CN103812451B - Normal temperature output port microwave alternating temperature noise source - Google Patents
Normal temperature output port microwave alternating temperature noise source Download PDFInfo
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- CN103812451B CN103812451B CN201410039962.8A CN201410039962A CN103812451B CN 103812451 B CN103812451 B CN 103812451B CN 201410039962 A CN201410039962 A CN 201410039962A CN 103812451 B CN103812451 B CN 103812451B
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Abstract
The present invention proposes a kind of normal temperature output port microwave alternating temperature noise source, aim to provide a kind of output port physical temperature be in normal temperature, equivalence output noise temperature in the microwave noise source of 50K～200K variable range, may be used for the measurement with the ultra-low noise coefficient of the microwave ultra-low noise amplifier of normal temperature input port.The technical scheme is that: the microwave pad (5) of noise source and microwave insulated delivery line (6), and the temperature sensor (7) of distribution monitoring microwave path physical temperature is installed on microwave coaxial output port (8), the cold head connecting firmly on refrigeration machine (1) main shaft is sealed in cooled cryostat (4) together with the temperature sensor that linear array is arranged on microwave insulated delivery line (6), cold head (2) in cooled cryostat (4) is connected Monitoring and Controlling circuit (3) by temperature monitor and control line, microwave insulated delivery line (6) is radial through outer normal temperature microwave coaxial output port (8) of chamber walls.
Description
Technical field
The present invention relates in a kind of electronic applications, for measuring the microwave alternating temperature noise source of microwave ultra-low noise amplifier noise coefficient, it is more particularly related to a kind of measurement has the microwave noise source of the noise coefficient parameter of the microwave ultra-low noise amplifier of ultra-low noise performance.It is believed that the present invention is in addition to for microwave ultra-low noise amplifier noise-factor measurement, can be also used for the amplitude linearity degree performance test of the microwave receiver such as noise-factor measurement and microwave radiometer of other similar microwave circuits with ultra-low noise performance.
Background technology
It it is known that noise is a kind of natural phenomena, is a kind of forms of motion of material.Inevitably all there is noise in electronic equipment and system, in general, noise is harmful, because the interference of noise even can flood useful signal.In the radio system such as radar, communication, the noise coefficient parameter of the microwave amplifier of radio-frequency front-end reflects electronic equipment and the size of system noise value, determining the key performance such as sensitivity of whole system, therefore, the accurately measurement to noise figure of amplifier is particularly important.The measurement of current noise figure of amplifier mainly uses the equipment such as noise source and noise testing receiver.During the noise-figure performance having less than the ultra-low noise amplifier of 0.5dB noise coefficient (conversion be 35K for equivalent input noise temperature) performance for measurement, for ensureing higher accuracy of measurement, prioritizing selection is answered to have the noise source of the equivalent output noise temperature being close with measured piece equivalent input noise temperature magnitude by noise testing theory.At present, generally use solid-state noise source to measure in industry, but its equivalence output noise temperature is in 1000K～10000K magnitude, it is clear that be not suitable for the accurate measurement of such ultra-low noise coefficient.
For solving the measurement problem of this ultra-low noise coefficient, the low temperature noise source of useful liquid nitrogen cooling and the noise source system of normal temperature noise source establishment are also studied by indivedual research institution both at home and abroad, and its equivalence output noise temperature is respectively about 80K and about 290K.Wherein, 6th phase " telecom technology " in 2005, disclose a kind of low noise automatically to test and noise source automated calibration system, this system uses the equivalent input noise temperature (i.e. noise coefficient) of cold/heat source measurement measured piece, but, noise source used by this system is owing to can only operate in two fixed temperature states, it is impossible to uses multi-temperature point measurement line number of going forward side by side to improve the accuracy of measurement of system according to statistics with the mode of matching, thus causes research difficulty greatly and to be difficult to realize through engineering approaches popularization and application.Such device is often confined to some high-end quantitative study mechanism and studies.
Owing to alternating temperature noise source can export multiple equivalence output noise temperature value in certain temperature range, therefore such noise source can carry out the measurement under multiple output noise state of temperature, obtain multiple measurement result value, such that it is able to the method for employing least square method or other mathematical statisticses and matching derives final noise-factor measurement result, therefore use alternating temperature measurement of noise source method on the premise of ensureing compared with the high measurement degree of accuracy, the accuracy requirement of noise source itself is relatively easily realized, popularization and application of being also more convenient for.Developing in some research institution has the alternating temperature noise source device of the variable equivalence output noise temperature with tens of K to hundreds of K.Wherein 2009, " whole nation microwave and millimeter wave proceeding " (volume two),Disclose the structure composition of a kind of wide aperture alternating temperature noise source being operated in 10GHz～90GHz frequency range.This equipment is made up of wide aperture radiant body, temperature control system, temp measuring system and liquid nitrogen container, and it is mainly used for calibrating the linearity being operated in microwave radiometer in 10GHz～90GHz frequency range, sensitivity and stability.Combining electrically heated double PID with relevant parameter output control mode owing to have employed liquid nitrogen cooling, this device can provide the brightened temperature of 85K～340K to export in the range of 10GHz～90GHz.But the temperature of this noise source uses liquid nitrogen cooling and electrically heated control mode, cause device alternating temperature mode complicated, the bigger ramp rates of wide aperture radiant body volume is slower, and this noise source exports without coaxial interface, antenna need to be connected and carry out wireless radiation output, it is impossible to directly the low-noise amplifier with the wired input of coaxial port be tested.Additionally, 2006, " Chinese journal of scientific instrument " the 3rd phase, disclose a kind of low temperature low noise amplifier test system, this system uses load temperature flexible method, for measuring the noise of low temperature low noise amplifier, but its microwave noise output port and all being put in cooled cryostat by amplifier, i.e. noise source and measured piece is in low temperature environment, may not apply to the noise coefficient test with the low-noise amplifier of normal temperature input port, and this system only carries out thermometric to the microwave pad in noise source, the physical temperature of microwave transmission line is not monitored in real time, in real time Registration cannot be carried out to its equivalence output noise temperature value when causing its work, thus its accuracy of measurement can be affected.
