Abstract: A system is offered of increasing signal quality within a cellular communication system through the use of directional antennas and random assignment of communication resources.

Abstract: An FSK demodulator is provided comprising means for receiving and digitizing an FSK signal (such as a signal comprising two frequencies f1 and f2 in which first and second logic states are represented by first and second periods of different durations). First, second, third and fourth consecutive transitions of the signal are identified and the times of said transitions are identified. A first period between the first and third transitions is calculated, as is a second period between the second and fourth transitions. A change of frequency in the signal is indicated when the first and second periods lie on opposite sides of a first threshold period (.tau.) and no change of frequency is indicated when the first and second periods lie on the same side of the threshold period (.tau.). In a further aspect of the invention, a transition is rejected as illegal when two consecutive transitions occur within a predetermined period of time.

Abstract: A metal sheet is attached to a ceramic substrate utilizing a weld pad formed of tungsten layer that is preformed onto the substrate and features a faying surface coated with a gold film. The sheet is superposed onto the gold film and scanned with a laser beam to fuse the sheet and the gold, without fusing the tungsten, thereby avoiding spalling of the metal and microcracking of the ceramic.

Abstract: A method for forming a plurality of solder bumps on an electronic component substrate utilizes a transfer plate to electrodeposit solder deposits and subsequently reflow the deposits onto the substrate. The plate comprises discrete pad electrodes formed of a ceramic material that is suitably electrically conductive to permit electroplating of the solder alloy, but is not wet by the molten solder to permit reflow onto the substrate. A preferred electrode material is an indium oxide compound. The solder deposits are plated onto the electrodes, and the transfer plate is superposed on the substrate such that the bumps rest upon bond pads on the substrate. The assembly is heated and cooled to melt and resolidify the solder alloy, whereupon the solder bonds to the substrate pads to form the bumps.

Abstract: A phase locked loop frequency synthesizer with DC data modulation capability is described. This synthesizer includes an arrangement for detecting one of a plurality of FSK data levels (61), generating a corresponding predetermined compensation signal (71) and utilizing the compensation signal to substantially continuously compensate the frequency synthesizer for normal response to the detected data modulation level.

Abstract: In a communication system having a time base for system synchronization, there is provided a method and apparatus for controlling the sensitivity of a receiver comprising the steps of (a) receiving a signal that was predeterminally transmitted by another relative to the time base (wherein signal reception is confirmed when the amplitude of the received signal exceeds a pre-established threshold), (b) determining signal transit time from the time difference between the instant of signal reception relative to the time base and the instant of signal transmission relative to the time base, (c) controlling the sensitivity of the receiver as a function of the transit time by: (1) increasing the gain of the receiver from a minimum sensitivity at the predetermined transmission instant to a maximum sensitivity at maximum range (maximum expected transit time) and (2) nominally maintaining the receiver's gain at the level prevailing at the instant the signal is received.

Abstract: A method of configuring directional antennas to more fully radiate a geographic region serviced by a simulcast radio system can reduce the number of omni-directional antennas used by prior art methods. Directional antennas having significant differences between frontal and rearward radiated signal levels are used to provide large signal amplitude differences when signal phase differences in the simulcast coverage area become appreciable.

Abstract: A shared data/voice communication system wherein data traffic may be guaranteed priority at a set, but programmable, level of system capacity and wherein interference between such data and voice traffic is effectively minimized. The system operates on standardized channel access rules in the data mode, as well as requesting permission to operate in the voice mode, which if granted, effects a specific protocol to condition the system for voice traffic and manage the same during such pendency. Long and short timers are selectively activated depending upon whether the system is in the voice or data mode to minimize collisions of the system radio data terminals requesting channel access.

Abstract: A selective call receiver displays messages in at least two scripts. The selective call receiver receives data including an address and a message to be displayed. A decoder decodes the data and recognizes a script select character therewithin. A memory stores at least two fonts corresponding to said at least two scripts, said scripts having different resolutions. A microcomputer is coupled to the decoder and the memory for selecting one of the fonts in response to the script select character, and a display is coupled to the microcomputer for displaying the message in the selected font.

Abstract: This key management system effectively solves the key distribution problems of distance, time, operator error, and security risk by transferring encryption keys with appropriate system information between a key management controller (101) and a remote keyloader (109). The keyloader (109) is then coupled to a communication device to transfer (327) the keys and receive (329) identification information from the communication device. The keyloader (109) then sends (323) the information to the key management controller (101) that controls the distribution of the encryption keys and collection of the communication device identifications.

Abstract: A mechanism using a convertible mounting apparatus (103 and 105) for installing a communication device in both a horizontal and vertical configuration is described. The position of a wedge shaped platform (103) on the installation interface of the communications device (105) may be changed without separating the wedge shaped platform (103) from the installation interface of the communication device (105). In a vertical installation configuration, an aperture disposed in the installation interface of the communication device (105) further encompassed by the wedge shaped platform (103) provides a volume of space to store excess electrical cord (205) used for the communication device.

Abstract: An automatic gain control apparatus and method which optimally adjusts the gain of an amplifier to compensate for time-varying energy levels of a received input signal. A control input signal for adjusting the gain of the amplifier is determined by the selective average energy level of a present input signal, the transfer function characteristic of the amplifier and a previous control signal. A fast loop response time maintains the energy level of the amplified output signal at a nominal level.

Abstract: A central controller operating as a pager terminal for receiving, handling, and transmitting messages is shown that adaptively alters its message handling characteristics in order to improve the overall throughput of the central controller. The channel loading characteristics, based upon the time of day, are used in order to vary the limitation of the size of message received by the central controller as well as vary the transmission size and age of messages prior to transmission. Additionally, channel loading may be determined by determining the total size of messages within the central controller. In response to the total size determination, the limitation of the message size received by the controller may be varied. Furthermore, the transmission size and age of messages prior to transmission may be varied in response to the total size determination.

Abstract: Errors in a predetermined digital sequence are detected by utilizing a detector which includes memory elements such as a series shift register, and logic gates for detecting a predetermined subsequence. Errors are detected by comparing each bit in the data stream with the output of the memory. Logic gates inhibit the detection of an error in response to the subsequence detection.

Abstract: Accelerated throughput of voice messages is accomplished by first filtering a normal 50-3000 Hz voice signal to a reduced bandwidth 350-1650 Hz (with loss of identifying features), the reduced signal then accelerated X3 and translated downward to bandwidth 50-3950 Hz for transmission. The receiver recovers the 350-1650 Hz signal.

Abstract: A method for generating alphanumeric messages in a telephone-entry selective call system comprises programmable selective call source identification for selected selective call receivers and numerically coded canned alphanumeric messages.

Abstract: A frequency agile, dielectrically loaded bandpass filter is disclosed in which capacitive layers on the top surface of the filter are selectively switched to ground in order to affect a change in the center frequency of the passband response of the filiter. A PIN diode switching network, including a means for biasing the diode, is used to effectively place the capacitive layers in parallel with the quarter-wavelength transmission line resonators contained within the block of the filter.