A hydraulic drive device for performing load sensing control. The hydraulic drive device fulfills the same function as devices provided with an unload valve, recovers the energy of hydraulic oil discharged to a tank from a main pump, and effectively uses the energy of hydraulic oil generated at the main pump. A hydraulic motor (52) is disposed on a control oil path (51) for connecting a tank (T) with a second hydraulic oil supply path (4a) which supplies the discharge oil from a main pump (2) to flow control valves (26a to 26h). A power generator (53) is connected to the rotating shaft (52a) of the hydraulic motor (52). The maximum load pressure (PLmax) is detected by means of a pressure sensor (54). A second control device (55) controls the power generation of the power generator (53) such that the hydraulic motor (52) rotates when the discharge pressure of the main pump (2) becomes higher than the target control pressure (Pun) in which a pre-set value (Pb) is added to the maximum load pressure (PLmax). The alternating-current power generated by means of the power generator (53) is stored in a battery (41).

Hydraulic drive device for construction machine

A digital filter is designed by combining unit filters (L 10 ′, H 10 ′) having a predetermined asymmetric numerical sequence as filter coefficients (H 1 to H 3 ) Thus, it is possible to automatically obtain a desired digital filter coefficient only by combining the unit filter Moreover, a symmetric numerical sequence {−1, 0, 9, 16, 9, 0, −1}/32 is divided at the center into two parts and one of them is used as the asymmetric filter coefficients (H 1 to H 3 ) This reduces the number of taps required for the digital filter designed, eliminates use of a window function, and prevents generation of a discretization error in the filter characteristic obtained

Digital filter design method and device, digital filter design program, and digital filter

Disclosed is a method of volume controlling, including: (a) receiving a volume adjusting command; (b) determining if the volume corresponding to the volume adjusting command is in a predetermined volume range; (c) if the volume corresponding to the volume adjusting command is in the predetermined volume range, utilizing the volume adjusting command to adjust a current volume; (d) if the volume corresponding to the volume adjusting command does not fall in the predetermined volume range, then (d1) utilizing the volume adjusting command to adjust the current volume; and (d2) computing the using time for the current volume, and adjusting the current volume referring to the predetermined volume range when the using time reaches a predetermined value.

Method of volume controlling

When an emphasis setting of a next track is different from that of a current track, a silent signal having the emphasis setting of the next track written in its subcode information is output for a predetermined time prior to reproduction of the next track. The emphasis setting is changed for the next track while the silent signal is being output, so that the next track can be reproduced appropriately without involving an unwanted lack in its leading portion.

Digital audio signal reproducing apparatus

Provided is an auditory sensibility correction device which can add a preferable loudness characteristic to an output sound without depending on a sound source characteristic of an audio signal even when the audio signal has a high band or low band subjected to a loudness correction. The auditory sensibility correction device (1) includes: loudness processing means (2) which executes a loudness process on an audio signal in accordance with a band; level difference calculation means (4) which calculates a level difference between a signal level of each band and a signal level of all the bands; gain offset means (4) which performs an offset process of a gain required by the entire band signal level according to the level difference of each band; and gain setting means (5) which applies the correction gain of each band to the audios signal of each band which has been subjected to the loudness process.

Auditory sensibility correction device

PURPOSE:To make the sound quality control variable in response to a volume step or the like while preventing the saturation of sound by constituting each sound quality control circuit in a digital signal processor (DSP) and controlling each function from a control microcomputer in the lump. CONSTITUTION:Various commands such as sound source selection, sound volume adjustment and sound quality control are inputted to a CPU 4 from a key pad matrix 6. A program memory (ROM) 21, a program counter 22, an I/O interface 23 and a clock oscillator 24 are connected to a program bus 20 and the interface 23 is connected to a control microcomputer 4 and A/D, D/A converters 8, 11. On the other hand, a data memory (RAM) 25, an address counter 26 or a multiplier 27, an adder 28, an accumulator 29, an arithmetic unit 30 are connected to the data bus 31. The communication between the DSP 10 and the CPU 4 are executed by the serial clock synchronization system using 8-bit address and 10-bit data and the address is the RAM address in the DSP defined by the DSP program.

