Hitachi, Ltd.

Hitachi Video Eng. Inc.

Hitachi Microcomputer Eng. Co.

Masataka Sekiya

Hideo Nishijima

Kaneyuki Okamoto

Isao Fukushima

Michio Masuda

Hitoaki Owashi

Hiroyasu Ohtsubo

Kohji Minabe

Shigemitsu Higuchi

Yasunori Kobori

Atsuo Suga

Morito Rokuda

Hisashi Ohta

Fumiaki Fujii

Kenji Kano

Jun Kobayashi

Tetsuo Sakae

Katsumi Sera

Hideyuki Usami

Eiichi Funaki

Takashi Furutani

Kiyoshi Hiramatsu

An auto-tracking system for a helical scan type magnetic recording/reproducing unit comprises a synchronizing signal separating circuit from video signals on a running magnetic tape reproduced by a rotary video head, a periodicity variation measuring and comparing circuit in the synchronizing signals separated in the synchronizing signal separating circuit, and a tracking control means which controls the running condition of the magnetic tape with reference to a phase difference between a reference signal in association with the rotary video head and a signal representing the running condition of the magnetic tape and changes tracking by a predetermined amount in response to the periodicity variation measured by the measuring and comparing circuit so as to minimize the periodicity variation measured by the same, thereby an optimum tracking position is obtained without being interfered by cross-talks between the adjacent tracks.

Auto-tracking system for magnetic recording/reproducing apparatus

This invention relates to a method and apparatus for processing a color video signal. The processing method separates an input composite color video signal into a luminance signal and chrominance signal, demodulates the separated chrominance signal into color difference signals, stores the separated luminance signal and color difference signals in a memory, reads out the luminance signal and color differnece signals in units of 1-field period from the memory, implements the extension or reduction of the field period length alternately for every certain number of fields in reading out the luminance signal and color difference signals from the memory thereby to fix the phase relation between a residual chrominance signal component in the luminance signal read out of the memory and a chrominance signal produced by modulating the color subcarrier with the color difference signals read out of the memory, implements an intended signal processing for the readout signals, modulates the color subcarrier with processed color difference signals to produce a chrominance signal, and mixes the chrominance signal with processed luminance signal to produce a composite color video signal.

Method and apparatus for processing a color video signal

A magnetic recording and reproducing apparatus having a construction in which a digital signal including index signals recorded on a magnetic tape is reproduced and rotary magnetic heads are movable. The digital signal is reproduced by digital signal reproducing means including the rotary magnetic heads. A particular index signal among the index signals is detected by index signal detecting means. Further, the timing for reproducing the particular index signal is detected by timing detecting means. The rotary magnetic heads are moved and deviated in the direction of the rotary shaft of the rotary cylinder by rotary magnetic head position deviating means. Tape speed detecting means compares a reproduction clock with a reference clock and outputs a tape speed signal. First rotary magnetic head position deviation control means forms a control input for the rotary magnetic head position deviating means on the basis of the tape speed signal. Second rotary magnetic head position deviation control means forms the control input for the rotary magnetic head position deviating means on the basis of an output signal of the timing detecting means.

Digital magnetic reproducing apparatus with variable tape speed

A digital noise reducer includes an addition circuit for adding a digital input video signal supplied at one input thereof and a signal supplied at the other input thereof and for outputting a resultant sum signal, a delay circuit for delaying the output signal of the addition circuit by an input unit period of the digital input video signal, a subtraction circuit supplied with the digital input video signal and an output signal of the delay circuit, the subtraction circuit forming and outputting a difference component signal for the digital input video signal and the output signal of the delay circuit, and a characteristic adjustment circuit for manipulating a signal characteristic of the difference component output of the subtraction circuit in accordance with the characteristic of the difference component signal outputted from the subtraction circuit and/or a characteristic of a digital output video signal outputted from the addition circuit and for outputting a resultant manipulated signal to the other input of the addition circuit.

Digital noise reducer

A memory controlling apparatus for a magnetic recording and reproducing apparatus which records and reproduces a field image signal in each read or write cycle performed by a video head for reproducing the image signal from a magnetic tape, and by a video head position detector for detecting the position of the video head. A reference circuit obtains a signal defining a reference timing which is independent of the position of the video head and which is also used to determine the phase of the video head. A memory is provided having storage sufficient to store the field image signal, and a controller is provided for controlling the operation of reading and writing the image signal from and into the memory. The controller is synchronized with a signal of the video head position detector when storing the image signal into the memory and when reading out the image stored in the memory, the controller and the head position detector are synchronized with the reference timing so as to enable production of a slow-motion image signal free from fluctuations caused by feeding of the magnetic tape.

A memory controlling apparatus for a magnetic recording and reproducing

In a slow-motion device of a helical scan type video tape recorder, detection is effected to detect a noise in a reproduced signal which is caused when the magnetic tape is fed such that the magnetic heads which have reproduced a preceding still image at a track transfer to the succeeding track and thereafter the magnetic heads scan the succeeding track, and the position of the magnetic tape is controlled by a tape control system so that the noise is confined within a position at a noise bar due to the noise is prevented from being displayed on the reproduction screen.

Slow-motion device of magnetic recording and reproducing apparatus

A still picture reproducing system for a magnetic recording and reproducing apparatus is disclosed. The system sends one frame in order to shift a reproduction mode from ordinary reproduction to reproduction of a still picture by use of so-called 'fine slow', sends one more frame if a noise is detected on a picture at this time, and stops if no noise is detected.

Still picture recording system with noise detection and frame counting

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.

Speed and phase control system

Growing community of inventors

Mito, Japan

Masataka Sekiya