Biasing circuit and temperature compensation low-frequency amplification circuit for microwave radiometer

Abstract

The invention relates to a biasing circuit for a microwave radiometer and a temperature compensation low-frequency amplification circuit comprising the biasing circuit. According to the biasing circuit, one end of a resistor R3 is connected with a power supply, the other end of the resistor R3 is connected with a negative electrode of a voltage stabilization diode VD2; a positive electrode of the voltage stabilization diode VD2 is grounded; the power supply, the resistor R3 and the voltage stabilization diode VD2 form a current loop; a capacitor C3 and a capacitor C4 are connected in series to form a series circuit; the series circuit is connected in parallel with two ends of the voltage stabilization diode VD2; one end of a resistor R4 is connected with the negative electrode of the voltage stabilization diode VD2, and the other end of the resistor R4 is connected with a thermistor; the other end of the thermistor is grounded; the resistor R4 and the thermistor form a series circuit; and the series circuit is connected in parallel with two ends of the voltage stabilization diode VD2. The biasing circuit can compensate output voltage change caused by temperature change of a low-signal detection circuit, has a good temperature control effect and reduces influence of outside temperature on the amplification circuit.

Description

technical field [0001] The invention relates to a microwave radiometer, in particular to a bias circuit and a temperature-compensated low-frequency amplifier circuit for the microwave radiometer. Background technique [0002] The microwave radiometer is a passive ground-based passive microwave remote sensing device. A microwave radiometer generally includes four basic components, namely: optical system, detector, amplifier, recording and display device, reference radiation source and modulator. After the radiometer system is integrated, when it is used for open-air measurement, the change of temperature will cause the change of the parameters of the detection diode in the small signal detection circuit of the amplifier, especially the voltage drop at both ends of the detection diode will change with the temperature, making the work of the detection diode Point (that is, Q point) changes, which in turn affects the output voltage of the small signal detection circuit to chang...

AI Technical Summary

Problems solved by technology

Therefore, the measurement results of the microwave radiometer will be greatly changed by the influence of the external temperature, which is not conducive to the experimental measurement.

The reason for this situation is that the output signal of the existing bias circuit is a fixed value or the output terminal of the bias circuit is grounded, which cannot compensate for the change in the output voltage of the detection diode caused by temperature, and cannot compensate for the small The output voltage variation of the signal detection circuit is compensated for

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