Abstract: An apparatus and method for controlling driving of a apparatus such as a motor. A signal representing the position and/or velocity of the motor is received by a drive control unit. A microprocessor in the drive control unit provides a division ratio signal and a rotation judging signal to a clock pulse divider and two-phase pulse generator, respectively, and also calculates the velocity of the apparatus in accordance with the condition data. The clock pulse divider divides a clock pulse signal in accordance with the division ratio signal and outputs a divided clock pulse signal. The two-phase pulse generator generates two-phase pulses having a 90-degree phase shift of a given polarity with respect to one another in accordance with the divided pulse signal, and reverses the polarity of the phase shift in accordance with the rotation judging signal. The microprocessor further outputs a control signal to control driving of the apparatus in accordance with the calculated velocity and the two-phase pulses.

Abstract: Apparatus and method for detecting rotor (12) position in a switched reluctance motor (18) having multiple stator phases (A-A', B-B', and C-C'). A multiplexer (48) intermittently connects a known resistor (54) to a non-conducting stator phase. Circuitry (62 and 68) detects the amplitude of the current passing through the resistor (54) and the phase difference between the varying voltage and the current passing through resistor (54). The resulting signal is proportional to the position of rotor (12).

Abstract: A motor servo system for controlling a motor includes a first synthesizing portion which synthesizes a speed detection signal and a phase detection signal with each other to produce a synthesized signal which is in turn filtered by a low-pass filter portion and then becomes a first motor control signal. The first motor control signal is applied to an equivalent motor portion (software motor) which is included in an observer and has a transfer function of as the same as that of the motor. A detection signal which is detected by the equivalent motor portion and a synthesized signal from the synthesizing portion are compared with each other by a first comparing portion. An output signal of the first comparing portion is applied to a second comparing portion or a second synthesizing portion.

Abstract: A rotation drive device for driving a rotator is disclosed, comprising an electric motor for driving the rotator, a phase detecting circuit for detecting the phase of rotation of the rotator, a reference signal source for forming a reference signal of a constant period, a phase control circuit for controlling the motor in such a manner that the phase difference between the output of the reference signal source and the output of the phase detecting circuit becomes a constant value, a detecting circuit for detecting a fact that the reading-out of the phase difference is not completed in the time interval between the successive two outputs of the phase detecting circuit, a control circuit for varying the number of cycles of phase difference computing operation of the phase control circuit depending on the time interval between the successive two outputs of the phase detecting circuit, another detecting circuit for detecting a fact that the phase detecting circuit has produced no output in one period of the refer

Abstract: An apparatus for preventing torque variation in a digitally controlled servomotor. Electrical angles .theta..sub.1 and .theta..sub.2 of the exciting magnetic field or the armature coil at respective timings of detecting and controlling a load current are obtained. The current is dq-transformed with .theta..sub.1 and inverse-dq-transformed with .theta..sub.2. As a result, even if there is a displacement of the actual electrical angle owing to the rotation of the armature during computing, it is possible to execute accurate current control. Further, at the time of calibration of the control system, the load currents are detected to be dq-transformed. From the d-axis components and q-axis components, values related to the offset and the amplification factor of the current detection systems are calculated. During the actual operation of the servomotor, the detected current value is corrected using the values. Further, the detection of the load current is performed plural times in one control cycle.

Abstract: A quantizing error removing circuit for a rotational control device applied to a servo circuit and the like of a video cassette recorder, designed to removing the quantizing error generated upon controlling the speed and phase, minimizing a change of gain characteristic of a control device, thereby improving its efficiency.

Abstract: A motor control apparatus for rotating a motor smoothly. A sine wave form which is an ideal wave form of a signal is stored, and the motor is driven by a signal having the ideal wave form obtained by correcting the period and the phase of the stored sine wave form. A comparator receives a detection signal which indicates the rotating state of the motor through an A/D converter, and obtains the correction values of the current period and phase. A wave form setting means corrects the set period and phase, generates a sine wave having the corrected period and phase on the basis of the sine wave data stored in a sine wave data region, and outputs a driving signal having the sine wave form through a D/A converter.

