Abstract: A wireless device (104) selectively opreates near protected sites (110) including equipment at least intermittently using an operating frequency. The wireless device upon detecting a beacon signal from a beacon system (112) ascertains interference parameters. The interference parameters are used to control operation of the wireless device to prevent harmful interference with the equipment at the protected site. The operation is selectively altered depending upon the interference parameters ascertained. The wireless device can be intelligently controlled from a control system (105).

Abstract: A method and apparatus is provided for creating a composite waveform. This composite waveform is created by coding a plurality of input digital information signals. Subsequently, the plurality of coded input digital information signals are communicated over a communication medium to a digital combiner. The digital combiner combines the plurality of coded input digital information signals. Finally, the digitally combined information signal is spectrally shaped to form a composite waveform. These composite waveform creation principals may be applied to digitally encoded voice subbands in a subband coding system as well as channel information in a direct sequence code division multiple access (DS-CDMA) communication system transmitter.

Abstract: A radio communications device is arranged to communicate time divided signals (60 and 70) over first (40) and second (50) time discontinuous systems having first and second frame structures respectively. Switching device (120) switches between communicating signals (60) over the first system (40) during time periods of the first frame structure and communicating signals (70) over the second system (50) during time periods of the second frame structure. Hence over a given period of time the device simultaneously communicates time divided signals over the first (40) and second (50) systems.

Abstract: A method as shown in FIG. 2 for allocating resources in a radio communications system having a plurality of communications resources for at least one receiver and transmitter to communicate over where the communications resources have signal levels which vary due to a multipath environment resulting in periods of poor communication quality over at least one particular communications resource including measuring at a first receiver a parameter indicative of a quality of communications between the first receiver and a first transmitter over a currently assigned communications resource and determining whether to allocate a different communications resource based on the measured parameter in order to effectively reduce periods of poor communications quality between the first receiver and the first transmitter.

Abstract: This invention relates to a time division multiple access (TDMA) trunked radio system and it relates to a frame structure for communication between fixed, mobile and portable radios in such a system. The radio system comprises: a base station and a plurality of remote radio units for communicating over time slots of a time divided radio channel, the base station having means for transmitting a synchronization signal for defining the timing of the time slots, and each of the remote units having a power amplifier with linearization means, characterized in that the channel comprises predetermined linearization time slots (120, FIG. 2) for transmission of training signals, interspersed between other time slots and each remote radio unit comprises means for generating a training signal during a linearization time slot and linearizing its power amplifier during that time slot in advance of and independent of transmission of signals during one of said other time slots.

Abstract: This invention relates to a trunking radio system (FIG. 1) having a central station and at least one remote station for communication with the central station over a number of frequency-divided radio channels. The central station has a transmitter (10) for transmitting a number of signals to different remote units on different channels and a trunking controller (12) for allocating channels to different remote units. The trunking controller monitors the excess number of channels over the number of channels allocated to remote units. The central controller signals to a remote unit to allocate a channel to the remote unit when there is at least one excess channel. Signals received from the remote unit over the at least two channels are diversity combined (21). The remote unit has a receiver for receiving signalling from the central station and a diversity transmitter (34, 35, 39) responsive to the signalling for transmitting a signal over the at least two channels.

Abstract: A method and apparatus is provided for creating a composite waveform. This composite waveform is created by coding a plurality of input digital information signals. Subsequently, the plurality of coded input digital information signals are communicated over a communication medium to a digital combiner. The digital combiner combines the plurality of coded input digital information signals. Finally, the digitally combined information signal is spectrally shaped to form a composite waveform. These composite waveform creation principals may be applied to digitally encoded voice subbands in a subband coding system as well as channel information in a direct sequence code division multiple access (DS-CDMA) communication system transmitter.

Abstract: A bulletin board communication resource provides a message to communication units regarding available communication systems in a particular geographic area. The bulletin board resource also supports registration of the communication unit with one or more of these systems as selected by the communication unit.

Abstract: A radio communication system includes a central station such as a repeater for transmitting FM signals to a plurality of radios. The repeater 11 is capable of receiving both analog speech FM signals and compressed voice signals. This permits the use of energy efficient transmission schemes by some of the radios operating in the system while permitting use of both types of transmission by the various remote radios.

