Abstract: A brushless direct current motor control system is disclosed in which a permanent magnet rotor induces voltages in phase windings and wherein these voltages are compared to a reference signal to provide for the proper cyclic and sequential energization of the motor drive phase windings. A protection circuit is utilized to couple a reference level, corresponding to the level about which the phase induced signals vary, as an input to the motor control circuit for effective comparison with the phase induced signals so as to provide for the proper sequencing of phase excitation. The protection circuit typically provides a substantially constant voltage drop between the reference level of the induced voltages and the input terminal of the motor control circuit with the protection circuit also preventing any excessively large magnitude voltages from being applied as an input to the motor control circuit.

Abstract: A signal wrap for transducer fault isolation for use in a telephone system providing remote isolation and identification of malfunctions in end-user telephone equipment such as a handset microphone and handset receiver (earpiece speaker) with an associated sound source and sound receiver.

Abstract: There is disclosed an ignition control circuit of the type which facilitates the storage of energy in an external inductive load during a dwell period and the release of the stored energy from the inductive load through a spark gap at the end of the dwell period. The circuit includes switch means for conducting current through the inductive load during the dwell period, and an integrated circuit for turning the switch means on during the dwell period and off at the end of the dwell period. The integrated circuit includes an output transistor for controlling the switch means, a current source for driving the output transistor, and control means for enabling the current source during the dwell period and disabling the current source at the end of the dwell period.

Abstract: A reference pulse verification circuit is disclosed in which a sensor senses the passage of a number of teeth which project from a wheel rotated by an engine crankshaft. The projecting teeth are uniformly disposed about the wheel except for a missing tooth area corresponding to a predetermined angular reference position of the engine crankshaft. A missing pulse detector provides unverified reference pulses corresponding to the occurrence of the missing tooth reference position, and a verification counter is incremented in response to each sensor pulse produced in response to the passage of each rotating tooth. The counter output and the missing pulse detector output are combined such that a verified reference pulse is provided in response to each missing pulse detection which coincides with the occurrence of a predetermined tooth pulse count that was initiated after the occurrence of a preceeding missing pulse detection.

Abstract: An electronic pressure transducer for providing a pressure-indicative analog output signal includes a capacitive pressure sensing oscillator having a frequency dependent on an applied pressure. A combining circuit combines the oscillator signal with a constant frequency signal generated by a reference oscillator to generate a difference signal having a duty cycle dependent on the frequency difference between the oscillator signals. The difference signal is applied to an integrating circuit and amplified by a variable-gain output amplifier to develop the pressure-indicative analog output signal. A pair of D-type flip-flops and an EXCLUSIVE OR logic gate in the combining circuit enable the combining circuit to function with oscillator frequency ratios of 1:1 to 2:1, thereby enabling the capacitive pressure sensing element of the pressure sensing oscillator to operate over a wider range of sensitivities.

Abstract: A preconverged color display station is disclosed which is compatible with a computer controlled control unit that provides electrical convergence control signals. Compatibility is obtained by causing the control unit to transmit the electrical convergence signals to the screen storage memory RAM (random access memory) which normally stores information defining the character and character attributes to be visually provided by the display station CRT screen. The stored convergence signals are read back to the control unit from the screen RAM. After all of the convergence signals have been received by the display station and prior to the transmission of character and character attribute information signals to the screen RAM, the contents of the screen RAM is erased. Subsequently, the contents of the screen RAM, which now contains character display information signals, is read out and utilized to define a visual display on a CRT.

Abstract: An integrated circuit (IC) assembly 10 using an IC carrier is disclosed. An IC 15 and IC carrier together form a carrier subassembly 11 in which two parallel rows of IC leads 20 and 21 are received by carrier contacts 28 mounted in openings 27 in a horizontal portion 14 of a main carrier member 13. Extending pin portions 30 of the carrier contacts vertically extend from the horizontal portion openings into two carrier channels 31 and 32 wherein the extending pin portions and carrier channels are dimensioned so as to recess the pin portions and prevent finger access thereto. A socket subassembly 12 is provided comprising a main socket member 40 having two raised islands 44 and 45 each with a row of socket contacts 41 fixed therein. Each socket island is dimensioned for removably fitting within one of the carrier channels with the carrier pin portions mating with the socket contacts.

Abstract: Digital circuitry adaptable for controlling dwell in 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.

Abstract: A duplex FM communication transceiver 10 is disclosed in which a modulated transmit carrier signal is utilized as the receiver first mixer (32) injection signal. The receiver portion of the transceiver comprises dual conversion circuitry, and the transmit information signal used for modulating the transmit carrier signal is phase and amplitude adjusted and then utilized to modulate the receiver second injection local oscillator 41 which provides the input injection signal to the receiver second mixer 36. The second mixer substantially cancels all of the transmit information signal and provides just received information signals to a demodulator 43 which provides audio signals to a speaker 46.

Abstract: A duplex FM communication transceiver 10 is disclosed in which a modulated transmit carrier signal is utilized as the receiver first mixer (32) injection signal. The receiver portion of the transceiver comprises dual conversion circuitry, and the transmit information signal used for modulating the transmit carrier signal is phase and amplitude adjusted and then utilized to modulate the receiver second injection local oscillator 41 which provides the input injection signal to the receiver second mixer 36. The second mixer substantially cancels all of the transmit information signal and provides just received information signals to a demodulator 43 which provides audio signals to a speaker 46.