Abstract: Apparatus and method for detecting rotor (12) position in a switched reluctance motor (18) having multiple stator phases (A--A', B--B', and C--C'). A multiplexer (48) intermittently connects a known resistor (54) to a non-conducting stator phase. Circuitry (62 and 68) detects the amplitude of the current passing through the resistor (54) and the phase difference between the varying voltage and the current passing through resistor (54). The resulting signal is proportional to the position of rotor (12).

Abstract: The flow of power through a field effect transistor to a DC motor is controlled by the output of a frequency modulator having a low frequency pulsed signal applied to one input thereof and a high frequency pulsed signal applied to a second input thereof. The pulse width of each "on" pulse of the low frequency pulsed signal is varied in response to a signal representing a desired motor speed. Optionally, the pulse width of each "on" pulse of the high frequency pulsed signal can also be varied in response to the signal representing the desired motor speed. A filter circuit can be employed to prevent rapid changes in the pulse width of the low frequency pulsed signal. Similarly, a filter circuit can be used to avoid rapid changes in the pulse width of the high frequency pulsed signal. A freewheeling diode can be used to minimize inverse voltage spikes across the motor.

Abstract: A circuit for controlling the velocity of the spindle motor in an electronic device using a disk is disclosed. Particularly, an abnormal rotation preventing circuit is disclosed which monitors the angular velocity of the spindle motor and forcibly controlls it to rotate within a predetermined velocity range when it deviates from the predetermined range. The duty value of a phase difference between two signals among first, second and third phase control signals for driving a three-phase motor is measured. Then, the phase difference is counted and the velocity is sampled. An abnormal rotation control signal is generated when the sampled velocity deviates from the predetermined range. The motor's velocity is then forcibly controlled so as not to deviate from the predetermined range, thereby preventing abnormal rotation of the motor.

Abstract: A feedback controller inputs a reference signal instructing a controlled variable output from an object operated in accordance with a control signal and a feedback signal, to calculate the control signal such that the feedback signal is equal to the reference signal, and to supply the calculated control signal to the object. The controller has a transfer function Gf, and functions to generate the following response waveform f (t) due to a disturbance. That is, a response waveform of the controlled variable at the time when the disturbance is added to the controlled object is set to f (t), a response waveform of the feedback signal in an opened loop state, such that feedback of said controlled variable is turned off, is set to p (t), a relative degree of the disturbance is set to "d", and a relative degree of the controlled object is set to "g".

Abstract: Where T.sub.1 is a period of a dynamic operation range of a phase comparative waveform of a motor servo apparatus, and a period T.sub.0 of a reference phase signal is measured, the reference phase signal is delayed by T.sub.3 =T.sub.0 -T.sub.1 /2 to obtain a gate signal. The dynamic operation range is started by the gate signal. Thus, the operational center of the phase system is brought in line with the dynamic operation range. The operation is made symmetrical in the dynamic operation range to achieve a rapid servo lock and a stable phase control over the motor servo apparatus, even at the start of the motor or when an external perturbation occurs.

Abstract: A speed controller is equipped to a step motor for controlling the rotation of the step motor with a desired angular velocity. The step motor speed controller utilizes a phase-locked stepping servomechanism (PLSS) in which a phase-controlled oscillator (PCO) comprised of an adaptive digital-pumped controller (ADPC) and a voltage-controller oscillator (VCO) is employed. The step motor speed controller utilizes a tachometer comprised of an optical encoder for detecting the angular speed of the step motor. The tachometer sends out a first pulse train with the frequency thereof indicating the angular velocity of the step motor as a feedback signal to the ADPC. A reference signal source is employed for sending a second pulse train to the ADPC. The ADPC compares the phase difference between the first pulse train and the second pulse train and whereby a signal corresponding the phase difference is sent to the VCO, causing the VCO to output a third pulse train to the step motor.

Abstract: A motor speed controller implements a speed control to phase control switch over. When the switch over occurs on initial offset between the reference speed signal phase and the current motor position phase is determined. The reference speed signal is then offset by this phase difference thereby achieving a quicker servo lock.

