Abstract: Read data from a selected address is compared with read expected value data stored in an expected value holding circuit, and the read expected value data stored in the expected value holding circuit is scrambled according to the selected address by a data scrambling circuit, to generate cell expected value data indicative of an expected value of storage data at a cell level. According to a failure mode instruction signal for instructing a failure mode of detecting the expected value of the storage data at the cell level, the possibility of occurrence of a failure is identified. According to the result of identification, a result of determination on whether internal read data coincides with the read expected value data can be selectively validated or invalidated. In such a manner, the failure mode of storage data at a memory cell level can be detected.

Abstract: A method is provided for associating an address with data. The method includes precharging a matchline connected to a plurality of tag match functions to a first potential, wherein each tag match function comprises one or more match logic devices, discharging two tag lines for a first tag bit to ground, and reading a plurality of tag bits and corresponding data bits onto a plurality of tag lines and a plurality of data lines respectively. The method further includes determining a match between the tag bits and data bits, and pulling the matchline to a second potential upon determining a match for each of the tag bits. The method further provides a way to bank the random access memory structures where data is stored.

Abstract: A pre-charge circuit for a memory device having a sense amplifier shared between right and left banks of memory cells and a method of pre-charging the shared sense amplifier. The circuit is operated according to the method of the invention such that the sense amplifier is always pre-charged from the side that was previously active. The circuit includes right and left bank isolation transistor pairs connected between the shared sense amplifiers and the right and left banks. The isolation transistor pairs are controlled by a flip flop having a left bank state and a right bank state and complementary left and right outputs that turn off the left isolation transistor pair and turn on the right pair during row operations to the right and vice-versa.

Abstract: The present invention is in the field of memory device architecture. More particularly, the present invention provides a method, apparatus, system, and machine-readable medium to use a set of word-lines to access a row of memory cells.

Abstract: A dynamic sense amplifier is provided that reduces the amount of time required to perform a memory cell restoration in a DRAM following a read operation. The dynamic sense amplifier can be isolated from the bit lines that it is sensing to avoid the capacitance affects of the bit line during a restoration operation. By avoiding the capacitance effects of the selected bit line during a restoration operation the dynamic sense amplifier is able to restore the just read memory cell to its original state in a more efficient manner.

Abstract: A memory device is operable in either a high mode or a low speed mode. In either mode, 32 bits of data from each of two memory arrays are prefetched into respective sets of 32 flip-flops. In the high-speed mode, the prefetched data bits are transferred in parallel to 4 parallel-to-serial converters, which transform the parallel data bits to a burst of 8 serial data bits and apply the burst to a respective one of 4 data bus terminals. In the low speed mode, two sets of prefetched data bits are transferred in parallel to 8 parallel-to-serial converters, which transform the parallel data bits to a burst of 8 serial data bits and apply the burst to a respective one of 8 data bus terminals.

Abstract: A memory control apparatus for controlling the operation of a memory array in a serial memory such as a serial EEPROM employs a command control section for registering in a shift register the bits of an instruction which is received as an externally supplied set of serial data in conjunction with a corresponding series of cycles of a clock signal, with each set of serial data formatted as a command data portion preceded by a start bit, whereby the shifting of the start bit into the MSB stage of the shift register is detected and used to terminate supplying the clock signal to the shift register, thereby eliminating the use of a counter circuit for such clock signal control.

Abstract: An address generating circuit of a DRAM includes five fuses, a trimming switching circuit generating five signals in accordance with whether or not each fuse is blown, a voltage converting circuit generating a control voltage of a level corresponding to the five signals, a voltage control oscillation circuit generating a clock signal of a cycle according to the control voltage, and an address counter generating an address signal in synchronization with the clock signal. Thus, unlike a conventional example, a plurality of counting circuits and a detection circuit are eliminated, resulting in reduction of power consumption and circuit scale.

Abstract: A semiconductor memory capable of reducing refresh cycle time is provided.

Abstract: In a semiconductor memory device which requires a refresh operation, a control method stops supplying a word line voltage which is a boosted voltage higher than an external supply voltage, a memory array substrate voltage which is a negative voltage supplied to a semiconductor substrate, and a bit line precharge voltage for use in reproducing data held in memory cells for a predetermined period at the end of each refresh operation. In this event, voltage output terminals of the word line and memory array substrate voltages are respectively driven to a ground potential. For recovering these voltages, the delivery of the word line voltage is stopped until the memory array substrate voltage rises to some extent.

