Abstract: A DC to DC converter has an unregulated input and provides a pair of regulated outputs which independently provide variable power on demand to two independent loads at a substantially constant output voltage. The converter includes three major sections, the input oscillator and pulse width modulation section, the isolated negative DC regulator and the isolated positive DC regulator. Each of the DC regulators is current limited and each is provided with overvoltage protection. One of the output regulators provides improved efficiency through the use of a pair of appropriately connected catch diodes which decrease current change through a filtering inductor, and through implementation of a combined regulator preload resistor and AC pulse width modulating switching transistor drive current source. The converter is a compact modular unit having a low profile with circuit components arranged to minimize temperature instability.

Abstract: This concise paper determines the required laser power to achieve a given probability of bit error using a pulse-interval modulation (PIM) (discrete pulse position modulation) system with resolution much smaller than a laser pulsewidth. An approximation to the first crossing density for a threshold detector operating on a filtered Poisson process is used. Both analytic and computer simulation results are presented.

Abstract: Clock generating apparatus for a computer system has selective pulse delay and pulse width control. Selection of pulse delay and pulse width is accomplished by loading registers with predetermined data patterns. The registers can be loaded under program control or by data entry units, such as a keyboard, switches, etc. The registers are located in coarse and fine pulse delay and pulse width adjustment units. These units have the same physical structure, but are functionally definable by a settable control element. A dither delay element is included in these coarse and fine adjustment units, and it is selectable to provide a small increment of delay. The coarse pulse delay and pulse width adjustment units also include pulse mode control circuitry to control operation in either normal oscillator mode or in single cycle mode.

Abstract: The advent of large power semiconductors has made it possible to apply inverters and ac motors to traction applications. Either synchronous or induction motors and several types of power converters can be considered. The induction motor and the pulsewidth modulated (PWM) inverter are selected as favorable for application to a transit car drive. A general method of sizing the PWM inverter and induction motor in terms of the car performance requirements is out-lined. This method results in a minimum size inverter and allows optimization of system weight and cost. A discussion of wheel size effects and the optimization of regenerated energy is included.

Abstract: A digital logic level signal indicates whether a first signal in a phase-locked loop is locked in phase and frequency with a second signal provided to the loop. The digital logic level signal is provided from the sequentially last stage of a counter having a predetermined number of stages. The counter counts cycles in an input signal corresponding to one of the first signal and the second signal. A reset signal pulse having a first predetermined duration is provided to the counter from a pulse width discriminator when the pulse width discriminator detects a phase difference between the first and second signals of greater than a second predetermined duration. The reset signal pulse resets the counter. The digital logic level signal is in a state indicating an in-lock condition when a predetermined number of input signal cycles occur without the counter being reset.

Abstract: It is shown that relaxation oscillation in the light outputs of injection lasers can be suppressed by an external electrical circuit. This method can be applicable to high-speed pulse modulation. For this purpose, an electrical resonant circuit connected to the laser diode (LD) and tuned to the relaxation oscillation is considered as an example. Frequency response of direct modulation and the device-transient characteristics are analyzed. These results were verified experimentally. A brief discussion on the upper limit of the repetition frequency of pulse modulation is given and it is shown theoretically that stable pulse modulation of an LD up to a few Gbit/s may be obtained by applying this method.

Abstract: A switching regulated power supply apparatus, comprising: an alternative current power source, a first rectifier for rectifying the alternate current output, a high frequency reference pulse generator, a pulse width modulator for modulating the pulse width of the reference pulse output as a function of a control signal, a switching transistor for on/off controlling the output from the first rectifier as a function of the pulse width modulated output, a high frequency transformer connected in series with the first rectifier and the switching transistor, a second rectifier for rectifying the output from the high frequency transformer, and a smoothing circuit for smoothing the output from the second rectifier, the output from the smoothing circuit being applied to the pulse width modulator as a control signal, characterized in that the said apparatus further comprises a resonance capacitor coupled to the said high frequency transformer for causing resonance cooperatively with the said high frequency transformer when the said switching transistor is turned off, and a switching device coupled to the output of the second rectifier to be turned on responsive to a flyback pulse obtained from the smoothing circuit when the switching transistor is turned off, whereby the said resonance is suppressed by means of the second rectifier and the switching device in the latter half cycle of the resonance during the off time period of the switching transistor.

Abstract: A digitally controlled power system for controlling one or more power supplies having an output voltage including an analog to digital converter for sensing a difference between a reference voltage and the output voltage. Also included is a digitally controlled processor to provide a pair of control pulses to control the power supplies and a control memory to provide a program of instructions to said processor such that the processor provides a programmed change in the pulse width of the control pulses whereby the power supply provides a change in the output voltage.

