Trio Kabushiki Kaisha

Hitachi, Ltd.

Tsuneo Yamada

Yukihiko Miyamoto

Takeshi Wada

Masanori Ienaka

Yasuo Kominami

A satellite receiver which can selectively inhibit the reception of radio wave of the improper program. This receiver comprises: a receiver unit; a reproducer unit to reproduce the signal received by the receiver unit; a control unit including (a) a first memory to store the designated transponder number, (b) a second memory to store the transponder number which is parental locked, and (c) a generator to generate a parental lock signal when the memory contents of the first and second memories coincide; and means for disabling the signal from the designated transponder to be reproduced by the reproducer unit in response to the parental lock signal. With this receiver, the radio wave from the designated transponder cannot be received.

Satellite receiver

A satellite receiver which selects one of radio waves from a plurality of satellites and receives the selected radio wave. This receiver comprises; a satellite number designation switch; an antenna controller for allowing a parabola antenna to face the designated satellite in accordance with the designation by the designation switch; a memory to store the data corresponding to a correction amount of the position of a probe for each satellite; a drive motor to drive the probe to the position corresponding to the data outputted from the memory; and a control circuit to allow the data for the satellite designated by the designation switch to be supplied from the memory to the drive motor. The probe position is corrected in accordance with the designated satellite.

A monostable multivibrator circuit is disclosed. It is characterized by comprising a time constant circuit which includes a capacitor, an amplifier circuit which receives an output signal of the time constant circuit and in which a signal amplifying transistor operates in the non-saturated state, a positive feedback circuit which is connected between the output end of the amplifier circuit and the input end of the time constant circuit and in which a signal amplifying transistor operates in the non-saturated state, and a trigger terminal which is disposed in a circuit loop constructed of the time constant circuit, the amplifier circuit and the positive feedback circuit. Further, it is characterized in that a signal which is produced by the shift from the non-conductive state to the conductive state of the signal amplifying transistor connected to an output terminal of the positive feedback circuit is supplied to the time constant circuit as a positive feedback signal.

Monostable multivibrator circuit and FM detector circuit employing

A monostable multivibrator circuit including a time constant circuit which includes a capacitor, an amplifier circuit which receives an output signal of the time constant circuit, and a positive feedback circuit which is connected between an output end of the amplifier circuit and an input end of the time constant circuit, characterized in that a trigger circuit is incorporated in a part of a circuit loop which is constructed of the time constant circuit, the amplifier circuit and the positive feedback circuit, the trigger circuit comprising an emitter-follower transistor which receives a feedback signal, another emitter-follower transistor which receives a trigger signal and whose emitter is connected to an emitter of the first-mentioned emitter-follower transistor in common, and a constant-current circuit which supplies a constant current to the emitters connected in common. Thus, the monostable multivibrator circuit can provide a predetermined pulse signal without any interference attributable to a trigger input circuit.

Monostable multivibrator and FM detector circuit employing differential

This invention discloses a monostable multivibrator which is useful for an FM detector circuit of a pulse count system. The monostable multivibrator has a time constant circuit which includes a capacitor, an amplifier circuit which receives an output of the time constant circuit, a positive feedback circuit which is connected between an output end of the amplifier circuit and an input end of the time constant circuit, and a trigger terminal which is disposed in a circuit loop constructed of the time constant circuit, the amplifier circuit and the positive feedback circuit; and is characterized in that the amplifier circuit is a differential amplifier which is made up of a pair of transistors connected in the differential form, the transistors being connected in common through emitter resistances connected in series with respective emitters thereof. Thus, the monostable multivibrator can provide pulse signals of a fixed pulse width without being influenced by noise.

Monostable multivibrator and FM detector circuit employing common

This invention relates to a monostable multivibrator which is operated in the non-saturated state. The monostable multivibrator circuit includes a time constant circuit which has a capacitor, an amplifier circuit which receives an output signal of the time constant circuit, a positive feedback circuit which is connected between an output end of the amplifier circuit and an input end of the time constant circuit, and a trigger terminal which is disposed in a circuit loop constructed of the time constant circuit, the amplifier circuit and the positive feedback circuit; and it is characterized in that the positive feedback circuit comprises a signal amplifying transistor which has a base receiving an output of the amplifier circuit and a collector supplying a signal to the time constant circuit, and a level clamp circuit which is coupled to the collector of the transistor in order to hold a collector output potential of the transistor higher than a base input potential thereof.