Abstract: The volatile semiconductor memory is constructed from a plurality of memory segments. The information stored in the memory cells must be regularly reconditioned. Here, the time interval after the expiry of which the memory contents of the memory cells are reconditioned is set individually for each memory segment using corresponding subcircuits. The subcircuits receive, in a cyclical sequence, a refresh instruction. The passing on of the refresh instruction to the respective memory segment is interrupted if the segment-specific refresh time has not yet expired. This method of driving is implemented very easily and in a space-saving and cost-effective way in terms of circuitry.

Abstract: A memory system comprising at least one memory cell in which information can be stored and a refreshing means refreshing the memory cell in predetermined time intervals is provided. In addition, the memory cell comprises a driving means driving the refreshing means in such a way that it only refreshes the memory cell when useful information is stored in the memory cell.

Abstract: An apparatus and associated method are provided to improve the programming of anti-fuse devices in an integrated circuit. A programming circuit capable of programming a plurality of anti-fuse devices in parallel permits a state-changing voltage to be applied to multiple anti-fuses substantially simultaneously using a common control signal.

Abstract: Systems and methods are provided for regulating a memory circuit. The memory circuit regulation system includes an array regulator adapted for distributing an array supply voltage to a memory cell array, and at least one periphery regulator adapted for distributing at least one periphery supply voltage to at least one periphery circuit. In one embodiment, the array supply voltage is higher than the at least one periphery supply voltage to account for the fundamental lower limit of voltage operation for the LL4TCMOS SRAM cells. The higher array supply voltage provides appropriate stability margins for the SRAM cells so as to discourage or prevent accidental writes to the cells. In another embodiment, the array regulator sources a temperature-dependent current to provide an offset to the temperature-dependent subthreshold leakage current in the plurality of LL4TCMOS SRAM cells.

Abstract: A zero power standby mode in a memory device used in a system, such as a battery powered hand held device. By disconnecting the internal power supply bus on the memory device from the external power supply during standby mode, the junction leakage and gate induced drain leakage can be eliminated to achieve a true zero-power standby mode. A p-channel field effect transistor (FET) may be used to gate the external power supply such that the internal power supply bus on the memory device may be disconnected from the external power supply.

Abstract: A zero power standby mode in a memory device used in a system, such as a battery powered hand held device. By disconnecting the internal power supply bus on the memory device from the external power supply during standby mode, the junction leakage and gate induced drain leakage can be eliminated to achieve a true zero-power standby mode. A p-channel field effect transistor (FET) may be used to gate the external power supply such that the internal power supply bus on the memory device may be disconnected from the external power supply.

Abstract: The present invention provides a semiconductor memory circuit capable of reducing current consumption at non-operation in a system equipped with a plurality of chips that share the use of a power supply, address signals and a data bus. The semiconductor memory circuit has an internal circuit which is capable of selectively performing the supply and stop of an operating voltage via switch means and includes a memory array. An input circuit, which receives a predetermined control signal therein, controls the supply and stop of the operating voltage by the switch means to reduce a DC current and a leak current when no memory operation is done, whereby low power consumption can be realized.

Abstract: A method and apparatus for active termination control of a memory module is disclosed. A memory controller provides a single active termination control line per memory module which is used to control memory devices on both sides of a module. The active termination control signal is active for all write functions to the memory devices on the modules. A device read signal generated by the memory devices on one side of the module disables the active termination control signal for memory devices on both sides of the module to enable faster turnarounds between write and read operations..

Abstract: In a semiconductor memory device, a memory cell array has an even bank activated based on even numbered addresses and an odd bank activated based on odd numbered addresses. Even read data is outputted from the even bank in response to a first control signal, and odd read data is outputted from the odd bank in response to the first read control signal. A relaying unit receives the even read data on the first even data bus to output the even read data to the second even data bus in response to a second read control signal, and receives the odd read data on the first odd data bus to output the odd read data to the second odd data bus in response to the second read control signal. An I/O circuit receives the even read data from the second even data bus and the odd read data from the second odd data bus, and outputs one of the even read data and the odd read data to the common data bus and then outputs the other to the common data bus, in response to a third read control signal.

