Vaisala Oy

Jorma Ponkala

Ari Paukkunen

Lars Stormbom

Veijo Antikainen

Hannu Jauhiainen

Heikki Turtiainen

Simo Tammela

Ingmar Stuns

Electrical impedance detector for measurement of physical quantifies, in particular of temperature or humidity. The detector comprises conductor electrodes (10a, 10b; 10A,10W), between which the electrical impedance (C.sub.M) that represents the physical quantity to be measured is measured. Between the conductor electrodes (10a, 10b;10A, 10W) there is an active material (11;11P) whose impedance properties are a function of the physical quantity to be measured. The detector is composed of pieces cut-off out of a continuous detector filament (20; 20H;20K), which detector filament (20;20H;20K) comprises a conductive electrode wire or an assembly of electrode wires (10a, 10b; 10A, 10W), on/between which there is an active material (11;11P) whose impedance properties are a function of the physical quantity to be measured. Further, a novel process is described for the manufacture of said detectors.

Electrically detected impedance detector for the measurement of physical

An impedance detector, in particular for radiosonde operation. The detector comprises a substrate (10 . . . 10E) made of an insulating material, onto which substrate the electrode and contact patterns (11, 11a, 13) necessary for the formation and connecting of the detector impedance have been applied. Between the detector impedance electrodes (11, 13), there is an active film (12), whose impedance values are a function of the physical quantity measured by means of the detector. The substrate of the detector is an oblong core filament (10; 10B; 10C; 10D; 10E) of an insulating material, onto and around which core filament said electrodes (11, 13) and said active insulating film (12) have been applied. Also, a novel process is described for the manufacture of said impedance detector.

Impedance detector, in particular for radiosonde operation, as well as a

Method, in particular in radiosondes, for measurement of relative humidity by using a capacitive humidity detector (10) or a combination of detectors (10.sub.1,10.sub.2 ;10P), as well as humidity detectors. In the detector, between the capacitor plates, an insulating material (12) is used, whose permittivity is a function of the amount of water vapor absorbed by the insulating material (12). The detector (10) or the combination of detectors is heated in order to remove any ice, frost or condensed humidity deposited on the face and/or in the environment of the detector. The detector capacitance (C.sub.M) or a part (C.sub.1 . . . C.sub.N) of same is heated, in time and/or in place, periodically by means of electric current (I). The detecting of the detector capacitance (C.sub.M) is carried out without measurement of the detector temperature after the detector capacitance or a part (C.sub.1 . . . C.sub.N) of same has cooled down substantially to the temperature of the environment where the ratio of the duration of the measurement cycle to the duration of the heating cycle is selected from a minimum range of 10 to one, up to a maximum range of 3000 to one.

Method for measurement of relative humidity, in particular in

Method, in particular in radiosondes, for measurement of relative humidity by using a capacitive humidity detector (10) or a combination of detectors (10.sub.1, 10.sub.2 ; 10P), as well as humidity detectors. In the detector, between the capacitor plates, an insulating material (12) is used, whose permittivity is a function of the amount of water absorbed by the insulating material (12). The detector (10) or the combination of detectors is heated in order to remove any ice, frost or condensed humidity deposited on the face and/or in the environment of the detector. The detector capacitance (C.sub.M) or a part (C.sub.1 . . . C.sub.N) of same is heated, in time and/or in place, periodically by means of electric current (I). The detecting of the detector capacitance (C.sub.M) is carried out without measurement of the detector temperature after the detector capacitance or a part (C.sub.1 . . . C.sub.N) of same has cooled down substantially to the temperature of the environment.

Method of measurement of relative humidity, in particular in

Method in improving of the precision of impedance detectors in radiosondes. In the method, the temperature of the detector or detectors (30 and/or 10) is measured by means of a thermocouple (20), in which the joint (23) of one branch of its thermoelements (21,22) is placed in connection with, or at the proximity of, the detector to be measured. In the thermocouple (20) the joint (24) of the other branch is placed in the atmosphere (SA) surrounding the detector. By means of the thermocouple (20), the difference (T.sub.1 -T.sub.0) between the temperature (T.sub.1) prevailing in connection with the detector and the temperature (T.sub.0) in the surrounding atmosphere (SA) is detected. The output signal (f.sub.out) of the measurement coupling of the radiosonde is affected by means of an electric signal (U(t)) representing the difference (T.sub.1 --T.sub.0) in temperature, which output signal contains the data concerning the meteorological quantity or quantities measured by means of the detector (30) or detectors (10,30). The DC voltage (U.sub.o) obtained from the thermocouple (20) is converted by means of an inverter (60) or equivalent into an AC voltage (U(t)), by means of which the output signal (f.sub.out) of the measurement coupling is affected.

Method related to impedance detectors in radiosondes

A capacitance to be measured is connected between the input and output of an inverting amplifier. A bistable circuit has an input connected to the output of the inverting amplifier and an output impedance inversely proportional to the capacitance to be measured. A resistive feedback is connected from the output of the bistable circuit to the input of the inverting amplifier.

Circuit for measuring low capacitances

The output of each of a plurality of CMOS inverting amplifiers is connected to a corresponding one of a plurality of impedances to be measured. A stepping circuit is connected to the inputs of the amplifiers. A voltage supply is connected to the amplifiers and provides a signal to be measured which is directed via a corresponding one of the amplifiers to an impedance measuring circuit connected to the impedances to be measured in common. The impedance measuring circuit produces an output impedance proportional to the impedances to be measured.

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Ylonkyla, Finland

Jorma Ponkala