Abstract: A method is disclosed whereby adjacent transmitting antenna arrays may be more closely spaced to each other and to receiving antenna arrays while still maintaining a high level of isolation between arrays. In each antenna array, first and second parts thereof are identified. The two parts of each transmitting array are driven in phase quadrature with each other and at substantially equal power levels, and the antenna arrays are spaced sufficiently close to each other so that radiation emitted by one array and received by another array undergoes a cancelling effect before reaching the RF generator associated with the other array. The two parts of each receiver array are coupled to their associated receiver by a signal path such that substantially quadrature phasing is established between the first and second parts thereof to cause received radiation to cancel in the signal path before reaching the receiver.

Abstract: This invention is directed to a same frequency repeater (SFR) for use in a multiple SFR system in which only one SFR at a given time is allowed to retransmit a received signal thereby preventing simulcast distortion which could occur due to multiple SFR retransmissions. The SFR includes a receiver for receiving a signal carrying information at a given frequency and a transmitter for rebroadcasting the received signal at the given frequency. A mechanism is provided for keying the transmitter upon the reception of a received signal. A detector senses if a predetermined pilot tone is carried by the received signal. A mechanism responsive to the detection of the pilot tone inhibits the keying of the transmitter if the pilot tone is detected before the transmitter is keyed. A tone generator encodes the output signal of the transmitter with the pilot tone.

Abstract: A method for preparing a printed circuit board for mounting of surface mounted RF components such that the lead inductance of the components is minimized. The process consists of producing plated through apertures in the printed circuit board to create a component body hole with lead contacts extending to the edge of the component body hole. The resulting aperture is then blanked to remove portions of the metal lining to provide electrical isolation between the lead contacts while maintaining lead contacts that extend to the edge of the component body hole. A component is then soldered into position such that solder is wicked through the plated through apertures to create solder contact of the leads at the edge of the component body hole. This results in substantial reduction in lead inductance improving RF amplifier gain and stability and improving bandwidth characteristics.

Abstract: A frequency synthesized transceiver capable of tuning to a plurality of communication channels is disclosed. The transceiver includes a receiver section and a transmitter section which are coupled to the synthesizer which generates the appropriate injection signals to achieve tuning. The frequency synthesizer includes a multiposition switch which accesses various addressable memory locations in a programmable read-only memory where the appropriate divisors are stored to cause tuning of the synthesizer to the appropriate communication channel. A zone selector switch enables grouping and easy retrievability of channels. The divisors are supplied to a single synchronous binary swallow counter which works in conjunction with a dual modulus prescaler to monitor the frequency output of the voltage controlled oscillator. A programmable divider coupled to a reference oscillator source is compared with the output of the synchronous counter in a digital and analog phase detector.

Abstract: An absorptive resonant cavity filter suitable for use on the output of a transmitter power amplifier and capable of substantially constant predetermined resistive input impedance at all frequencies. The structure comprises a bandpass cavity which instead of an input coupling loop employs a conductor coupled from the input and configured along the wall of the cavity to form a transmission line of predetermined impedance and terminated by a resistor of similar impedance value.

Abstract: An apparatus for minimizing the spillover signal from the transmitter to the receiver in a same frequency repeater includes a mechanism for generating a receiver first injection signal carrying the modulation component of the transmitter signal, and a first mixer for mixing the received signals and the first injection signal to produce a first IF signal having one unmodulated IF component signal and another modulated IF component signal. A correlation and cancellation circuit is utilized to cancel the unmodulated IF component signal. A mechanism is provided for generating a second injection signal which carries the modulation component of the transmitter signal. A second mixer mixes the first IF signal and the second injection signal to produce a second IF signal such that the modulation component of the spillover signal is substantially cancelled.

Abstract: In a transceiver, a synthesizer includes a multiposition switch which accesses various addressable memory locations in a programmable read-only memory (PROM), where the appropriate divisors are stored to cause tuning of the synthesizer to the appropriate communication channel. A zone selector switch enables grouping and easy retrievability of channels. The divisors are supplied to a single synchronous binary swallow counter which works in conjunction with a dual modulus prescaler to monitor the frequency output of the voltage controlled oscillator. In the swallow counting device, two latches receive divisor related information supplied by the PROM. When the sampled state of a single up counter reaches a first latched number, the prescaler changes the modulus. Synchronous counting then continues, without reprogramming new values. When the up counter reaches a second latched number, a predetermined frequency ratio has been achieved, and the counter is reset.

Abstract: This invention relates to a holder and mounting arrangement which can be mounted at any angle to various surfaces, for use with a radio telephone handset. Operation of the holder will permit insertion or removal of the handset from either end. The geometry of the retainer member allows pivoting action of either pair of spring washer set which enables the user to lift either the front or rear edge of the handset to clear the recess and slide it free of the guiderails for operation. The assembly is adaptable to various mounting surfaces within the passenger compartment of any vehicle. During operation, the grooved handset is inserted between the top rails of the retainer member and pushed along the guiderails, which lifts the retainer member against the spring load of the captivated spring washers until the handset is seated in the associated central cavity of the base member.