Abstract: In a memory device having a controller and multiple memory modules both of which are mounted together on a motherboard, a high-speed operation is executed by suppressing waveform distortion caused by signal reflection. Since signal reflection occurs when a controller performs the writing/reading of data relative to memory units on memory modules, active terminator units are included in the controller and the memory units. These active terminator units are provided for a data bus and/or a clock bus in order to terminate these buses in memory units. The active terminator units provided for the controller and the memory units may be put into an inactive state when data is to be received.

Abstract: The present invention provides a memory device having a mode register with a selectable bit which sets the memory device to operate with a selected one of a plurality of possible clock input signals, for example, a single clock input or differential clock input.

Abstract: A synchronized mirror delay circuit is used to generate an internal clock signal from an external clock signal applied to the synchronized mirror delay. The internal clock signal is then coupled through a clock tree, and a feedback signal is generated that is indicative of the propagation delay of the internal clock signal through the clock tree. The feedback signal is applied to the synchronized mirror delay to allow the synchronized mirror delay to delay the internal clock signal by a delay interval that compensates for the propagation delay in the clock tree. A lock detector may be used to initially generate the internal clock signal directly from the external clock signal. A fine delay circuit that delays the internal clock signal in relatively fine increments may be used to couple the internal clock signal to the clock tree.

Abstract: A NAND flash memory device includes a first and second memory blocks. A shared row selection circuit is provided between the first and second memory blocks, selectively or simultaneously selecting the first and second memory blocks, and transferring wordline voltages to a selected memory block by means in a multi-boosting manner.

Abstract: The invention relates to a new process for producing powdered preparations for inhalation wherein a substance having a smaller particle size distribution is metered continuously through a suitable feed device onto a moving bed of a powdered substance having a larger particle size distribution.

Abstract: A low-profile tank and system for mixing dry chemicals with water to form a concentrated hemodialysis solution, the tank having a fluid supply nozzle projecting into a cylindrical side wall of the tank, and a drain connection at an apex of a conical bottom wall of the tank. A cavity having a ramp-like bottom wall extends from the cylindrical side wall of the tank. A venturi eductor provides for transfer of dry chemicals to the tank using compressed air to aspirate the chemicals and deliver them to the tank. A plurality of load cells may be used to measure the weight of the tank and contents. Manual transfer of dry chemicals to the tank is facilitated by the low profile of the tank. A tapered shipping container is provided for nesting when empty.

Abstract: A static mixer comprises a mixing chamber with an inlet mixing module, fluids to be mixed being fed into the module to undergo swirling and jet collision, at least one intermediate mixing module connected to the inlet mixing module and provided with means for splitting liquid flow into a plurality of jet flows with subsequent recombination of said jets and mixing action of vortices formed around the jet flows, and an outlet mixing module connected to the intermediate mixing module and provided with means for further swirling premixed fluids.

Abstract: Methods and apparatus for processing materials employ two cylindrical members, one mounted within the other, defining an annular processing chamber. Preferably, the outer member is stationery (stator), while the inner rotates (rotor). The radial spacing between the stator inner surface and the rotor outer surface is equal to or less than the back-to-back radial thicknesses of the two laminar boundary layers formed on the two surfaces by the material being processed. The surfaces are made smooth, as by buffing to a finish of not more than 10 microinches. This structure inhibits formation of Taylor vortices in the processing passage, which cause unstable flow and consequent incomplete mixing. Preferably, the relative velocity between rotor and stator surfaces is at least 1.2 meters per second. The surfaces may be coated with catalysts. Transducers may be provided to apply processing energy, such as microwave, light or ultrasonic waves, through the stator wall.

Abstract: The invention involves a mixing device for mixing a base material with a liquid using a vertical feeder shaft for the base material and a mixing chamber which is arranged below the feeder shaft and into which the liquid is supplied and in which a mixing tool can be driven in rotation, whereby in the feeder shaft, a propeller rotating around a vertical axis is provided, in which blade elements extending in the radial direction are provided. In order to not cause any clogging in the feeder shaft at the propeller, it is proposed to keep individual segments blade-free all the way through over the entire height of the propeller parallel to the axis, when the propeller is rotating in the circumference direction. In this way, a homogenization of the supplied base material is also achieved.

Abstract: A system for detecting a subterranean reservoir or determining the nature of a subterranean reservoir 12 whose position and geometry is known from previous seismic surveys. An electromagnetic field 24, 25, 26, 27 is applied by a transmitter 18 on the seabed 14 and detected by antenna 21, 22, 23 also on the seabed 14. A refracted wave component is sought in the wave field response, to determine the nature of any reservoir present.

