CN102944323A - Temperature fluctuation instrument based on true root-mean-square converter - Google Patents

Abstract

The invention discloses a temperature fluctuation instrument based on a true root-mean-square converter. The temperature fluctuation instrument comprises two sensors, a sensor supporting rod and a circuit board unit taking a true root-mean-square calculator AD637 as a core calculating circuit; the sensors comprise a polished white alloy tungsten filament with the diameter of 8mum and a bracket, wherein the polished white alloy tungsten filament is used for measuring temperature fluctuation signals, the bracket comprises silver-plated copper bars and high temperature resistant tubes, one end of each silver-plated copper bar is provided with a groove, the high temperature resistant tubes are sleeved outside the silver-plated copper bars, and two ends of the polished white alloy tungsten filament are fixed in the grooves of the two silver-plated copper bars. The temperature fluctuation instrument has the advantages that because of the application of the true root-mean-square calculator AD637, the circuit structure is simplified, the manufacturing cost is reduced, and the high sensitivity of the temperature fluctuation instrument is ensured; in addition, the temperature fluctuation instrument is very high in precision and capable of greatly improving the accuracy of a measurement result.

Description

A kind of micro-temperature sensor based on true Root Mean square Converter

Technical field

The invention belongs to a kind of electronic measuring instrument of measuring atmospheric optical parameters, specifically a kind of micro-temperature sensor based on true Root Mean square Converter.It mainly is applicable to atmospheric science research, and the field such as meteorology, aviation, Laser Atmospheric Transmission, military affairs.

Background technology

Micro-temperature sensor is mainly used in atmospheric optical turbulence and measures.From early 1970s so far, the countries such as the U.S., Germany and India have developed the series of temperature oscillometer, constantly get a promotion on the reliability of method of production and degree of ripeness.As, the micro-temperature sensor of the direct current bridge of Darryl and David design, but the sounding balloon of Demos design and aircraft carry the equal measurement of Atmospheric Turbulence profiles such as micro-temperature sensor.At home, Anhui Inst. of Optics and Fine Mechanics, Chinese Academy of Sciences has carried out micro-temperature sensor development work at first, utilizes micro-temperature sensor to carry out a large amount of experimental studies, has obtained at home generally approval.At the beginning of the eighties, Ceng Zongyong etc. develop a kind of intermittent power supply direct current bridge-type micro-temperature sensor, have carried out a large amount of Air Close To The Earth Surface optical turbulences and have measured, and have then developed again the temperature fluctuation sonde, are used for whole atmosphere optical turbulence profile and measure.

Summary of the invention

The objective of the invention is provides a kind of micro-temperature sensor based on true Root Mean square Converter for the deficiencies in the prior art.

In order to achieve the above object, the present invention adopts following technical scheme:

Based on the micro-temperature sensor of true Root Mean square Converter, comprise two sensors, sensor support bar and take the circuit board unit of true root mean square calculator AD637 as the core calculations circuit; Described sensor comprises the white tungsten filament of polishing alloy and the support of diameter 8 μ m, polishing white metal tungsten filament is used for measuring the temperature fluctuation signal, described support comprises silver-plated copper bar and high-temperature resistant tube, silver-plated copper bar one end arranges groove, high-temperature resistant tube is enclosed within the high-temperature resistant tube outside, the white tungsten filament of polishing alloy two ends are fixed in the groove of two silver-plated copper bars, and a sensor is respectively supported at the two ends of described sensor support bar; Described sensor support bar unit adopts the aluminium-alloy pipe of long 1m; Circuit board unit comprises voltage difference measuring unit, filter and amplification unit and root mean square calculation unit; The voltage difference measuring unit mainly comprises constant current source, square wave circuit for generating, on-off circuit, sampling holder, Wheatstone bridge and differential amplifier circuit, by the power-on time of square wave circuit for generating and on-off circuit control Wheatstone bridge, for the sensor batch (-type) provides continuous current; Two sensors are as two gage beams of Wheatstone bridge, and its magnitude of voltage carries out Difference Calculation through differential amplifier circuit, obtains voltage differential signal; This voltage differential signal is the discontinuous signal synchronous with square wave, after sampling holder is sampled, keeps, amplified, obtains the continually varying signal, then carries out filtering and compensation amplification; The filter and amplification unit arranges passband according to the atmospheric turbulence spectrum distribution; The signal that the root mean square calculation unit is crossed filter amplifying processing carries out root mean square calculation, and output signal is carried out bias compensation and impedance matching.

Advantage of the present invention and effect are:

The sensor of 1 micro-temperature sensor has adopted special design, and sensor material has been selected the white tungsten filament of polishing alloy of diameter 8 μ m, has reduced the measuring error that solar radiation is introduced, and has improved the response frequency of sensor; The groove of sensor stand has increased effective contact area of tungsten filament and support, and high-temperature resistant tube has reduced the impact of heat radiation that support produces on measuring accuracy.

