Abstract:
A method and data storage device determine an equalized signal-to-noise ratio (ESNR) in the storage device. The equalized signal-to-noise ratio is determined by generating an analog read signal (200), passing the read signal through an equalizer (208) in the storage device, and sampling the equalized signal using an analog-to-digital converter (210) in the storage device. The samples from the analog-to-digital converter (210) are then used in the equalized signal-to-noise calculation (308).
Abstract:
The tracks in a read-only area are divided into sector regions having the same capacity, error correcting codes are added to 1st data signals to generate 2nd data signals and pit rows are formed in the sector regions to record data. In a rewritable area, recorded user data are correlated with 1st data, the same error correction codes used for the read-only area are added to the 1st data signals to generate 2nd data signals in a similar way and data signals for making rewritable are added to the 2nd data signals to generate 3rd data signals. A format is set up by adding a header region where sector address information is recorded to a region in which the 3rd data signals are recorded. The region is divided into two areas radially, the outer area being made a rewritable area and the inner area being made a read-only area. Control data signals are recorded in the read-only area.
Abstract:
A method and device for controlling the tracking of an optical memory card by which synchronism can be established easily, a track holding mistake can be detected and corrected easily, high speed operation can be realized and the double-writing, etc. can be avoided. The guide tracks (2) for optical memory cards are composed of the rows of guide track segments (4, 4a, 4b, 4c and 4d). A synchronizing signal is extracted from the row pattern of the guide tracks detected by photodetectors (11 and 12) and a data recording track (1) is identified to establish synchronism and a track holding mistake is detected and corrected.
Abstract:
A method for reducing write errors in a disk drive system is presented. When the flying height of a read/write head above a disk surface becomes too great, the signal strength diminishes and data write errors will occur. Often these increases in flying height are transient. Flying height increases are determined by detecting servo mark and sector information read errors. Recently written data is verified after detection of flying height induced errors.
Abstract:
In the method disclosed, an erasable-recording medium (1) with recorded data which must be retained is passed in the direction of motion through a test-signal read-out device (R2), a first erasing device (E1), a test-signal recording device (W1), a test-signal read-out device (R1), a second erase device (E2) and a recording device (W2) for the data read off by the test-signal read-out device (R2). The test signal is generated and tested in a device (6) which also controls a signal-processing and control device (8) located in the path (7) of the signals.
Abstract:
A device for obtaining statistical characteristics of a magnetic record-reproduction channel comprises pulse generators (1, 2) connected to pulse counters (13, 12) and further connected to a code dialing unit (3) and to an electron key (10). The code dialing unit (3) is connected to a record amplifier (5) connected in its turn to the magnetic head (7) which is connected to a reproduction amplifier (6). The device comprises as well a delay element (18) which is connected to the output of the code dialing unit (4) and further comprises a logical unit (17) connected with its inputs to the electron key (10) and to the delay element (18) and connected with its outputs to pulse counters (15 and 19).
Abstract:
The invention relates to a method and recording device for selecting an optimal write strategy for a specific type of optical recording disk. Such an optimal write strategy is selected even when the optical recording disk is of a type that has not been previously encountered or when the optical recording disk is otherwise unrecognized by an optical disk drive. The optimal write strategy and associated settings are selected from a set of write strategies stored in a disk drive. The disk drive bases its selection of the write strategy on the performance results of test writings conducted on the optical disk. The method entails testing the write strategies first at the maximum possible write speed and if necessary, at successively lower speeds until a write strategy that achieves a minimum acceptable write quality is identified or until the minimum write speed is reached. The selected optimal write strategy may be stored in the recording device or, alternatively, on the optical recording disk itself.
Abstract:
An optical recording method and recording apparatus using this method is described in which an optimum write power of a radiation beam in the apparatus is set by writing a series of test patterns on an optical recordable medium, forming a read signal from the patterns, reading a preset value of the derivative of the modulation of the read signal with respect to the write power from the medium, and processing the read signal together with the preset value to derive an optimum value of the write power.
Abstract:
Waveform equalization is carried out for a reproduction signal of a test signal recorded with data in each unit recording area of a recording medium by an adaptive type waveform equalization means while a tap coefficient is changed, and a tap coefficient at the time when the equalization signal approaches most closely to an ideal equalization signal is used as an optimum tap coefficient. The reproduction signal of data in each unit recording area is subjected to waveform equalization by using this optimum tap coefficient. In this way, a data reproduction apparatus can be obtained which can effect waveform equalization of data stably, reliably and quickly and can accomplish high density recording by a small scale circuit.