Monostable multivibrator circuit with clamped non-saturating common

A trigger pulse forming circuit for converting a pulse signal into a trigger signal waveform is disclosed. It is characterized in that a time constant circuit is comprised in a collector output circuit of one of a pair of transistors for differential amplification and that a clamp circuit which employs a diode of the base-emitter path of a transistor is inserted between collector output circuits of the transistors for differential amplification. The input pulse signal to be subjected to the waveform conversion is impressed across the bases of the transistors for differential amplification, and the trigger pulse output signal is derived from the collector of the other of the transistors for differential amplification.

Pulse forming circuit

In a monostable multivibrator including a gate circuit having first and second inputs, a differentiating circuit responsive to the output of the gate circuit and a voltage comparison circuit responsive to the output of the differentiating circuit where the gate circuit is adapted to have a trigger pulse applied to the first input thereof and the output of the voltage comparison circuit fed back to the second input thereof, the improvement in the monostable multivibrator of means for setting the reference level of the trigger pulse at the first input lower than the reference level of the output of the voltage comparison circuit fed back to the second input of the gate circuit.

Monostable multivibrator

A first intermediate frequency amplifier stage which executes the amplitude limiting operation of a double-converting FM tuner employing the integrated circuit technology is constructed in the form of an integrated circuit. An output signal of the first intermediate frequency amplifier stage is put into a square pulse waveform on the basis of the amplitude limiting operation, and therefore has higher harmonic components of high frequencies. When the higher harmonic components are injected into a second mixer circuit in a second frequency converter circuit, various higher harmonic components which have frequencies higher than a second intermediate frequency appear at the output of the second mixer conduit. When the higher harmonic components at the output of the second mixer circuit are injected into an FM demodulator circuit, beat trouble is induced. The second frequency converter circuit is also constructed in the form of an integrated circuit, and filter means to pass the fundamental waves of a first intermediate frequency signal and to reject the higher harmonic frequency components thereof is connected between the output of the first intermediate frequency amlifier stage executing the amplitude limiting operation and the input of the second mixer circuit, whereby the beat trouble can be prevented.

Double-converting FM tuner

A trigger pulse forming circuit comprising a first power supply; a second power supply whose voltage is less than that of the first power supply, a differential amplifier including a first transistor whose operating voltage is supplied from the first power supply and a second transistor whose operating voltage is supplied from a second power supply, at least the first transistor being adapted for application thereto of an input pulse signal; a load resistor connected to an output terminal of the first transistor; an integrating circuit connected to an output terminal of the second transistor; and a third transistor whose base and collector are connected respectively to opposite ends of the integrating circuit and its emitter is connected to the output terminal of the first transistor whereby the trigger pulse output is obtained from the output terminal of the first transistor. A diode may preferably also be included, the anode of the diode being connected to the output terminal of the second transistor and the cathode thereof being connected to the second power supply whereby the probability of the trigger pulse output saturating the transistors of the next stage is substantially lessened.

Trigger pulse forming circuit

A pulse shaping circuit comprising a difference amplifier having an input terminal for receiving an input pulse to be shaped and first and second output terminals, an integration circuit connected to the second output terminal, and an AND circuit connected to the first output terminal and the integration circuit for developing an output pulse corresponding to the shaped input pulse.

Pulse shaping circuit

A tuning meter circuit for use with a pulse count FM demodulator of an FM receiver. The circuitry comprises a limiter circuit for amplitude limiting a frequency modulated input signal to produce a train of pulses the width of which varies in accordance with the frequency modulation of the input signal; a pulse shaping circuit for generating a trigger pulse for each of the pulses of the pulse train; a monostable multivibrator responsive to each trigger pulse for generating a train of pulses of substantially constant width, the number of which per unit time interval varies in accordance with the frequency modulation of the input signal; a low pass filter responsive to the last mentioned pulse train to produce a low frequency signal and thereby demodulate the frequency modulated signal; a difference amplifier also responsive to the last-mentioned pulse train, the difference amplifier having a threshold level at which it changes state; a tuning meter responsive to the direct current component of the output of the difference amplifier; the duty cycle of the monostable multivibrator and the threshold level of the difference amplifier being so related that the tuning indicator indicates the FM receiver is tuned correctly when a signal of exact intermediate frequency is applied to the limiter circuit; and where the monostable multivibrator includes means for varying the duty cycle thereof to compensate for undesired variations in the FM demodulator.

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Tokyo, Japan

Tsuneo Yamada