Abstract: A self oscillating inverter including a DC to DC converter and method for control thereof which senses the onset of a transformer core saturation to control its operation without dependence thereon. Linearizing inductors in the transformer secondary function to maintain a ramp shaped collector current waveform under full load conditions to allow control of output voltage by varying the oscillator frequency.

Abstract: This invention relates to a process for servo-controlling a magnitude TI depending on a parameter .theta., whereby: the variations in time of a second magnitude TG which varies as a function of the parameter .theta. and to which the magnitude TI is related are monitored; a control signal TGE=TDS+TER is provided, TER being a function of the deviation between the reference value TR and the real value TI of the first magnitude, and the value of TDS being equal to the arithmetical mean between maximum and minimum values, TGEMX and TGEMN respectively, of the second magnitude TG determined previously; and the value of the parameter .theta. is adjusted to servo-control the second magnitude TG by the calculated value TGE.

Abstract: An acceleration fuel enrichment system is disclosed in which if the rate of increase of throttle position is determined as exceeding a predetermined minimum threshold (V.sub.1), asynchronous acceleration enrichment fuel control pulses are developed and effectively added to steady state synchronous base fuel control pulses provided by an engine control microprocessor. When the rate of throttle position increase falls below a preset level, the development of the asynchronous fuel control pulses is terminated and synchronous acceleration enrichment fuel pulses are provided which are effectively added to the base synchronous fuel control pulses. The durations of these synchronous acceleration enrichment pulses are initially fixed, but when a decrease in engine manifold pressure is sensed, these durations are determined in accordance with the rate of change of the magnitude of sensed engine manifold pressure.

Abstract: A speed-dependent ignition controller and method utilizes a sensor output signal to provide spark occurrence and dwell initiation at retard and advance angles for an internal combustion engine. The sensor signal has a pulse width proportional to the difference between a desired ignition advance and retard angle. At low rpm, the sensor signal is inverted to produce a retarded ignition angle while at high rpm's the signal is utilized without inversion to produce an advance ignition angle.

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: A visual display mounting assembly is provided wherein a substantially rectangular parallelopiped central body 18 of a display module 17 is sandwiched between a planar surface 29 of a printed circuit board 23 and a substantially planar chassis wall 15 having a rectangular opening 16 therein for a front viewing surface 19 of the display module. The chassis wall opening 16 is formed with two opposing planar edge portions 32 of the chassis wall and two opposing nonplanar edge portions 33 of the wall comprising bent portions of the wall projecting towards the module. Peripheral portions 34 of the front surface 19 of the display module are positioned in pressure contact with the planar edge portions 32, and the front surface 19 is positioned between the non-planar edge portions 33 of the chassis wall. The display module 17 is held in place by retaining twist tabs 24 fixing the circuit board to the chassis wall and thereby having the circuit board press the display module body against the chassis wall.

Abstract: During engine cranking and after cranking if engine coolant temperature has not yet exceeded a minimum value, an air bypass valve (dashpot) provides maximum additional air to the engine fuel mixture in addition to the air provided in accordance with engine throttle position. During normal engine run conditions with the throttle not effectively closed, the dashpot provides minimum additional air to the fuel mixture. During deceleration when engine throttle is effectively closed, if engine speed is at least a maximum speed IDLEH and then declines, effective dashpot actuation will be 100% (maximum additional air) for engine speeds at least equal to IDLEH, 0% for engine speeds below a minimum speed IDLEL, and for engine speeds between IDLEH and IDLEL, the change (decrease) in dashpot actuation will be proportional to the change in current engine speed and substantially independent of time. If during deceleration engine speed decreases to IDLEL, then dashpot actuation remains at a minimum.

Abstract: A preconverged color display station is disclosed which is compatible with a computer controlled control unit that provides electrical convergence control signals. Compatibility is obtained by causing the control unit to transmit the electrical convergence signals to the screen storage memory RAM (random access memory) which normally stores information defining the character and character attributes to be visually provided by the display station CRT screen. The stored convergence signals are read back to the control unit from the screen RAM. After all of the convergence signals have been received by the display station and prior to the transmission of character and character attribute information signals to the screen RAM, the contents of the screen RAM is erased. Subsequently, the contents of the screen RAM, which now contains character display information signals, is read out and utilized to define a visual display on a CRT.

Abstract: A scanning CRT visual display system is provided in which the operation of the CRT controller which provides video blanking pulses and horizontal and vertical sync pulses for controlling the CRT display is temporarily halted when a larger than normal vertical spacing between horizontal scan lines is desired. During the time that the operation of the CRT controller is halted, which is accomplished by the selective blocking of clock timing pulses to the controller, an auxiliary synchronous counter circuit effectively counts the clock timing pulses and provides a substitute horizontal sync pulse for the CRT display such that during the implementation of a larger than normal vertical step for the scanning CRT display system, horizontal sync pulses are always provided even though the operation of the CRT controller is temporarily suspended during this time.

Abstract: A combined tone only and tone and voice multiple alert pager is provided which implements separate tone only and tone and voice alert modes in response to the reception of different predetermined signal codes. The pager also includes an audio monitor switch for monitoring audio frequency information received by the pager. During the tone only alert mode the operation of the audio monitor switch is inhibited and only a distinct audible alert tone is provided by the pager. During the tone and voice alert mode, a different audible alert tone is provided and this is automatically followed by audible voice information. Actuation of the audio monitor switch is also utilized to terminate the audible alert tone in the tone only mode whereas actuation has no effect on terminating the audible alert tone in the tone and voice alert mode.