Abstract: A position-controlling system which comprises a reference counter periodically giving a referential pattern numeral; a resolver forming an excited waveform from the referential pattern numeral given by the reference counter and detecting the position (angle of rotation) of a movable machine section in the term of a phase data per prescribed period of time; a buffer register loaded with the content of the reference counter corresponding to the phase data; and a controller supplied with a data on the detected position of the movable machine section stored in the buffer register and a data of the position instruction thereby to produce an output denoting an accumulative position errors occurring per prescribed period of time in the actual moving of the movable machine section, and wherein a servo system is operated upon receipt of a periodic output from the controller according to instructions on the momentarily changing positions of the movable machine section, thereby controlling the machine positions.

Abstract: A periodic electric signal component in a variable input signal of a servo system is compensated by providing an electric signal corresponding in wave form to the periodic signal component, synchronizing the corresponding signal with the periodic electric signal component and compensating the periodic electric signal component with the synchronized corresponding signal.

Abstract: The speed and direction of rotation of an electronically commutated brushless D.C. motor is controlled by utilizing a resolver to provide both phase locked servo feedback and motor commutation. The resolver in response to orthogonal signal voltages on its primary coils, provides a signal whose phase is a function of the motor shaft angle. A phase detector provides a signal whose phase varies in accordance with the difference between the phase of the signal from the resolver and the phase of a reference signal. The reference signal phase varies in a predetermined manner as a function of time dependent upon the desired shaft speed and direction of rotation. The phase detector output signal is then used to amplitude modulate the signal from the resolver. The amplitude modulated signal is then demodulated with respect to the orthogonal signal voltages so as to provide signals to energize the control coils of the motor.

Abstract: A phase-sensitive transducer apparatus comprises first and second relatively movable members, the first relatively movable member having a plurality of windings and the second relatively movable member having a winding. Means are included for applying a first input signal to one of the windings of the first relatively movable member and a second input signal to another of the windings of the first relatively movable member, an output signal being induced on the winding of the second relatively movable member. The first and second input signals are sinusoidal in nature of substantially identical frequency and peak amplitude and are phase-displaced by a predetermined amount, and the output signal is substantially constant in peak amplitude and variable in phase during relative movement of the first and second relatively movable members.

Abstract: A phase-sensitive transducer apparatus comprises first and second relatively movable members wherein the first relatively movable member has a plurality of windings and the second relatively movable member has a winding. Means are included for applying a first input signal to one of the windings of the first relatively movable member and a second input signal to another of the windings of the first relative movable member. An output signal is induced on the winding of the second relatively movable member. The first and second input signals are sinusoidal in nature of substantially identical frequency and peak amplitude and are phase-displaced by a predetermined amount, and the output signal is substantially constant in peak amplitude and variable in phase during relative movement of the first and second relatively movable members.

Abstract: A digital signal processor is provided for processing analog signals with digital circuits. In a preferred embodiment, a servo feedback signal is processed with a digital arrangement to derive servo velocity information. Processing is performed by synchronizing a counter with a servo feedback signal and comparing the period of the feedback signal with a reference signal from the counter as being indicative of servo velocity.

Abstract: A limiter circuit is installed in a servomechanism that establishes a signal at the output terminal of a filter contained therein, in the absence of an input signal within the lock range of the servomechanism, in a manner that maintains the charge on the filter consistent with the established output signal, thus providing favorable initial conditions for rapid reacquisition and smooth reacquisition transients.

Abstract: A numerical control system having a digitized phase loop comprising a motor for moving an object being controlled, a servo amplifier for driving the motor, feedback means coupled to the motor for generating a first signal indicative of the actual position of the object, and means for converting the first signal to a digital signal indicative of a change in the actual position of the object. Further provided is means for comparing a command digital signal indicative of the desired change in position of the object with the digital signal indicative of the actual change in position of the object to generate an error digital signal and for converting the error signal to an analog signal for driving the servo amplifier.

Abstract: In a frequency selective steering system for automatic vehicle guidance, a phase locked loop is used to derive from a sum signal containing wanted and unwanted signal frequencies a reference signal equal in phase and frequency to the wanted signal. The reference signal is used to derive from a difference signal also containing wanted and unwanted signal frequencies an error signal dependent on the phase of the wanted signal only. The error signal is used to control the steering of the vehicle.

Abstract: A hybrid servo control system for controlling, for example a rotation of a capstan driving motor or a head motor of a video tape recorder comprises at least an integral control loop including an analog phase comparator for detecting in an analog mode a phase difference between a signal related to the rotation of the capstan driving motor or the head motor to be controlled and a reference signal so as to produce an analog amount corresponding to said phase difference, an analog-digital converter for converting said analog amount into a digital amount and a digital frequency modulator for frequency modulating in a digital mode clock pulses with said digital amount.

Abstract: Method and apparatus for phase averaging of two phase position signals to derive a single phase position signal. The apparatus comprises phase discriminators for comparing each of the two phase position signals to the phase of the single phase position signal and a combining circuit for summing the output signals from the phase discriminators to derive an error signal when the single phase position signal is not midway between the phases of the two phase position signals. Circuitry is provided to modify the phase of the single phase position signal in response to the amplitude of the error signal.

Abstract: A speed control system for a fluid driven prime mover, for example, a turbine wherein the speed of the prime mover is controlled by the positioning of at least one fluid inlet valve. The inlet valve is positioned by a valve operator responsive to an output voltage from the speed control system. The output voltage is directly proportional to the phase difference (error) between a variable reference digital pulse train input representing a desired speed and a feedback digital pulse train input representing the actual prime mover speed. During steady-state operation, prime mover load changes will first cause a phase difference between the reference input and the feedback input whereupon a corrective output voltage is immediately applied to the inlet valve operator prior to the occurrence of an actual speed error.

Abstract: A system for intermixing large and small size type in a photocomposer by coordinating speed of a disc font storage medium with the size of type to be set. The speed of the disc drive motor is controlled by pulses of power to the motor. A signal frequency which is used to produce the pulses simultaneously controls the speed of the disc driven motor and a counter which is allowed to count out only at specified times in relation to the matrix relative position and thereby inform a controller of the matrix position.