Abstract: An apparatus for reproducing signals which are recorded on a tape to form oblique tracks thereon. The apparatus includes a drum which has a plurality of rotary heads adjoining each other for scanning respective oblique tracks simultaneously to produce reproduced signals. The tape is wrapped around the drum and overlaps a first lead angle so that each of the rotary heads scans a plurality of the oblique tracks during one rotation in a still mode in which the tape is not transported. A control unit is also provided for controlling a rotational speed of the rotary heads and a transport speed of the tape; and a processes unit for processing the reproduced signals.

Abstract: A cost-effective videophone includes a programmable video/general-purpose processor capable of readily updating program-related data. The processor includes a first circuit section used to process data for videoconferencing and to detect codes data used for revising software-related data provided from a remote location, and a second circuit section used for executing the executable program data stored in the second memory circuit. A volatile memory circuit is coupled to and accessed by the programmable video/general-purpose processor, and is used for storing the revision data until it is validated. Once validated, the revision data is transferred from the first memory circuit to a non-volatile memory circuit. The non-volatile memory circuit is then used by the processor in a subsequent video-related application, such as a videoconferencing application or a web browser application.

Abstract: The present invention comprises a telephone system and method for self-announcing a caller of an incoming telephone call. After an incoming telephone call is received from a caller, the telephone answers the incoming telephone call before any ring signals are generated. A message is then generated requesting the caller to self-announce him/herself. A speaker on the telephone is activated to enable the telephone users to listen to the announcement. After the caller self-announces him/herself, a user, if present, may decide to answer the incoming telephone call. The user may answer the incoming telephone call either by placing the telephone in speakerphone mode or by activating the handset and engaging in a conversation with the caller. If the user is not present or chooses not answer the incoming telephone call, the telephone transfers control to an answering machine unit so that the caller is given the choice of leaving a message. In one embodiment, the answering machine is built-in to the telephone.

Abstract: An enhancement of the precision of the positioning of the head in a magnetic recording device having a magnetoresistive head is provided. The burst pattern stored in a storage medium is read by the head, and the two triangular waves are demodulated in the demodulation portion through the read/write portion. The actual head position signal generated in the head position signal generation portion is compared in the comparison portion with the target position generated in the target position generation portion. The deviation .DELTA.P as the output is controlled and calculated in the proportional and integral control portion, and the resultant output is compensated with regard to the reading gain difference of the head in the gain difference compensation portion. An arc-sine function transformation is carried out in the linearity compensation portion to compensate for the linearity. The position of the head is adjusted by the voice coil motor based on the signal after the compensation.

Abstract: A disk drive having an improved method of adjusting the head switch time to improve disk drive performance. In the process of writing or reading long data files, the heads on the actuator are sequentially selected in order to access all the data tracks forming a cylinder in the shortest time. Head offsets are significantly smaller for switching between heads mounted on the same actuator arm than for switching between heads mounted on different actuator arms. Therefore improved disk drive performance is obtained by using two values of head switch time instead of one. The head switch time allocated for switching from a first head on one actuator arm to a second head on a second actuator arm is made longer than the head switch time allocated for switching from a first head on one actuator arm to a second head on the same actuator arm. By allocating longer time for the head switches between different actuator arms, the error flag rate for heads not ready is reduced.

Abstract: A signal reproducing circuit for a magneto-resistive effect head includes a constant current source for supplying a sense current to an MR head in a read state, first constant current sources for supplying first constant currents to a pair of reproduction transistors in the read state, and a capacitor connected between the emitters of the transistors. Furthermore, second constant current sources for supplying second constant currents are connected in parallel with the first constant current sources. Control is given so that when switching an idle state to the read state is commanded, the second constant current sources remain on for a given period of time. Owing to this circuitry, a transient period during which the idle state is switched to the read state or a transient period during which heads are switched in the read state can be shortened to a great extent.

