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: 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: 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 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.

Abstract: A bandwidth agile, dielectrically loaded resonator filter is disclosed in which conductive strips (320, 322), plated on the top surface (302) of the filter and disposed between resonators (310, 312, 314), are selectively switched to ground in order to affect a change in the bandwidth without appreciably changing the center frequency of the filter response. PIN diode switching networks (316, 318), including a means for biasing the diode, are used to effectively ground the strips between the nearly quarter-wavelength transmission line resonators contained within the block (300) of the filter, thereby capturing a portion of the capacitive coupling (402, 404) which occurs mostly beneath the surface of the filter between adjacent resonators.

Abstract: An Ytrium Barium Copper Oxide-based thick-film paste is disclosed, which when deposited on an alumina substrate is superconducting above the termperature of liquid nitrogen and substantially free of mechanical defects such as cracking or peeling. A method of applying the paste, including the curing process, insures that the YBC superconductor is boned to the substrate.

Abstract: A low current CMOS translator arrangement is disclosed that utilizes a low current inverting stage, having a peak current requirement, fed by a constant current source at a supply node that also has a capacitor coupled to it. This low current inverter is useful for a number of applications, including generating a sinusoidal signal when it is coupled to a crystal. When one or more are cascaded and coupled to a square wave input signal, the arrangement becomes a low current translator that level-shifts, or translates, the input signal having a first voltage range to a translated square wave output signal having a second voltage range. In another embodiment called a low current squaring translator, a squaring stage is coupled between the low current inverter and a low current translator that includes one or more inverting stages. This arrangement is able to achieve an output signal that maintains a precise duty cycle with low noise at a very low current.

Abstract: A speech detection circuit uses a peak detector and a valley detector including offset voltages to reliably detect the absence or presence of speech at audio base band level. This circuit provides a pulse train output when speech is detected which may be used to control an automatic gain control circuit.

Abstract: A method of joining surface mount components includes screen printing a single layer of solder paste or other adhesive onto a substrate, positioning a component with a planar lead with a hole through the planar lead over the solder and mounting a second component over the hole in the first lead. The assembly is heated or otherwise processed until the solder or adhesive flows by capillary action through the hole and into the space between the components such that it forms solder joint between the stacked components.

Abstract: A crystal oscillator circuit for use with overtone crystals restricts its resonant frequency to either fundamental or overtone frequencies. An inverting amplifier, which provides 180 degrees of phase shift by inverting an input signal, includes components which effectively provide another 180 degree phase shift at a particular frequency by adding a time delay. The 180 degree phase shift by a signal inverting amplifier, with the included 180 degree phase shift provided by the time delay comprises an oscillator by the addition of a crystal with a resonant frequency equal to the particular frequency determined by the time delay. Suppression of unwanted oscillation frequencies is accomplished by adjusting a current source, which changes time delay, without using inductors or other reactive components.

Abstract: A radio transceiver is disclosed for use in an SSB communication system having FM data capability. The dual-mode radio transceiver of the present invention includes a receiver capable of demodulating and deriving AFC from either (a) the voice channel having voice messages transmitted via single sideband amplitude modulation with a pilot carrier, or (b) the data channel having high speed data messages transmitted via narrowband frequency modulation in the same channel bandwidth. Furthermore, the dual-mode radio transceiver includes a transmitter capable of transmitting one of either of the above types of modulation on the appropriate channel, as determined by information received from the high speed data messages transmitted on the control channel.

Abstract: An improved TDMA radiotelephone cellular communication system employs an improved cell site scan monitoring technique. The technique includes monitoring radiotelephone calls, and tracking and recording their signal qualities. The records are used to maintain and determine which frequencies and which time partitions at the base site equipment are being utilized for radiotelephone communication. When a new call assignment is required at a cell site, it is assigned to a time partition of a base site equipment frequency in a frequency prioritized manner such that radiotelephone calls are concentrated within each frequency so as to reduce the number of frequencies carrying radiotelephone calls.