Abstract: A pulse width modulator digital servo system combines a digital feedback signal, which is developed in response to a time based signal directly indicative of a positional physical parameter of a servo actuator, and a digital command signal, which is indicative of a desired position of the servo actuator, to produce a digital resultant signal. A pulse width modulator produces a control signal output that is pulse width modulated in accordance with the digital value of the resultant signal to control operation of the servo actuator to achieve the positional relationship commanded. The pulse width modulated control signal is balanced when the combined resultant signal has a predetermined or constant value and is unbalanced in respective directions depending on whether the combined resultant signal is larger or smaller than such predetermined value.

Abstract: The mains connected supply system has a switching transistor and a control and regulating circuit which has a pulse width modulating stage which reacts to the ratio between the desired and actual value. It also contains an overload protection circuit which limits the switching transistor when a predetermined energy storage current is reached. This achievement is a voltage supply for a t.v. receiver. A voltage is rectified (27) via the self-induction of the power supply during the transmission phase of the switching transistor (6). This is used to generate the supply voltage for the remote control circuit (6). The circuit contains a resistance matrix in the pulse width modulation stage which produces a negative current to reduce the voltage of the remote control circuit.

Abstract: An analog to digital converter wherein an incremental pulse width modulator controls first and second modes of operation of a bridge network of switches such that the bridge network of switches passes a precision current from a current source into a summing input of an integrator during the first mode of operation and away from the summing point of the integrator during the second mode of operation. The bipolar precision current from the bridge network of switches is summed with an analog current at the summing input of the integrator to cause the integrator to develop a voltage signal proportional to the integral of the sum of these currents. In response to the voltage signal and to clock pulses, the incremental pulse width modulator precisely controls the first and second modes of operation of the bridge network of switches and enables an output circuit to generate a digital representation of the amplitude of the analog current.

Abstract: An electro-mechanical transducer driver circuit for an electronic timepiece characterized in that the pulse width of a driving pulse which drives an electro-mechanical transducer is controlled in a step-wise manner by the induced voltage of a driving coil.

Abstract: A pulse detection system comprises, in series, a pulse amplitude detector, pulse width detector and a recorder. The pulse amplitude detector comprises a voltage comparator having an input for receiving a voltage pulse, a reference d.c. voltage input, a ground and an output for producing an output voltage when the input pulse equals a predetermined fraction of the reference voltage. The pulse width detector comprises a positively-triggered monostable having: a trigger input connected to the comparator output, a ground, a RESET, a RESET reference, a reference d.c. voltage input connected through a resistor to the RESET and through a capacitor to the RESET reference, and a Q output; and a positive-going clocked flip-flop having a clock input connected to the Q output of the monostable, a data input connected to the comparator output, a ground, a reference d.c. voltage input, a RESET, and a Q output connected through a delay resistor to the RESET and through a capacitor to ground. The recorder is a conventional digital counter.

Abstract: In a video tape recorder having a tape on which are recorded "0" and "1" binary coded bits of a pulse width modulated signal as for identifying frames of a video signal also recorded on the tape, the tape being advanced past a head detecting the pulse width modulated signal at speeds variable with the fast forward, normal and slow motion mode of operation of the recorder so as to change the bit frequency of the pulse width modulated signal in correspondence with the speed of the tape, a circuit which demodulates the "0" and "1" bits of the detected pulse width modulated signal by comparing the coded pulse width of each succeeding bit (B i +1) with the width of the preceeding bit (B i ) to make the demodulation substantially independent of the bit frequency and the corresponding speed of the tape so that the circuit operates in each mode of recorder operation. In the preferred embodiment of the circuit, each bit is quantized into periodic pulses which correspond in number to the width of the bit. The number of pulses corresponding to the pulse widths of successive bits are then digitally compared in a comparator to obtain a two-level discrimination signal. More particularly, only selected higher value digits of the pulse numbers are compared to simplify the comparison and the comparator changes the level of the discrimination signal only during a preselected portion of each bit relative to the preceeding bit to assure accurate demodulation. The preferred circuit also has a circuit for deriving an edge pulse signal from the coded pulse width of each bit and a logic circuit operating on the edge pulse signal and the discrimination signal from the comparator for providing a signal corresponding only to bits of the one value, for example the "1" bits.

