Abstract: During recording operations, decay processing is performed with regard to reflected light information signals (I1 and I2) during periods wherein the laser output is recording power which is comparatively high level, i.e., wherein data pits are being formed on the disk, and during recording operations, decay processing is not performed with regard to reflected light information signals during periods wherein the laser output is reproducing power which is comparatively low level, i.e., wherein the pits are not being formed on the disk. Accordingly, address information can be extracted in a stable manner while recording.

Abstract: The invention is an optical disk apparatus including a generating unit which generates an RF signal and a wobble signal detected from the optical disk, a detection unit which detects a sink or a VFO on the optical disk on the basis of the wobble signal, an adjustment unit which adjusts the RF signal on the basis of timing of the detection signal detected by the detection unit, and a processing unit which reproduces the RF signal adjusted by the adjustment unit. In the optical disk of the invention, adjustment of an RF signal and the like can be easily performed by recognizing a VFO position, even in a header is not provided like the next-generation DVD-RAM.

Abstract: An offset adjusting circuit for an optical disc comprises a plurality of offset-adjustment differential operational amplifiers, each of the amplifiers having an input terminal to which an output signal of an optical pickup is input and another input terminal to which a control voltage is applied, an adding circuit that adds output signals of the offset-adjustment differential operational amplifiers, an A/D converter that outputs a digital signal based on an output signal of the adding circuit, and a control voltage adjuster that varies the control voltage applied to the offset-adjustment differential operational amplifiers based on the digital signal so as to remove an offset.

Abstract: An adder circuit (41) adds four main electric signals to produce an HF signal (a picked-up signal). A peak hold circuit (43) holds a peak of the HF signal to a peak held signal. The peak held signal is a signal indicative of a level of I-TOP of the HF signal. Again control amplifier (44) amplifies the HF signal by a gain equal to a reciprocal of the peak held signal to produce an amplified signal.

Abstract: A device in accordance with the invention for recording or reproducing information onto/from a rotating information carrier (10) has rotating element (16) for rotating the information carrier. The device further has conversion (16) for converting a write signal (SW) into a detectable pattern on the information carrier, or for generating a read signal (SLS) in response to a detectable pattern on the information carrier. The device also includes control unit (25, 26) for supplying at least one control signal (SR, SF) to the conversion unit in response to an error signal (RE, FE). The device also includes detection unit (25A, 26A) for generating a detection signal (DR, DF) which is a measure of a periodic variation in the error signal (RE, FE). The device in accordance with the invention is characterized by adjustment unit (29) for influencing the response of the control unit (25, 26) to the error signal (RE, FE) in dependence on the detection signal (DR, DF).

Abstract: An optical head device includes: an optical element collecting light reflected from a reproduction information layer (a target information layer in an optical information recording medium) and light reflected from information layers adjacent to the reproduction information layer at different positions; a light receiving element obtaining a detection signal from the reflected light collected by this optical element; and arithmetic circuitry obtaining a reproduction signal from this detection signal.

Abstract: An photoreceptive amplifier circuit includes a first differential amplifier having two input resistors, two input voltage dividing resistors, two feedback resistors, for providing temperature characteristic of sensitivity=0 of a photodiode with respect to light having wavelength of 650 nm, and a second differential amplifier having two input resistors, two input voltage dividing resistors, two feedback resistors for providing temperature characteristic of sensitivity=0 of a photodiode with respect to light having wavelength of 780 nm. One of outputs from these differential amplifiers is selected depending on the wavelength. Therefore, it is possible to cancel changes of the temperature characteristic due to variation of wavelength by the temperature characteristic of the sensitivity of the photoreceptive amplifier circuit so that the temperature characteristic of the whole optical pickup element becomes 0.

Abstract: The present invention has an object to stably reproduce wobble signals of all disks of CD-R/RW, DVD-R/RW and DVD-RAM by one wobble signal reproducing circuit. In the wobble signal reproducing circuit, an AGC (AUTOMATIC GAIN CONTROL) circuit for equating a push-pull circuit output of a wide range and an RF amplitude of an optical detector output of two systems obtained by push-pull, and an AGC circuit for making a wobble amplitude uniform are provided with a function to hold a gain or to change over a response time constant, and an address information recording region (PID region) at the time of reproduction, the AGC (AUTOMATIC GAIN CONTROL) is held or the response time constant is changed over.

Abstract: A prepit detecting apparatus which uses an optical recording medium having information recording tracks on which information is recorded and guide tracks each of which guides a light beam to the information recording track and on which prepits for saving pre-information are formed such that the light beam is applied to the information track of the optical recording medium, the prepit detecting apparatus comprising: light receiving means divided into a first divided light receiving portion and a second divided light receiving portion divided along an optically parallel division line in a direction of tangent of the information tracks and arranged to receive reflected light of the light beam with which the optical recording medium has been irradiated; and a difference calculator for calculating the difference between a first read signal output from the first divided light receiving portion and a second read signal output from the second divided light receiving portion so that the prepit is detected in response

Abstract: A tracking error balance adjustment circuit, and a current control circuit used for a variable gain RF amplifier automatically controlled to output a signal having a predetermined amplitude. The tracking error balance adjustment circuit comprises two separate gain adjusting circuits, each having variable attenuation circuit having first gm amplifier of variable gm type, a second gm amplifier of variable gm type connected to the variable attenuation circuit, and an output circuit connected to the second gm amplifier, comprising an operational amplifier circuit having feedback resistor, wherein the first and second gm amplifiers are differentially controlled commonly by a control current.