Abstract: A TDM cellular communication (100) system includes a plurality of repeaters (102) each providing communication coverage for a cell site. A plurality of communication units communicate with the repeaters. The communication units are handed off from one cell site to another by measuring the range of the communication units from the repeaters. If the range exceeds a predetermined range the received signal quality of the adjacent cell site repeaters are measured. An available cell site which provides the best received signal quality is selected by the communication unit for hand off.

Abstract: A harmonic signal is created from a limited spectral representation of a voice signal. The harmonic signal is combined with the at least a portion of the limited delayed spectral signal to provide a reconstructed speech signal having perceptually improved audio quality.

Abstract: An RF communications system that can determine when a requesting subscriber unit comprises a TDM capable unit, and when it doesn't. Channel assignments are based upon this determination. The system also includes repeaters that can translate communications in a TDM format as transmitted by a TDM capable unit into non-TDM format for subsequent transmission to a non-TDM capable unit, and vice versa.

Abstract: According to the invention, an information signal, such as a information signal, is sampled, quantized and processed digitally through an information encoder. Digitally processed samples produced by the encoder are modulated onto a communication channel to create channel symbols having a magnitude of modulation proportional to a characteristic of a respective digitally processed sample. Both a radio frequency (RF) transmission embodiment, and a wireline embodiment are provided. In a final aspect of the present invention, encryption is provided to ensure communication privacy.

Abstract: A communication system that provides TDM and FDM communications between communication units. At least two control slots are provided in each TDM frame window to provide communication control information such as channel assignment information.

Abstract: In a digital communication system, a residual signal is generated, encoded, and combined with an encoded information signal in a manner that does not appreciably degrade the encoded information signal. The information contained within the residual signal may be used by the receivers to improve the quality of the recovered signal. The residual signal is modulated such that it may only be recovered when the signal-to-noise ratio is sufficiently high. In this way, the quality of the recovered signal improves with increased signal-to-noise ratio.

Abstract: An improved arrangement and method for use in a radio communication system is disclosed which makes possible mobile radio channel assignments on narrower channel spacings with a minimum amount of adjacent channel interference or splatter occurring at an included base station receiver. In a first embodiment, the mobile radios modify at least one transmission parameter, such as maximum allowable deviation, a given amount of transmitter output power, and a modulation limiting bandwidth, if a processed value of receive signal strength exceeds at least one predetermined threshold value. The processed value of receive signal strength is taken from a plurality of sampled and stored receive signal strength values in the mobile radio. By determining that the processed value of receive signal strength exceeds a predetermined threshold value, the mobile radio is able to adaptively control the amount of splatter caused at the base station, thus keeping the amount of splatter within acceptable levels.

Abstract: An improved mounting system for surface mounted components is described. The mounting system of the present invention provides preparations for surface mounted components and the printed circuit substrate which render the resultant assembly highly resistant to stresses which occur due to thermal cycling. The printed circuit substrate is conditioned by removing selected areas of media surrounding the points of attachment between the surface mounted component and the printed circuit media. In addition, a spacing element is disposed between the surface mounted component and the printed circuit media to promote the formation of a virtual lead during assembly.

Abstract: A variable impedance synthesis circuit is provided for generating a selected impedance, whether real or complex, at a predetermined port. The variable impedance synthesis circuit exhibits the selected impedance in response to control signals applied thereto.

Abstract: Apparatus is provided for inhibiting the generation of intermodulation products in a radio frequency amplifier coupled to a circulator. A control circuit generates a control signal exhibiting indicia of the amount of isolation provided by the circulator. The control signal is provided to a variable impedance synthesis circuit coupled to the circulation isolation port such that the impedance synthesis circuit exhibits the appropriate impedance to maximize circulation isolation. Intermodulation is thus minimized.

Abstract: An apparatus and a method are provided for determining when a moving body assumes a motionless state. A rate of turn sensor is attached to the moving body. A signal indicating that the body is substantially motionless is generated when the rate of turn signal generated by the sensor is substantially constant.