39results about How to "No high frequency interference" patented technology

The invention provides a spacecraft fluid ring reaction performing mechanism. The spacecraft fluid ring reaction performing mechanism comprises a mounting base used for mounting a fluid ring and corresponding devices, the fluid ring used for generating angular momentum, an electromagnetic pump assembly which mainly comprises a permanent magnet or an electromagnet and an electrode board pair and is used for driving liquid in the fluid ring to do controllable-speed flowing, a filling liquid which employs a conductive liquid material, is mounted in the fluid ring and flows under the driving action of the electromagnetic pump assembly, and a shielding box which covers outside an electromagnetic pump and is used for shielding an electric field and a magnetic field to prevent interference of external devices. The spacecraft fluid ring reaction performing mechanism utilizes the electromagnetic pump to drive the liquid ring to generate angular momentum to realize attitude control of a spacecraft, can provide multi-axial control moments for attitude control of spacecrafts especially micro satellites, requires no mechanical rotation bearing part and further has properties of high reliability, simple structure and small energy consumption.

The invention relates to a motor speed adjusting device. A control circuit of the motor speed controller mainly comprises a PWM (pulse-width modulation) unit, a main control unit and a load unit, wherein the PWM unit outputs a pulse wave with an adjustable duty ratio to the main control unit, the main control unit is connected with two ends of a capacitor of the load unit in parallel so as to be used for controlling the capacitor to charge or discharge, the capacitor of the load unit is in serial connection on a motor needing of speed adjustment, the PWM unit outputs the pulse wave to the main control unit, the main control unit taken as a switch is connected at the two ends of the capacitor of the load unit in parallel, the load unit and the capacitor are connected on the motor in series, the pulse wave controls the connection and the disconnection of the switch to carrying out charge and discharge on the capacitor, when the duty ratio of the pulse wave is adjusted, and changed pulse signals are converted into the change of charge and discharge time of the capacitor by the main control unit, so that the reactance value of a reactor can change along with the change of the charge and discharge time, so as to realize stepless speed adjustment. Compared with the prior art, the motor speed adjusting device is easy in circuit, easy to realize, low in manufacturing cost, simultaneously can not generate high-frequency interference and can realize the stepless speed adjustment on the motor.

The invention discloses a direct current feedback electronic load. The direct current feedback electronic load comprises a mains supply rectifying circuit, a power supply circuit, a control loop, a DC/DC booster circuit, a voltage-multiplying direct current feedback circuit, a mains supply synchronous drive DC/AC circuit and a tested power supply. The direct current feedback electronic load overcomes the defects of existing electronic load products and is a novel power electronic device which is used for delivery tests of various power supplies and chargers and can simulate the charging and resistance load characteristics of various mobile phones; the direct current feedback electronic load can achieve stepless regulation of a simulated resistance value and the regeneration and utilizationof electric energy and has the advantages of being capable of saving the energy, free of high-frequency interference, small in size, low in weight, capable of saving the installation space, excellentin test performance and the like.

The invention discloses a fiber sensing system based on a fiber laser, and belongs to the technical field of fiber sensors. The main structure of the system comprises a pump source (1), an optical multiplexer (2), and an Er-doped optical fiber (3). According to the invention, a sine signal is taken as a modulation signal, and no high-frequency interference can be generated, so the system is more reliable in working, is high in sensing precision, and is wide in application range.

The invention provides a micro-stress sensor for bridge monitoring, and belongs to the technical field of optical fiber sensors. The sensor is mainly provided with a pumping source (1), an optical wavelength division multiplexer (2), and an erbium-doped optical fiber (3). The sine signal is used as a modulation signal, high-frequency interference cannot be generated, and the sensor has the advantages of being more reliable in work, and high in sensing precision.

The invention discloses an electric heating control circuit for an air resistance furnace. The electric heating control circuit is composed of four stage heating control circuits, a main switch and a main control circuit. In the four stage heating control circuits, a first stage heating control circuit is used for controlling an air preheating section of the air resistance furnace, and a controlled electric heating element is arranged at the front end of the air resistance furnace and close to an air inlet; an electric heating element controlled by a fourth stage heating control circuit is arranged at the position close to an air outlet; and electric heating elements controlled by second and third stage heating control circuits are arranged between the first stage heating control circuit and the fourth stage heating control circuit. An external alternating current power supply is accessed through the main switch, and the four stage heating control circuits are arranged at the lower end of the main switch; and the four stage heating control circuits are connected with the main control circuit which sends drive signals and temperature setting signals to control the four stage heating control circuits.

The invention discloses a temperature sensor based on a Mach-Zehnder interference structure, and belongs to the technical field of optical fiber sensors. The main structure of the temperature sensor comprises a pumping source (1), an optical wavelength division multiplexer (2), an Er-doped optical fiber. By use of the temperature sensor, a sinusoidal signal is taken as a modulation signal, no high-frequency interference is generated, and the temperature sensor has the characteristics of being reliable in working, high in sensing accuracy, wide in application range and the like.

The invention relates to a temperature detection system based on a Michelson interference structure and belongs to the technical field of optical fiber sensors. The temperature detection system mainlycomprises a pumping source (1), a first optical coupler (2), an optical wavelength division multiplexer (3) and the like. The temperature detection system provided by the invention uses a sinusoidalsignal as a modulating signal, can not produce high-frequency interference and has the characteristics of more reliable work, high sensing precision and wide application range.