Abstract: Method and apparatus for closed-loop microprocessor control of an electric motor having one or more phase windings and commutation of the phases by rotor/stator position sensors to provide improved efficiency in motor operation wherein the conduction angle of a phase energization of the motor at a given speed of operation is measured, the phase advance adjusted in a positive or negative direction to obtain a subsequent conduction angle, and the two sequential conduction angles compared. Based on the comparison, further phase advance and comparison of sequentially measured conduction angles is carried out, in positive or negative directions of phase advance, to maintain a minimum conduction angle and improve operating efficiency of the motor.

Abstract: An apparatus and a method are provided for controlling the frequency of vibration of a compacting machine. The frequency control is carried out by the apparatus which determines the actual time at which a ground contacting member of the compacting machine is at its true vertically lowest position. This is determined by measuring the time at which the vertical acceleration of the ground contacting member has a maximum value during one rotation of an eccentrically mounted, vibration inducing mass. The time difference between the time at which the vibration inducing eccentric mass is at predetermined position and the time at which the acceleration of the ground contacting member is at the maximum value is used to calculate a phase angle relationship (.phi.) between the ground contacting member and the eccentrically attached member. This method of determining the phase angle relationship (.phi.

Abstract: A rotational position detection encoder includes at least two detection heads located along a slit string of a code plate. The detection signals of one of the detection heads are processed to generate a plurality of phase offset signals having successively differing phases with respect to each other. The phase offset signals are compared with the detection signals of another of the detection heads, and the phase offset signals having a phase closest to that of the detection signals of the other detection head are selected and added to the detection signals of the other detection head. As such, detection signals having conforming phases are obtained without minute positional adjustment of the detection heads.

Abstract: A phase comparing apparatus which outputs a signal of an amplitude corresponding to phase difference between a first and second signals, includes a difference signal operating device for outputting a difference signal generated according to the difference in voltage between the first and second signals, first and second maximum value detecting device for respectively generating first and second maximum value detecting signals when maximum values of the first and second signals are respectively detected, a timing comparing device for outputting a first timing signal in response to one of the first and second maximum value detecting signals which is generated earlier than the other thereof and outputting a second timing signal in response to the other thereof, first and second sample-and-hold devices for respectively sampling and holding the difference signal outputted from the difference signal operating means, in response to the first and second timing signals, respectively, and a differential device for outp

Abstract: A method and apparatus for accurately and reliably positioning an actuator arm (12) is disclosed. The actuator arm (12) is driven by a conventional DC motor (38). The conductors which supply current to the motor (38) serve as primary windings (60) of a current transformer (58). The signal induced on secondary windings (62) of the transformer (58) responds to fluctuations in average current flowing in the motor (38). These fluctuations are amplified (64) and filtered (66) so that an AC burst (68) is produced in response to each commutation of the motor (38). The AC burst (68) triggers a one-shot timing circuit (72), which generates a pulse that remains active until the AC burst (68) has decayed. The pulse disappears prior to a subsequent commutation of the motor (38). Thus, one pulse is generated for each commutation of motor (38). A counter (76) is clocked by these pulses. The counter (76) increments when the motor (38) moves in one direction and decrements when the motor (38) moves in the opposing direction.

Abstract: A device for controlling the rotational speed of a motor carries out feedback control by a speed difference control signal and a phase difference control signal. A first time period from a reference time point to a time when a newest detection pulse is outputted is calculated every time a predetermined number of detection pulses are counted by detection pulse counters. A second time period from the reference time point to the time when a command pulse, which is assigned an ordinal number equal to the ordinal number of the newest detection pulse and which thereby corresponds to the newest detection pulse, is calculated on the basis of the total number of pulses counted by the detection pulse counters in the time period from the reference time point to the time when the newest detection pulse is outputted, and the period of the command pulse.

Abstract: A position control system equipped with a driving unit including a mover and a stator giving a relative moving force to the mover comprises a position detector for outputting polyphase alternating signals different in phase from each other, a carrier signal generator for generating carrier signals to be modulated by the signals thus outputted, a digital sample-holder for demodulating a position-angle information signal of the modulated carrier signals and a digital calculator for calculating a driving signal to the driving unit. Thus, the position control system makes it possible to provide with a high resolution positioning, low power consumption, high stiffness, prevention of out of stepping, and high speed and vibrationless settling.

