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 fault indicating circuit for an automobile alternator battery charging system is disclosed. The charging system comprises an alternator providing a rectified battery charging signal in response to alternator field coil excitation which is controlled by a voltage regulator that senses battery voltage. The fault indicating circuit comprises a low voltage detector circuit which provides constant DC excitation for an indicator lamp in response to low alternator output voltage and a high voltage detector circuit which provides intermittent excitation for the lamp in response to an excessively high alternator output voltage, the lamp being maintained in a de-energized state in response to the normal alternator output voltage.

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: A frequency synthesizer is disclosed in which a single read only memory (ROM) is utilized to directly control programmable frequency dividers in a phase locked loop while also directly controlling the excitation of seven segment visual digital display modules. During the tuning of the frequency synthesizer, an enable circuit disables the programmable dividers while altering the input signals to the read only memory such that direct drive signals are produced by the output of the read only memory which alternately excite two separate seven segment displays modules. After the tuning operation is completed, the enable circuit alters the input signals to the read only memory, simultaneously enables the programmable dividers, and effectively disables the digital display modules such that they hold their previous visual displays.

Abstract: A transceiver is disclosed that has a manual scanning electronic channel selection switch with a single actuator that can readily select any one of a predetermined plurality of discrete channels by step tuning the transceiver to each of the discrete channels in either an up or down scanning sequence. An up and down scan actuator is mounted to the housing of the transceiver and another is attached to the microphone of the transceiver, thus providing for remotely tuning the transceiver when access to the transceiver housing is inconvenient. The transceiver is selectively tuned by use of a phase lock loop having a programmable divider that is controlled by a counter which counts clock pulses during up and down scan tuning. An illegal channel detector is provided which prevents the counter from selecting a channel which does not correspond to one of the selectable channels.

Abstract: A pushbutton switch assembly having a hand-insertable snap-in subassembly comprising the switch chassis and the switch actuator is disclosed. Dome switch electric contacts are contained within a chassis having a plastic wall with a through opening therein. The chassis has a pair of integral flexible retaining tangs projecting into the through opening. A plastic switch actuator having recesses thereon is hand-inserted into the through opening, and the flexible tangs and recesses cooperate to provide a snap-in subassembly. The flexible retaining tangs bias the actuator into a first predetermined position in which an actuating plunger on the actuator is maintained out of contact with the electrical dome switch contacts. The flexible tangs permit inward movement of the switch actuator into the opening such that the actuating plunger can contact and actuate the dome switch electrical contacts.

Abstract: A pushbutton tunable radio having an integral audio graphic equalizer is disclosed. During a tuning mode of operation for the radio actuation of any of five presettable pushbuttons results in the selection of a predetermined radio channel frequency within the AM or FM band, and a five digit display is provided indicating the selected channel frequency. During an equalizer mode of operation caused by actuation an equalizer mode selecting pushbutton, the radio remains tuned to the previously selected radio channel, but the frequency indicating display is now replaced by an electronic display indicating the relative emphasis of a plurality of subbands for the corresponding audio signals produced in response to the received radio channel. In the equalizer mode, actuation of any of the presettable radio pushbuttons results in selecting a corresponding one of the audio subbands for adjustment of its relative emphasis.

Abstract: Selected radio circuits are fabricated on modules which plug into a "mother" board located in the radio chassis. The circuitry includes a plurality of RF front ends (including at least one AM and one FM front end), each tunable over a selected radio band by tuner circuitry. The AM front end includes a saturable core reactor whose tuning inductance varies as a function of the tuning current provided to it by a voltage-to-current converter in the tuner.Both AM and FM signals are translated by a frequency synthesizer to a common IF frequency, namely 10.7 MHz. The synthesizer employs a quartz crystal controlled oscillator feeding a phase lock loop whose frequency is varied via the tuning control. Quartz crystal filters for AM, and ceramic filters for FM provide required selectivity. As all signals are at the same IF, a common IF amplifier is employed. Further, a single phase lock loop is adapted to demodulate both AM and FM signals.The resultant demodulated signals are amplified, and tone shaped, via D. C.

Abstract: A cam assembly is disclosed which is used for the selection of different track positions for a magnetic tape head in a magnetic tape player/recorder. The tape track position of a magnetic tape head is determined by the position of a cam follower member which is selectively positioned with respect to a reference surface by selectively positioning a number of different diameter ball bearings between the cam follower member and the reference surface. Specifically, a solenoid actuated armature causes the linear movement of pawl members which in turn rotate a ratchet wheel member. The ratchet wheel member forms part of a cam apparatus that includes four ball bearings of different diameters. Sequential rotation of the ratchet member selectively positions ball bearings of different diameters between a non-rotatable reference surface and the cam follower member.

Abstract: An alarm circuit indicating a defect in a car alternator, said circuit comprising a voltage divider formed by two resistors connected between the positive terminal B+ and a negative terminal D- of the alternator, the center point of the voltage divider being connected to the control electrode of a commutation circuit of which the output path is serially connected with a lamp between the terminals of the battery, and rectifier means being provided for preventing the battery to discharge through the voltage divider.

