Abstract: The present invention relates to a divider for dividing a dividend by a divisor. The divider includes a subtractor for subtracting the divisor from the dividend to produce a result, storage space with a preliminary answer, and a processor for revising the dividend and preliminary answer based on the result. Each interation the divider is adapted to reiterate the subtraction and revision multiple times, based on a revised dividend and revised preliminary answer.

Abstract: A graphical management interface for a radio station that simplifies programming interactions for a user. The interface has a display region for presenting programmed functions of the station. The region has first and second controls for user selection of input conditions to form programmed functions, and for user selection of output actions to be carried out by the station in response to the selected input conditions. At least one further control for user editing of the functions is also provided. The first and second controls list substantially every available input condition and every available output action of the station for selection by the user. Backplane management of the station can also be done in software.

Abstract: A latching assembly for securing a battery package (12) to a portable communication device. The latching assembly includes a pair of opposed moveable latches (10), each latch (10) being located toward a side of the battery package, and a biasing member or members (13) arranged to bias the latches (10) away from each other to engage with respective catches on the portable communication device to thereby secure the battery package (12) to the portable communication device. User contacts (15) are also provided and these are operable to cause the latches (10) to move toward each other to disengage from their respective catches to enable the battery package (12) to be removed from the portable communication device.

Abstract: A method of arbitrating group calls in a digital mobile radio system without need of a central component. In general terms the base station that are serving mobile units in a call each announce the nature of the signals that they are receiving. The stations then each compare the signals and decide which signal will be broadcast to the mobile units. The signals are preferably transmitted between base stations via a packet network using IP multicast.

Abstract: A control loop (10) for producing an output signal with a stable nominal frequency is provided. The control loop includes inputs for reference (11) and oscillator (25) output signals, a beat frequency generator (12) for producing a signal with a frequency that is the difference between the oscillator and reference signal frequencies, an ADC (14) to convert the beat frequency to a digital beat frequency signal, an estimator (17) for estimating the frequency or phase of the beat signal, an adder (18) for combining an offset and modulation signal and the estimated frequency or phase of the beat signal into an added signal, and a DAC (23) for generating an analogue control signal for controlling the oscillator output frequency.

Abstract: The invention involves a proactive shift of a control channel among a range of available channels in a mobile radio network, particularly traffic channels. The control channel is intermittently shifted in a periodic or non-periodic manner, thereby making the frequency available for use in other networks. A round-robin process may be used to re-allocate the control channel among traffic channels. This is useful in a network operating within a common channel environment where activity on a fixed the control channel can be unfair or interfere with other networks.

Abstract: A simulcast system for transmitting and receiving signals through a plurality of remote sites within a certain area is generally described. The system automatically equalizes signal characteristics in transmission overlap regions between adjacent sites so that mobile units within the area receive signals of acceptable quality. A particular site is chosen to provide reference characteristics and a series of consecutively adjacent sites are then equalized in pairs. A control site sequentially transmits and receives a training signal through each site to determine an adjustment which will equalize the signal characteristics of successive sites in the series.

Abstract: A zero intermediate frequency radio receiver that comprises mixing stages, an A to D converter, a digital demodulator, a carrier tracking system and a carrier nulling system is disclosed. The mixing stages receive FM or PM signals and produce analogue in-phase and quadrature baseband signal which are in turn converted to digital baseband signals by the A to D convertor. DC offsets in the baseband signals are removed by high pass filtering prior to demodulation. Tracking enables the baseband signals to be maintained at a centre frequency of substantially zero hertz, while signal strength at this frequency is minimized or mulled before the DC offset filtering. Information which might otherwise be removed by the filtering is thereby retained in the baseband signals, which are relatively less distorted.