Abstract: A microcomputer 1 servo controls a rotational speed of a capstan motor 10 in a VTR in a digital manner. A value of a timer counter 6 is stored in an ICR 7 at a timing of each edge of FG signal pulses generated as the capstan motor rotates. Thereafter, in the microcomputer 1, a FG interrupt processing is carried out corresponding to the value of ICR 7. More specifically, the microcomputer 1 alternately measures a first period from a rise of one pulse of the FG signal to a rise of a subsequent pulse thereof and a second period from a fall of one pulse to a fall of a subsequent pulse to determine an amplitude of a speed error signal based on these periods. Therefore, a sampling frequency for the digital servo control can be double that of a prior art.

Abstract: The present servosystem positions a movable member such as an optical head over a rotating disk with a constant velocity and high positional accuracy by utilizing a fast analog feedback loop that is controlled by a slower digital loop. The analog feedback loop locks the speed of the movable member to the speed of the rotating disk in a spiral recording track. The progress of the movable member is constantly monitored with the digital loop. A velocity error of known magnitude and direction is introduced into the system. When the error exceeds a preset limit an error of the known magnitude but of the opposite direction is introduced. The servosystem thus zig-zags about the desired position with small velocity changes to provide a substantially constant velocity system with high positional accuracy.

Abstract: A delay circuit which compensates for a variable phase output of an index signal by delaying the read out index signal. The delay time of the delay circuit depends on the cylinder on which a read/write head is located, and is chosen so that the delayed index signals are generated at an essentially constant phase angle with respect to a reference angular position. The delay circuit may include a counter which is pre-loaded with an address of the cylinder on which the head is located, and which counts number of clock pulses input to the counter. Overflowing of the counter generates the compensated index signal. Thus, synchronous operation of plural disk apparatus is accomplished, when the head seeks a new cylinder.

Abstract: A DC to DC sine/cosine positioning servo system has an electro-mechanical DC to AC converter. The latter includes a DC torquer, having a rotor with respective windings for receiving two DC input signals proportional to the error signals detected. Mechanial movement of the rotor is proportional to the relative values of the two input signals. The rotor of a synchro control transmitter is mechanically coupled to the rotor of the DC torquer. A reference oscillator is provided which produces an AC output voltage at a predetermined frequency. The oscillator output is connected to the rotor of the control transmitter. The stator windings of the control transmitter are connected to the stator windings of a control transformer. The rotor of the control transformer produces an output voltage directly proportional to the relative angle between the rotor of the control transformer and the stator windings.

Abstract: A method of synthesizing a system which forces finite value of an impedance to zero comprising a positive current feedback of a prescribed functionalism and a negative voltage feedback to ensure stability of the system. The prescribed functionalism of the current loop uses arithmetic elements as well as voltage and current measurements to provide for a parameter-free synthesis of the converter whereby the converter operates in the measurement-based mode, the measured variables being the voltage and the current associated with the impedance of interest, without a need to supply values of both resistive and reactive components of the impedance of interest. The converter is used in synthesizing electric motor drive systems, incorporating any kind of motor, of infinite disturbance rejection ratio and zero-order dynamics and without specifying the resistive and the inductive values of the motor impedance.

Abstract: Angular position and rotation rate of a function generator having stator windings and rotor windings are determined by first amplitude modulating a carrier oscillation to form a sine signal and a cosine signal and then feeding the sine signal and cosine signals to opposite stator windings and thereby inducing in the rotor winding an analog function-generator signal. In turn this analog function-generator signal is converted into a digital function-generator signal from which is derived by means of an algorithm a digital rotation-rate signal which is numerically integrated to obtain an angular-position signal. This angular-position signal is itself used to modulate the carrier oscillation.

Abstract: A shock resistant hard disk drive system employs a plurality of magnetic disks for recording data, a plurality of magnetic heads for performing input/output operation on the magnetic disks, with at least one of the magnetic heads being used as a servo head, a head-positioning mechanism for controlling the movement of the magnetic heads, a servo control mechanism or servo loop for opposing shifts in the location of the servo head, detecting device for detecting and measuring certain accelerations applied to the system, and filtering device for filtering the output of said detecting device and for providing the signal to the head-positioning mechanism. The detecting device detects and measures the magnitude of internal or external accelerations or shocks applied to the system, and provides the necessary signals to counter such accelerations.

