14 results about "Noise-equivalent temperature" patented technology

The application provides a MEMS differential thermal analysis sensor and a DTA / DSC testing method, the sensor comprising a detection thermocouple, a reference thermocouple, an ambient resistance and a shielding ring, wherein the detection thermocouple and the reference thermocouple each comprise a single crystal silicon substrate, a heat insulation cavity, a plurality of single crystal silicon thermocouple pairs and a supporting film, the heat insulation cavity is located in the single crystal silicon substrate, the plurality of single crystal silicon thermocouple pairs are connected in series and are supported by the supporting film to be suspended above the heat insulation cavity to achieve thermal isolation, and the single crystal silicon thermocouple pair comprises an N-type single crystal silicon thermocouple and a P-type single crystal silicon thermocouple connected in series, the temperature and power sensitivity of the sensor are significantly improved, reach 28 mV / K and 100 V / W, and the noise equivalent temperature difference and the noise equivalent power reach 0.5 mK or 0.2 muW. Based on the output signal of the sensor, differential thermal analysis testing and differential scanning calorimetry testing on physical or chemical processes of material heat absorption and release can be realized, the sample consumption is small, and the testing precision is high.

The invention provides a broadband radio frequency noise high-precision measurement system and method, and belongs to the technical field of terahertz detection. The system comprises a matching load module, a radio frequency link, a cold and hot load switching module, a superconducting detector module, an intermediate frequency module, an intelligent driving module, a bias module and a computer, firstly, the equivalent noise temperature of a system is represented for the first time through cold and hot load switching in a low-temperature Dewar; and then, after the radio frequency optical path is introduced, the second characterization of the equivalent noise temperature of the system is realized through cold and hot load switching again. Based on two characterization results, the broadband radio frequency noise temperature of the system can be accurately measured in combination with a noise cascade theory, so that the measurement precision and reliability are improved. The method has the remarkable advantages of high stability, efficient measurement, high precision, expanded application and the like.

The invention discloses a method and a system for measuring and calculating a signal-to-noise ratio of an uncooled infrared detection system, relates to the technical field of infrared target detection, and solves the problems that parameters of an uncooled detector are lost during research and development of a low-cost infrared system and detection effects of different view field angles of a large-view-field system are different. The radiance at the entrance pupil is calculated through the target radiance and the atmospheric transmittance, the irradiance and the illuminance from the pupil to the center of an image plane are derived based on optical system parameters, the irradiance related to a field angle is obtained according to a geometrical relationship for large-field edge illuminance attenuation, and the irradiance related to the field angle is obtained according to a geometrical relationship for a point target which is not filled with a photosensitive element. Calculating the projection on the photosensitive element and the signal radiation quantity received by the pixel; the noise equivalent temperature difference is tested by adopting a collimation method, and the value is obtained by combining a collimator and the spectral transmittance of an optical system so as to calculate the noise power; and the signal-to-noise ratio is calculated by combining the signal amplitude-flux. The method solves the problem of parameter loss through actually measured noise equivalent temperature difference value estimation, considers view field energy attenuation in the evaluation process, and is suitable for fine evaluation of a large view field system.

An embodiment of the present invention provides a method, device, and equipment for calibrating the gain of the reflection channel of an occultation detector. The method includes: under preset ambient temperature conditions, inputting two or more calibration sources into the reflection channel of the occultation detector respectively, and outputting the DDM noise observation values corresponding to each calibration source; obtaining the gain deviation values caused by the deviation of the AD sampling values of each calibration source from the target values; determining the equivalent noise temperature corresponding to each calibration source, and determining the equivalent input noise power based on the equivalent noise temperature; determining the total gain of the reflection channel of the occultation detector and the system noise figure based on the DDM noise observation values, the gain deviation values, and the equivalent input noise power. Through the embodiment of the present invention, the calibration of the gain of the reflection channel of the occultation detector is achieved.

The invention discloses a synthetic aperture radiometer on-orbit antenna stability correction method, which comprises the following steps of: calibrating two parameters of receiver on-orbit gain and equivalent noise temperature through a single standard calibration source by utilizing a receiver on-orbit observation matching load and combining a receiver calibration parameter acquired by a laboratory; receiver calibration parameters are reversely transmitted to an antenna output end face, forward modeling is carried out to an antenna input end face in combination with an observation scene, an antenna loss calculation model is constructed by adopting apparent temperatures of the antenna input end face and the antenna output end face, loss parameters of an antenna are calibrated in an on-orbit mode, and the antenna loss is obtained by adopting three times of cold air calibration. According to the method, the characteristic model that the antenna loss changes along with the physical temperature is constructed, meanwhile, the antenna loss is corrected in real time at any physical temperature of the on-orbit antenna, correction of the stability of the on-orbit antenna is completed, and the stability of an on-orbit data product of the synthetic aperture radiometer is effectively improved.

A kind of receiver noise figure test method based on high-precision radiation measurement, different brightness temperature signals of calibration source output are used to calibrate receiver in real time, and high-precision measurement of receiver noise figure can be realized by calculating equivalent noise temperature.The whole simulates actual brightness temperature scene, and radiation measurement method is more accurate, which improves test precision;Calibration source realizes accurate and stable cold source and heat source based on liquid nitrogen refrigeration and physical heating, has the advantages of high output precision and long stability time, and long-time stability precision can reach 0.1k / 3 days;At the same time, the output brightness temperature of high-precision calibration source is between 90K and 330K, which is closer to actual brightness temperature scene, and can avoid the large non-linear error of receiver caused by the non-linearity of its internal amplifier, greatly improving the test precision.

