Sony Corporation

Dmg Mori Seiki Co., Ltd.

Dmg Mori Company Limited

Mitsugu Yoshihiro

Masaaki Kusumi

Shigeru Ishimoto

Yusuke Takei

Masaaki Sakai

Kazuhisa Nishimura

Osamu Shimizu

Yasuo Iwasaki

Noboru Yanagita

Masahiro Miyamoto

Yasuo Nagai

Hirofumi Murakami

Mikio Kita

Kazuyuki Sugizaki

Takashi Sasao

Seiichi Hataoka

Kenichi Iwasaki

An automatic correction method, for an encoder system for reading periodic signals on a scale as 'SIN' and “COS” signals and converting the periodic signals into position signals, includes performing feedback to the “SIN” or “COS” signal to reduce an interpolation error after the conversion.

Automatic correction method

A magnetism detecting element detects a leakage magnetism from a scale, on which a magnetic signal with a constant period is recorded, and a relative position between the scale and the magnetism detecting element is detected. The magnetism detecting elements are arranged, along a detection direction of the magnetic signal relative to the scale, in a pattern with a pitch of &#xbd;n (n is a prime number of 3 or more) of a wavelength &#x3bb;' of a signal output by the element. Furthermore, as the pattern for cancelling m odd-order harmonics, the m-th power of 2 magnetism detecting elements are arranged within a range in which a pitch distance L of the magnetism detecting element farthest in the detection direction is expressed by L=(&#x3bb;&#x2032;/2)&#xd7;(&#x2153;+&#x2155;+ 1/7+ . . . 1/(2m+1)).

Position detecting device

A magnetism detecting element detects a leakage magnetism from a scale, on which a magnetic signal with a constant period is recorded, and a relative position between the scale and the magnetism detecting element is detected. The magnetism detecting elements are arranged, along a detection direction of the magnetic signal relative to the scale, in a pattern with a pitch of 1/2n (n is a prime number of 3 or more) of a wavelength &#x3bb;' of a signal output by the element. Furthermore, as the pattern for cancelling m odd-order harmonics, the m-th power of 2 magnetism detecting elements are arranged within a range in which a pitch distance L of the magnetism detecting element farthest in the detection direction is expressed by L=(&#x3bb;&#x2032;/2)&#xd7;(1/3+1/5+1/7+ . . . 1/(2m+1)).

The object of the present invention is to reduce the load and specification requirements on the network and the video server. The buffer usage rate is counted and supplied to the tape driving controller. In the reproduction mode, the tape driving controllerdecreases the running speed of a video tape when the buffer usage rate is larger than the proper value. And when the buffer usage rate is smaller than the proper value, the tape driving controllerincreases the running speed of the video tape. Moreover, in the recording mode, the tape driving controllerstops the tape motion temporarily if the transmission speed of the network is slow and the buffer usage rate declines lower than the proper value. And if the buffer usage rate increases over the proper value, the tape driving controllerresumes the tape driving to record signals. Thus, the reproduction speed or the recording speed by the tape driving devicecan be coincided with the transmission speed of the network.

Videotape recording and playback device, and videotape player

The present invention has as its object to reduce the time and and effort in the work of finding a portion necessary for editing work from a video signal recorded on a video tape. A VTR apparatus (12) reproduces a video signal and sampling data showing the start and end of the shot from a video tape (120). A VP circuit (22) reduces the size of the video signal. A detection circuit (24) detects the boundaries of scenes or important portions based on the reproduced sampling data. The sampling memory (30) samples and records the video signal reduced by the VP circuit (22) at a timing of detection of the boundaries of the scene or important portions by the detection apparatus (24). A display device (34) displays the video signal stored in the sampling memory (30) in a predetermined array along with a time code etc.

Video signal editing apparatus

A digital tape recording and reproducing apparatus includes a rotary drum, a magnetic tape helically wrapped around the rotary drum, a mechanism for advancing the magnetic tape relative to the rotary drum, and a recording/reproducing magnetic head mounted on the drum which scans the magnetic tape for recording or reproducing digital signals. The digital signals are recorded in, or reproduced from, successive inclined tracks formed on the tape as the tape is advanced. During recording of the signals, a timing signal is generated at a predetermined interval of time after detection of a reference signal that represents a phase of rotation of the drum, and then the timing signal is recorded in at least one of the inclined tracks, interspersed with the digital signals recorded in the track. During reproduction of signals from the tape, the drum phase reference signal is detected and the timing signal is reproduced and detected, and the time interval between detection of the two signals is measured. The mechanism for advancing the tape is controlled on the basis of the measured interval so that the magnetic head properly scans the recorded tracks.