Sound quality controller

PURPOSE: To keep an input level to a volume control circuit in constant invariably, by changing the factor of a multiplier which multiplies by the factor on an audio signal, corresponding to a ratio between the output level, and the targeted level of the multiplier. CONSTITUTION: In a volume control device using a digital signal processor DSP, the audio signal from a terminal IN is inputted to a multiplier KA. The output INP, from which a DC component and high frequency noise are eliminated, is smoothed at an LPF 1 through a full-wave rectifying absolute value circuit ABS, and the level LEV of it is inputted to a comparator CMP. The CMP compares the LEV with a targeted level Vc, and inputs a multiplier KB which corrects a ratio component COM to a control factor. The output control factor of the KB is inputted to an LPF 2 which varies response speed, and the output changes a factor value multiplied on an input signal by the multiplier KA, through a limiter LIM, and a regulator LEG, corresponding to the COM. Therefore, the level INP inputted to a volume control circuit KV can be kept in constant even when the level of the input IN changes. COPYRIGHT: (C)1987,JPO&Japio

Sound volume control device

PURPOSE: To issue plural number of instructions for sound quality by a common switch, by allowing a control microcomputer to incorporate with a program which performs different kinds of sound quality control corresponding to the instruction of the number of times of switch operations from the outside. CONSTITUTION: Each output of an FM tuner 1, an AM tuner 2, and a cassette deck amplifier 3, is inputted to an A/D converter 8 having a switching function, and each signal level of the tuners 1 and 2 is inputted to an A/D converter 9. A control microcomputer CPU4 controls change-over switches in the converters 8 and 9 corresponding to the key operation of a key pad matrix 6, and inputs the output of the converter 8 to a digital signal processor DSP10. Also, the CPU4 selects a built-in program corresponding to the number of times of the key operations of the matrix 6, and changes a factor supplied to a sound quality control device constituted in the DSP10, and performs the sound quality control, such as loudness, bass treble, and tone control. COPYRIGHT: (C)1987,JPO&Japio

Sound quality control device

PURPOSE:To attain a simple program ATC function in a digital signal processing processor by obtaining a filter coefficient KT obtaining a high frequency attenuation corresponding to a signal level in a microcomputer and giving it to the processor so as to apply signal processing of sound quality control. CONSTITUTION:In figure (a) shows a signal flow and the transfer function of the ATC circuit is expressed as H(z)=KA/(1-KT.Z ), where KA=SV/2 and KT=1-KA. The attenuation of the ATC circuit at 10kHz is changed by the signal level SV as shown in figure (b). However, the region A is not attenuated because of a strong field area. Further, since the region C is a weak electric field region, the attenuation is made constant as -24dB and the intermediate region B is a linear change region.

Automatic sound quality control circuit

PURPOSE:To change smoothly the stereo separation of an FM receiver in response to the reception electric field by obtaining a matrix coefficient to obtain an optimum stereo separation. CONSTITUTION:A signal level obtained from an FM receiver is inputted to a control microcomputer and main/sub stereo sound signals (L+T), (L-R) demodulated by the receiver are inputted to a digital signal processor, they are separated into left/right signals L, R by stereo demodulation matrixes L=(L-R).KS0+(L+R).KS1, R=(L-R).KS2+(L+R).KS3, and in such a signal processing, matrix coefficients KS0.KS3 realizing the optimum stereo separation to the signal level are obtained in the microcomputer. That is, in changing the coefficients KS0-KS3 of the stereo demodulation matrixes in the digital signal processor, the stereo separation is changed, then the stereo separation is changed smoothly at the fluctuation of electric field of the FM receiver.

Hashimoto Junji

Papers

Sound quality controller

Sound volume control device

Sound quality control device

Automatic sound quality control circuit

Control circuit of automatic stereo separation