2 in the micro-temperature sensor circuit design, and by the root mean square of true root mean square calculator AD637 accounting temperature difference signal, chip internal is comprised of analog device.With respect to digital computing circuit, the sort signal disposal route has been simplified circuit structure, has reduced cost of manufacture, has reduced the measuring error that digital-to-analog conversion is introduced, and has improved the measuring accuracy to the atmospheric turbulence high frequency spectrum.

Description of drawings

Fig. 1 is the sensor construction synoptic diagram based on the micro-temperature sensor of true Root Mean square Converter;

Fig. 2 is the signal flow block diagram based on the micro-temperature sensor of true Root Mean square Converter;

Fig. 3 is that the present invention surveys air index textural constant diurnal variation situation in the experiment place.

Embodiment

Below in conjunction with specific embodiment, the present invention is described in detail.

1, micro-temperature sensor design concept

The air index textural constant is commonly used to describe the Fluctuation Strength of optical turbulence, can the quantitative description atmospheric turbulence on the impact of light wave transmissions.According to the local uniformity isotropic theory of Kolmogorov, the computing formula that can obtain the air index textural constant is as follows:

${\mathrm{<figure-callout\; id="2"\; label="C\; n"\; filenames="HSA00000814673200011.png"\; state="\{\{state\}\}">C</figure-callout>}}_n^{}={(79\&times;{10}^{-6}\frac{P}{T^2})}^2{C}_T^2---\left(1\right)$

${\mathrm{<figure-callout\; id="2"\; label="C\; T"\; filenames="HSA00000814673200011.png"\; state="\{\{state\}\}">C</figure-callout>}}_T^{}=\frac{<{[T(x+r)-T\left(x\right)]}^2>}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HSA00000814673200011.png"\; state="\{\{state\}\}">r</figure-callout>}}^{2/3}}---\left(2\right)$

In the formula: C _T ²Be the temperature configuration constant, T is thermodynamic temperature, and P is atmospheric pressure, and r is the distance in 2 in space,＜[T (x+r)-T (x)] ²＞be the ensemble average of the temperature difference square in 2 in space.

By formula (1) and (2) as can be known, if air pressure P, temperature T, all be known quantity apart from the ensemble average of r and temperature difference, can calculate air index textural constant C _n ²Air pressure P and temperature T are measured and can be got by conventional meteorologic instrument, use the instruments such as meter ruler and vernier caliper can accurate distance r, and the ensemble average of temperature difference need to be carried out Inversion Calculation to the measurement data of micro-temperature sensor and be obtained.

By said method as can be known, micro-temperature sensor should comprise two sensors and a block signal treatment circuit plate, and two sensors are used for the transient temperature of 2 of measurement spaces, and signal processing circuit board is used for temperature difference and the root mean square thereof that calculating sensor is measured.

2, based on the micro-temperature sensor sensor design of true Root Mean square Converter

With reference to figure 1, sensor construction synoptic diagram of the present invention.In various temperature sensors, the platinum resistance thermometer sensor, silk has higher response frequency and temperature coefficient, meet the requirement that temperature fluctuation is measured, therefore adopt the tinsel resistor as the micro-temperature sensor sensor, consider emphatically that when carrying out selection wiry micro-temperature sensor is to the requirement of sensitivity and two major parameters of response frequency.Resistance wiry is larger, and the sensitivity of micro-temperature sensor is higher; Diameter wiry is less, and the response frequency of micro-temperature sensor is higher; The tinsel reflectivity is larger, and solar radiation is less on the impact of micro-temperature sensor measurement result.Based on above some and market supply ability, selecting diameter is that the white tungsten filament of polishing of 8 μ m is made sensor.

Support Design must guarantee: 1. tinsel exposes in air; 2. do not destroy the atmospheric turbulence space structure; 3. the heat radiation of support release can be ignored impact wiry; 4. the resistance value of support in current return can be ignored.Therefore the support of sensor has been selected structural design as shown in Figure 1, comprise silver-plated copper bar 1 and high-temperature resistant tube 2, silver-plated copper bar 1 one ends arrange groove 3, high-temperature resistant tube 2 is enclosed within high-temperature resistant tube 2 outsides, the white tungsten filament of polishing alloy 4 two ends are fixed in the groove 3 of two silver-plated copper bars 1, the groove 3 of sensor stand has increased the effective contact area of the white tungsten filament 4 of polishing alloy with support, and high-temperature resistant tube 2 has reduced the impact of heat radiation that support produces on measuring accuracy.