Recording and reproducing apparatus with helical scan tracking

A magnetic recording and reproducing apparatus, e.g., a video tape recorder for recording and reproducing digital video signals etc., is intended to reliably perform a tracking control even when recording tracks are formed with high density. A first pilot signal having a large azimuth loss and a second pilot signal without azimuth loss are recorded in a recording track, and a rough tracking control operation and a fine tracking control operation are executed on the basis of the second pilot signal and the first pilot signal respectively.

Magnetic recording and/or reproducing apparatus

A drum servo circuit (310) is controlled by one (301) of a pair of microprocessors, and a reel servo circuit (220) and a capstan servo circuit (240) are controlled by the other microprocessor (201). Accordingly, the burden on each microprocessor is relatively light, and interrupt processing is performed with predetermined timing to improve servo performance. Further, tape movement can be controlled smoothly and quickly.

Servo control device for a VTR

In a tape loading apparatus having a loading ring with guides for withdrawing a magnetic tape from a tape cassette and wrapping it around a rotary drum, the rotating speed of the loading ring is controlled in accordance with the loading position, that is, the rotation angle of the loading ring, to protect the magnetic tape from being damaged during a loading operation, and a torque for resisting unwinding of the tape from a reel in the cassette during the loading operation is varied in accordance with the amount of tape wound thereon.

Tape loading apparatus

A time base corrector for correcting time base fluctuations in a video signal is effective to remove both low frequency time base fluctuations and repetitive high frequency time base fluctuations repeating at the field period of the video signal. The time base corrector includes a memory having a plurality of addresses for storing residual phase error data corresponding to iundividual horizontal lines of each field period. A control circuit supplies corresponding residual phase error data from the memory to be used in compensating a present phase error signal whereby the high frequency time base fluctuations may be removed, and further mixes the present phase error signal with corresponding residual phase error data to generate new residual phase error data for storage in the memory in place of the original residual phase error data.

Time base corrector

In a magnetic tape cassette recording and/or reproducing device having a tape loading apparatus for withdrawing tape from an operatively positioned cassette and wrapping the withdrawn tape about a guide drum having a rotary head for recording or reproducing signals on the tape; supply and take-up reel motors apply torques to resist unwinding of the tape from supply and take-up reels in the operatively positioned cassette, a servo-control maintains the supply reel in a stopped condition during a loading operation, the ratio of currents supplied to the supply and take-up reel motors, respectively, for achieving the stopped condition of the supply reel and for applying a constant torque to the take-up reel is determined and the radius of the tape wound on one of the reels is calculated from such ratio, whereupon, a value of the torque that has to be applied to that one reel for maintaining a predetermined tension in the tape during the loading operation is calculated in accordance with the calculated radius of the tape wound on that one reel.

In a helical-scan video tape recorder, when the color framing of a reproduced video signal when a magnetic tape is stopped and of a reference video signal when an activation command signal is sent to control means for controlling a capstan motor do not coincide, the activation state of a magnetic tape of the video tape recorder (VTR) is so controlled that the color framings of both video signals are quickly matched with each other.

Still picture reproduction system with color framing phase

A capstan servo system for a video tape recording and/or reproducing apparatus permits recording of a new video signal precisely commenced at a selected edit point. For this, the capstan servo system is provided a tape speed error dependent feedback control feature and a phase error dependent feedback control feature. Tape speed error dependent feedback control is carried out when the recording and/or reproducing apparatus operates in recording or assemble edit mode. Phase error dependent feedback control is carried out when the recording and/or reproducing apparatus operates in reproducing or playback mode.

Capstan servo system

An apparatus for controlling a deflectable head mounted on a bimorph leaf having a detector connected to the latter for detecting a deflection of the bimorph leaf, a drive signal generating circuit for generating a drive signal to deflect the bimorph leaf in response thereto, a combining circuit for combining output signals of the detector and the drive signal generating circuit, a damping signal generating circuit for generating a damping signal to attenuate a distortion of the bimorph leaf that is produced by the deflection of the bimorph leaf, a signal producing circuit for generating a signal corresponding to a variation of the detector that remains after application of the damping signal to the bimorph leaf, and a circuit connected between the signal producing circuit and the combining circuit for compensating and thereby reducing the signal corresponding to the remaining variation of the detector.

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Kanagawa, Japan

Mitsugu Yoshihiro