39results about How to "Eliminate zero drift" patented technology

The invention discloses a portable and non-intervention X-ray generator tube current measuring instrument, comprising a detector and a host. The detector is connected with the host by a multi-core cable and comprises a pincerlike current sensor and a control component in the pincerlike current sensor. The detector and the host are in a dual-wire connection structure with V+ and V- wires to avoid the influence on output signals by differential voltage signals formed on a ground wire by supply currents; as a calibration factor memory module is added in the host, the detector has interchangeability; an FPGA (Field Programmable Gate Array) data processor enhances precision of measurement on narrow-pulse-width current signals; and the host and an upper computer connected with the host control range gear and zero setting of the pincerlike current sensor and obtain working conditions of the pincerlike current sensor, thereby overcoming the defect of inconvenience in host operation and data reading for a measuring person.

The invention discloses an electrophysiological catheter with a pressure sensing function. By the electrophysiological catheter, temperatures can be compensated according to temperature changes in theapplication, zero temperature drifts of contact pressure measurements can be remarkably eliminated, measuring errors can be reduced, the stability of the contact pressure measurements can be improved, and the production cost of the electrophysiological catheter can be reduced. The electrophysiological catheter comprises a head electrode, a second electrode, a pressure sensor, a catheter body, a handle, a connector and an internal circuit board. The head electrode, the second electrode and the pressure sensor are sequentially arranged at the front end of the catheter body. The catheter body isinserted into the human body from the outside, and the rear end of the catheter body is connected with the handle to facilitate holding. The connector is arranged at the tail end of the handle, and is constructed as a data and power combined interface to be connected with a radio frequency energy source, a power source and a data transmission interface. The internal circuit board is arranged in the handle, is provided with a pressure detecting circuit to receive signals of the pressure sensor, and is also provided with a micro processing unit to acquire pressure data according to the signalsof the pressure sensor.

The invention discloses a test method for obtaining the Darcy coefficient of a hole wall, and application thereof, and aims to solve the problems as follows: the Darcy coefficient of the hole wall isobtained mainly through a comparative measurement method of a test model at home and abroad currently; but, only the Darcy coefficient in the forms of a specific model and a single wall plate can be obtained through the method; hole wall boundary layer change influence due to model blockage change cannot be evaluated; furthermore, a measurement result includes deviation due to different trains andmodels; and the result accuracy is relatively low. The invention provides the test method for conventional transonic wind tunnel hole wall Darcy coefficient measurement, and application thereof in asubsonic and transonic open-hole wind tunnel. Darcy coefficients different in Mach number and model attack angle state can be obtained in the invention; furthermore, influence of hole wall boundary layer characteristics, test running Reynolds numbers and the like can be included in the relation of the Darcy coefficient and a model lift coefficient; the method is suitable for a subsonic and transonic running range, the Mach number of which is less than 0.95; and a limiting condition is that large-area flow separation does not occur on a model lift surface.

The invention provides a liquid level detection system for medical instruments, which is used to solve the problem of inaccurate sample needle sampling in the prior art, excessive sampling of unnecessary liquid by the sample needle, resulting in cross-contamination. The system includes: an excitation source, which excites the sample needle to generate an induced charge; a sample needle, which is used to absorb the measured liquid and output its own induced charge; an acquisition circuit, which collects the induced charge output by the sample needle in real time and converts it into a corresponding induced charge analog signal; AD sampling circuit, which converts the analog signal of the induced charge into a digital signal of the induced charge; MPU circuit, which is used to compare the digital signal of the induced charge with the preset non-contact digital signal, and confirm whether the sample needle is in contact with the liquid surface; digital output circuit for outputting confirmation results. The invention can accurately confirm that the sample needle touches the liquid surface, thereby controlling the liquid suction stroke of the sample needle and ensuring that the liquid sucked by the sample needle is the preset sampling liquid.

The invention relates to the field of machinery, in particular to a magnetic resistance measurement sensing system and a magnetic resistance measurement sensing method, through which the zero drift amount can be decreased during long-term use. The magnetic resistance measurement sensing system comprises a rigid lever, a pendulum magnet, two limit magnets, a Hall element and a computation system, wherein the rigid lever is provided with a fixed rotation shaft, a force application end and a measurement end; the force application end and the measurement end swing by taking the fixed rotation shaft as center; the pendulum magnet is connected with the measurement end of the rigid lever; the limit magnets are respectively arranged at two sides of the pendulum magnet and in a magnetic field range of the pendulum magnet; the limit magnets are opposite to the magnetic poles with same polarity of the pendulum magnet; when the rigid lever swings by taking the fixed rotation shaft as center under the action of external force, the pendulum magnet is close to the limit magnet at one side and far away from the limit magnet at the other side at the same time; the Hall element is arranged in the magnetic field range of the pendulum magnet and between the pendulum magnet and the limit magnets, and used for detecting the magnetic field change of the pendulum magnet and outputting signals; and the computation system is used for receiving the signals and computing the signals to obtain the magnitude of the external force stressed by the rigid lever.

