CN2465401Y - Differential square law detecting circuit - Google Patents
Differential square law detecting circuit Download PDFInfo
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- CN2465401Y CN2465401Y CN 01205856 CN01205856U CN2465401Y CN 2465401 Y CN2465401 Y CN 2465401Y CN 01205856 CN01205856 CN 01205856 CN 01205856 U CN01205856 U CN 01205856U CN 2465401 Y CN2465401 Y CN 2465401Y
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Abstract
The utility model relates to a differential square-law detection circuit which is a special detection circuit for a microwave radiometer. The circuit is used for connecting the input end of an original zero bias square-law detection circuit with the input end of the AD620 '+' of a differential amplifier for a low power consumption meter, and the input end of AD620 '-' is connected with a temperature compensation circuit having the same temperature characteristic as the original zero bias square-law detection circuit. The utility model not only has the advantage of the zero bias square-law detection circuit well working in a square-law detection zone during low-power signal input, but also overcomes the temperature characteristic of the zero bias square-law detection circuit.
Description
The utility model belongs to the special-purpose detecting circuit of the microwave radiometer of one of microwave passive remote sensing instrument in the microwave remote sensing field.
Microwave radiometer is the high passive receiver of microwave of a kind of sensitivity in the passive microwave field, and it can measure and be in the atomic weak microwave irradiation power that the above material of absolute zero is launched.Typical microwave radiation meter systems generally is made up of microwave antenna, radio-frequency (RF) switch, field-effect amplifier, frequency mixer, local oscillator, intermediate frequency amplifier, wave detector, integrator, direct current amplifier and various reponse system thereof.The employed detecting circuit of microwave radiometer before the utility model is because the atomic weak power signal of system before will detecting self-recification, the square-law detection circuit that " zero " that generally all adopts the Ministry of Information Industry 55 to be provided setovered, and its circuit is as shown in Figure 1.This circuit is made up of input resistance to earth 1, detector diode 2, output resistance to earth 3, output direct-to-ground capacitance 4.Wherein the A end is output for input, B end.Though sort circuit is simple in structure, can make low barrier schottky detector diode, for example the WJ302 detection tube is operated in the square-law detection district when detecting circuit input low-power level signal well.But because the forward voltage-current characteristic of employed low barrier schottky detector diode has significant temperature characterisitic under different temperatures, the square-law detection circuit that causes " zero " biasing is under identical input power, because the variation of ambient temperature has different output valves, has seriously influenced the certainty of measurement of radiometer system.
In order to overcome this temperature characterisitic of " zero " biasing square-law detection circuit, improve the certainty of measurement of microwave radiometer, the purpose of this utility model is to design a kind of differential type square-law detection circuit, the inventive concept of sort circuit is to have adopted a kind of temperature-compensation circuit that has the uniform temp characteristic with " zero " biasing square-law detection circuit in circuit inside, as shown in Figure 2, it is made up of a voltage-stabilizing device 5, divider resistance 6, potentiometer 7, temperature compensated diode 8, resistance to earth 9, positive supply 10.This differential type square-law detection circuit has also adopted a low-power consumption instrument differential amplifier AD620.
Detailed content of the present utility model as shown in Figure 3.Form with differential amplifier AD620 three parts by " zero " biasing square-law detection circuit (11,12,13,14), temperature-compensation circuit (15,16,17,18,19,20), low-power consumption instrument.
" zero " biasing square-law detection circuit is made up of input resistance to earth 11, detector diode 12, output resistance to earth 13, output direct-to-ground capacitance 14.Temperature-compensation circuit is made up of a voltage-stabilizing device 15, divider resistance 16, potentiometer 17, temperature compensated diode 18, resistance to earth 19, positive supply 20.21 is general low-power consumption instrument differential amplifier AD620.
Sort circuit is connected on the input of low-power consumption instrument with differential amplifier AD620 "+" to the output of " zero " biasing square-law detection circuit, and inserts a temperature-compensation circuit that has the uniform temp characteristic with " zero " biasing square-law detection circuit at the input of AD620 "-".Wherein D is that input, E are output.
