Trio Kabushiki Kaisha

Hitachi, Ltd.

Kabushikikaisha Kenwood

Nippon Hoso' Kyokai

Matsushita Electric Industrial Co., Ltd.

Yukihiko Miyamoto

Tsuneo Yamada

Takeshi Wada

Hirokazu Kobayashi

Masanori Ienaka

Yasuo Kominami

Hiroshi Miyazawa

Masaoki Takai

Syuichi Fujisawa

Syoichi Suzuki

Kenichi Shiraishi

Tatsumi Sumi

Atsushi Ogawa

Shiro Mizutani

Yoshinori Morimoto

Masaru Onishi

A transponder is selectively mounted on a vehicle. The transponder receives its operation energy through magnetic coupling with the loop coil when the vehicle comes over the loop coil, and transmits predetermined information specific to the vehicle to the vehicle detection circuit. The vehicle detection circuit time divisional performs a supply of the operation energy to the transponder and a reception of the information from the transponder, detects a presence of a vehicle in accordance with a change in the output from the loop coil, and judges from the information received from the transponder whether the detected vehicle is a predetermined vehicle.

Vehicle detection system

A time division multiplex transmission system includes: a time division multiplex encoder for supplying a master clock to a plurality of PCM digital signal sources having a same sampling requency and a same quantization bit number to effect clock synchronization and generating a time-divisionally multiplexed data signal based on a data word not D/A converted and sampled from each digital signal source; a transmission line for transmitting the multiplexed data signal from the time division multiplex encoder; and a time division demultiplex decoder for selecting a desired transmitted, multiplexed data signal and demultiplexing the selected data signal in accordance with a transmission rate before the time division multiplexing.

TDM transmission system

An addressable PCM music broadcast receiver which decodes a contraction identification code such as an address code allocated to the receiver and transmitted by a broadcasting station which performs a pay PCM music broadcast. The receiver is capable of receiving a contracted broadcast or channel on the basis of the decoded result. The receiver further has a demonstration function of receiving a non-contracted broadcast or channel for only a given time.

Addressable PCM music broadcast receiver

A time division multiplex transmission system includes: a time division multiplex encoder for supplying a master clock to a plurality of PCM digital signal sources having a same sampling frequency and a same quantization bit number to effect clock synchronization and generating a time-divisionally multiplexed data signal based on a data word not D/A converted and sampled from each digital signal source; a transmission line for transmitting the multiplexed data signal from the time division multiplex encoder; and a time division demultiplex decoder for selecting a desired transmitted, multiplexed data signal and demultiplexing the selected data signal in accordance with a transmission rate before the time division multiplexing.

A time division multiplex transmission system for time division multiplexing a plurality of information signals having different sampling frequencies and transmitting the time division multiplexed signal by one transmission path. The system includes the steps of: rearranging the plurality of information signals so as to have a format of the time division multiplexed signal by use of a reference sample signal which has a frequency obtained by multiplexing the maximum frequency or a frequency higher than the maximum frequency among the sampling frequencies of the plurality of information signals by the number of the plurality of information signals; and interposting a dummy signal into the portion where there is no available information signal.

Method and apparatus for multiplexing of input signals having differing

A frequency synthesizer includes a 1/N divider for generating an address clock signal the frequency of which is 1/N times the frequency of an input signal, a memory for storing samples in a unit sine and cosine wave which is read out in response to the address clock signal to produce a frequency deviation signal, and a quadrant modulator responsive to both of the input signal and frequency deviation signal for producing an output signal the frequency of which is the difference between the input signal and frequency deviation signal. The frequency of the frequency deviation signal is varied by digitally changing N to modify the frequency of the output signal while maintaining the continuousness of the output signal phase.

Frequency synthesizer suited for use in a time division multiplexing

A time division multiplexed signal demultiplexing system for regenerating original signals from a time division multiplexed signal which is obtained by time-division multiplexing information signals of N channels with mutually different sampling or clock frequencies by means of a reference clock signal of a frequency equal to N times of the highest one of the sampling or clock frequencies or an even higher frequency and inserting a dummy signal and a dummy flag bit in pairs in the portion where the information signal is lacking.

Time division multiplexing system for N channels in a frame unit base

A quadrature detector comprising a double balanced differential circuit including a constant current circuit, and a phase shifter circuit. The constant current circuit comprises a plurality of transistors having their collectors connected together, their bases connected together and their emitters connected to a reference potential level through respective resistors. By the arrangement of the constant current circuit, a current density in the transistors is reduced, a noise generated by the constant current circuit is reduced and hence the S/N ratio of the quadrature detector is improved.

Quadrature detector using a double balanced differential circuit and a

An AM stereo receiver for receiving AM stereo broadcasting of an AM-PM or AM-FM system. Between an IF AM signal amplifier and an limiter is interposed a 5 or more frequency multiplier so that the frequency of a spurious signal radiated from the limiter may lie outside of the frequency range handled by the RF tuner.

AM Stereo receiver

An FM/AM stereo receiver for receiving an RF FM stereo signal by FM stereo broadcasting and an RF AM stereo signal of AM-PM or AM-FM system by AM stereo broadcasting. One limiter is used both as a limiter for limiting an IF FM stereo signal in an FM stereo receiving system and as a limiter for obtaining an IF PM or FM difference signal in an AM stereo receiving system. One FM demodulator is employed both as an FM demodulator for obtaining a composite signal in the FM stereo receiving system and as an IF demodulator for obtaining an IF PM difference signal or a difference signal in the AM stereo receiving system.

FM/AM Stereo receiver

In a pulse counter-type FM detector circuit for obtaining audio signals at an output terminal by detecting FM signals in the following order through a limiter circuit, a trigger pulse generating circuit, a monostable circuit and an integrator connected to the output terminal where the monostable circuit comprises a gate circuit having at least two inputs where trigger pulses from the trigger pulse generating circuit are applied to a first one of the two inputs and a feedback signal to the other input, a differentiating circuit responsive to the output from the gate circuit, a differential inverter having a power supply and where the integrator includes an LC type low pass filter connected to the output side of the differential inverter circuit, the improvement comprising a terminal resistor connected between the power supply and the output terminal so that a part of the current flowing in the differential inverter circuit is diverted through the terminal resistor.

Pulse counter-type FM detector

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.

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Tokyo, Japan

Yukihiko Miyamoto