32results about How to "Improve the noise problem" patented technology

The present invention provides a driving circuit and a driving method for light-emitting diodes (LEDs), and a display apparatus using the same. The driving circuit comprises a power switch and a dimmer circuit. The method comprising: detecting a duty of a pulse width modulation (PWM) dimming signal; and when the duty of the PWM dimming signal is less than the predetermined duty, providing an analog dimming signal to the driving circuit. The present invention can be applicable to a display apparatus, and improve a noise problem when a duty of a conventional dimming is too low.

The invention discloses a ship course model predictive control algorithm design method under multiple constraint conditions. The method comprises the following steps of: establishing a ship low-noisemotion control simulation model; designing a course model prediction controller of the ship according to the ship motion control simulation model and establishing a control objective function for themodel prediction controller; determining hard constraint conditions like a rudder angle and a rudder speed of a rudder according to the control objective function and actual operation requirements ofthe ship, and processing the hard constraint conditions; properly broadening the course deviation according to the control objective function to form a soft constraint condition, and processing the soft constraint condition; and according to the control objective function, the hard constraint conditions and the soft constraint condition, performing online optimization to obtain optimal controlleroutput. According to the invention, the noise problem of the rudder device caused by frequent steering in the maneuvering process of the ship is effectively improved, and the stable and low-noise navigation of the ship is ensured.

The invention relates to a low noise stator core lamination and belongs to the field of manufacturing technology of matching parts used by a motor. The low noise stator core lamination is mainly composed of a stator core lamination (3) and a virtual groove which is opened on a pole piece at the bottom of the stator core lamination (3); 1-3 virtual grooves are opened according to the different number of the motor. The lamination has reasonable design and simple structure; the virtual grooves are added on the pole piece of the stator core to lead the frequency of slot ripples to be higher and the amplitude to be lower by taking steps on the inner parts of the motor, thus lowering the noise on the whole, improving the running noise of the motor effectively and improving the product quality.

The invention discloses an air guide assembly and an air supply device. The air guide assembly comprises a plurality of guide vanes, each guide vane is provided with a first end and a second end whichare opposite, each first end is used for being arranged close to an air outlet, each second end is used for being arranged close to the interior of an air outlet duct, and second ends of the at leasttwo guide vanes are not flush with each other, so that the lengths of the parts, extending into the air outlet duct, of the two guide vanes are unequal. Therefore, the plurality of guide vanes are subjected to air cutting and flow guiding in a layered mode, then the air direction is gradually changed through layered air cutting and flow guiding, so that airflow energy losses caused by air cuttingand flow guiding of the plurality of guide vanes can be reduced, the air supply distance and the air supply amount of airflow blown out of the air outlet are guaranteed, and meanwhile, the noise problem can be solved.

The invention discloses a ventilation device and an elevator car provided with the same. The elevator car comprises a car roof, a car bottom, a car wall, a car door and a ventilation device. The ventilation device comprises a ventilation equipment mounting plate, a lower sealing plate, a side sealing plate and ventilation equipment; the ventilation equipment mounting plate, the lower sealing plateand the side sealing plate are connected to form at least two cavities which are different in size and communicate with one another; the ventilation equipment mounting plate and the lower sealing plate are provided with ventilation openings; the ventilation equipment is installed on the ventilation equipment mounting plate, an air outlet of the ventilation equipment is in butt joint with the ventilation opening of the ventilation equipment mounting plate, the ventilation opening of the lower sealing plate is in butt joint with an air inlet of the car roof, and the ventilation opening of the ventilation equipment mounting plate and the ventilation opening of the lower sealing plate are staggered in the height direction and the horizontal direction. When the elevator runs, noise outside theelevator car can be greatly attenuated and running noise of the ventilation equipment and the like are transmitted into the elevator car through the elevator ventilation device, so that the noise problem in the elevator car is remarkably solved, and riding comfort is improved.

The invention is applicable to the field of road and bridge construction, and provides a crushing and screening device for road and bridge construction. The device comprises a screening box body and a crushing device, a cover plate is arranged on the screening box body, a conveying pipeline is arranged on the cover plate, the screening box body communicates with the crushing device through the conveying pipeline, a plurality of screening boxes, rotating supporting pieces and rod pieces are arranged in the screening box body, a support is arranged on the side, away from the crushing device, of the screening box body, a driving mechanism is arranged on the support, a plurality of first clamping pieces are fixed to the rod pieces in the length direction of the rod pieces, the rotating supporting pieces are rotationally connected to the two sides in the screening box body, and the rotary supporting pieces on the two sides are connected with screening boxes through second clamping pieces. The device has the beneficial effects that the plurality of screening boxes can be driven by the rod pieces to turn over, the screening effect is guaranteed, compared with a conventional vibration mode, the device generates low noise, and due to the fact that the two sides of the screen boxes are clamped to the second clamping pieces, the screen boxes can be taken out rapidly and conveniently.