Abstract: A control system for controlling the conduction period of the switching elements of a pulse width control type inverter is provided having a reference pulse generator that determines the output frequency of the inverter output voltage, a constant voltage control circuit for generating an analogue output voltage, an A-D converter for converting the analogue output voltage into a digital output signal and a up-counter which counts clock pulses. The outputs of the up-counter and the A-D converter are compared with each other by a digital comparator. The up-counter is cleared by the reference pulse when another up counter counts a predetermined number of output pulses from the comparator. The up-counter repeats a predetermined number of counting up and clearing operations until it produces a carry signal, and the conduction period of the switching element is determined by an interval between the generation of the reference signal and the generation of the carry signal. In a modified embodiment the up-counter is substituted by a down counter.

Abstract: An apparatus for removing a pulsive noise in an FM stereo signal including a stereo information signal and a stereo pilot signal, said composite signal further including a pulsive noise, said apparatus comprising an FM detector for providing said composite signal, a noise detector for detecting said pulsive noise for providing a control signal of a predetermined pulse width upon occurrence of said noise, a gate circuit to be normally closed for passing therethrough said composite signal and to be opened by the output from the noise detector, an amplifier for amplifying the output from the gate, a frequency band cut off filter coupled to said amplifier to form a negative feedback circuit, said filter being set to the pilot signal frequency and/or the subcarrier signal frequency, an attenuator coupled to the output of said amplifier, and a capacitor coupled to the output of said gate circuit and cooperative with said attenuator for holding, when the gate is opened, the signal level at the output of the gate to the value immediately before the gate is opened, said amplifier, attenuator and the capacitor constituting a closed loop, said closed loop forming a positive feedback circuit with respect to said frequencies of the pilot signal and/or subcarrier signal, which serves as an oscillator when said gate is opened, thereby to provide a pseudo pilot and/or subcarrier signals.

Abstract: A system for testing the dental pulp of a tooth by electrically stimulating the pulp with a pulsating signal having a continuously increasing amplitude. The system includes a probe having an electrode adapted to the tooth, and a contact device for sensing when the probe electrode makes contact with the tooth and for increasing the amplitude of the stimulus from an initial value. The intensity continues to increase as long as the probe electrode is in contact with the tooth. The electrical stimulus may be generated by a voltage controlled pulse generator driving the primary of a transformer, with the secondary of the transformer connected to the electrode probe. The transformer has a relatively low cutoff frequency so that the amplitude of the signal across the secondary is proportional to the pulse width of the incoming signal. Consequently, as the control voltage to the voltage control pulse generator increases, the amplitude of the pulses across the secondary also increases. The voltage control pulse generator also drives a counter, and the output of the counter is indicated on a digital display. Since the amplitude of the control voltage is a function of the number of pulses generated by the pulse generator, the output of the counter indicates the amplitude of the electrical stimulus. Alternatively, a ramp generator is connected to one end of the primary and the other end of the primary is periodically grounded responsive to fixed frequency, fixed duration pulses from the output of an oscillator.

Abstract: PURPOSE:To arrange so that an excitation voltage may be reduced without specially providing a low voltage power supply for purge excitation by shortening the pulse width of an electric signal to be applied to a trembler during non- recording compared to the pulse width during recording and decreasing a peak value of voltage of an electric signal. CONSTITUTION:The width of an electric pulse for driving a piezoconversion element 4 is so designed as to be variable with the use of a microcomputer (CPU)26. First an electric pulse is set during printing and during purge respectively. The above-mentioned certain pulse width is instructed by CPU26 and if a low signal is inputted to a base of TR1, TR1 is non-continuous and a voltage of a power supply 27 is applied to the piezoconversion element, thus charging the latter. Next, a signal ''Hight'' is inputted, TR1 is continuous and an electric energy charged to the piezoconversion element 4 is discharged. As described above, it is possible to easily obtain two different kinds or more of voltage pulse using a single power supply voltage according to the instructions of a pulse signal with two different kinds or more of pulse width from CPU.

Abstract: An analog speed error signal, developed by comparing actual and desired speeds, is processed into a control voltage through a two condition circuit network. When the error signal is more than a predetermined percentage of the desired speed, the network has a unity gain and the control voltage equals the error signal. When the error signal becomes less than the predetermined percentage, the network is shifted into a hybrid form by inserting an integrator loop into the gain circuit so that the control voltage and error signal are not directly proportional. The control voltage is converted into a series of proportional width pulses which are applied to vary the generator output to control locomotive speed. The pulse width varies in part from the error signal variation but also in part from an acceleration signal to anticipate the achievement of desired speed. When the hybrid network is in use, the pulse width speed control feeds back to drive the error signal to zero. The control voltage and acceleration signal are also applied to a clock and reversible counter network which controls the locomotive throttle position. The counter steps up or down, to increase or decrease the throttle, at a clock frequency established by the absolute value of the control voltage whose polarity further designates the requirement for speed increase or decrease. A high level of acceleration, however, overrides to reverse the count direction to prevent overshooting the desired speed. A moderate acceleration level inhibits further counting and speed is then varied only by the pulse width modulation network.

