autonomous trunking ("SCAT") RF repeater transmits and receives on a single duplex RF channel. The repeater operates alternately in a control channel mode and in an assigned channel mode. Digital control channel signalling results in temporary assignment of the single channel for assigned channel signalling (e.g., mobile generated messages). A holdover time period following reversion of the channel to control channel signalling minimizes collisions and permits priority to be given to emergency communications. Low speed data subaudible digital signalling may be used to provide late entry capabilities.

Abstract: A simple and effective "RF snubber" circuit resolves the problems associated with transient spectral noise caused by radio transmitter activation in nearby channels. By connecting an RF snubber circuit in parallel with the RF amplifier output, the rise time or turn-on characteristic of the RF signal generated by the transmitter is controlled. As a result, adjacent channel interference is substantially eliminated.

Abstract: An apparatus and method of modular electronic printed circuit board design for a radio communication transceiver in which the electronic circuitry forming a transmit/receive circuit board of the device is modularized in such a manner as to facilitate independent stand-alone functional testing of modules both on and off the board.

Abstract: The present invention provides a method for transmitting information on a communications channel, e.g. , a digital control channel between a base station and a mobile station in a cellular system. The method includes the steps of grouping the information into a plurality of information elements, providing at least one change flag to indicate whether the value of at least one of the information elements has changed and transmitting the change flag and the information element over the communications channel.

Abstract: In a mobile radio telephone system employing TDMA or CDMA, mobile units often must determine the timing and appropriate power necessary for transmissions to a base station. Information broadcast by base stations allows the mobile station to approximate its distance from each base station based on an average signal strength received and thereby determine the coarse sector location. Broadcast information may include the mean radial distribution of signal strength versus distance. From the broadcast information, the mobile station determines the propagation loss for a transmission to the base station and the appropriate power level and timing for transmissions. Accordingly, the mobile station transmits signals to the base station at the determined signal timing and power level.

Abstract: A malfunction position detection system is disclosed for a modular telecommunication facility. Each telecommunication facility is constructed out of a plurality of modular cabinets which are positioned in a station rack. The malfunction position detection system includes switches for setting the position of each cabinet in the station rack. The cabinet position is read off of a bus connected to the switches by a plurality of electronic units connected to the cabinet. The cabinet position is stored in some of the electronic units. As a result, the cabinet position can be sent along with an error message to the cellular system when an error occurs.

Abstract: A diversity antenna assembly for use with portable radiotelephones includes plural antennas physically connected by a non-conducting member to effect simplicity of deployment of the antenna assembly. The antennas are spatially separated to provide space diversity to minimize the deleterious effects of Rayleigh fading.

Abstract: A multisite network switch for a series of RF digital trunked radio transceivers and dispatcher consoles. Each transceiver covers a certain site area. The switch establishes audio communications between different sites and various dispatcher consoles. The multisite switch has a distributed architecture in which each node of the switch is supported by a microprocessor controlled card. Each node interfaces with a site, dispatcher console, system manager or other system component.