Abstract: A rotation drive device for driving a rotator is disclosed, comprising an electric motor for driving the rotator, a phase detecting circuit for detecting the phase of rotation of the rotator, a reference signal source for forming a reference signal of a constant period, a phase control circuit for controlling the motor in such a manner that the phase difference between the output of the reference signal source and the output of the phase detecting circuit becomes a constant value, a detecting circuit for detecting a fact that the reading-out of the phase difference is not completed in the time interval between the successive two outputs of the phase detecting circuit, a control circuit for varying the number of cycles of phase difference computing operation of the phase control circuit depending on the time interval between the successive two outputs of the phase detecting circuit, another detecting circuit for detecting a fact that the phase detecting circuit has produced no output in one period of the refer

Abstract: The present invention provides a circuit for shaping ripple in the armature current of a D.C. motor. The circuit includes a phase-locked loop (100). In addition, the circuit preferably includes a back-e.m.f. circuit (300) suitable for generating a signal proportional to the back-e.m.f. of the motor and for controlling the frequency of the phase-locked loop (100) on the basis of the signal obtained in this way and/or the back-e.m.f. circuit (300) suitable for generating a signal proportional to the back-e.m.f. of the motor, a voltage controlled oscillator (500) controlled by the signal proportional to the back-e.m.f., and a switched capacitor filter (400) controlled by the output of the oscillator (500), the filter being connected upstream from the phase-locked loop (100).

Abstract: A resistor is provided in parallel with the capacitor of a phase compensating circuit in order that a rapid transition may be made to a steady velocity state when a motor is started, a target velocity (reference velocity) is changed, or a large fluctuation in load occurs. When the steady velocity state does not prevail, the capacitor is isolated from the circuit and the resistor is connected into the circuit in its place.

Abstract: There is provided a motor control device comprising a motor; an apparatus for entering the number of revolutions of the motor; a detector that detects the number of revolutions of the motor; and a microcomputer for entering the output from the detector and a controlling the motor according to predetermined programs, wherein the microcomputer comprises a counter to which a count value is set according to a circuit from the input to form a reference frequency signal and a circuit for forming a phase error signal according to the reference frequency signal and the output of the detector and outputs a signal for driving the motor based on the phase error signal.

Abstract: A disk apparatus spindle motor control system has a control circuit including a frequency generator for generating a master clock signal of a predetermined frequency, a first frequency divider for frequency-dividing the master clock signal by 2.sup.1, 2.sup.2, . . . , 2.sup.N, a second frequency divider for frequency-dividing the signal frequency-divided by 2.sup.N to generate a master index signal upon each rotation of the spindle motor, a time interval detector for detecting a time interval between the master index signal and an index signal output from a magnetic disk unit and outputting a phase control signal and a select signal corresponding to the detected time interval, a data selector for selecting and outputting one of the signals frequency-divided by 2.sup.1, 2.sup.2, . . . , 2.sup.

Abstract: The actuator has a displacement detector and is driven intermittently through a given displacement. A mean amount of drive signals per one intermittent drive such as a mean duration of drive signals and a mean number of drive pulse signals is calculated through a predetermined number of intermittent drives. The mean amount of drive signals is intermittently applied to the actuator for a given number of intermittent drives without the displacement detection. After the given number of intermittent drives by the calculated mean amount, another intermittent drive with the displacement detection is carried out. At this time, the total duration of the drive pulse signals or number of the drive pulse signals outputted until the completion of the given displacement is compared with the calculated mean amount.

Abstract: A negative feedback control system includes a step of amplifying digital information by an amplifying operation at a high response speed and not including an integration. The negative feedback control system detects a predetermined amount of increase and decrease in the controlled variable, and outputs an increment signal or a decrement signal according to the predetermined amount of increase and decrease in the controlled variable, respectively, receives increment signals and the decrement signals from a controlled variable detecting unit 4, ignores the first successive n increment signals immediately after an arbitrary decrement signal, then begins to count each increment signal as a +1 unit from the n+1-th increment signal after the arbitrary decrement signal, and ignores the first successive n decrement signals immediately after an arbitrary increment signal, then begins to count each decrement signal as a -1 unit from the n+l-th decrement signal after the arbitrary increment signal (FIG.