The operation principle of differential type square-law detection circuit: in accompanying drawing 3, detector diode 12 must use the low barrier Schottky diode with same type and close parameter with temperature compensated diode 18.Energy is by D end excitation detector diode 12 before the detection of microwave radiation meter systems, the energy activation temperature that is provided by device in the temperature-compensation circuit 15,16,17 and positive supply 20 compensates diode 18, and respectively by resistance to earth 13 and resistance to earth 19, make two diodes respectively by certain electric current, by trimmer potentiometer 17, make two diodes 12,18 have close operating state again.When ambient temperature rises,, instrument is risen simultaneously with "+" input and "-" input of differential amplifier AD620, thereby keep the output valve of device 21 constant substantially because detector diode 12 has identical temperature characterisitic with temperature compensated diode 18.Equally, when falling at ambient temperature, instrument is descended simultaneously with "+" input and "-" input of differential amplifier AD620, device 21 output valves remain unchanged substantially, thereby have eliminated the influence of variation of ambient temperature to detecting circuit.
Good effect of the present utility model: differential type square-law detection circuit not only has " zero " biasing square-law detection circuit and be operated in advantage in the square-law detection district well when low-power level signal is imported, and overcome the temperature characterisitic that " zero " biasing square-law detection circuit is had, thereby improved the certainty of measurement of microwave radiation meter systems.
Description of drawings: accompanying drawing 1 is " zero " biasing square-law detection circuit.Accompanying drawing 2 is a temperature-compensation circuit.Accompanying drawing 3 is a differential type square-law detection circuit.Figure of abstract also adopts accompanying drawing 3.
Most preferred embodiment: in the accompanying drawing 3, input resistance to earth 11 adopts 2.4k Ω/0.125W, detector diode 12 adopts the low barrier Schottky diode of WJ302, output resistance to earth 13 adopts 1.2k Ω/0.125W, output direct-to-ground capacitance 14 adopts 1 μ F electric capacity, temperature compensated diode 18 adopts the low barrier Schottky diode of WJ302, resistance to earth 19 adopts 1.2k Ω/0.125W, the low-power consumption instrument adopts AD620 with differential amplifier 21, pressurizer 15 adopts LM336/2.5V, divider resistance 16 adopts and the add resistance value 8.2k Ω resistance that positive supply 20 adapts, potentiometer 17 adopts 20k Ω potentiometer.Circuit makes detector diode and temperature compensated diode close as far as possible, and is installed on the identical circuit substrate when design and installation.
Claims (1)
1, differential type square-law detection circuit, be based on " zero " biasing square-law detection circuit design, the output B that it is characterized in that " zero " biasing square-law detection circuit is connected on the input of low-power consumption instrument with differential amplifier AD620 "+", and insert a temperature-compensation circuit that has the uniform temp characteristic with " zero " biasing square-law detection circuit at the input of AD620 "-", the D end is the input of differential type square-law detection circuit, and the E end is output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01205856 CN2465401Y (en) | 2001-02-19 | 2001-02-19 | Differential square law detecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 01205856 CN2465401Y (en) | 2001-02-19 | 2001-02-19 | Differential square law detecting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2465401Y true CN2465401Y (en) | 2001-12-12 |
Family
ID=33626616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 01205856 Expired - Fee Related CN2465401Y (en) | 2001-02-19 | 2001-02-19 | Differential square law detecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2465401Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100391101C (en) * | 2002-11-20 | 2008-05-28 | 中国科学院沈阳自动化研究所 | Limiting amplifier for PSD photoelectric signal |
| CN102840920A (en) * | 2012-08-03 | 2012-12-26 | 中国科学院空间科学与应用研究中心 | Biasing circuit and temperature compensation low-frequency amplification circuit for microwave radiometer |
| US9702911B2 (en) | 2012-09-07 | 2017-07-11 | Keysight Technologies, Inc. | Adjustable power sensor |
-
2001
- 2001-02-19 CN CN 01205856 patent/CN2465401Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100391101C (en) * | 2002-11-20 | 2008-05-28 | 中国科学院沈阳自动化研究所 | Limiting amplifier for PSD photoelectric signal |
| CN102840920A (en) * | 2012-08-03 | 2012-12-26 | 中国科学院空间科学与应用研究中心 | Biasing circuit and temperature compensation low-frequency amplification circuit for microwave radiometer |
| US9702911B2 (en) | 2012-09-07 | 2017-07-11 | Keysight Technologies, Inc. | Adjustable power sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20011212 Termination date: 20100219 |