Abstract: A transistor circuit is used as a signal amplifier which has little possibility of oscillation in an IC. The transistor circuit includes a cascade connection of differential amplifiers. Each of the amplifiers comprises a differential pair of bipolar transistors and an enhancement-type MOSFET as a constant current source. The MOSFET of each amplifier is connected in the common source mode, and the drain is connected to the emitters of the differential pair of bipolar transistors. The sources of all the MOSFETs are connected to a common ground-line.

Abstract: Disclosed is a speed and phase control system for a moving apparatus driven by an electric motor, or the like, and provided with a speed control system for controlling the moving apparatus to an initially set speed, a phase control system for synchronizing the phase of the moving apparatus with a reference signal, and an error correction device storing therein a target value of and for comparing an actual speed or a phase of the moving apparatus with the target value to detect an error therebetween to thereby correct the initially set value in accordance with the error, whereby control is made such that the moving apparatus is operated at the target value of speed and phase thereof. Further, the error correction device is cut off from the speed control system when the speed reaches a value near the target value and at the same time the operation of the phase control system is started.

Abstract: A time constant circuit capable of switching the characteristic, which is realized by a combination of an equivalent resistor made up of a switched capacitor and an ordinary capacitor, comprises a capacitor of the switched capacitor or the time constant circuit connected in parallel to a series circuit including a switching device and an additional capacitor. The characteristic is switched by turning on and off the additional capacitor by the switching device. The direct connection of a plurality of equivalent resistors with a plurality of switched capacitors and ordinary capacitors makes up an equalizer. The capacitor making up a switched capacitor is connected with a switching device and an additional capacitor so that the frequency characteristic of the equalizer is switchable by turning on and off the switching device. Each of the capacitors making up the switched capacitors, the capacitors making up the time constant circuits and the additional capacitors has an end thereof grounded.

Abstract: A motor control apparatus for driving and controlling a motor, in which a signal frequency proportional to a rotation number of the motor is converted into a d.c. voltage by a frequency/voltage converter so as to drive and control the motor by the d.c. voltage.

Abstract: A power supply in which a single variable voltage supply device is used as a power source for a plurality of motors which are simultaneously or successively rotated, in which each motor is subjected to constant current driving by a current control device connected to the motor, and in which the variable voltage supply device is controlled so as to produce a voltage which is the sum of the highest one of the voltages required for driving the motors and necessary and minimum voltage with which all the current control devices are operable.

Abstract: A motor driving circuit in which the opposite ends of the motor driving coils of a video tape recorder (VTR) capstan motor are shorted by a group of switching elements when a control input voltage generated from a rotation detection/oscillator is in a predetermined range.

Abstract: A method for magnetic recording and reproducing suitable for the discontinuous recording, in which the magnetic tape is rewound during a predetermined length of time, the number of the synchronization pulses recorded on the magnetic tape is counted and stored during the rewinding of the magnetic tape, and the magnetic recording is re-started when the number of the synchronization pulses, counted during the winding of the magnetic tape after the pause period, reaches the value equal to the stored number of the synchronization pulses, whereby a satisfactory continuity is established between the pictures recorded before and after a pause period.

Abstract: A signal voltage dividing circuit in which two switched capacitors each including an input terminal, an output terminal and a capacitor connected selectively to the input terminal or the output terminal are connected in series and driven in opposite phase with each other. A holding capacitor is connected between the junction of the two switched capacitors and a reference potential. An input signal is supplied across the two switched capacitors to produce a divided output signal from the junction of the two switched capacitors.

Abstract: When operation mode is switched from recording to pause mode, a magnetic tape on which signals were recorded previously is slightly rewound backward by a predetermined length and is maintained in the pause mode operation state. When the pause condition is released, reproducing operation is performed to detect a phase difference between the reproduced control signal and a control signal of a video signal to be newly recorded. The tape speed is rapidly changed in accordance with the detected phase difference, so that the phase difference between the reproduced control signal and the control signal to be recorded is reduced to zero. Then, when a discontinuous scene recording is performed by switching from pause to recording operation mode, the phase coincidence has been achieved thereby enabling the phase-coincidence recording of video signals. Thus, upon reproducing, a clear picture with no disturbance can be presented even at the interconnection of signals for different scenes.

Abstract: When the number of revolutions of a motor, or a motor speed is reduced half, a gain of a frequency-voltage converter is doubled. By taking advantage of this fact, a gain of an error signal amplifier disposed at the poststage of the frequency-voltage converter is automatically changed to be half interlocking with a switching operation for switching the number of the motor revolutions to the half.