Abstract: A rotary body drive device for controlling rotation of a motor on the basis of the phase difference between a periodic signal produced in accompaniment with rotation of the motor and a reference clock signal so that their phase relationship becomes a prescribed one. When the phase difference between both signals detected in a certain state is largely different from that detected in the preceding time, a correction is given to the phase difference of both signals detected in the aforesaid certain state, so that the rotation of said motor is controlled in accordance with the corrected phase difference.

Abstract: A system for driving a drum includes a pulse motor including an annular rotor fixedly mounted within the drum for rotation therewith and rotatable relative to a stator disposed within the rotor. The pitches of the rotor teeth and stator teeth are determined in such a manner that a magnetic flux linking each of the coils is changed in a sinusoidal fashion in synchronism with the rotation of the rotor. A pole position-detecting device produces a multi-phase sinusoidal pole position-detecting signal representative of the position of the magnetic poles relative to the rotor. A speed control device produces a current amplitude command signal representative of a desired torque of the rotor. A multiplier multiplies the pole-position detecting signal by the current amplitude command signal to produce a multiplication signal.

Abstract: In a control loop for automatically adjusting variable-gain amplification, a sinusoidal signal with a frequency f.sub.o that is critical for the control loop is superimposed over a positioning parameter W. Two synchronous rectifiers S1 and S2 filter out the oscillation components of a control parameter x and of a control difference x.sub.d that contain frequency f.sub.o, and the components are compared in a comparator VL. A control and regulating circuit C continues to vary the variable-gain amplification at controls RG until the amplitudes of the oscillation components being compared in the comparator are equal. The variable-gain amplification is correct at that point. The variable-gain amplification can even be adjusted in a compact-disk player while the player is in operation.

Abstract: An absolute shaft position sensing circuit uses a magnetic sensor and a toothed wheel to produce two pulse trains which are used to determine the absolute position of a shaft which is coupled to the toothed wheel. One pulse train includes regularly spaced pulses which are fed to a phase locked loop to produce an oscillating output signal. A counter counts this signal and produces an output count which is representative of the relative angular position of the shaft. A second pulse train includes an irregularly spaced pulse. Circuitry is provided to detect the occurrence of this irregularly spaced pulse and to reset the counter in response to that occurrence, thereby making the count representative of the absolute angular position of the shaft.

Abstract: There is disclosed herein a servo data decoder which can decode both quadrature and non quadrature servo data. The decoder is comprised of a servo data amplitude demodulator to generate position error signals and a position error signal processor to generate a GPES signal to serve as a position error signal during the track following mode and a velocity signal and a track crossing signal for use in the seek mode. The user system may have either single or double pulse sync, and double pulse sync spacing, pulse window time and sync to first data pulse delay are user definable. The user may adjust the gain of the system in two manners and may program the frequency response characteristics of the phase locked loop. Many other user definable or user alterable features are provided.

Abstract: A PLL motor controller in accordance with the present invention comprises a driving system for driving a motor, a reference frequency generator for generating pulses with reference frequency that corresponds to the speed of motor rotation to be set, a counter which is run freely at the reference frequency from the reference frequency generator, a pulse generator for generating sampling pulses with a timing that responds to the actual rotation speed of the motor based on the pickup signal from the driving system, a latch circuit for latching a digital information in the counter at the timing of sending the sampling pulses from the pulse generator, and a D/A converter for analog-converting the digital information in the counter that is latched and for supplying the result to the driving system. The driving system is constructed so as to drive the motor to be rotated with a set speed of rotation according to the error signal from the D/A converter.

Abstract: In a thermal cutting machine provided with an NC system of the type having a manual pulse generator allowing the operator to manually adjust the working head height from a workpiece a profile control apparatus is provided to maintain a reference distance between the head and a non-flat workpiece. The profile control apparatus is installed in the cutting machine, by adding only a head distance sensor and a Z-axis controller in parallel with the manual pulse generator via a selector switch. The Z-axis controller generates a pulse signal having a frequency proportional to a differential voltage between a reference head height determined by the NC system and an actual head height detected by the head distance sensor to correct the reference head height from the non-flat workpiece. The V-F conversion characteristics of the Z-axis controller are of Z-type, in particular, to reduce the profile error.