Abstract: Near-offset and far-offset seismic data volumes are time-aligned by first selecting a plurality of time shifts. The near-offset and far-offset seismic data volumes are cross-correlated at the plurality of time shifts. An initial time-shift volume and a maximum correlation volume are created from the maximal cross-correlations at the plurality of time shifts. Areas of high time shift from the initial time-shift volume and areas of low cross-correlation from the maximum correlation volume are determined. The determined areas of high time shift and low cross-correlation are filtered from the initial time-shift volume, generating a filtered time-shift volume. The filtered time-shift volume is applied to the far-offset seismic volume to generate a time-aligned far-offset volume.

Abstract: An oscillating valve driven by the pressure in a mud pulser develops a pressure variation in the mud pulse signal that is at a frequency that is different than the frequencies of the mud system. The oscillating valve is coupled to or integral with the pulse drive cylinder, whether the drive means for operation of the pulser is upstream or downstream from the orifice, or whether or not the drive means and the poppet are on the same side or opposite sides of the orifice. The oscillating valve is a bistable valve which preferably forms one wall of the drive piston of the pulser. Pressure from the drive cylinder behind the drive piston is directed in such a way as to unseat the bistable valve. When the bistable valve unseats, pressure is bled from within the drive cylinder, which also bleeds the pressure that unseated the bistable valve in the first place.

Abstract: A signal processing system provides and processes a digital signal, converted from to an analog signal, which includes a noise component and possibly also an information component comprising small samples representing four mutually orthogonal items of measurement information representable as a sample point in a symbolic Cartesian four-dimensional spatial reference system. An information processing sub-system receives said digital signal and processes it to extract the information component. A noise likelihood determination sub-system receives the digital signal and generates a random noise assessment of whether or not the digital signal comprises solely random noise, and if not, generates an assessment of degree-of-randomness. The information processing system is illustrated as combat control equipment for undersea warfare, which utilizes a sonar signal produced by a towed linear transducer array, and whose mode operation employs four mutually orthogonal items of measurement information.

Abstract: A folded Sagnac fiber optic sensor array uses a common delay path to reduce distributed pickup in downlead fibers. The sensor array is used to detect perturbations (e.g., acoustic waves in water). By basing the folded Sagnac sensor array on operating principles similar to the Sagnac interferometer the sensor array has a stable bias point, has reduced phase noise, and allows a broadband signal source to be used rather than requiring a more expensive narrowline laser. A large number of sensors can be multiplexed into the architecture of the sensor array. In one particularly preferred embodiment, the sensor array is configured with couplers and amplifiers selected to direct substantially equal portions of an input light signal to each sensor in the array. In another particularly preferred embodiment, first and second delay paths are provided for light at first and second wavelengths to increase the dynamic range of the sensors.

Abstract: A folded Sagnac fiber optic sensor array uses a common delay path to reduce distributed pickup in downlead fibers. The sensor array is used to detect perturbations (e.g., acoustic waves in water). By basing the folded Sagnac sensor array on operating principles similar to the Sagnac interferometer the sensor array has a stable bias point, has reduced phase noise, and allows a broadband signal source to be used rather than requiring a more expensive narrowline laser. A large number of sensors can be multiplexed into the architecture of the sensor array. In one particularly preferred embodiment, the sensor array is configured with couplers and amplifiers selected to direct substantially equal portions of an input light signal to each sensor in the array. In another particularly preferred embodiment, first and second delay paths are provided for light at first and second wavelengths to increase the dynamic range of the sensors.

Abstract: The invention concerns a particular link structure (1) for a wristwatch including decorative elements made of hard materials such as ceramics. The sintering step carried out during manufacturing of these decorative elements increase the maximum uncertainties on their dimensions. The parts thereby obtained consequently do not have sufficiently precise dimensions to avoid the appearance of gaps at their common junctions. In order to overcome this drawback, the link (1) according to the invention includes a mechanical device (17, 26, 29, 34, 37, 53) allowing a precise adjustment to be made of the relative positions of these different decorative elements and consequently continuous junctions to be obtained between them.