Abstract: An optical disk pickup system includes an array of photodiodes 101 for converting photons reflected from an optical disk into a plurality of electrical signals each representing a channel. Driving circuitry 407, 408 drives at least one of the electrical signals as a current across a conductor of a flexible cable 403. A low impedance load 404 converts the electrical signal driven across the conductor as a current into a voltage for further processing.

Abstract: Servo circuitry for correlating signals using a correlation data structure is disclosed. The servo circuitry is comprised of a setup system coupled to a correlation system that contains the correlation data structure. The setup system receives four signals and converts the signals to digital values. The correlation system takes the digital values and enters them into the correlation data structure. The correlation data structure yields a correlation value based on the digital values. The servo circuitry advantageously yields the correlation value that is a function of all four signals using the correlation data structure.

Abstract: An information recording method for recording information by irradiating an information recording medium with light, including steps of providing the information recording medium with a physical identification field (PID) and a data field, and utilizing a head amplifier for amplifying a detection signal in the PID field with a first gain and amplifying a detection signal in the data field with a second gain different from the first gain to record the information to the data field.

Abstract: The invention pertains to a control circuit (4) for a radiation source (2). The circuit comprises means (43) for generating an error signal (Perr) which is indicative for a difference between a measured average value of the output power of the radiation source (2) and a desired average value (Pset) of the output power of the radiation source. The circuit further comprises combining means (44, 45, 46) for generating a control signal (Sout) for the radiation source (2) in response to said error signal (Perr) and to an information signal (Sin) for modulating the radiation source. The combining means comprise first means (44) for modifying the information signal by a multiplicative factor &ggr; which is dependent on the error signal, and second means (45, 46) for modifying the information signal by an additive factor &sgr; which is dependent on the error signal.

Abstract: Disclosed is a pick-up head controller for optical disk drives, structured particularly for optimal actuation characteristics of a pick-up head of optical disk drives. A framework, composed of a high-frequency digital controller and a low-frequency digital controller, accomplishing different order types of controllers required by optical head systems, is provided based upon the sampling rate dependence of response of digital controllers. Experimental results shows excellent performance in optical systems that high performance, low cost and easy designing can be achieved.

Abstract: An optical disk pickup system 400 using current mode signal transmission is disclosed. An operational amplifier 404 has an input for receiving an electrical signal and a feedback loop including a current path of a first transistor 405 of a first size, transistor 405 having a control terminal at a preselected voltage. A conductor 402 is coupled to an output of operational amplifier 404 for transmitting the electrical signal as a current. A second transistor 406 of a second size has a current path in series with a conductor 402 and a control terminal coupled to the preselected voltage, transistors 405, 406 forming a current divider.

Abstract: In a magneto-optical storage device, a digitally adjustable preamplifier stage balances polarization signal levels through use of a digital compensation value. A separate digital compensation value is stored for the signals corresponding to each detector head. Each time a different detector head is activated, the digital compensation value for the polarization signals corresponding to that head is accessed. The accessed digital compensation value is input to a digital to analog converter (DAC), which produces a voltage for setting the gain of the adjustable amplifier.

Abstract: An optical disc device including a laser light source for radiating a laser light beam illuminated via an objective lens on a signal surface of an optical disc, a laser light volume detection unit for detecting the light volume of the laser light radiated from the laser light source, an automatic power controlling unit for controlling a laser output of the laser light source so that a detection output by the laser light volume detection unit will be constant, a return light detection unit for detecting the return light of the laser light beam radiated by the laser light source and reflected by the signal surface of the optical disc, a focusing control unit for displacing the objective lens along the optical axis responsive to focusing error signals generated on the basis of a detection output of the return light detection unit for controlling the focusing state of a beam spot of the laser light on the signal surface of the optical disc and a controlling unit for controlling the closed-loop gain of the automat

Abstract: Data read from a disk is input to an RF amplifier. An RF amplifier generates, based on bit data, an RF signal constituted by a plurality of components of mutually different frequencies. The RF amplifier determines a relation between the frequencies and gains on the basis of a control clock and adjusts the gains of respective components in the RF signals on the basis of the relation (equalize-processing). A PLL circuit has a first VCO and first frequency divider to generate a bit clock and generates, on the basis of an output signal of a data slice circuit, a first control voltage for controlling the first VCO. The first control voltage, being passed through a lowpass filter, is converted to a second control voltage for controlling a second VCO. The second VCO has an arrangement and characteristic substantially the same as those of the first VCO.