Sony Corporation

Tokyo Shibaura Denki Kabushiki Kaisha

Susumu Hoshimi

Tadashi Kojima

Toshio Sato

Masashi Takeda

Takayasu Muto

Yoshihisa Mori

Kenzo Nakagawa

Hiroyuki Suzukawa

Shiro Yasuda

Keisuke Ikegami

Shingo Tamura

Ichiroh Saitoh

A disc drive apparatus with a tracking servomechanism, comprising at least one disc medium having data surfaces where servo signal and data signal are recorded; transducer means having a first head for reproducing the data signal from the data tracks in a playback mode, and a second head for recording the data signal on the data tracks in a recording mode; a rotary arm for supporting the transducer means at one end thereof; actuator motor means for driving the rotary arm in a manner to move the transducer means over the data tracks; servo signal processing means for receiving and processing the servo signal reproduced by the transducer means and outputting first and second servo control signals; and positioning control means for controlling the actuator motor means in the playback and recording modes respectively in accordance with the first and second servo control signals so that the first head of the transudcer means is positioned precisely on any selected one of the data tracks in the playback mode and also that the second head is positioned precisely on any selected one of the data tracks in the recording mode.

Disc drive apparatus with servo tracks offset from data tracks

A magnetic recording disk in which the level of the surface of the data tracks and servo tracks is higher than that of the guardbands.

Magnetic recording disk in which the level of the surface of the data

A magnetic disc apparatus wherein off-track quantities are stored with regard to reference servo tracks formed circularly in divided data areas on a magnetic disc and, at the time of displacing the magnetic head, the head is shifted an extent of the stored off-track quantity after being once positioned by a head position detector. Gradients of the off-track quantities corresponding to tracks at individual temperatures in the apparatus are previously stored and, after the actual temperature is detected by means of a temperature sensor, the off-track quantity relative to the reference servo track is corrected in accordance with the gradient of the off-track quantity to the relevant track at the detected temperature, whereby just tracking is achieved. The magnetic head can be positioned exactly with respect to a desired data track while the head displacement time is shortened. Furthermore, data can be written in the entire length of each circular data track to enhance the efficiency of utilizing the magnetic disc, and high-precision tracking is attainable with the off-track quantity reduced to zero in any data track.

Hard disk drive employing a reference track to compensate for tracking

A PCM signal processing apparatus adapted to receive successive transmission blocks, each of which comprise time-interleaved PCM data, error correction and error detection words, and which comprises a detecting circuit responsive to error detecting words for detecting if a received transmission block contains an error, error identifying means for identifying as erroneous each of the time-interleaved words included in the received transmission block which has been detected as containing an error, de-interleaving means for time-deinterleaving each received transmission block to recover a de-interleaved block which comprises de-interleaved PCM and error-correction words. An error compensating device is responsive to the identification by the error identifying device for compensating at least the erroneous PCM word in the de-interleaved block with a substitute PCM word when the error syndrome indicates the presence of an erroneous PCM word and the error correction device cannot detect the error or the location of the erroneous word is unknown. An inhibit device for inhibiting the error compensating device during the state when the location of the erroneous word is unknown follows a predetermined number of blocks, and slew rate control device or filter device is coupled to the de-interleaving device for passing the de-interleaved PCM word at a predetermined slew rate, and switching device is responsive to the output of the inhibit device and for selecting the slew rate of the control device or the filter device.

PCM Signal processing apparatus

A PCM signal processing apparatus adapted to receive successive transmission blocks, each of which comprise time-interleaved PCM data, error correction and error detection words. The apparatus has detecting means responsive to the error detection words for detecting errors in a received transmission block and error identifying means for identifying errors in each of the time-interleaved words included in the received transmission block which has been detected. A de-interleaver is provided for time-deinterleaving each received transmission block to recover a de-interleaved block comprising de-interleaved PCM and error-correction words, with errors in the de-interleaved words being respectively identified. A syndrome generating device is coupled to the de-interleaver for generating error syndromes using the de-interleaved PCM and error-correction words in the de-interleaved block. An error correcting device responsive to the error syndromes corrects erroneous PCM words in the de-interleaved block as a function of the remaining error free PCM and the error-correction words in the de-interleaved block. An error compensating device is responsive to the identification of errors by the error identifying device and compensates the erroneous PCM words in the de-interleaved block with a substitute PCM word when error correction by said error correcting device is impossible. An inhibit device inhibits the error correcting device when all of the error detection words in the de-interleaved block are identified as erroneous and it discontinues inhibiting when the relationship between the identification by the error identifying device and the error syndrome indicates that no error exists.

A PCM signal processor having a signal input terminal which receives a PCM data signal, a memory for storing the PCM data signal, a standardized signal input terminal for providing a standardized signal corresponding to a synchronizing signal for synchronizing the PCM data signal reproducing apparatus, an address counter for designating the address of the memory which is to be read and means for providing said address counter with preset data in response to the standardized signal.

PCM Signal processing circuit

A digital signal processing system in which the actual signal data obtained through digitalization of the information signal and control data of the digital control signals are used for the control of the actual signal data and are transmitted together with a sync signal between two circuits wherein the control data are provided to at least part of an actual signal data transmission line for transmitting the various data and the control data are transmitted during the period of absence of an actual signal data on the transmission line or during the period of the sync signal.

