Abstract: A dual slide switch voltage encoder is provided in which a plurality of analog voltages are produced as output signals of the encoder at a single output terminal. Two three position slide switches having manual actuators are utilized to provide a series of nine different analog output voltages having substantially equal increments in magnitude therebetween. A reference voltage from a microprocessor is utilized to develop these analog output voltages which are subsequently fed into an analog to digital converter in the microprocessor. Thus the present invention utilizes two three position slide switches to create a series of analog voltages having equal increments in magnitude therebetween wherein each of these analog voltages represents a different logic state corresponding to a specific combination of the various possible mechanical positions of the manual actuators of the two three position slide switches.

Abstract: An ultrasonic welding process is disclosed for the manufacture of alternator slip ring assemblies. An inclined gouging is provided in an exterior slip ring surface, a metallic wire is positioned in the gouging and ultrasonic pressure is applied by an electrode of an ultrasonic generator. The electrode has its working surface parallel to the exterior slip ring surface and therefore inclined with respect to the gouging and wire. This results in a tapered deformation of the wire resulting in a strong ultrasonic bond.

Abstract: A pushbutton tuner display apparatus for an entertainment device is disclosed in which a plurality of pushbuttons are used to tune a radio apparatus in the entertainment device in one mode of operation, while in another mode of operation the entertainment device operates as a cartridge tape player in which the pushbuttons are utilized as display devices which indicate which tape track is being monitored by the cartridge tape player. Additionally, one pushbutton is utilized as a display to indicate the reception of a stereo radio signal. Each pushbutton comprises a clear plastic light pipe surrounded by an opaque plastic part having openings at the front and rear. An associated light bulb mounted inside the frame of the entertainment device is utilized to provide light to each rear portion of each light pipe, and each light pipe has a prismatic portion which transmits received light to a front portion of the light pipe where an illuminated operative state display indication is produced.

Abstract: An amplitude modulated transmitter includes an audio amplifier which, via a radio frequency (RF) power supply modulator, modulates an RF amplifier and carrier. Fluctuations in the direct current DC bias to the RF amp, such as are common in mobile applications, vary the modulation index of the transmitted signal.To minimize DC bias affects on the modulation index, the invention contemplates an audio compressor which senses both audio signal level and DC bias level and, in response thereto, controls audio signal compression to maintain the desired percent modulation. Compression is effected by changing the bias on a semiconductor device which, in turn, attenuates audio signals at the input of a fixed gain audio amplifier. A feedback path around the audio amplifier senses both DC voltage and audio signal level and produces an appropriate control signal to bias the semiconductor device, thereby altering audio compression.

Abstract: An improved antenna system is disclosed in which a single antenna array is simultaneously used in conjunction with several independent radio devices. Isolated and independent radio transmitters are coupled, without any signal cancellation, to each and every one of a plurality of isolated independent antenna elements by a combining network which maintains the isolation between each of the radio transmitters and each of the antenna elements. The combining network comprises an array of hybrid networks and creates a predetermined electrical phase difference between each signal received by an individual antenna element. The antenna elements form a single antenna array consisting of circularly disposed corner reflector antennas. Each reflector independently creates an individual radiation pattern and these patterns combine to form a single desired composite radiation pattern.

Abstract: A radio receiver having a tunable RF stage with an electrically tunable inductor is disclosed. The tunable inductor consists of a magnetic device with a core whose degree of magnetic saturation is controlled by various control currents. A phase lock loop with a programmable frequency divider responds to inputs from a tuning control means and provides a local oscillator signal to a mixer in the radio receiver while also providing a control current to the magnetic device, defined herein as Current Controlled Inductor (C.C.I.), which is directly related to the frequency of the local oscillator signal supplied to the mixer. Each time the radio receiver is tuned to a different input frequency by changing the frequency of the local oscillator signal, a predetermined reference current is applied to the C.C.I. before a new control current corresponding to the new local oscillator frequency is applied. This results in always tuning the C.C.I. in a single direction and therefore accurately setting the C.C.I.

Abstract: Electronic signal processing circuitry for use in the ignition system of an internal combustion engine is disclosed herein. A signal generator which receives crankshaft position pulses from a sensor and produces periodic outut pulses which have durations equal to a constant percentage of the period of the input sensor pulses is disclosed. The generator includes a crankshaft position sensor feeding a bistable flip-flop which controls a dual slope integrator circuit having its output coupled to a comparator with the comparator output coupled back to the reset terminal of the flip-flop. The generator produces pulses at the output of the flip-flop which have durations equal to a constant percentage of the period of the crankshaft position sensor pulses.

