Abstract: An ethylene-acrylic acid copolymer can be used as a flux or a solder-through conformal coating. The copolymer can be melted and used as a coating or core for solder, or applied directly to a component, or made into a thixotropic gel with mineral spirits and/or alcohol, then applied as a coating to a component or assembly. Terpenes may be added as tackifiers in some applications. Whether used as a flux or simply solder-through coating, the material provides a self-healing moisture barrier which can safely remain on the component.

Abstract: An AM stereophonic pilot tone is detected using two signals derived from a received broadcast signal. One signal is proportional to the phase deviation and one is a two-level signal which is a function of the magnitude of the phase deviation. The detector controls activation of the visual indicator, muting of the stereo channel of mono/stereo mode switching with almost complete elimination of false detections during monophonic transmission and poor stereo transmission.

Abstract: A low frequency oscillator of the astable type having good frequency stability, fast starting, good immunity to DC loading, and suitable for fabrication in integrated circuit form. First and second switching transistors of the astable multivibrator are cross-coupled by a coupling capacitor and a frequency determining crystal. Base drive to the respective switching transistors and charging current to the capacitor and crystal are provided by a pair of differential amplifiers which are referenced to a forward biased diode. The differential amplifiers are also connected to respective collector terminals of the switching transistors. The capacitor is of small value suitable for containment within an integrated circuit with the oscillator circuit. The differential amplifiers substantially increase the impedance levels in the oscillator and shift base drive to the switching transistors to minimize the effects of DC loading at the output terminals of the oscillator.

Abstract: The positive and negative peak detectors in the interface are reset during each input signal cycle and the reference level used for comparison is switched from one level to another to improve decoding accuracy, with each level determined by the previous two peaks. The input signal is DC coupled and DC offset. The scanner light source is pulsed by a low duty cycle power source if code is not being scanned. The circuit is applicable for digitizing any analog signal with varying amplitudes and/or DC levels and is adaptable to microprocessor control.

Abstract: A microprocessor controlled radio receiver system for switching bandwidths of an intermediate frequency stage from a normally scanning mode using a relatively narrow bandwidth to a second mode using a relatively wide bandwidth automatically when there are no interfering signals from adjacent channels of a channel or station selected for receiving. Upon selection of a channel for listening the microprocessor controlled synthesizer causes the synthesizer to scan up one adjacent channel and down one adjacent channel to determine if there is an interfering signal therefrom and then returns to the selected channel. In the event of no interfering signal from an adjacent channel, switching is effected in the IF stage from a narrow bandwidth to a wide bandwidth to improve the quality of reception. If there is an adjacent channel signal detected of sufficient IF energy next to the selected channel, then the narrow bandwidth mode used during the scan will be maintained.

Abstract: An analog signal processing circuit for detecting engine knock is disclosed. A sensor mechanically resonant at characteristic engine knock frequencies provides an analog signal related to engine knock and engine background noise. An envelope detector provides the signal envelope of the sensor signal. An integrator means provides an average signal related to the average of the envelope signal while an attenuator and subsequent filter (integrator) provide an integrated and attenuated signal which responds faster to amplitude changes in the envelope signal than the average signal. The integrated and attenuated signal level is set below the average signal level for conditions of no-knock. A comparator receives both the average signal and the integrated and attenuated signal and provides an output signal indicating knock detection in response to the amplitude of the integrated and attenuated signal exceeding the amplitude of the average signal.

Abstract: A ceramic capacitive pressure transducer adaptable for use in automobiles is disclosed. The pressure transducer comprises a relatively thin diaphragm 13 having a capacitive electrode 20 thereon, a base substrate 10 having an opposing electrode 22 thereon, and an annular sealing ring 16 mounting the diaphragm to the base substrate. The base substrate has a peripheral lead bonding area 24 extending laterally beyond the perimeter of the diaphragm with two lead through holes 25, 26 in the bonding area.

Abstract: A resilient spacer for use in a membrane switch assembly is formed of an open-cell, non-reticulated foam felt layer, allowing air from the space between the upper and lower switch contacts to move into the foam material surrounding the contacts when a switch contact is made. The switch contacts remain protected from atmospheric contamination regardless of whether the assembly is edge sealed or not.

Abstract: A configuration of two transistors and two capacitors provides a current mode second-order active filter for IC implementation with low-pass, bandpass and high-pass capabilities. The filter frequency is tunable over a wide range, independently of filter Q and gain, by varying a DC bias current. The filter can provide one-port impedance functions, and two-port voltage, current and impedance transfer functions. With the addition of a second biasing current source, the filter Q can be controlled by adjusting the ratio of the two biasing current sources. Enhanced dynamic range and large-signal performance can be achieved by the addition of linear resistors, with trade-offs in tunable frequency range and frequency linearity.

Abstract: This invention relates to the use of a multiplexing technique to allow for the unambiguous enabling of remotely located receiving devices. In particular, a plurality of pushbutton switches, each capable of controlling a distinct function, has a common node whose output is transmitted through the single slip-ring usually found on the steering column of an automotive vehicle. This slip-ring is normally used to conduct an electrical voltage from the horn ring to the horn control relay independent of the position of the steering wheel. The multiplexing technique disclosed herein allows for separate and independent control of not only the horn but also other functions such as a cruise control using the existing single slip-ring as the mechanism to transmit the desired signal commands. The demultiplexed signals are derived from logic circuitry located at the distal point of the slip-ring assembly.