Abstract: An electromagnetic actuator drive circuit suppresses mechanical resonance which occurs in a magnetic head or an optical device whose position is controlled and giving a very small displacement to an electromagnetic actuator. By feeding back the terminal voltage E of the electromagnetic actuator to the signal current I.sub.s of the electromagnetic actuator through a feedback circuit, a Q factor in the case where short-circuit control is performed by voltage drive is realized so as to be about 0.5 which is the size of critical damping. The actuator drive circuit is applied for improving the picture quality reproduced by a video tape recorder, a projection image display, or the like and is capable of enhancing the ability to damp a moving object such as a magnetic head by performing short-circuit control by voltage drive.

Abstract: A headerless, fault-tolerant sample-data servo pattern, comprising an alternating sequence of first and second servo sectors, with the first servo sectors each including a partial track address and circumferential orientation information, and the second servo sectors each including a full track address, provides an absolute indication of a read/write head's circumferential orientation along a given track on a magnetic disk which is robust in the presence of defects in the magnetic recording medium.

Abstract: A servo writer optimizes a write current during servowriting a magnetic disk recording device by measuring the head performances at the inner, outer, and middle regions prior to writing the servo information with optimal write current in order to obtain the best qualified servo.

Abstract: A spindle synchronization technique is described which is useful in a disk array subsystem comprising a plurality of disk drives (40,41,42,43) connected by means of serial links (25,26,27,28) to a disk drive controller (20). Data and command information is transmitted over the link in the form of multi-character frames, the flow of which is regulated by special ten bit protocol characters. A SYNC protocol character is defined which is used to synchronize the spindles of the disk drives. This SYNC character is issued by controller to selected ones of the drives over the same link used for the transmission of the command and data information. The SYNC character may be interleaved between the characters of frames being transmitted over the link.

Abstract: A rotary head type magnetic recording/reproduction apparatus according to the present invention includes a recording format in which a plurality of pilot signals of different frequencies are recorded to be superimposed sequentially on a main signal for every other track. The magnetic recording/reproduction apparatus includes a single head structure where a plurality of magnetic heads are attached to a plurality of actuators in a one-to-one correspondence. For one magnetic head detecting a relative position error signal out of the plurality of magnetic heads, dynamic tracking under closed loop control is carried out. For another magnetic head that does not detect a relative position error signal, open loop control or semi-closed loop control is carried out according to information concerning the amount of displacement of the one magnetic head.

Abstract: A sampled amplitude read channel is disclosed for reading data recorded on a disk storage medium by asynchronously sampling an analog read signal, equalizing the asynchronous sample values according to a desired partial response, and interpolating the equalized sample values to generate synchronous sample values substantially synchronized to a baud rate of the recorded data. The read channel further comprises a gain control circuit which generates a gain error for adjusting the amplitude of the analog read signal to a nominal value through a variable gain amplifier (VGA). During acquisition, the gain error is computed from the asynchronous sample values at the output of the sampling device in order to avoid the delay associated with the discrete equalizer filter and the timing recovery interpolation filter. This decreases the acquisition time and the corresponding length of the acquisition preamble, thereby reserving more area on the disk to record user data.

Abstract: A disk drive comprising a plurality of read/write transducers, a programmable preamplifier, and a controller for furnishing control and data signals to the programmable preamplifier and for receiving data signals therefrom, is disclosed. The programmable preamplifier comprising a write data input circuit for receiving data signals to be supplied to a transducer, a read data output circuit for manifesting data signals supplied to said preamplifier unit by a transducer, and a transducer interface circuit for providing write data signals to a transducer and receiving read data signals from a transducer.

Abstract: A system and method for playing and recording digital media such as digital audio. The system allows for seamless punch-out (exiting record mode) during a recording session by continuing to transfer playback data for a sequence from the mass storage to a buffer simultaneous with transferring record data for the sequence into the buffer and the mass storage. This allows the user to seamlessly switch between record mode and playback mode, presenting only a negligible (if any) delay between the time the user requests punch-out and the time the user experiences the correct original playback data. In a preferred embodiment, the invention is implemented as a digital audio playing and recording system providing seamless punch-out for multiple channels of digital audio using RAM buffers and rotating magnetic disk devices for storing the digital audio.