3, based on the micro-temperature sensor circuit design of true Root Mean square Converter

With reference to figure 2, measuring principle according to micro-temperature sensor, should realize on the micro-temperature sensor circuit part function: measure the voltage difference of two sensors and it is amplified and filtering, then carry out root mean square calculation and export root-mean-squared, and reduce to greatest extent the impact of environment heat interchange by circuit design.Divide according to this function, circuit is divided into three unit, i.e. voltage difference measuring unit, filter and amplification unit and root mean square calculation unit.The voltage difference measuring unit mainly comprises constant current source, square wave circuit for generating, on-off circuit, sampling holder, Wheatstone bridge and differential amplifier circuit, power-on time by square wave circuit for generating and on-off circuit control Wheatstone bridge, for the sensor batch (-type) provides continuous current, under the prerequisite that improves the working sensor electric current and do not increase equivalent current, effectively improve sensitivity, reduced simultaneously the impact of tinsel Ohmic heating on measurement result.Two sensors are as two gage beams of Wheatstone bridge, and its magnitude of voltage carries out Difference Calculation through differential amplifier circuit, obtains voltage differential signal.This voltage differential signal is the discontinuous signal synchronous with square wave, after sampling holder is sampled, keeps, amplified, obtains the continually varying signal, then carries out filtering and compensation amplification.Filter amplification circuit arranges passband according to the atmospheric turbulence spectrum distribution, according to the reasonable classification measurement by magnification of the dynamic range of main chip signal.The signal that the root mean square calculation unit is crossed filter amplifying processing carries out root mean square calculation, and output signal is carried out bias compensation and impedance matching.According to as above mentality of designing, finished the circuit design of micro-temperature sensor.

4, make and measure based on the micro-temperature sensor of true Root Mean square Converter

Micro-temperature sensor is integrated, need to be with sensor and circuit board electric and physically effectively link together, installation of sensors is in rational position, and circuit board adds necessary packing to satisfy the requirement of work and storage environment, and the external unit that connects for needs provides compatible interface.

The distance of two sensors is to be determined by the characteristic dimension of atmospheric turbulence, according to the regularity of distribution of Air Close To The Earth Surface turbulence characteristics yardstick, this distance is chosen to be 1 meter.Therefore, employing length is 1 meter aluminium-alloy pipe fixation of sensor, and passes connecting circuit board with thin wire in managing.Circuit board is screwed in the waterproof plastic box, and 4 cores (+Vs ,-Vs, GND, Signal) Aviation Connector is installed on the waterproof plastic box, as micro-temperature sensor and external unit connecting interface.

After completing based on the micro-temperature sensor of true Root Mean square Converter, select DT80 intelligent data acquisition unit collecting temperature oscillometer signal, carried out the continuous coverage experiment, obtained 1 day around-the clock measurement data, to measurement data get 5 minutes average after, drawn data diurnal variation curve figure, as shown in Figure 3.

Should be understood that, for those of ordinary skills, can be improved according to the above description or conversion, and all these improvement and conversion all should belong to the protection domain of claims of the present invention.

Claims (1)

1. the micro-temperature sensor based on true Root Mean square Converter is characterized in that, comprises two sensors, sensor support bar and take the circuit board unit of true root mean square calculator AD637 as the core calculations circuit; Described sensor comprises the white tungsten filament of polishing alloy and the support of diameter 8 μ m, polishing white metal tungsten filament is used for measuring the temperature fluctuation signal, described support comprises silver-plated copper bar and high-temperature resistant tube, silver-plated copper bar one end arranges groove, high-temperature resistant tube is enclosed within the high-temperature resistant tube outside, the white tungsten filament of polishing alloy two ends are fixed in the groove of two silver-plated copper bars, and a sensor is respectively supported at the two ends of described sensor support bar; Described sensor support bar unit adopts the aluminium-alloy pipe of long 1m; Circuit board unit comprises voltage difference measuring unit, filter and amplification unit and root mean square calculation unit; The voltage difference measuring unit mainly comprises constant current source, square wave circuit for generating, on-off circuit, sampling holder, Wheatstone bridge and differential amplifier circuit, by the power-on time of square wave circuit for generating and on-off circuit control Wheatstone bridge, for the sensor batch (-type) provides continuous current; Two sensors are as two gage beams of Wheatstone bridge, and its magnitude of voltage carries out Difference Calculation through differential amplifier circuit, obtains voltage differential signal; This voltage differential signal is the discontinuous signal synchronous with square wave, after sampling holder is sampled, keeps, amplified, obtains the continually varying signal, then carries out filtering and compensation amplification; The filter and amplification unit arranges passband according to the atmospheric turbulence spectrum distribution; The signal that the root mean square calculation unit is crossed filter amplifying processing carries out root mean square calculation, and output signal is carried out bias compensation and impedance matching.

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