Abstract: An atmospheric differential pressure sensor is disclosed comprising a pressure transducer, having a diaphram, mounted within a two piece protective transducer housing. An ambient atmospheric pressure receiving cavity is formed by the housing and coupled to the transducer diaphragm by a pressure transmitting tube that has a isolating oil drop within the tube to keep atmospheric contaminants away from the diaphram. The atmospheric pressure receiving cavity has external openings extending peripherally over more than 180.degree. of rotation about a central axis of said housing, and the ambient cavity provides a non-linear directional path between the end of the tube connected to the cavity and the exterior of the housing.

Abstract: A combination radio and tape player is disclosed which includes a signal equalization selector wherein the audio program selection switches which select either an AM or FM radio mode or a tape player mode of operation also simultaneously select various different sets of stored control signals which implement predetermined audio signal equalization in accordance with the type of audio mode of operation (program) that was selected. This is accomplished by the use of a random access memory which stores three pluralities (sets) of control signals, each plurality of control signals corresponding to a predetermined desired equalization for either the AM, FM or tape player modes of operation of the combination radio and tape player. Manual controls are provided which allow selective adjustment of the equalization provided in any of the AM, FM or tape player modes of operation.

Abstract: A capacitive pressure transducer 10 with an analog output voltage which varies linearly as a function of sensed pressure is provided. A capacitive pressure sensor C.sub.x provides a pressure variable capacitance that determines the frequency of a sensor oscillator 11. The oscillator frequency is combined with a reference frequency by a pair of D-type flip-flops 18 and 19 to provide a resultant signal having a duty cycle related to the sensed pressure. The resultant signal is integrated to provide a first analog signal as an input to a controllable gain amplifier 24 which receives gain control information from a non-linear gain control circuit 40 that receives an analog control signal as an input. The analog control signal varies as a function of sensed pressure in an opposite manner to said first analog signal. Said non-linear circuit provides for non-linearly varying the gain of amplifier 24 as a function of sensed pressure. Preferably the non-linear circuit 40 includes temperature compensating diodes 47.

Abstract: A mechanical radio receiver tuner with microphonics elimination circuitry is disclosed. During a mechanical tuning mode, the mechanical position of a movable tuning element provides an associated adjustable reactance which determines a control voltage for controlling the output of a voltage controlled oscillator (VCO) that serves as the local oscillator for a superheterodyne radio receiver. After initially selecting a channel frequency by adjusting the output of the VCO with the mechanically movable tuning element in the tuning mode, a switch means disconnects the movable tuning element from operative control of the local oscillator frequency and implements a locked tuning mode by providing the VCO with a control voltage related to the difference between the frequency of the output signal of a mixer stage and the center frequency of a fixed tuned narrow passband IF stage that follows the mixer. Preferably, this control voltage for the locked tuning mode is provided by a phase locked loop.

Abstract: A printed circuit board assembly usable in a transceiver microphone is disclosed. The assembly comprises a first printed circuit board having components mounted thereon which is fixed to one side of a circuit board carrier by retaining tangs. Second and third printed circuit boards also having components thereon are mounted on an opposite side of the circuit board carrier also by retaining tangs. The first circuit board is connected to the second and third circuit boards via pluralities of bare jumper wires extending between end portions of the first circuit board and adjacent end portions of the second and third circuit boards. The carrier is substantially planar and has integral end projections which form associated notches for receiving each of the jumper wires.

Abstract: An electrical switch assembly (10) is provided having upper (11) and lower (12) housing portions which house a dome switch contact assembly (13). A switch actuator (20) substantially comprising a planar oblong plate (21) is mounted to a housing wall (41) of the upper housing portion (11) in a through opening (44) of the housing wall. The actuator (20) forms a hand insertable snap-in subassembly with the wall (41). The actuator (20) is intended for substantially pivotal movement from first to second predetermined positions such that in the second position a contact projection (26) attached to a second longitudinal end portion (25) of the actuator contacts the dome switch assembly (13) while flexible bias tangs (45, 46) apply mechanical bias to the actuator at a first longitudinal end portion (24) to position the actuator toward its first position.

Abstract: A regulated automotive alternator battery charging system is disclosed. The system comprises an engine-powered alternator which provides a rectified alternator output signal for charging an automobile battery in accordance with an alternator field coil excitation signal provided by a voltage regulator which senses the battery voltage and alters the field coil excitation in response thereto to maintain the battery in a charged condition. The voltage regulator comprises an oscillator for developing a constant frequency signal which is independent of engine speed and battery load. The regulator includes circuitry for varying the duty cycle of this constant frequency signal in accordance with the sensed magnitude of battery voltage, and the constant frequency but variable duty cycle signal is utilized to provide field coil excitation for the alternator wherein the system maintains the battery voltage at a substantially constant magnitude.

Abstract: A dual slope pulse width modulation regulator for separate control of two independently operative power supplies is provided. An oscillator supplies a triangle wave having a period T signal to each of two separate DC comparators each of which also receives an analog error signal related to the difference between a power supply output signal and a predetermined reference level. The outputs of the DC comparators are coupled to a pair of AND gates which are alternately enabled by a digital output signal of the oscillator with the digital output signal having output states corresponding to the duration of first and second rates of change of the triangle wave signal which occur during each period T. The outputs of the AND gates correspond to pulse width modulated drive signals which are utilized to control the excitation of independently operative power supplies having output sensor circuits which sample the output of the power supplies and result in providing the first and second analog error signals.

Abstract: A method of utilizing anodic bonding to bond a conductive semiconductor wafer to a metallized dielectric glass plate so as to form a capacitive pressure sensing element is disclosed. The method includes positioning the semiconductor wafer in contact with the glass plate, heating the wafer and glass plate and applying a substantial positive DC potential to the semiconductor wafer and metallization on the glass plate while applying a negative DC voltage potential to the glass plate. The glass plate metallization forms one capacitor plate of the capacitive pressure sensing element while the semiconductor wafer forms the other capacitor plate.

Abstract: An improved ceramic capacitive pressure transducer adaptable for use in automobiles is disclosed. The pressure transducer 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.

Abstract: A four-cylinder engine control system (10) for controlling the functions of ignition or fuel injection is disclosed. The control system includes cylinder identification apparatus (30, 50, 60) which operates in conjunction with a rotary member (11) rotated by the engine crankshaft having timing projections (14, 17) corresponding to specific rotational positions of the crankshaft. A pair of fixed sensors (20, 21) sense the passage of the timing projections and provide corresponding signals to an engine timing calculation and control circuit (40) which provides control signals that are sequentially selectively routed to control ignition and/or fuel injection of the engine cylinders in a predetermined sequence. One timing projection (14) comprises two individual radial extensions (15, 16) whereas another comprises a single extension (17).

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: 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: 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: 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: A radio transceiver is disclosed having manual controls on a microphone and the remainder of the circuitry located in a main chassis. The microphone and chassis are connected by means of a multiconductor cable, and time sharing multiplexing techniques are utilized and serially transmit information, bidirectionally, along a common data line while a clock line is utilized to synchronize the operation of main chassis and microphone circuitry. Multiple bit binary coded digital words are sent to the microphone to activate microphone displays while analog signals are sent from the microphone to the main chassis to provide analog control signals for the transceiver.A digital synchronizing pulse detector is disclosed for use in the above transceiver multiplexing system. The detector identifies synchronizing pulses which occur in the clock signal wherein the identification insures the synchronization of microphone and main chassis circuitry.

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.