Abstract: Disclosed is a drive system for a motor, wherein a current proportional to a change of a load of a motor is sensed by a sensing resistor. A voltage produced across the sensing resistor controls an electronic switch in a manner that the output DC voltage of a DC - DC converter is used for a motor drive power source at a normal load and yet a DC power source with a higher voltage than the output DC voltage of the DC - DC converter is used therefor at an increased load.

Abstract: A diode limiter circuit comprising a low-pass filter for suppressing noise pulses superposed on a demodulated signal and for passing only the noise-suppressed demodulated signal, and a circuit means including limiter diodes whose conduction starting levels are varied according to the waveform of the demodulated signal by superposing the noise-suppressed demodulated signal having passed through the low-pass filter on voltage sources for determining the current conduction starting levels of the limiter diodes to attenuate in a shunting manner the noise pulses exceeding in amplitude of the current conduction starting levels of the limiter diodes.

Abstract: A first pulse train has repetition pulses in proportion to the frequency of an input signal. A second pulse train has repetition pulses obtained by shifting the timing phase of the pulses of the first pulse train. One of the pulse trains is used to drive a saw-tooth wave generator circuit, thereby producing a saw-tooth wave voltage, which is supplied to a sample-and-hold circuit, which in turn is driven by the other pulse train so that the saw-tooth wave voltage is sampled and held, thereby producing a DC voltage.

Abstract: A signal holding circuit is disclosed in which a parallel circuit of a constant current source circuit comprising a transistor having a constant voltage supplied to a base thereof and a hold capacitor is connected to an emitter follower transistor, a first control transistor is connected between a base of the emitter follower transistor and ground, a second control transistor is connected between the base of the transistor of the constant current source circuit and ground, and a control pulse corresponding in time to a duration of the pulsive noise is applied to the bases of the first and second control transistors to render the first and second control transistors conductive only during the application of the control pulse so that a charging time constant of the hold capacitor during the conduction of the emitter follower transistor is reduced and a discharging time constant of the hold capacitor during the cutoff of the emitter follower capacitor is increased.

Abstract: A limiter circuit comprises a low-pass filter which passes only a modulation signal out of the modulation signal having pulsive noises superimposed thereon and circuit means for supplying the modulation signal extracted by the filter to current source circuits for a limiter differential amplifier to control the current source circuit for the limiter differential amplifier in accordance with a waveform of the input modulation signal applied thereto.

Abstract: A limiter circuit comprises circuit means for variably controlling a current source for a differential amplifier in accordance with the magnitude of a modulating signal carried by a carrier or a percentage modulation.

Abstract: In a dynamic drive circuit for light-emitting diodes, at least one of the rise and fall times of the current flowing through the light-emitting diode is elongated to reduce the higher harmonic components contained in the current.

Abstract: A variable impedance circuit comprises a differential current circuit having a diode and a first transistor connected so as to operate differentially with respect to each other, and a current control circuit for controlling current flowing through the differential current circuit, whereby variation of the operative resistance of the differential current circuit causes variation of impedance thereof. The current control circuit comprises a second transistor having a collector connected with the differential connection of the differential current circuit, and an emitter grounded via a resistor, and a third transistor having a base applied with a control voltage and an emitter connected with the emitter of the second transistor. A fourth transistor is also provided having a collector connected to the base of the second transistor, a base connected to the collector of the third transistor and an emitter applied with source voltage independently from the current flowing through the differential current circuit.

Abstract: In an FM receiver having an amplifier for amplifying an FM signal of intermediate frequency applied to an input terminal, and a phase multiplier type FM demodulator for demodulating the FM signal of intermediate frequency amplified by the amplifier, a noise muting circuit is disposed between the demodulator and the amplifier for muting noise transmitted from the amplifier to the demodulator when no FM signal input appears at the input terminal. This noise muting circuit comprises a pair of diodes connected in inverse-parallel with each other.

Abstract: A phase-shifting multiplication type FM demodulation circuits comprises a gate circuit including a first and a second switching circuit adapted to be switched for an FM intermediate frequency signal, a resonance circuit and a phase-shifting element. The FM intermediate frequency signal is phase-shifted for about .pi./2 (or 90.degree.) and the phase-shifted signal (frequency) is fed to the second switching circuit of the gate circuit after the phase-conversion of the phase-shifted FM signal by means of a phase-shifter device. The demodulation circuit further includes a bias resistor for the second switching circuit which resistor serves also as a resonance resistor of the resonance circuit, a substraction circuit for detecting output signal from the gate circuit, an output resistor for determining magnitude of the output signal from the subtraction circuit, and a lowpass filter for eliminating higher harmonics from the output signal appearing across the output resistor thereby producing a demodulated output.