Abstract: An AM transmitter of the type including apparatus for generating a subcarrier signal, pulse width modulating this subcarrier with audio, amplifying this resulting pulse width signal using active devices operating in the more efficient switching mode is disclosed. The amplified pulse width signal is passed through a low pass filter wherein the audio is recovered and used to amplitude modulate a radio frequency stage. The improvement herein includes a means for providing an offset voltage to the RF stage so that the system will develop zero carrier output when the pulse width of the modulating signal to the active devices has a relatively small finite value.

Abstract: Spectrally efficient modulation, involving the maximization of the transmitted data rate through a specified bandwidth, may aid in alleviating the problem of spectral congestion in the electromagnetic spectrum. Attention is given to pulse-shaping and nonbinary modulation, and particularly to combined amplitude- and phase-modulation. Theoretical performance limits, such as Shannon's bound, are used to assess the effectiveness of the systems described. Consideration is also allotted to spectrally efficient modulation for terrestrial microwave systems, required to provide 1000 voice channels in the 4- and 6-GHz band.

Abstract: This invention deals with significant innovations on multiphase signal oscillators including quadrature oscillators for the use in frequency shifters, or sequential gating devices for special multichannel sound effects, or three-phase power sources or other electronic apparatus. These innovations or the combination thereof consist of (1) the serial arrangement of two or more than two all-pass phase filter sections in a feedback loop to form an oscillator with a frequency stability and purity heretofore not attainable with cascaded integrator type quadrature or multiphase signal oscillators, (2) the inclusion of circuitry to secure an immediate start of oscillation at very low frequencies, (3) the inclusion of known means for amplitude limitation, (4) the inclusion of operational transconductance amplifiers for wide range voltage controlled frequency determination or (5) alternate types or means for frequency control including but not limited to known means for pulse width control of the frequency determining resistors.

Abstract: A missing pulse detector is provided which has the capability of monitoring a varying frequency pulse source to detect the loss of a single pulse or total loss of signal from the source. A frequency-to-current converter is used to program the output pulse width of a variable period retriggerable one-shot to maintain a pulse width slightly longer than one-half the present monitored pulse period. The retriggerable one-shot is triggered at twice the input pulse rate by employing a frequency doubler circuit connected between the one-shot input and the variable frequency source being monitored. The one-shot remains in the triggered or unstable state under normal conditions even though the source period is varying. A loss of an input pulse or single period of a fluctuating signal input will cause the one-shot to revert to its stable state, changing the output signal level to indicate a missing pulse or signal.

Abstract: There is disclosed a circuit for controlling the expression of an electronically controlled keyboard instrument and is an improvement on the circuit disclosed in application Ser. No. 680,996. The circuit works on the principle that by switching a solenoid on and off at a rapid rate and then varying the time on versus the time off, the energy supplied to the solenoid varies and therefore the striking force of the piano is changed. In accordance with the present invention, precise control over the width of the pulses is achieved by first setting a set voltage level and then adding thereto increments of set voltage according to a binary weighting. These voltages are then added and compared with a triangular voltage in a comparator. Both the up ramp portion and the down ramp portion of the triangular waveform are utilized and compared against the sum voltages. The pulse width of the comparator output is thus a function of the intersection of the ramp voltage, both up and down ramps, with the sum voltage. By varying the sum voltage in digital increments the width of the pulses is varied and these pulses which are supplied to the solenoid thus have the power or energy of the solenoid varied to vary the expression effects on the playback of the piano, for example.

Abstract: The present paper describes AM mode locking for homogeneously broadened systems, a procedure for measuring linewidths under laser conditions, and finally, experimental results for a 1-atm CO 2 laser. Working in the frequency domain, analytic solutions are given for the pulse bandwidth and pulse shape as a function of frequency detuning. We arrive at a simple expression for the maximum positional shift of the mirror distance. It turns out that the linewidth is inversely proportional to the maximum frequency shift and can be obtained independent of the modulation parameters and time constant of the pulse-signal detector. Applying this analysis to an amplitude-modulated CO 2 laser the pulsewidth and linewidth have been measured as a function of gas composition and modulation depth. In contrast to predictions deduced from absorption measurements under neutral conditions we find the striking result that under laser-discharge conditions the linewidth increases and the pulsewidth decreases with increasing helium percentage.