Abstract: A vertical magnetic recording apparatus is provided which can diminish thermal decay of magnetization to ensure a high reliability of the life of recorded information and which can stably effect the write of magnetic information. Light assist is performed by obliquely applying light to a gap between a main pole of a vertical recording head and a medium. The light is radiated from the head side of the apparatus with respect to the medium. Utilizing the present invention, the thermal decay of magnetization at room temperature is diminished, the life of the recorded information is increased, and the storage reliability of the disk is increased.

Abstract: A method for determining a track-cross direction of a pick-up head of an optical disk drive includes the following steps. (1) When a track-cross velocity of the pick-up head was determined to be greater than a predetermined velocity, it is determined whether the track-cross velocity of the pick-up head is changed to be less than the predetermined velocity. If not, the track-cross direction remains unchanged. (2) When the track-cross velocity of the pick-up head was determined to be less than the predetermined velocity, it is determined whether the track-cross velocity of the pick-up head is changed to be greater than the predetermined velocity. If not, the track-cross direction is determined according to a phase difference between a first track-cross signal and a second track-cross signal.

Abstract: A digital audio signal player having a simulated analogue record includes a laser pick-up used for reading the data of an analogue CD, a microprocessor, a digital audio signal processor electrically connected to the microprocessor, a digital/analog converter electrically connected to the audio signal processor, and a turnable control element. The data of the CD is stored in a RAM of the audio signal processor. The control element is made of conductive materials, and electrically connected to both the audio signal processor and the microprocessor, and can send a glitch to the microprocessor when touched by the user's hands. The microprocessor will make the audio signal process and send out the data on detecting that the difference between the glitch and an original signal exceeds a preset amount. The control element has a sensor for sensing the rotating speed and direction thereof so as to make the audio signal processor to process and send out the data according to the movement of the control element.

Abstract: An apparatus and method of ejecting/loading a tray of an optical disk player using a digitizer connected to a personal computer (PC) or a keyboard, even though an EJECT button is not installed on a control panel of an optical disk includes using a optical disk control program stored in the optical disk player. The optical disk control program is to be installed in a personal computer (PC) and controls the ejection/loading of a tray of an optical disk player. If a predetermined key or key combination is entered through the computer, an EJECT or LOAD command is applied to the optical disk player in response to entering of the predetermined key combination via the optical disk control program. The tray of the optical disk player can be ejected/loaded using the keyboard or digitizer, and thus there is no need to install the EJECT button in the optical disk player.

Abstract: A rotary tray having a plurality of disk mounting sections is pivotally supported by a central shaft arranged on a tray support face of a casing, a rim protruding from a lower face of the rotary tray is movably set on a sliding face block arranged in an outer circumferential section of the tray support face, and disk mounted on a desired disk mounting section is opposed to an optical pickup when the rotary tray is intermittently rotated by a predetermined angle, and the sliding face block is engaged in a space formed between a recess step circumferential face, which is formed along an inner edge of an outer circumferential section of the tray support face, and a support frame integrally formed in the outer circumferential section and being opposed to the recess step circumferential face.

Abstract: An optical disc changer includes a main body, a tray installed in the main body to be capable of sliding, a roulette rotatably installed at the tray and where a plurality of optical discs are accommodated, an optical pickup device to selectively reproduce one of the optical discs accommodated on the roulette, a drive gear member installed at the main body, rotated by being connected to a drive unit, and selectively engaged with a rack gear member formed on the bottom surface of the tray, and a tray gear unit installed adjacent to the drive gear member and having a tray gears selectively engaged with the rack gear member and the drive gear member.

Abstract: US vi A calibration of input signal offsets for stray light in an optical disk drive is presented. The input signal offsets can be determined by setting a laser power level, receiving digitized input signals, and setting the input signal offsets so that the digitized input signals are zero. The laser power level can be a read power or a write power. In some embodiments, input signal offsets for both read power and write power are determined and stored.

Abstract: To increase the vibration resistance of an optical disk device with respect to vibrations in the focus direction. More specifically, an optical disk device is provided with a multiplication means for generating a focus vibration component FC from the focus error signal FE, a multiplication means for generating a tracking vibration component TC from the tracking error signal TE, an adder for adding the focus vibration components FC and TC, and a low-pass filter for extracting the vibration component VC from the added results. Thus, the vibration component VC is extracted considering not only vibrations in the tracking direction but also vibrations in the focus direction, so that vibrations acting on the device can be more accurately detected, and vibration resistance is increased.

