Abstract: The present invention provides a sound-field production apparatus comprising a direct-sound-generating means for generating a direct sound from a sound signal supplied to the direct-sound-generating means and a reflected-sound-generating means for generating a sound serving as a substitute for a sound obtained as a result of reflection of the direct sound at a level lower than the direct sound with a timing lagging behind the direct sound from the sound signal supplied to the reflected-sound-generating means. The sound-field production apparatus makes it possible to reproduce an impressive sound field that gives a better feeling of presence on the scene as a sound field in a movie theater or the like does by creating a sound-field space having an effect of sound-image broadening.

Abstract: A recording and/or reproducing apparatus for a disc-shaped recording medium includes an optical head, a disc rotationally driving unit, a transfer unit, and an eccentricity amount measuring unit. The eccentricity amount measuring unit includes a controller and an error signal generator which generates an error signal exhibiting the amount of relative displacement of a light beam irradiated from the optical head onto the disc-shaped recording medium with respect to a track on such medium. The controller detects the peak and trough values of the error signal supplied from the error signal generator and compares a difference signal exhibiting a difference between the detected peak and trough values and a reference value to calculate the amount of eccentricity of the disc-shaped recording medium based on a comparison output signal.

Abstract: A recording and/or reproducing apparatus for a disc-shaped recording medium which includes an optical head, a motor driven table for rotating the disc-shaped recording medium, a slider for moving the optical head relative to the motor driven table in a radial direction of the disc-shaped recording medium, an error signal generator for generating an error signal exhibiting the amount of the relative shifting of a spot of a light beam irradiated from the optical head on the disc-shaped recording medium with respect to a track on the disc-shaped recording medium, and a controller which detects a peak value and a trough value of the error signal supplied from the error signal generator and compares the difference between the detected peak value and the detected trough value with a reference threshold value to generate a drive signal for the slider on the basis of the comparison, wherein the drive signal from the controller is supplied to the slider to shift the optical head relative to the motor driven table in t

Abstract: A sound reproducing system in which virtual image orientation processing of audio signals for at least two rear speakers disposed in directions from a listener close to the right-back direction from the listener is performed by a virtual sound orientation processor so that the listener can have a sound image at a position different from each of real speaker positions at which the rear speakers are placed, and/or so that the listener is unconscious that sounds are radiated from the rear speakers placed at real speaker positions. This virtual image orientation processing is performed according to acoustic transfer coefficients of transfer of sounds from the rear speakers to the listener's ears when the rear speakers are placed at virtual speaker positions different from the real speaker positions.

Abstract: A differential pressure &Dgr;PLS between a delivery pressure of a hydraulic pump 2 and a maximum load pressure among a plurality of actuators 3a-3c is maintained at a target differential pressure &Dgr;PLSref by pump displacement control means 5. The target differential pressure &Dgr;PLSref is modified depending on an engine rotational speed by introducing a differential pressure &Dgr;Pp across a throttle 50 disposed in a delivery line of a fixed pump 30. An unloading valve 80 has first and second auxiliary control pressure chambers 80e, 80f to which the differential pressure p across the throttle 50 is introduced, and a target differential pressure &Dgr;Pun of the unloading valve is also modified in match with change in the target differential pressure &Dgr;PLSref modified by the operation driver 32. Stable load sensing control is thereby achieved without being affected by the engine rotational speed.

Abstract: An engine speed control system for a construction machine is arranged in association with its hydraulic circuit, which has main pumps, a communication line through which input ports of travel-controlling directional control valves are connected with each other, and a travel-controlling communication valve arranged in the communication line.