The invention provides an infrared image multi-point correction method, device, equipment and medium, and the method comprises the steps: collecting more than or equal to 10 frames of infrared images in four temperature scenes of dark field, low illumination, medium illumination and high illumination in real time, carrying out the multi-frame average processing of each frame of image to suppress the time domain noise, and generating a to-be-analyzed image; pixel feature parameter extraction is carried out on the to-be-analyzed image, and blind pixel detection parameters based on the response rate, the noise voltage, the noise equivalent temperature difference and the linearity feature of each pixel are generated; marking blind pixel pixels and normal pixel pixels of the to-be-analyzed image according to a constructed blind pixel table based on blind pixel detection parameters; and for blind pixels, carrying out average interpolation filling by adopting adaptive gain and offset parameters of normal pixels in a 3 * 3 neighborhood to realize correction. According to the method, the multi-frame data, multi-criterion blind pixel detection and multi-point temperature correction methods are combined, wide-temperature-range and high-precision infrared image correction is achieved, and noise suppression and pixel nonlinear compensation are considered at the same time.

The present invention relates to a method for calculating the effective range of an infrared polarization imaging system. The method takes system performance parameters and atmospheric radiation characteristics of the infrared polarization imaging system as input parameters, and constructs an effective range calculation model for the infrared polarization imaging system based on the noise equivalent temperature difference, in combination with the noise equivalent polarization degree difference and the minimum resolution polarization degree difference between a target and a scene. The method comprehensively considers the detection advantages of the infrared polarization imaging system and the difference in polarization radiation characteristics between the target and the background to calculate the effective range of the infrared polarization imaging system under a specified target detection probability. The method has the advantages of strong system matching, good scene adaptability, high calculation accuracy, and the like.

The invention provides a detection system and a detection method for an intelligent sensor and the intelligent sensor. The detection system comprises: a multi-dimensional adjustment platform having a bearing surface corresponding to a mechanical reference surface of an intelligent sensor to be detected; the laser collimator is arranged on the multi-dimensional adjusting platform, and an angle between a light path of the laser collimator and the bearing surface is known; the blackbody radiation source and the multi-dimensional adjusting platform are separately arranged; the oscilloscope is used for measuring output signals of the sensor, the multi-dimensional adjusting platform can respectively move along a first axial direction and a second axial direction and can respectively rotate around the first axial direction and the second axial direction, and the first axial direction and the second axial direction are vertical to a light path of the laser collimator. The detection system can directly measure a plurality of technical indexes of the sensor, including at least one of a sensor visual axis, a field angle, a response rate, a noise equivalent temperature difference, an upper side frequency and a lower side frequency, and provides an efficient, reliable and consistent detection means for sensor admission inspection, manufacturing and product delivery inspection.

The invention relates to an operating distance calculation method of an infrared polarization imaging system, which comprises the following steps of: taking system performance parameters and atmospheric radiation characteristics of the infrared polarization imaging system as input parameters, and calculating the operating distance of the infrared polarization imaging system on the basis of noise equivalent temperature difference; combining the noise equivalent polarization degree difference and the minimum resolution polarization degree difference of the target and the scene to construct an operating distance calculation model of the infrared polarization imaging system; the detection advantage of the infrared polarization imaging system and the polarization radiation characteristic difference between the target and the background are comprehensively considered to calculate the operating distance of the infrared polarization imaging system under the specified target detection probability, and the method has the advantages of being high in system matching degree, good in scene adaptability, high in calculation precision and the like.

The present application relates to the technical field of testing, in particular to a noise figure test automatic calibration, compensation and correction method and system. The method comprises the following steps: obtaining the loss L of a microwave switch matrix; obtaining the equivalent noise temperature obtained by a test of a measured object and the test gain of the measured object; obtaining the real equivalent noise temperature of the measured object based on the loss L of the microwave switch matrix, the equivalent noise temperature obtained by the test of the measured object, the test gain of the measured object, a standard noise temperature; and converting the real equivalent noise temperature of the measured object into the real noise figure of the measured object. The present application can realize automatic calibration and compensation of noise figure test based on the Y-factor method, and support full-automatic testing of an automatic test system.

The application discloses a kind of low-noise amplifier equivalent noise temperature measurement system and method, measurement system includes: load component, for providing thermal noise signal, including first load and second load, the first load and the second load are located in temperature different first temperature zone and second temperature zone respectively;The input end of the low-noise amplifier to be measured is electrically connected with the first load or the second load and receives thermal noise signal;Second amplification component is connected with the output end of the low-noise amplifier, amplifies the output signal of the low-noise amplifier, and the second amplification component meets impedance matching with the low-noise amplifier;Measuring device is used to measure the signal output by second amplification component, and obtain the equivalent noise temperature of the low-noise amplifier.The end of the low-noise amplifier connected with load is switched in different temperature zones, and the uncertainty factor in measurement is reduced.

The application provides a detection system, a detection method and a smart sensor for the smart sensor. The detection system comprises a multi-dimensional adjustment platform having a bearing surface corresponding to a mechanical reference surface of a to-be-detected smart sensor; a laser collimator arranged on the multi-dimensional adjustment platform, an optical path of the laser collimator being known to the angle of the bearing surface; a blackbody radiation source arranged separately from the multi-dimensional adjustment platform; and an oscilloscope for measuring a sensor output signal, wherein the multi-dimensional adjustment platform is capable of being displaced along a first axial direction and a second axial direction respectively and is capable of being rotated around a first axis and a second axis respectively, the first axial direction and the second axial direction being perpendicular to each other and being perpendicular to the optical path of the laser collimator respectively. The detection system is capable of directly measuring a plurality of technical indexes of the sensor, including at least one of a sensor visual axis, a field of view angle, a response rate, a noise equivalent temperature difference, an upper edge frequency and a lower edge frequency, thereby providing an efficient, reliable and consistent detection means for sensor incoming inspection, production and manufacturing and product delivery inspection.