Sony Corporation

Mitsubishi Denki Kabushiki Kaisha

Takeo Ohba

Takeo Eguchi

Hirohisa Koga

Ryusuke Moriya

Hitoshi Sakamoto

Yoshiaki Wakisaka

Takashi Furumura

A control circuit for driving a step motor with at least first and second phase coils each having corresponding phase control elements. A memory stores phase switching data and is connected to the phase control elements. A first counter supplies phase switching data addresses to the memory to identify the coil or coils and phase thereof to be driven in response to step driving pulses and a second counter supplies data addresses to control the ON/OFF of the phase switching data and hence the phase current value. An oscillator drives the second counter at a frequency greater than the frequency of the step driving pulses.

Control circuit for driving step motor

Apparatus for simultaneously reproducing video signals having block synchronization signals and that have been recorded in successive, parallel channel tracks extending obliquely on a magnetic tape, with adjacent ones of the tracks having the video signals recorded therein with different azimuth angles, the apparatus including two magnetic heads movable in a direction along the channel tracks for reproducing the signals recorded therein; a phase detecting circuit for detecting a phase error between the block synchronization signals reproduced from adjacent ones of the tracks by the two magnetic heads; and a control circuit for controlling the relative positions between the tracks and the magnetic heads in response to the detected phase error so that the two magnetic heads accurately scan respective ones of the tracks.

Tracking control system for magnetic recording and reproducing system

A rotary magnetic head assembly for a helical scan video tape recorder comprises a tape guide arrangement including coaxial rotatable and fixed drum portions about which a video tape is helically guided, a pair of substantially parallel bi-morph leaves each secured, at one end, to the rotary drum portion and being both deflectable in the same direction in response to the application of a control signal thereto, and a deflectable member carrying a transducer head and being connected to the opposite free ends of said bi-morph leaves, such deflectable member having at least portions thereof which are elastically flexible and located between the free ends of the bi-morph leaves and the head to deflect in response to deflection of the bi-morph leaves for maintaining the head in proper contacting relation to the tape guided about the drum portions.

Rotary transducer head assembly

A deflectable transducer mounting assembly for mounting a transducer on a member, such as a rotatable member. A first deflectable element has one end thereof coupled to the member so as to be cantilevered outward therefrom, and a free end on which the transducer is mounted. The first deflectable element is deflectable in response to drive signals supplied thereto. A pair of second deflectable elements, which also are deflectable in response to drive signals supplied thereto, are disposed at the one end of the first deflectable element so as to sandwich that one end therebetween. The pair of second deflectable elements are adapted to be secured to the member. In a preferred embodiment, the first deflectable element is comprised of a pair of elements whose free ends are interconnected via a support element which is flexibly coupled to each of such free end; and the one end of each of these pair of elements is sandwiched between a respective pair of the aforementioned second deflectable elements.

Deflectable transducer mounting assembly

Apparatus for simultaneously reproducing information signals that have simultaneously been recorded in four successive, parallel channel tracks on a record medium, with a first pair of first and second ones of the four channel tracks being adjacent to each other and having the information signals recorded therein with different azimuth angles and with the information signals recorded in one of the first or second channel track being delayed relative to the information signals recorded in the other of the first and second channel tracks, and with a second pair of the remaining third and fourth ones of the four channel tracks being adjacent to each other and having the information signals recorded therein with different azimuth angles; said apparatus including four magnetic heads movable in a direction along the four channel tracks for reproducing the signals recorded therein; and a tracking control circuit for controlling the relative positions of the four magnetic heads and the record medium so that the four magnetic heads accurately scan respective ones of the four channel tracks in response to the phase difference between the signals recorded in the first pair of channel tracks or the phase difference between the signals recorded in the second pair of channel tracks.

Tracking control system for an information signal recording and

In an apparatus for reproducing video or other information signals recorded in a track on a magnetic tape or other record medium; a magnetic head or transducer is moved along the track for reproducing the information signals recorded therein while a bi-morph leaf which supports the head receives an electrical drive signal for deflecting the head in a direction transverse to that along the track. A deflection signal is generated in correspondence to the deflection of the head from a rest position by a circuit which includes a strain gauge fixed on the bi-morph leaf. A control circuit for controlling the deflection of the head includes an oscillator providing a dither oscillation signal which, on application to the bi-morph leaf, causes transverse oscillation of the head about a null position, an envelope detector detecting the envelope of the reproduced output of the head, a multiplier for synchronously demodulating the detected envelope by means of the deflection signal so as to obtain a tracking error signal accurately representative of the deviation of the null position of the head from the center of the track, and an adder adding the tracking error signal to the dither oscillation signal so as to provide therefrom the electrical drive signal and by which the null position of the oscillated head is aligned with the center of the track.

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Sagamihara, Japan

Takeo Ohba