Abstract: Method and system for phase comparison which uses a ramp-form signal generated from a reference frequency signal and a sampling pulse train signal synchronized with an input signal whose phase change is to be detected. The reference frequency signal, through a dividing circuit is normally utilized for generating the ramp-form signal while a shift pulse signal is generated when a phase of the sampling pulse train signal is deviated outside a predetermined section of each ramp portion of the ramp-form signal, and utilized for generating the ramp-form signal. By this feature, sampling times of the ramp-form signal are always maintained within the predetermined section of each ramp portion of the ramp-form signal even if a frequency of the input signal deviates very widely from the frequency of the reference frequency signal.

Abstract: A noncontacting signal and energy transmission device includes a stationary microstation and a moveable microunit, wherein data is transmitted between the microstation and the microunit simultaneously by phase shifted signals and by synchronously switched signals, which also supply power to the microunit.

Abstract: An apparatus for compensating for a quantization error has a time detector circuit for detecting a time signal on the basis of the number of clock signals occurring within the period of such time signal, a quantization error detector circuit for generating a quantization error time signal corresponding to a time difference between the time signal and the clock signal and being in the form of an analog voltage value, and a compensator circuit for compensating a digital detected time derived from the time detector circuit on the basis of an analog quantization error time from the quantization error detector circuit.

Abstract: A position control system for positioning a D.C. motor at a desired position operates in a speed detection mode in which the D.C. motor is driven to rotate at a predetermined high speed, and in a position detection mode wherein the position of the D.C. motor is precisely controlled. In the speed detection mode, the control circuit forms a phase-locked-loop (PLL) control circuit which compares the phases of the speed instructing pulse signal and the rectangular signal derived from the actual rotation of the D.C. motor. The motor speed is controlled in accordance with the phase difference between the speed instructing pulse signal and the rectangular signal derived from the actual rotation of the D.C. motor.

Abstract: A digital servo apparatus according to the present invention latches a count output of a counter (11) for counting reference clock signals in response to output of a speed detecting pulse from a speed detecting pulse generator (10a) in a latch circuit (141), thereby to latch the count output latched in the latch circuit (141) in another latch circuit (142) upon output of a subsequent speed detecting pulse. The digital servo apparatus further latches the count output of the counter (11) in a latch circuit (16) in response to output of a phase detecting pulse from a phase detecting pulse generator (10b). A comparator (15) compares difference between the count outputs latched in the latch circuits (141) and (142), so that the compared output difference and the count output latched in the latch circuit (16) are converted into analog signals to be sampled and held respectively thereby to produce a speed error signal and a phase error signal, which are added up to be supplied to a driving circuit (22).

Abstract: A control apparatus whereby each time a motor adapted to start and stop its rotation repeatedly a plurality of times is rotated, the phase reference of a rotating object is adjusted and the rotating object is locked to a normal speed in a short period of time from the start. The control apparatus includes circuitry for detecting that the difference between the phase of a detection clock signal and the phase of rotation of the motor is less than predetermined value and the control of the motor is switched between the speed control and the phase control in accordance with the phase difference.

Abstract: A control system for an impact printer having a cooling fan, in which a current for driving a printing device is detected as a voltage and the detected voltage is compared with a reference value. When the detected voltage is lower than the reference value, the current for driving the cooling fan is decreased.

Abstract: A servo system for controlling the rotational speed of a rotating body or the moving speed of a moving body to be a desired speed. The system comprises a voltage source which generates at least two predetermined voltages, a comparator which compares a voltage of an AC signal containing a speed information of the moving body with each of the voltages generated by the voltage source and outputs at least two output signals in each half period of the AC signal, a counter for counting reference clock signals, a memory for storing a count value of the counter when the comparator outputs each of the output signals, a processor for producing a speed error signal from the count value stored in the memory, and a driver for supplying a driving power to the moving body in accordance with the speed error signal thereby to keep a desired speed of the moving body. Further, an error compensator may be provided for compensating a voltage shift of the predetermined voltages.