The invention discloses a seven-forward-gear double-clutch automatic gearbox transmission device. A first-gear driving gear is meshed with a first-gear driven gear; the second-gear driving gear is meshed with the second-gear driven gear; the third-gear driving gear is meshed with the third-gear driven gear; the fourth-gear and sixth-gear driving gear is meshed with the fourth-gear driven gear and the sixth-gear driven gear; the fifth-seventh-gear driving gear is meshed with a fifth-gear driven gear and a seventh-gear driven gear; the reverse gear is meshed with the second-gear driven gear; and the upper output shaft normally engaged gear and the lower output shaft normally engaged gear are engaged with the main reduction gear. The transmission mechanism solves the problem that the cost of a transmission mechanism in two modes cannot be effectively controlled because a traditional DCT gearbox is provided with an independent reverse gear shaft or a reverse gear idle wheel is welded to a gear.

The invention relates to an integrated circuit of a current multiplexing gm-boost low-noise amplifier. The integrated circuit comprises a cascode amplification module, a negative feedback loop module,a direct current isolation module and a cascode amplification module; the cascode amplification module is connected to the negative feedback loop module and the cascode amplification module, and thenegative feedback loop module and the cascode amplification module are connected through the direct current isolation module. The integrated circuit of the current multiplexing gm-boost low-noise amplifier comprises a cascode amplification module, a negative feedback loop module, a direct current isolation module and a cascode amplification module, and can alleviate the noise problem under the condition that the gain is improved.

The invention provides a compressor and an air conditioner including the compressor, and relates to the technical field of refrigerating equipment. The compressor comprises a shell, a crankshaft and arotor. A containing cavity is formed in the shell, and the crankshaft and the rotor are arranged in the containing cavity. The crankshaft comprises a first shaft segment and a second shaft segment, the first shaft segment and the rotor are fixed, and a first magnetic part is arranged on the end face of the second shaft segment. A second magnetic part is arranged at the position, opposite to the first magnetic part, of the inner wall face of the shell. The magnetism of the second magnetic part is opposite to that of the first magnetic part. The crankshaft is sawn through attraction force between the second magnetic part and the first magnetic part, and meanwhile the crankshaft can transmit the attraction force to the rotor; and therefore upward jumping of the crankshaft and the rotor is reduced, the noise problem generated due to the fact that the crankshaft collides with other components of the compressor is solved, stability of the crankshaft is improved, and then operation stabilityof the compressor is improved.

The invention, belonging to radio frequency communication technical field, provides an integrated RF GPS active antenna, aiming at solving the problems that the GPS receivers of current active antennas are difficult to miniaturize, the modules are complex in connection and low in receiving sensitivity, which influences initial positioning time and positioning precision. The technical proposal of the invention adopts an integrated RF GPS active antenna; a GPS active antenna is optimized, and impedances are matched between the component parts, interconnected losses are reduced; total noise index is reduced and the receiving sensitivity of the GPS positioning device is improved, thus the initial positioning time and precision of the GPS positioning device are remarkably improved. The integrated RF GPS active antenna is easy to be miniaturized and is particularly suitable to be integrated with the functional module of mobile communication equipment such as mobile phone and PDA.

The invention provides a dust collecting combination cabinet. The combination cabinet comprises a cabinet body and a dedusting module, wherein the cabinet body is used for placing mechanic equipment, and the dedusting module is arranged in the cabinet body and used for conducting dust collecting treatment on dust which is produced by the mechanic equipment during working. The dedusting module comprises a funnel solder mask part and a sand-blasting cabinet draught fan unit, wherein the funnel solder mask part is fixedly arranged inside the cabinet body, and the lower portion of the funnel solder mask part is sleeved with a dust collecting bag; the sand-blasting cabinet draught fan is arranged on the lower portion of the funnel solder mask part and used for sucking dust on the upper portion of the funnel solder mask part into the dust collecting bag. The mechanic equipment is placed on the funnel solder mask part. According to the dust collecting combination cabinet, the strength of dust absorbing is high; meanwhile, the mechanic equipment is stored in the dust collecting combination cabinet body, so that the noise problem is also solved greatly; in addition, the design of the cabinet body enables the cabinet body to have high-strength sealing performance, and accordingly the purposes of water resistance, dust resistance and corrosion resistance are achieved.