Abstract: A hydraulic drive system wherein differential pressures across flow control valves are controlled by pressure compensating valves to become the same value, i.e., a differential pressure .DELTA.PLS, and the differential pressure .DELTA.PLS is maintained at a target differential pressure .DELTA.PLSref by a pump displacement control system. For modifying the target differential pressure .DELTA.PLSref depending on change in rotational speed of an engine, a flow rate detecting valve is disposed intermediate between delivery lines of a fixed displacement hydraulic pump and a differential pressure .DELTA.Pp across a variable throttle of the flow rate detecting valve is introduced to a setting modifying unit to thereby modify the target differential pressure .DELTA.PLSref. The flow rate detecting valve changes an opening area of the variable throttle depending on the differential pressure .DELTA.Pp depending on the rotational speed of the engine.

Abstract: A hydraulic drive system of the invention comprises a plurality of flow rate sensors (10A, 10B) for detecting respective flow rates supplied to a plurality of hydraulic actuators (3A, 3B), valve controllers (11A, 11B) for respectively controlling a plurality of flow control valves (40A, 40B) such that the flow rates detected by the plurality of flow rate sensors are coincident with the flow rates instructed by a plurality of control levers (5A, 5B), and a pump tilting controller (12; 12A-12F) for controlling a delivery rate of a hydraulic pump (1) such that the delivery rate of the hydraulic pump is smaller by a predetermined flow rate (.DELTA.Q.sub.ref ; X.sub.ref) than the total of the flow rates instructed by the plurality of control levers. The pump tilting controller controls the delivery rate of the hydraulic pump (1) by using flow rate deviations (.DELTA.Q.sub.1, .DELTA.Q.sub.

Abstract: A pair of equilibrium output signals P(+) and P(-) from a 1-bit D/A converter IC, which is made up of an oversampling filter, noise shaper and a pulse converter, are supplied to a pair of field effect transistors connected in a common drain configuration. A constant current I.sub.0 is supplied to the common drain from a constant current source and at least one of the source output currents is converted by an output circuit into a voltage. In this manner, a 1-bit D/A converted output signal freed of fluctuations of the power source is provided at an output terminal.

Abstract: A signal input selecting circuit comprises a plurality of signal input terminals, a first switch device for selecting one of signal electrodes of the signal input terminals to be connected with a signal processing block, a second switch device for selecting one of reference electrodes of the signal input terminals to be connected with a reference potential point, a third switch device for connecting the second switch device with a current supplying portion, and a voltage detector for detecting a voltage corresponding to an impedance of the second switch device.

Abstract: A valve apparatus (30) of a hydraulic valve system has a plurality of directional control valves (78, 79) that control the flow of the hydraulic fluid to a plurality of actuators (34, 35). Check valves (59, 60) are provided for taking out, as a first control pressure, a maximum load pressure among load pressures of the plurality of actuators, first pressure generating devices (89, 91) for generating second control pressures different from the first control pressure, and second pressure generating devices (90, 92) for generating third control pressures different from said first and second control pressures.

Abstract: A first hydraulic circuit comprises a variable displacement hydraulic pump driven by a prime mover, a variable displacement hydraulic motor connected in a closed circuit to the variable displacement hydraulic pump, and a displacement control means for controlling a displacement of the variable displacement hydraulic motor. A second hydraulic circuit comprises a hydraulic pump driven by the prime mover, and drives a loader attachment. A displacement limitation means limits the maximum value of the displacement of the variable displacement hydraulic motor in accordance with a load pressure of the second hydraulic circuit. For example, the displacement limitation means reduces the maximum value of the displacement of the variable displacement hydraulic motor in proportion to the pressure in the second hydraulic circuit. The motor torque is controlled by directly adjusting the displacement of the motor, and a load of the hydraulic motor can thus be stably controlled.

Abstract: A magnetic disk device, where a slip pad is adhered on a hub table secured to a spindle, is disclosed, in which the hub table has a circular groove portion formed in the disk hub attracting surface portion coaxially to the spindle and at least a part of the outer peripheral portion of the slip pad is installed in the groove portion.