Abstract: An electronic cylinder identification system is disclosed for identifying the occurrence of a predetermined cycle position for a reference cylinder and synchronizing fuel injection for a multi-cylinder engine in accordance thereto. A four cylinder engine rotates a rotary body having two 90 degree spaced peripheral projections and two stationary reluctance sensors are positioned 180 degrees apart about the body and sense the passage of the rotary body projections. Logic circuitry receives signals from the two sensors and determines which sensor is currently providing a logic pulse indicating the passage of a projection and which sensor previously provided such a pulse. The logic circuitry utilizes this information to identify the rotational position of the rotary body by differentiating between occurring identical sensor pulses based upon which sensor previously produced a pulse.

Abstract: Electronic engine synchronization and timing apparatus for use in controlling fuel injection and/or spark ignition for an internal combustion engine is disclosed. An engine crankshaft rotates a rotary body having a plurality of radial projections, and a single crankshaft reluctance sensor is utilized to provide pulses in response to the passage of these projections and thereby provide a signal related to crankshaft position. An engine camshaft rotates a rotary body with radial projections at half of the crankshaft speed, and a pair of camshaft sensors provide signals in response to the passage of the camshaft projections which are indicative of the rotational position of the camshaft.

Abstract: The signal as transmitted is a compatible AM stereophonic signal with amplitude directly proportional to the monophonic signal 1+L+R. The instantaneous phase angle is the quadrature phase angle modified in that high level, high frequencies in the L-R channel are reduced before carrier modulation. The gain in the high frequency L - R channel may be reduced in proportion to the signal level only, or to both level and frequency, or to the percent of distortion introduced into the high frequencies of the L - R signal by RF filtering of the modulated carrier.

Abstract: A crystal is mounted on a low, centrally located pedestal. Connections to the lower side of the crystal are made by way of conductive areas on the pedestal. Multiple wiring connections are made at the edges of the crystal by allowing the bonding tool to depress the edge of the crystal so that the crystal bonding pad is supported by the base structure only during the bonding process, then released thereafter to allow free vibration of the crystal plate. Complex circuitry, possibly involving more than one frequency can thus be put onto one plate.

Abstract: Digital dwell circuitry for a spark and dwell ignition control system is disclosed. Maximum advance and reference sensors are utilized to produce pulse transitions which determine positions of maximum and minimum possible advance for spark ignition with respect to the position of the engine crankshaft. For each maximum advance sensor pulse transition a main counter starts a sequential running count of speed independent clock pulses wherein the maximum count obtained by the counter is related to engine crankshaft speed. The running and maximum counts of the main counter are utilized by dwell circuitry to determine the time prior to the next maximum advance pulse at which spark coil excitation should occur. The main counter running count also determines several inputs to a read only memory (ROM) circuit whose output controls a rate multiplier.

Abstract: An improved tuning apparatus for a receiver of the automotive type which includes a tuning core axially slidable within a tubular coil form having an inductance coil wound therearound in which vibratory movement is minimized. The tuning core is formed with a channel at one end to receive one end of an elongated flexible member. The opposite end of the flexbile member extends away from the axis of the tuning core and abuts against the interior surface of the tubular coil form. In this manner, sliding movement between the tuning core and tubular form and wire is permitted during the tuning operation but a resistance to side-to-side (radial) movement of the core is maintained at other times to minimize the effect of mechanical vibrations thereon which give rise to undesirable microphonics on an associated receiver.

Abstract: An improved system for indicating a tuned broadcast band frequency in which a rotatable turret projects a beam of illumination along a predetermined path towards a dial scale with marking indicia indicating a selected band frequency. A carriage operative to move in a linear path tunes a predetermined band frequency as selected by an operator. The carriage engages a pivotable line on said turret so as to rotate the turret on its axis to project the light beam on the dial scale at a band frequency corresponding to the position of the carriage.

Abstract: A cassette tape player (11) has an integral combined tape guide and stripper (32) which is mounted adjacent to a capstan shaft (26) and has an end portion (52) that extends beyond a free upstanding end (38) of the capstan shaft and effectively forms a guide plane for insuring that when a cassette housing (12) containing a tape (15) is inserted into the tape player, the tape will be positioned between the capstan shaft and a pressure roller (29) which is selectively, linearly movable toward and away from the capstan shaft. The tape guide and stripper is fixed to the tape player frame (19) and includes stripper portion (54, 55) which partially surround the section (39) of the capstan shaft that will contact an inserted tape, but still permit selective engagement with the movable pressure roller such that the tape will be pressed between the capstan and pressure roller while the stripper portions prevent the tape from being wrapped around the capstan shaft.

Abstract: An electronic pushbutton tunable radio (10) having various audio controls is disclosed. A single pushbutton (22) is utilized to implement volume, fader and balance modes of operation during which up/down pushbuttons (20,21) control the overall and relative magnitude of audio signals produced by four speakers (24-27) while at the same time a single display (17) is utilized to display, respectively, either the channel to which the radio is tuned, the relative magnitude between right and left speaker audio signals, or the relative magnitude between front and back speaker audio signals. The radio has tuning pushbuttons (14) for direct recall of preset radio channels in a tuning mode operation.

Abstract: A television transmission system for asynchronously transmitting a television picture as a plurality of video samples over a narrow bandwidth medium from at least one remote transmitting site to a receiver at a base station. Improved synchronization between the transmitter and receiver are achieved by a dotting pattern consisting of alternating logic ones and zeros being sent by the transmitter to precede the video samples such that a sampling clock at the receiver synchronizes to the phase of the dotting pattern and thereafter samples the video signal. The video signals are also preceded by at least one predetermined digital word which identifies the particular remote transmitter and prepares the receiver to begin receiving the video samples. DC restoration circuitry determines the average value of the incoming video signals and to add an appropriate DC offset to the video signals to correct for any change in the gray scale of the video samples.