Abstract: An improved ceramic capacitive pressure sensor adaptable for use in automobiles is disclosed. The pressure sensor comprises a thin flexible diaphragm disc having a capacitor electrode deposited on it. A thick cylindrical base substrate has a top surface with a second capacitor electrode deposited thereon and the diaphragm is bonded to the top surface of the base substrate by an annular glass ring such that the first and second electrodes are separated from each other and face each other directly across an air gap. The diaphragm, the top surface of the base substrate and the annular glass ring form an internal cavity in which a reference vacuum is stored. In response to pressure changes outside of this cavity, the diaphragm will flex and thereby change the capacitance created by the first and second electrodes. At least one channel portion is provided in the base substrate top surface which opens into the cavity storing the reference vacuum.

Abstract: A balanced, doubly tuned gate couples between the mixer and intermediate frequency (IF) stages of a conventional radio receiver. The network is comprised of a pair of matched transformers interconnected in a balanced configuration, with the first transformer tuned to the mixer and the remaining transformer tuned to the IF stage. Capacitors interconnect the two transformers resulting in a Butterworth filter network.Two diode pairs connect in shunt across selected windings of the transformers. Direct current bias normally biases the diodes to a nonconducting state, thereby allowing the mixer signals to pass to the IF stage. A blanking signal from the receiver blanker drives the diodes to conduction thereby decoupling the mixer from the IF and blanking the receiver.Due to the doubly balanced nature of the gate, blanking is accomplished with a minimum of switching time. Moreover, the shunt diode switching scheme provides superior attenuation in the blanking mode and enhanced operation in the normal mode.

Abstract: A pointer and scale indicating assembly for a radio receiver is disclosed. A scale with indicia thereon is fixed to a radio receiver chassis and a pointer arm is movably mounted in the chassis to positions corresponding to the frequency to which the radio receiver is tuned. A resilient pointer rod is mounted on the pointer arm and has an end portion visually cooperating with the scale indicia to indicate the receiver frequency. The pointer rod is hand insertable onto the pointer arm and is attached thereto by having an end portion of the pointer rod cooperating with a raised surface and a holding projection of the pointer arm.

Abstract: A disengageable transmission device is provided in which a driving pinion is used to selectively drive a driven wheel via a wheel train mounted on pivotal lever. The fulcrum of the pivotal lever is positioned so as to minimize the rotational torque effects on the wheel train lever of the contact between the driving pinion and the wheel train and of the contact between the driven wheel and the wheel train. An energy escapement control device is also provided and the torque effects of this device on the wheel train lever are also limited by the positioning of the fulcrum of the lever.

Abstract: A low leakage integrator used in a carburetor feedback control system is disclosed. The integrator comprises an operational amplifier having a feedback capacitor coupled between its output and its inverting input terminal. Input voltages are coupled through a resistor to the inverting input terminal and a pair of controllable gates are utilized to implement an integrate and hold mode of operation for the integrator while minimizing the drift of the integrator output due to leakage currents during the hold mode of the integrator.The carburetor control system utilizes the above integrator in combination with a fuel mixture sensor and an engine position sensor to produce an output voltage related to the sensed fuel mixture. This output voltage is utilized to control a solenoid that adjusts the setting of a carburetor valve to thereby alter the carburetor fuel mixture as desired.

Abstract: A battery saver circuit for a tone coded personalized radio pager device or the like is described which includes a switchable frequency tone filter to detect a predetermined sequence of tones. One of several alert signals is generated when the correct sequential tone code of the device has been detected.Power is periodically applied to a receiver by a power supply circuit and a control circuit. The first code tone is sampled three times to protect against false identification of this tone. After this first (preamble) tone has been validated, power is supplied for an additional duration of time and the filter is set to detect the next code tone. Once the second code tone has been detected, if the next code tone is not detected within a predetermined time window, the control circuit resets the switchable filter to again search for the second tone of the code. By resetting the filter to detect the second tone, it is possible to condense the broadcast time required for a string of coded messages.

Abstract: The present invention provides a play-back and/or recording apparatus which has an improved positioning device for determining a working position of play-back heads and pressing devices (pressure rollers). The positioning device comprises a rigid support which rigidly carries at least one play-back head and one pressing device. The rigid support, along with elements rigidly attached to it, is moved into a working position in the apparatus by forming three points of contact with block elements fixed with respect to the frame of the apparatus. These three points of contact form an imaginary triangular configuration and insure the accurate positioning of the play-back head and pressing device while resulting in a simplified positioning device.