Abstract: A computer disk drive unit having a control system that uses a separate velocity profile for read seeks and for write seeks is disclosed. Appropriate velocity profiles are provided according to whether a seek operation is a read seek operation or a write seek operation. The control system includes a memory for storing an initial velocity profile and a processor for determining whether a read seek operation or a write seek operation is to be performed. The processor obtains the initial velocity profile from memory to produce a read velocity profile or a write velocity profile. The processor multiplies the velocity profile obtain from the memory by a predetermined constant to derive the read velocity profile when the processor determines that a read operation is to be performed. Then the processor repositions the head according to the write velocity profile or the read velocity profile.

Abstract: A method for recording the port number of a servo track writer for efficiently managing a manufacturing process of a magnetic storage device. In a manufacturing process of a hard disk drive having a disk as a recording medium, the disk including a data band for recording user data and a plurality of protection bands, the port number of a servo track writer is recorded in at least one of the bands during servo information writing in the method, so that the port number can be read and used for the manufacturing process.

Abstract: A sampled amplitude read channel is disclosed for reading data recorded on a disk storage medium by detecting an estimated binary sequence from a sequence of discrete time sample values generated by sampling pulses in an analog read signal from a read head positioned over the disk storage medium. The read channel comprises a sampling device, such as an analog-to-digital converter (A/D), for sampling the analog read signal to generate the discrete time sample values and for sampling at least one other auxillary analog input signal, such as a servo control signal. In this manner, performance characteristics of the read channel can be measured, such as the driving current applied to the servo control voice coil motor (VCM), without requiring additional hardware.

Abstract: Data (such as digital audio data) is reproduced from a disk medium at a variable data rate and is then converted to a constant data rate by storing the reproduced data in a buffer memory and reading out the stored data at the constant data rate. Overload of the memory is detected and the reproducing head repeats reproduction of such data from the disk medium that has not been stored. When the data is configured in blocks, memory overload can be detected by input and output block counters and a buffer space comparator which compares the input and output block counts to the memory so as to provide an indication of memory overload.When the disk medium is driven at constant speed, the storage capacity of the disk medium can be increased compared to that of a constant angular velocity with constant read/write data rate system.

Abstract: The invention relates to a head mechanism control apparatus for magnetic recording device which ensures that the transducer head has been unloaded in a head unloading operation. A head slider having a transducer head is mounted on a head arm and is unloaded from the disk by the swinging of the head arm. The retract position is at the limit portion of the swingable range of the head arm. When the head slider is successfully unloaded to the retract position, a drive force applied to the head arm in the unload direction causes little movement of the head arm. After an unloading is performed, a position check drive force is applied to the head arm and the moving speed of the head slider is detected. Based on the moving speed, it is judged whether the head slider has been unloaded to the retract position. If the head slider has not been unloaded to the retract position, re-unloading is performed for moving the head slider to the retract position.

Abstract: A tracking apparatus for a helical scan magnetic recording/reproducing system includes a rotation speed controller for controlling the rotation speed of a capstan motor which transports a magnetic tape, a speed deviation generator for applying a deviation to the rotation speed, an envelope level detector for detecting the envelope level of a reproduced signal, a memory for storing the value of detection by the envelope level detector, and an envelope level comparator for comparing envelope levels before and after the deviation is applied to the rotation speed, whereby the rotation of the capstan motor is controlled so that the envelope level becomes a value in the vicinity of a maximum value. The tracking apparatus further includes a steady speed deviation detector for detecting a steady speed deviation between a recording apparatus and a reproducing apparatus, and a steady speed deviation corrector for correcting the detected speed deviation.