Abstract: A frequency synthesizer for a citizens band transceiver is disclosed. The synthesizer utilizes a single master crystal oscillator whose output is coupled to a difference mixer that receives the output of a voltage controlled oscillator (VCO) and provides an input to a programmable frequency divider. This programmable divider provides an output to a phase-frequency comparator which commpares this signal to a reference signal supplied by a fixed divider coupled to the master crystal oscillator. The comparator output, through a low pass filter, controls the voltage controlled oscillator output.

Abstract: High frequency power transistor carriers are made by bonding a metalized ceramic base to a lead frame strip, subsequently gold plating the resultant structure and then cutting the lead frame strip to isolate the base and collector leads while still maintaining the transistor carriers in strip form. Transistor dice are then attached to each ceramic carrier, and each transistor carrier in the strip is then electrically tested. The individual carriers are then separated from the lead frame strip. The individual carrier has wide base and collector leads extending outward from the ceramic base for a substantial distance and then the base and collector leads are narrowed down. When the individual transistor carrier is used in combination with a hybrid assembly, a reduction in lead inductance and total hybrid package size is obtained while exact carrier placement relative to the hybrid assembly is not required.

Abstract: An ignition spark timing circuit with switchable hysteresis for an internal combustion engine is disclosed. A crankshaft sensor produces a periodic input sensor signal, having a predetermined period, which initiates the action of a programmable voltage slope generator that produces a predeterminedly varying signal. This varying signal serves as an input to a comparator which also receives a switching threshold input, and the comparator output is utilized to determine the time occurrence of spark ignitions. A switchable feedback path is provided between the output of the comparator and its switching threshold input such that hysteresis for the comparator threshold input is provided during critical portions (T.sub.C) of the time period of the crankshaft position sensor signal when the comparator is expected to produce output signal transitions that determine the occurrence of spark ignitions. At other portions (T.sub.

Abstract: A housing contains a circuit board having a Hall effect sensor attached thereupon and a magnetic circuit positioned to provide magnetic flux through the Hall effect sensor. The magnetic flux through the Hall effect sensor is interruptable by a high permeability vane moving through an air gap in the magnetic circuit, activating the Hall effect sensor to provide timing signals for an automotive ignition distributor system. The base of the housing has locating bosses for positioning the housing on a swing arm of the ignition distributor which is pivotable about the axis of the distributor shaft. Mutually perpendicular surfaces contained within the housing provide reference locations for positioning the circuit board with respect to the housing. The housing has respective portions for containing a flux concentrator and a magnetic and pole piece assembly on opposite sides of the circuit board.

Abstract: A rotatable capacitor of variable capacitance is utilized to produce modulation of a signal, and demodulation of the signal produces a signal usable for determining the state of rotation of a shaft used for rotating the capacitor.

Abstract: A pushbutton (keyboard) tuning apparatus for a radio receiver is disclosed. The apparatus comprises a flat tuning key carrying an adjustable and lockable tuning cam means (plunger) which is guided in a slot in the tuning key and locked into position by applying force to an appendage forming part of said slot. Slideable end caps are positioned on each tuning key and each cap carries a pin for selectively applying the force to the locking appendage. Each cap also carries a resilient tongue for actuating clutch disengagement of a manual rotary knob tuning apparatus having a shaft axially displaceable for releasing any pushbuttons previously depressed and being held in their depressed condition.

Abstract: A digital spark and dwell ignition control system is disclosed. Maximum advance and reference sensors are utilized to 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 a main counter starts sequentially counting clock pulses wherein the maximum count obtained by the counter is related to engine crankshaft speed. The count of the main counter is utilized by a dwell circuit to determine the time prior to the maximum advance pulse at which spark coil excitation should occur. The main counter count also determines several inputs to a read only memory (ROM) circuit whose output controls a rate multiplier. The rate multiplier receives input clock signals and provides selective frequency division for these clock signals in accordance with the ROM output.

Abstract: A friction device for coupling the manual tuning knob of a keyboard (pushbutton) radio to a reciprocal tuning slidebar is disclosed. The friction device comprises a cylindrical rod attached to the tuning slidebar which selectively is drivingly engaged by a peripheral V-shaped groove in a pulley rotated by the manual tuning knob.

Abstract: A method for constructing a capacitive transducer by depositing a uniform glass insulating ring. The capacitive transducer consists of a circular base substrate and a circular diaphragm, each supporting one of two capacitor electrode and separated by a uniform glass insulating ring which determines a uniform air gap between the capacitor electrodes. Pressure changes cause the diaphragm to flex and thereby produce capacitance changes in relation to the pressure being sensed. The thickness of the glass insulating ring is critical to the production of an accurate pressure transducer and is produced in the following manner. A first glass insulating ring layer is screen printed onto a substrate through a mask having a pattern therein. Subsequently, the relative rotational orientation between the mask pattern and the first screened layer is altered by a predetermined number of degrees and a second screened layer is deposited on top of the first layer.

Abstract: A converter cartridge for reception and operation of a cassette record and insertion into a host cartridge player. The converter cartridge carries drive means for transporting the tape within the cassette; cam means for advancing and withdrawing tape heads and a pinch roller toward and away from the cassette in response to insertion and withdrawal of the converter cartridge; push buttons and associated linkage and drive elements effective to advance and reverse the tape within the cassette and to reinstate the playing or recording mode upon release of the appropriate push button; each of said buttons serving to lock the other when desired, the converter cartridge being capable of independent operation when fitted with power means.