Digital signal processing system

A PCM (pulse code modulation) signal recording system including a first signal processor for processing a recording signal into a predetermined PCM signal, a second signal processor for processing a reproduced PCM signal into a recording signal, a first clock signal generator generating a master clock signal, a second clock signal generator generating at least one recording clock signal from the master clock signal, the recording clock signal is supplied to the first signal processor, a third clock signal generator generating at least one reproducing clock signal from the master clock signal, the reproducing clock signal is supplied to the second signal processor, a comparator digitally comparing the phases of the second and third clock signals and producing a control signal, and a controller receiving the control signal and controlling the second or third clock signal so that they are synchronized.

PCM Signal recording system

A single pickup head generates an alternating signal proportional to the rotational speed of a DC motor which can be rotated in either of two directions, and such alternating signal is employed by speed and/or phase control circuits to control the motor speed relative to a reference speed in a selected one of the two directions. An overspeed sensing circuit detects speed runaway, which can occur when the motor is rapidly rotated in the direction opposite to the selected direction, and the overspeed sensing circuit then interrupts the motor drive voltage until the motor speed decreases to below its normal speed. At and below normal speed in the undesired direction, the normal torque acts in the selected direction to rapidly reverse the direction and to accelerate the motor to normal speed in the selected direction.

Apparatus for controlling the speed and direction of rotation of a DC

In a brushless DC motor, the rotor has a rotor shaft with a rotor yoke attached thereto and an annular rotor magnet mounted on the rotor yoke, the stator has a stator yoke with stator coils disposed on the stator yoke so as to face the rotor magnet, and two magnetic field sensing elements, such as, Hall elements, are provided for detecting the rotational position of the rotor. A printed wiring board and the stator coils are arranged on the same surface of the stator yoke so as to make the motor flat. The printed wiring board also serves as a thrust pad for the rotor shaft and provides a ground for the latter.

Brushless DC motor

A gramophone record player comprises a movable body to be placed on a stationary gramophone or phonograph record, a drive in the movable body to drive the movable body on the record, a sound pick-up arranged to be energized by the sound groove of the record and mechanically connected to the movable body, and a gramophone record sound groove following guidance member coupled to the movable body in such a manner that the pick-up traces along the sound groove of the record.

Record player

A drive circuit for a brushless motor of the type having a rotor magnet and energizable stator windings. The drive circuit includes position sensors for sensing the rotary position of the rotor magnet and for generating varying position signals corresponding to the sensed rotary position. A plurality of amplifier stages is coupled to the position sensors, the amplifier stages being responsive to the position signals to produce drive currents which are supplied to the stator windings. In one embodiment, each amplifier stage includes a voltage amplifier having a linear gain characteristic for amplifying the position signal applied thereto, a current amplifier connected in cascade with the voltage amplifier and responsive to the amplified position signal to produce a drive current, and a feedback circuit interconnected between the output of the current amplifier and the input to the voltage amplifier, the feedback circuit including a resistor and a capacitor connected in parallel and operative as a low pass filter circuit to prevent harmonics of the drive current frequency from being transmitted to the stator winding, thereby preventing notching in the drive current. In another embodiment, the drive circuit also includes a speed sensor for sensing the speed of the motor and for generating a signal whose frequency varies in accordance with the motor speed, a converter coupled to the speed sensor for converting the frequency of the generated signal to a voltage, a circuit for applying the converted voltage to the position sensors so as to modify the position signals in accordance with the sensed motor speed, and a circuit for supplying an offset voltage to the last-mentioned circuit such that if the speed of the motor exceeds a predetermined amount, the offset voltage exceeds the converted voltage whereby the resultant voltage which is applied to the position sensors causes a modification in the drive currents supplied to the stator windings, to produce an opposite torque in the motor. In this embodiment, excess motor speeds are rapidly corrected.

Drive circuit for a brushless motor

A cylindrical core with toroidal windings at angularly spaced locations on the core, for example, as in the stator of a brushless, slotless DC motor for a record player or tape recorder, is formed of a plurality of annular core elements each having an axial slot and initially being axially superposed with the respective slots in axial alignment. The windings are conveniently formed individually on respective bobbins which are dimensioned to pass through the axially aligned slots for installation on the superposed core elements, whereupon, the latter are preferably turned relative to each other for angularly offsetting the respective slots and thereby minimizing the turbulence of magnetic flux that can result therefrom.

Cylindrical core with toroidal windings at angularly spaced locations on

In a phonograph record player having a normal automatic operating cycle consisting of a lead-in operation initiated by actuation of a trigger for moving a tone arm from an elevated rest position outside the perimeter of the turntable to a set-down position on a phonograph record supported by the turntable, a play operation in which a pickup stylus carried by the tone arm engages the record at the set-down position and thereafter tracks the record groove for reproducing the sound recorded therein, and a return operation also initiated by operation of the trigger upon completion of the play operation for returning the tone arm to its rest position; a stop command signal for aborting the above automatic operating cycle and/or a repeat command signal for causing repetition of the automatic operating cycle is temporarily retained in a respective memory which provides a corresponding memory output, the completion of the lead-in operation and/or of the return operation is detected by a respective sensor to provide a corresponding sensor output, and, upon coincidence of the sensor output corresponding to completion of the lead-in operation or the return operation with the memory output corresponding to a retained or stored stop command signal or repeat command signal, respectively, an AND circuit provides an output for operating the trigger. Thus, the stop or repeat command signal can be generated, as by manual actuation of a respective switch, at any time during the automatic operating cycle and takes effect at an appropriate point in such cycle.

Phonograph record player

An electric braking circuit for a.c. motors is disclosed. When the a.c. power is cut off from the motor windings, at the same time a switch is thrown to connect the a.c. source of power to the same windings via a rectifier and a smoothing circuit, to thereby bring the motor to an immediate smooth stop.

Growing community of inventors

Yokohama, Japan

Susumu Hoshimi