The invention relates to a nonlinear correction microphone. The nonlinear correction microphone comprises a sensitive film, a base main body, a low-sensitivity rear polar plate, a high-sensitivity rear polar plate, a shielding cavity, a high-sound-pressure output electrode, a high-sensitivity output electrode and an amplification circuit board. A capacitor microphone with high sound pressure and low sensitivity and a capacitor microphone with low sound pressure and high sensitivity are compounded together, the same sound pressure is detected, the two capacitors share one diaphragm; the small area of the center of the rear pole plate is the rear pole of the high-sound-pressure capacitor microphone; the large area of the periphery of the rear pole plate is the rear pole of the low-sound-pressure condenser microphone, the output of the low-sound-pressure condenser microphone is approximately linear, the output of the high-sensitivity condenser microphone is nonlinear, and the output of the high-sensitivity condenser microphone is corrected by using the output signal of the high-voltage condenser microphone in the amplifier.

The invention discloses a liquid turbidity measuring device and a measuring method thereof. The liquid turbidity measuring method comprises: step 1 of correspondingly driving two light sources to give out light according to two sine-wave current signals; step 2 of collecting and converting transmission light and scattered light emitted by each light source to obtain two paths of digital signals; step 3 of obtaining a transmission light strength parameter and a scattered light strength parameter of each light source according to each path of digital signals; step 4 of obtaining the liquid turbidity according to the transmission light strength parameter and the scattered light strength of each light source.

The invention belongs to the technical field of isolation amplifier circuits, and particularly relates to a programmable gain isolation amplifier circuit and an implement method thereof. The programmable gain isolation amplifier circuit comprises an isolation unit U1 and a programmable gain amplifier circuit, wherein the isolation unit U1 comprises an input end, a conversion capacitor, a micro-electronic digital single-pole double-throw switch, gating signals, and control signals of the micro-electronic digital switch, and the programmable gain amplifier circuit comprises a precise integrated operational amplifier, a programmable resistor network and a gain measuring circuit. The programmable resistor network is composed of digital potentiometers, and the gain measuring circuit comprises a digital switch, standard voltage and the control signals of the digital switch. The programmable gain isolation amplifier circuit can achieve complete isolation between a signal end and the amplifier, can overcome the zero-shift phenomenon of the amplifier circuit, is strong in continuity of gain selection, and can remarkably improve amplification precision.

A self-adaptive control method for eliminating sensor drift, involves: reading one-dimensional table data representing the relationship between an oil temperature and a sensor zero drift value with a self-adaptive control system of an automatic gearbox control unit; collecting signals for self-adaptive control with a single chip microcomputer analog / digital module of the automatic gearbox control unit; judging the running condition of a self-adaptive algorithm by a program. By inquiring the one-dimensional table data, the sensor zero drift value is generated by the self-adaptive algorithm.

The invention discloses a measuring device which utilizes a common electronic balance to realize the measurement requirements of a high-performance thermobalance and comprises a PID (Proportion Integration Differentiation) temperature control system, an interface set through mechanical coupling, the electronic balance, a resistance furnace and a moving component, wherein a publicly-known computeris connected with the electronic balance for collecting parameters of the electronic balance and is also connected with a step motor in the moving component for outputting a start command and a closecommand of the step motor. In the invention, from the exterior of the mechanical part of the thermobalance, the resistance furnace, a supporting plate, an outer cover, a glass cover and the electronic balance are arranged from bottom to top, supporting posts and glass tubes are arranged between the resistance furnace and the supporting plate, and a sleeve, the moving component and the outer coverare mounted on the supporting plate; the glass cover is mounted on the glass cover, and the electronic balance is mounted on the glass cover. The invention utilizes the function of the mechanical coupling by the program control of a computer to be combined with the automatic self clearing function of the electronic balance so as to effectively clear the self zero drift of the electronic balance and realize the durable continuous measurement of the applied common balance.