Abstract: Apparatus for rotating and driving a magnetic disk in which a hub of a magnetic disk is magnetically attracted against a hub support, and a driving pin provided on the hub support is engaged with an engaging hole provided in the disk hub. The hub support has a magnetic attractive surface which is high in magnetic flux density in the vicinity of the driving pin and continuously and gradually lowers in magnetic flux density as a function of distance from the driving pin, so that the magnetic disk can be attracted by an approximately uniform net attractive force over the entire surface of the hub support.

Abstract: A variable displacement hydraulic pump and a hydraulic motor are connected in a closed circuit. A pressure oil supply means includes the variable displacement hydraulic pump and a tilting controlling means for controlling a tilt angle of the hydraulic pump and supplies an amount of pressure oil corresponding to the tilt angle of the hydraulic pump to the hydraulic motor. When rotation of a prime mover is detected by a rotation detecting means, an opening and closing valve is changed over to a first position in which the pressure oil supply means is permitted to supply pressure oil. When stopping of the prime mover is detected by the rotation detecting means, the opening and closing valve is changed to a second position in which the pressure oil supply means is inhibited from supplying pressure oil.

Abstract: A PWM digital-to-analog converter is disclosed in which a value representing a differential between a first pulse width modulated waveform based upon input digital data and a second pulse width modulated waveform representing a 2's complement version of the input digital data is produced by a differential amplifier and high frequency components thereof are attenuated to produce an analog output signal and with an improved distortion factor.

Abstract: A hydraulic drive system is equipped with an engine, a plurality of hydraulic pumps adapted to be driven by the engine and including a variable displacement hydraulic pump provided with a displacement varying mechanism, a hydraulic motor connected to the variable displacement pump, a hydraulic actuator for actuating the displacement varying mechanism of the variable displacement hydraulic pump, a working fluid feeding means for feeding the hydraulic actuator with a hydraulic fluid of a pressure according to the degree of control of an accelerator lever which is adapted to instruct a target revolution number of the engine, and a low-pressure circuit for allowing the hydraulic fluid to be discharged therethrough from the hydraulic actuator.

Abstract: The present invention relates to a digital transmission system provided with a transmitter 11 and a receiver 12, wherein the transmitter 11 comprises a first clock extracting device 13, 14 for detecting a synchronizing signal contained in a first digital audio interface (DAI) format signal from the receiver 12 and generating a first clock signal of a predetermined frequency in being phase-locked with the synchronizing signal, a data read-out device 4 for reading out data from a recording medium on the basis of the first clock signal, and a first encoder 5 for encoding the data from the data read-out device 4 in a second digital audio interface (DAI) format signal on the basis of the first clock signal, while the receiver 12 comprises second clock extracting device 6, 7 for detecting a synchronizing signal contained in the second DAI format signal and generating a second clock signal of a predetermined frequency in being phase-locked with the synchronizing signal, a decoder 8 for decoding data from the second

Abstract: By a process for preparing halogenated benzene derivatives comprising distilling or stripping a mixture of the isomers of a halogenated benzene derivative containing a hydrogen halide to remove the hydrogen halide from the isomeric mixture of the halogenated benzene derivative and then contacting with a zeolite adsorbent for selectivity separating the desired isomer of the halogenated benzene derivative, it is possible to prevent from degrading the zeolite adsorbent. And it is possible to separate selectively industrially an desired isomer of the halogenated benzene derivative for a long time without reduction of productivity and to separate selectively the desired isomer in high purity.

Abstract: A solenoid operated valve apparatus in which a solenoid device includes an inner yoke, a plunger guide disposed in the opposed relationship with the inner yoke, a plunger movably accommodated in s space formed between the inner yoke and the plunger guide, a bobbin frame disposed to surround the inner yoke and said plunger guide, a coil wound around the bobbin frame, and an outer yoke disposed to surround the coil. The bobbin frame is made of a polymeric material, and is adhered to the inner yoke and the plunger guide in a unitary structure.