Abstract: An improved ceramic capacitive pressure sensor adaptable for use in automobiles is disclosed. The pressure sensor comprises a thin flexible diaphragm disc having a capacitor electrode deposited on it. A thick cylindrical base substrate has a top surface with a second capacitor electrode deposited thereon and the diaphragm is bonded to the top surface of the base substrate by an annular glass ring such that the first and second electrodes are separated from each other and face each other directly across an air gap. The diaphragm, the top surface of the base substrate and the annular glass ring form an internal cavity in which a reference vacuum is stored. In response to pressure changes outside of this cavity, the diaphragm will flex and thereby change the capacitance created by the first and second electrodes. At least one channel portion is provided in the base substrate top surface which opens into the cavity storing the reference vacuum.

Abstract: Apparatus for visually indicating a particular operational condition of a radio transmitter, such as the transmitter being activated or the percentage amplitude modulation of the transmitted carrier. An electrical or electronic character display module having an integral decimal point display portion is utilized to visually indicate a transmitter circuit condition. Transmitter activation may be shown by coupling the push-to-talk circuit to the decimal point display. More specifically, the character display module is oriented to be viewed with the decimal point portion in a superscript position relative to the character.A method for visually indicating the operational status of a radio transmitter includes the steps of providing a character display module having an integral decimal point, generating a signal indicative of a transmit circuit condition, and activating the decimal point display in response to the indicative signal.

Abstract: A directional antenna system is disclosed which selectively couples two radiating antenna elements to a transceiver through a selective phase, magnitude and matching network which is controlled by the output of a logic circuit. The network provides for equal magnitude current coupling between the transceiver and the two antennas while simultaneously selectively producing either positive or negative approximately 90.degree. phase shifts between the two antennas to produce either of two discrete directive cardioid radiation patterns directed in substantially opposite directions. The logic circuit, in conjunction with a manual step switch, provides for a manually selecting either of the two cardioid radiation patterns, as well as producing a figure eight or an omnidirectional radiation pattern. For generating a transceiver omnidirectional pattern, one antenna is used and the other is connected to a standard broadcast band receiver.

Abstract: Electronic signal processing circuitry for use in the ignition system of an internal combustion engine is disclosed herein. A signal generator which receives crankshaft position pulses from a sensor and produces periodic output pulses which have durations equal to a constant percentage of the period of the input sensor pulses is disclosed. The generator includes a crankshaft position sensor feeding a bistable flip-flop which controls a dual slope integrator circuit having its output coupled to a comparator with the comparator output coupled back to the reset terminal of the flip-flop. The generator produces pulses at the output of the flip-flop which have durations equal to a constant percentage of the period of the crankshaft position sensor pulses. The dual slope integrator circuit produces a periodic ramp (sawtoothed) signal which is processed by a clamping circuit and a comparator to produce an ignition dwell pulse which occurs a fixed time before the occurrence of the crankshaft position sensor pulses.

Abstract: An electronic ignition timing system for an internal combustion engine which rotates a crankshaft is disclosed. The ignition system comprises a plurality of variable engine condition sensors which produce corresponding analog output signals and a crankshaft position sensor. A timing control logic circuit periodically multiplexes each of the variable engine condition sensors such that they are sequentially connected as inputs to an analog to digital (A/D) converter which produces an output signal comprising a pulse train for each of the multiplexed engine conditions. The total number of pulses in each pulse train is related to the magnitude of the variable engine condition currently being connected to the A/D converter. In addition, high resolution crankshaft position pulses are produced, preferably by an electronic angle divider which receives coarse crankshaft position pulses and produces high resolution crankshaft position pulses.

Abstract: An assembly for adjusting the azimuth (rotational) orientation of a magnetic tape head with respect to the chassis of a tape player is disclosed. A planar portion of a first plate is welded to the top side of a tape head and an adjustment screw is threaded through a bent portion of this plate. A planar portion of a resilient second plate is bonded to the bottom side of the tape head and a hollow cylindrical member is mounted to a bent portion of the second plate such that the resiliency of the second plate biases the hollow cylinder toward the adjustment screw. The hollow cylinder is slidably mounted on a guide post which is rigidly mounted to the chassis of a tape player. By means of the adjustment screw the angular disposition of the tape head with respect to the hollow cylinder, and thereby with respect to the tape player chassis, is altered.