Hitachi, Ltd.

Mitsuru Kudo

Yoshinori Okada

Mitsuhiko Watanabe

Hiroyuki Kimura

Isao Nakagawa

Tetsuo Sakae

Hajime Takasugi

Setsuo Arita

Tetsuo Ito

Yukiharu Ohga

Fumio Murata

Hideyuki Sato

Yuuzi Yamasawa

Yuichi Higashikawa

Masahiro Tanaka

Akihiro Yamamoto

Isao Fukushima

Takashi Kubota

Kuniaki Miura

Koichi Hirose

Kazuo Kondo

A recording/reproducing apparatus includes a recorder which records plural types of picture signals and picture information representing types of picture signals on recording tracks of a recording medium; a setting circuit which sets a type of picture signal to be reproduced from the plural types of picture signals; a search reproducer which scans transversely across the recording tracks and reproduces the picture signal and the picture information of the type set by the setting circuit from the recording tracks; a tracking controller which controls the search reproducer so that the picture information of the type set by the setting circuit can be normally detected during search reproduction; and a memory which stores the picture signal reproduced by the search reproducer during plural scans and forms a search reproduction picture based on the picture information reproduced by the search reproducer. The recording/reproducing apparatus may include a reader which reads the search reproduction picture from the memory. The search reproduction picture may changes intermittently during search reproduction.

Recording/reproducing apparatus including search reproducer controlled by tracking controller so that picture information of a selected type can be normally detected during search reproduction

A time lapse magnetic recording/reproduction apparatus for recording and reproducing picture signals while intermittently thinning them out in a frame unit is used for monitoring and burglar-proofing in plants, shops, banks, etc. Recording picture information is generated and added to one continuous picture signal obtained by sequentially switching the output of each video camera, and is then recorded. A speed multiple k for a normal tape travelling speed is optimally set by servo circuit on the basis of the recording picture information (the total number m of channels) detected from the reproduction picture signals reconstructed by double-azimuth four heads at the time of search reproduction, and a search reproduction picture throughout the full screen of a monitor television is obtained in full recording channels. At the same time, a write period into an image memory is controlled in accordance with the recording picture information (the total number m of detection channels) and a reproduction head signal level, and read controller then controls sequentially readout of the picture signals from image memory storing therein only specific channels.

Magnetic recording and reproducing system including search reproduction circuit for reproducing an entire screen of one picture channel selected from a plurality of picture channels intermittently recorded on a magnetic tape

In an apparatus for operating and monitoring a plant, a manipulating device provides the plant with manipulation signals for operating the plant. In response to information supplied from the plant and a manipulating signal of the manipulating device, a first display data producing device produces first display data needed for the operation of the plant changing every moment. On the basis of data supplied from the first display data producing device, a first display device displays information relating to the operation of the plant. In response to information supplied from the plant and a manipulating signal of the manipulating device, a second display data producing device produces data needed for monitoring the plant. On the basis of data supplied from the second display data producing device, a second display device displays information relating to the monitoring of the plant on a larger display screen than that of the first display device. Information displayed by the first display device and information displayed by the second display device complement each other and make it possible to accurately operate and monitor the plant.

Plant operating and monitoring apparatus

Magnetic recording and reproducing system

The present invention provides a magnetic recording and reproducing unit of a helical scan type having a slow speed tape running mode in which the speed of running a magnetic tape is slower than that of a standard running mode. The magnetic recording and reproducing unit of the present invention has a pair of azimuth heads of mutually different azimuthal angles which are mutually adjacently disposed on the outer periphery of a rotating cylinder and another pair of azimuth heads of mutually different azimuthal angles which are mutually adjacently disposed at positions symmetrical with the first pair of azimuth heads with respect to a rotating center of the rotating cylinder. Each pair of the two pairs of azimuth heads alternately traces tracks recorded with image signals on a magnetic tape to reproduce the recorded image signals. Further, the magnetic recording and reproducing unit of the present invention has a control head for reproducing from the magnetic tape a control signal which is synchronous with a header position of the recorded tracks, a traced azimuth predicting signal generating unit for generating a predetermined azimuth change over signal in response to the control signal, and a switching unit for selecting one of reproduced image signals from the pair of azimuth heads according to the change over signal in the slow speed running mode.

Magnetic recording and reproducing unit with selection of reproduced

An integrated filter circuit including at least integrated resistances and integrated capacitances, said integrated filter circuit comprising a plurality of filter circuits connected in parallel and in which at least either resistance values or capacitance values are different, a switch for switching said parallel filter circuits, and means for controlling said switch to select one of said parallel filter circuits.

Integrated filter circuit having switchable selected parallel filter

An output section of an electronic circuitry having differentially connected transistors is connected to the emitter of a first transistor having an inverted conductivity type relative to that of differentially connected transistors and to the collector of a second transistor in combination with the first transistor to constitute an inverted Darlington amplifier. The output current is derived from the emitter of the second transistor, so that the electronic circuitry can be operated under the application of a low supply voltage and suited for an integration circuit.

Electronic circuitry utilizing an inerted Darlington amplifier output

A time-constant circuit suitable for being fabricated into an integrated circuit comprising a resistive element with its one end connected to a first input terminal, an impedance converting circuit with its input connected to another end of said resistive element and its output connected to an output terminal, a variable gain differential amplifier with its one input connected to the output of said impedance converting circuit and its another input connected to a second input terminal, an adder circuit for adding an output from said amplifier and an input signal appearing on said second input terminal, and a capacitive element connected between the junction of said resistive element and said impedance converting circuit and the output of said adder circuit. A plurality of the time-constant circuits are combined to construct a filter circuit. The gain of the variable gain differential amplifier in each time-constant circuit is controlled by a common DC voltage, whereby the spread of characteristic values of the integrated circuit elements can be compensated.

Filter circuit suitable for being fabricated into integrated circuit

A chrominance signal reproducing apparatus is proposed, in which an oscillation frequency of a first voltage-controlled oscillator is controlled by each of the error control voltages produced from APC and AFC circuits and the signal having the frequency component of the 1/4 output frequency of the first VCO and the output frequency signal of a second VCO are added to produce a sum frequency, which is used to frequency-convert a low-frequency converted carrier chrominance signal to a carrier chrominance signal before low-frequency conversion. The AFC circuit operates only when the frequency F'.sub.sc of the carrier chrominance signal before the low-frequency conversion is deviated 1/8 f.sub.H (f.sub.H : horizontal synchronizing frequency) or above with respect to the carrier chrominance frequency f.sub.sc, so as to apply the control voltage to the first VCO thereby to drive the deviation within the range of .+-.1/8 f.sub.H. When the f'.sub.sc is in the range of f.sub.sc -1/8f.sub.H &lt;f'.sub.sc &lt;f.sub.sc +1/8f.sub.H, the APC circuit controls the first VCO so that f'.sub.sc = f.sub.sc.

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Katsuta, Japan

Mitsuru Kudo