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: The volume of gases in a container or the volume of liquid in the container is determined by creating cyclic pressure waves in the gases and detecting the waves by a second transducer. The signals produced by the second transducer are a function of the volume of gas in the container, and the volume of any liquid can be obtained by simple calculation. The signals can also provide detection of an open container and, when coupled to signals relating to the velocity of a vehicle, can provide other data such as a miles-per-gallon reading.

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: 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: 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 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 battery charging device wherein the charging current level is controllable by a thermal circuit responsive to battery temperature also includes a circuit responsive to battery voltage and a timing circuit. The timing circuit is activated when a battery is inserted into the device for charging and immediately times a very brief interval. If the battery voltage exceeds a predetermined level during the timed interval, the charging current level is reduced as by the thermal circuit. The circuit protects both cold and charged batteries from damage due to overcharging.

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: The invention is a controlled ferroresonant power supply with an improved feedback circuit resulting in improved output stability. The feedback circuit is responsive to the low voltage secondary output of the power supply to provide a variable output signal to activate the switch which controls the resonant winding circuit. The improved feedback circuit is responsive to the rectified AC low voltage secondary output for only a portion of its frequency period.

Abstract: Improved noise reducing circuitry for high frequency signal sideband (SSB) receivers is described that substantially eliminates interference caused by impulse noise from a noise source 160. The SSB receiver includes first and second mixers 102 and 106 intercoupled by a crystal filter 104 having a passband that is approximately the same as the noise bandwidth of the antenna circuitry 100 when the SSB receiver is tuned to the lower frequency in its frequency band. A second intermediate frequency (IF) signal from second mixer 106 is coupled to an IF amplifier 122 and a noise amplifier 126. An envelope decector 128 is coupled to the output of noise amplifier 126 and provides an output signal having a magnitude proportional to the envelope of the noise amplifier output. Automatic gain control circuitry 132 is coupled to the output of the envelope detector for generating a gain control signal that reduces the gain of noise amplifier 126 as the magnitude of the envelope detector output increases.

Abstract: A circuit providing a known change in a parameter of a function without interfering with the basic operation of the function is utilized in an audio circuit "loudness contour" control. Bass and treble controls function independently of the volume setting while desired contours are obtained at each volume control setting.

Abstract: A semi-duplex communication system provides high channel efficiency by having the base station transmit a reference signal which each terminal uses as a sync signal. Each unit having data to send to the base responds with a very brief signal such as a burst of silent carrier transmission during an assigned time slot in a queue of slots. Only those units which responded thus are polled during the subsequent polling cycle. During the transmission time slots, the base can be sending acknowledgments to those terminal units having sent messages during the previous polling cycle. While polling for data or acknowledgments or sending acknowledgments, the base can also be listening for the respective responses. The address code of a terminal unit is further encoded to carry other required information in both directions.

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.