32results about How to "Eliminates temperature drift" patented technology

The head/disk tester of the invention has a housing 43 that houses spindle 44 that rotatingly supports a magnetic disk 31. The housing supports a moveable carriage 30 that, in turn, supports a magnetic head 32. Positioning means 39 and 41 are used to move the carriage and the magnetic head across the magnetic disk. These positioning means include stepper motors that realize coarse positioning of the magnetic head, and a piezo actuator 37 that is used for fine positioning. Linear encoders 40 and 42 located at both sides of the carriage provide feedback information to a closed-loop positioning system that controls the piezo actuator. A set of special signals ("servo bursts") pre-written at a given track of the magnetic disk is used as an additional source of feedback information for the same closed-loop positioning system. This positioning system includes a servo analyzer 45 that reads and processes servo burst signals from the magnetic disk, and a position controller 49 that controls the piezo actuator. The controller contains two control loops: a proportional-integral-derivative (PID) loop and an additional servo burst loop. During any movement of the magnetic head to a prescribed command position, the servo burst feedback is turned off, and feedback from linear encoders is used by the PID loop to move the head. When the magnetic head reaches the prescribed command position, servo burst loop is turned on; it changes the command position of the PID loop in a way to keep the ratio of pre-written burst signals constant. As a result, the position of the magnetic head with respect to the data track remains the same for as long as necessary, even in unstable temperature conditions.

The invention discloses an optical carrier microwave gyroscopic method for detecting angular velocity, which is used for measuring the rotational angular velocity through the forward and backward bidirectional high-stability microwave generated in the optical fiber ring by a bidirectional photoelectric oscillator based on the phase-locked frequency doubling technology. The core of the method is the application of the frequency doubling technology, the microwave oscillation frequency in one direction is locked to the high-stability standard time reference source, the relative cavity length of the photoelectric oscillator in the other direction is stabilized, temperature drift and optical parasitic noise of the fiber ring-shaped cavity are eliminated, and the signal-to-noise ratio of the bidirectional oscillation difference frequency signal caused by the Sagnac effect is improved greatly. The optical carrier microwave gyroscopic method for detecting angular velocity, provided by the invention, has the characteristics of being high in measurement precision and easy to realize, and so on.

A pressure regulator includes: a pressure-regulating valve configured to regulate pressure of a fluid supplied from a fluid supply source; a first pressure sensor configured to measure the pressure regulated by the pressure-regulating valve; a second pressure sensor located downstream of the first pressure sensor; a PID controller configured to produce a correction pressure command value for eliminating a difference between a pressure command value and a pressure value of the fluid measured by the second pressure sensor; and a regulator controller configured to control operation of the pressure-regulating valve so as to eliminate a difference between the correction pressure command value and a pressure value of the fluid measured by the first pressure sensor.

The invention provides a digital power supply control circuit and method. The digital power supply control circuit comprises an EMI filter, a filter capacitor, a phase-shifted full-bridge converter, a high-frequency transformer, a rectifier filter circuit, a driving protection circuit and a DSP control circuit. The phase-shifted full-bridge converter outputs high-frequency AC square wave voltage with adjustable pulse widths according to bus voltage. The high-frequency transformer is used for realizing electrical isolation and boosting. The DSP control circuit is used for sampling the output voltage and the output current, comparing the output voltage and the output current with reference values, and outputting a PWM control signal with a certain duty cycle according to a comparison result. The driving protection circuit is used for driving a switching tube in the phase-shifted full-bridge circuit to operate according to the PWM control signal. When a power supply generates over-voltage, over-current or an over-temperature fault, the driving protection circuit may switch off the switching tube in the phase-shifted full-bridge circuit according to the PWM control signal output from the DSP control circuit to realize the protection of a power device.

The invention relates to a correcting method, a correcting device and a measuring apparatus for laser ranging. The correcting method for the laser ranging solves the problems of long circuit response time, easiness in mechanical fault generation, short service life or high cost and easiness in same frequency interference generation of the prior art. The correcting method includes steps of enabling an emitting device to emit a first light wave, wherein one part of the first light wave is received by a first receiving device and serves as the first signal of an external light path, and the other part of the first light wave is received by a second receiving device and serves as the second signal of the external light path after being reflected by a measured object; enabling an emitting device to emit second light wave of different wavelengths, wherein one part of the second light wave is received by the first receiving device and serves as the first signal of an internal light path, and the other part of the second light wave is received by the second receiving device and serves as the second signal of the internal light path; comparing phases of the four paths of signals, outputting internal light path phase signals and external light path phase signals which only have part of basal reference, and comparing the phases of the internal light path phase signals and external light path phase signals to output phase signals without basal reference.

The invention relates to the technical field of nuclear instruments, and in particular relates to a corrective LED spectrum-stabilization device based on a program-controlled constant-current source and a photodiode, and a method thereof, used for solving the spectrum line drift problem to a scintillator-based energy spectrum detection system due to temperature change. The program-controlled constant-current source is controlled by a main controller to drive an LED, so that an optical pulse signal capable of simulating photon emission after a gamma ray is absorbed by a scintillator is generated; a spectrum line peak position generated by LED optical pulse can be obtained in a gamma energy spectrum detected by the energy spectrum detection system; drift of the LED light emission amount along with temperature change is corrected through a photodiode path; then, the gain is adjusted by utilization of the corrected LED peak position as the spectrum line reference peak, so that spectrum stabilization is carried out; temperature drift of a photomultiplier and electronics is eliminated; finally, the gain is adjusted again by calling in of a scintillator photoyield temperature change curve; and thus, temperature drift of the scintillator is eliminated. Precise spectrum stabilization of the scintillator energy spectrum detection system in different temperature conditions can be realized.

The invention discloses an electronic load precise dual-temperature correction method. The method includes the steps of obtaining a referential correction value under the current environment temperature, conducting correction on a tensile load value obtained through measurement under the current environment temperature according to the referential correction value so that the influence on factors such as temperature drifting of circuit components can be eliminated, thereby obtaining an actual tensile load value under the current environment temperature, conducting comparison operation through the actual tensile load value under the current environment temperature and a set value which is stored in a calculating and processing unit in advance, and obtaining a precise correction value, and outputting the precise correction value to a tensile load circuit so that the tensile load value in the tensile load circuit can be changed and the tensile load value in the tensile load circuit can be accurately corrected. The invention further discloses an electronic load precise dual-temperature correction circuit.

The present invention discloses an improved mass flow detector interface ("MFSI") circuit for detecting and measuring the mass flow of a gas and providing an output voltage proportional to said mass flow in a mass flow controller. The mass flow detector interface circuit includes upstream and downstream mass flow detection elements, and an accurate current source for driving the circuit. The circuit also includes an operational amplifier for summing the upstream voltage of the upstream sensing element and the downstream voltage of the downstream sensing element and providing an output signal. A reference voltage source is electrically connected to the positive node of the operational amplifier. The upstream shunt resistor and the downstream shunt resistor share a common node at the negative node of the operational amplifier, and are electrically connected in parallel with the upstream and downstream mass flow detection elements. The mass flow detector interface circuit of the present invention also includes a reference resistor electrically connected between the reference voltage source and the positive node of the operational amplifier, and a feedback resistor electrically connected between the operational amplifier between the positive node and the output. The operational amplifier of the mass flow detector interface circuit provides an output signal proportional to the change in resistance of the upstream and downstream detection elements and thus proportional to the gas mass flow.