Abstract: An optical pick-up actuator for optical pick-up devices is disclosed. In the actuator of this invention, the blade positioned to float above a yoke plate has one focusing coil, two tracking coils and two tilting magnets. The yoke plate has two side yokes holding two tilting coils at positions vertically aligned with the two tilting magnets. The tilting magnets are formed on the lower surface of the blade at positions, which are symmetrical around the perpendicular optical path of an object lens of the blade or around the tilting axis of the blade. The tilting magnets of the blade and the tilting coils of the yoke plate are operated under the control of a solenoid. When a current flows in the tilting coils, the tilting magnets generate electromagnetic fields to tilt the blade at a desired angle relative to the perpendicular optical path of the object lens.

Abstract: An optical disk device for driving an optical disk having an emboss section and a data section comprises an optical pickup for replaying address information by irradiating a laser beam onto the emboss section of an optical disk and writing data by irradiating the laser beam onto the data section of the optical disk, and a control unit for controlling the focus position when address information is replayed at the emboss section and the focus position when data are written onto the data section to a common focus position. By using the common focus position as the focus position when the emboss section is replayed and as the focus position when the data are written to the data section, it is possible to eliminate any need for rapidly switching the focus position at the boundary between the emboss section and the data section.

Abstract: The disclosed invention provides a tracking method of an optical storage. When proceeding with tracking, the optical pickup head can be moved constantly and the TE signal can be detected. Then differentiation of the TE signal is obtained. If the differentiation is less than 0, then the TE signal is masked; otherwise, the TE signal is not masked. Therefore, the TE Hysteresis signal can be determined by the TE signal and its differentiation. The TE Hysteresis signal of 0 represents that the laser beam is in the Pit, and then the tracking procedure is finished. Otherwise, the aforementioned steps are repeated until the end of the tracking procedure.

Abstract: A storage medium is provided having a relatively large number of relatively small servo sectors. The storage medium includes a plurality of tracks. Each track includes a plurality of data sectors and a plurality of servo sectors. Each servo sector includes a plurality of servo marks and a synchronization gap. A plurality of first servo sectors includes a synchronization gap having a first length and a plurality of second servo sectors includes a synchronization gap having a second length. The first length is different from the second length, whereby, an unsynchronized reading device may recognize the longer synchronization gap and synchronize to the servo sector and a synchronized reading device may remain synchronized by recognizing the shorter synchronization gap.

Abstract: An optical disk apparatus that records data on an optical disk whose linear velocity is not constant. The optical disk apparatus includes an optical pickup that irradiates a laser beam of a recording power on the optical disk, converts light reflected from the optical disk into an electric signal; a detector that detects a level of the reflected light signal; and a controller that controls a recording power such that the reflected light signal level matches a target value set according to the linear velocity. When adjusting the recording power such that the reflected light level matches the target value, the target value is not set to a constant level, but set in accordance with the linear velocity. Target values at different linear velocities differ and, with this configuration, an appropriate target value is set and an appropriate recording power corresponding to the linear velocity is obtained.

Abstract: A phase change optical recording medium together with methods for optimally initializing and recording feasible for carrying out read/write/erase operations at multiple recording velocities ranging from 4.8 m/sec to 30 m/sec. Preferably, a recording layer included in the recording medium essentially consists of Ag, In, Sb and Te, with the proportion in atom % of a(Ag): b(In): c(Sb): d(Te), with 0.1≦a≦7, 2≦b ≦10, 64≦c≦92 and 5≦d≦26, provided that a+b+c−d≧97. Initializing the recording medium uses a scanning beam spot from a high power semiconductor laser having energy density input equal to, or less than, 1000 J/m20, scanning speed of the beam spot in the range of 3.5 m/sec to 6.5 m/sec0, and intensity of laser emission equal to, or greater than 330 mW.

Abstract: An optical disc apparatus for recording test data on a predetermined area of an optical disc under varied recording powers to determine an optimum recording power based on the quality of a signal obtained by reproducing the recorded test data. The test data is recorded under adverse recording conditions so as to evaluate the amount of change in quality of the reproduction signal. In order to create adverse recording conditions, the optical disc is tilted or the laser is defocused. A recording power for which the change in signal quality due to the deteriorated recording conditions is sufficiently small is determined as an optimum recording power capable of providing adequate recording margin.