Abstract: A switching-type charging circuit is described wherein the power factor of the circuit has been optimized. The switching-type charging circuit utilizes a dual loop feedback system to control the input and output current of the circuit. The dual feedback loop system utilizes a sinusoidal voltage reference in conjunction with a pulse width modulation circuit to force the input impedance of the circuit to appear substantially purely resistive.

Abstract: A shock-resistant low profile crystal package and internal crystal mounting apparatus capable of adequately protecting a multi-electrode crystal plate from high-G forces occasionally experienced by the mishandling of the particular article in which the component has been mounted. The crystal plate is positioned within an aperture of the base member and is supported about its edge during wire-bonding of the electrode pattern to the terminal connecting pins of the base member. Since the crystal plate is free-floating about its central position, the crystal can undergo thin film metallization of an electrode pattern from either side of the crystal plate to achieve desired frequency parameters. A ceramic retaining ring is placed on top of the crystal plate and the overall package is hermetically sealed by the welding of a cover to each end thereof.

Abstract: A circuit for changing the frequency of a pulse train in response to a change in the average value of an applied digital signal applies the signal to be changed to a pulse subtractor. Application of a predetermined number of digital data signals of one sign causes the periodic subtraction of a pulse at the subtractor, thus reducing the average frequency at the output from the pulse subtractor. The signal at the output from the subtractor is applied to a pulse adder which adds a pulse to the subtracted pulse train in response to a predetermined number of data pulses of the opposite sign. The output pulse train is thus varied in frequency in respose to variation in the average value of the digital data input. The order of addition and subtraction may be reversed, and one of the functions can be performed in the feedback loop of a frequency synthesizer which receives the output pulse train as a reference signal.

Abstract: A portable battery device is provided which dampens shock incident upon the battery device such that an electrical energizable apparatus connected to the battery device is subject to reduced shock whenever the battery device receives an impact. The battery device includes a battery housing of resilient shock absorbing material injection molded around an interconnecting structure which mechanically and electrically interconnects the battery housing to an electrically energizable apparatus.

Abstract: A thick film capacitor with more than two layers configured to enable trimming of the lower layers to increase the capacitance per area ratio while maintaining a linear trimmability of the capacitor's complete range.

Abstract: A digital voice storage system adapted for use in a multiple unit land mobile radio communications system. The system utilizes a PSK signalling system with fixed length data packets to control a system capable of multiple message storage of speech at mobile stations. Up to eight 64K dynamic RAMS are used in conjunction with a microprocessor to store up to 42 seconds of speech comprising up to eight separate messages. In addition, the system permits base interrogation of mobiles to determine if a message has been stored for review by the base operator and to determine the remaining recording capacity and total recording capacity of the mobile.

Abstract: A Rayleigh fader for use with signals such as single-sideband and AM radio signals applies those signals to a 90-degree power divider. Each of the outputs of the power divider is taken to a separate double balanced mixer. Each separate double balanced mixer receives a mixing input from a noise source that includes a voltage-to-current converter. Mixed outputs of the two double balanced mixers are re-combined in a power combiner to produce a Rayleigh faded output.

Abstract: A unique RF signal combining/sorting apparatus is disclosed that includes first and second filters each comprised of one or more bandstop/bandpass filters intercoupled by transmission lines. The bandstop/bandpass filters include a shunt inductor or capacitor and a dielectric block having an input electrode plated on its top surface and a hole located at predetermined distance from the input electrode. The dielectric material is preferably a ceramic comprised of BaO, TiO.sub.2 and ZrO.sub.2. The dielectric block is entirely plated with copper or silver except for a portion of the top surface surrounding the hole and electrode and is essentially a capacitively coupled, short-circuited coaxial transmission line. Each of the first and second filters is tuned to pass the frequencies of one signal and attenuate the frequencies of the signal passed by the other. The unique RF signal combining/sorting apparatus can be configured as a multi-signal combiner, multi-signal sorter, or multi-signal combiner/sorter.

Abstract: A helical cavity resonator filter utilizes varactor tuning diodes positioned within each helical resonator coil. The diodes are positioned along the longitudinal axes of the coils so as not to interfere with the non-axial electromagnetic fields of the cavities associated with each helical resonator coil.

Abstract: A method for adjusting the frequency of a piezoelectic resonator such as a quartz crystal is disclosed. The resonator is placed within its enclosure facing a metallic surface. The atmosphere within the enclosure is made suitable for supporting a glow discharge. An electrical potential is then established between the resonator electrode and the metallic surface causing mass to sputter between the electrode and to the metallic surface to vary the characteristics of the resonator.