At present, the document delivered both at home and abroad, substantially uses the method for solid-state noise source measurement noise coefficient, occasionally has document to relate to use low temperature noise source and the measurement of room noise source, and uses the report of the alternating temperature measurement of noise source with low temperature output port.But pertinent literature and data also do not have normal temperature output port microwave alternating temperature noise source, especially in the microwave pad of noise source and microwave insulated delivery line and microwave coaxial output port, a series of temperature sensor is installed, the physical temperature distribution of microwave pad and microwave insulated delivery line and microwave coaxial port, and the record of the equivalent output noise temperature value of further Registration microwave coaxial port can be monitored when measuring work in real time.
Content of the invention
The task of the present invention is the weak point existing for above-mentioned prior art, a kind of accuracy of measurement is proposed high, easy popularization and application, in real time Registration can be carried out to its equivalence output noise temperature value, it is adaptable to there is the microwave alternating temperature noise source of the microwave ultra-low noise amplifier noise-factor measurement of normal temperature coaxle input end mouth.The problem being difficult to accurately measure with the noise coefficient parameter solving microwave ultra-low noise amplifiers numerous at present and similar products or system.
nullThe above-mentioned purpose of the present invention can be reached by following measures: a kind of normal temperature output port microwave alternating temperature noise source，Including upper end is placed in the refrigeration machine 1 in cooled cryostat 4 vacuum environment、The cold head 2 being connected on refrigeration machine 1 main shaft and the microwave pad 5 being positioned at radiation generation thermal noise source above cold head 2，It is characterized in that，On the microwave insulated delivery line 6 that microwave pad 5 radially connects firmly，The temperature sensor 7 of distribution monitoring microwave path physical temperature is installed，The connection of microwave insulated delivery line carries out the microwave pad of alternating temperature to the microwave coaxial output port being under normal temperature in being in low temperature range，The arrangement of temperature sensor 7 linear array is connected Monitoring and Controlling circuit 3 by temperature monitor and control line，Temperature monitor and control circuit 3 arranges instruction according to calibration calculation procedure，Monitor the physical temperature of each link of microwave path in real time，Temperature monitoring numerical value according to temperature sensor 7 feedback on microwave insulated delivery line 6，The temperature of refrigeration machine is controlled，The noise temperature of the microwave pad changing changing with control temperature in noise source，Equivalence exports the microwave coaxial output port 8 to normal temperature.
The present invention has the following technical effect that compared to prior art
The present invention passes through vavuum pump, by microwave pad, series of temperature sensor and microwave insulated delivery line are placed in the low temperature environment that sterlin refrigerator and cooled cryostat build, when measuring work, through temperature monitor and control circuit and microwave coaxial output port, its physical temperature is made to be in normal temperature, and in being in low temperature range by the connection of microwave insulated delivery line, carry out the microwave pad of alternating temperature, pass through microwave pad, it is mounted on series of temperature sensor on microwave insulated delivery line and microwave coaxial output port and carry out real-time physical temperature distribution monitoring, equivalent output noise temperature value with further Registration microwave coaxial port, solve the problem that the noise coefficient parameter of microwave ultra-low noise amplifiers numerous at present and similar products or system is difficult to accurately measure.
The present invention is provided with a series of temperature sensor 7 in the microwave pad 5 of noise source and microwave insulated delivery line 6 and microwave coaxial output port 8, the physical temperature distribution of microwave pad and microwave insulated delivery line and microwave coaxial port, and the equivalent output noise temperature value of further Registration microwave coaxial port can be monitored when measuring work in real time.
The present invention uses the connection of microwave insulated delivery line to carry out the microwave pad of alternating temperature to the microwave coaxial output port being under normal temperature in being in low temperature range, the equivalent output noise temperature making noise source is variable in the range of 50K～200K, and its noise output port its physical temperature when measuring work is in normal temperature.Do not only reach noise source equivalence output noise temperature purpose variable in tens of K to hundreds of K magnitudes, in turn ensure that this alternating temperature noise source has the ability of the noise coefficient parameter measurement of the ultra-low noise amplifier that accurately measurement input port temperature is normal temperature.Use series of temperature sensor to carry out real-time Temperature Distribution monitoring, further ensure the accuracy of output port equivalence output noise Temperature Scaling.Overcome in prior art low temperature noise source and room noise source building technology difficulty to be difficult to greatly promote, or the alternating temperature noise source that output port the is low temperature noise-factor measurement that may not apply to there is the low-noise amplifier of normal temperature input port and not there is monitoring in real time and the shortcoming of scaled noise source equivalence output noise temperature value.And have:
1) being applied to the measurement of ultra-low noise coefficient, the degree of accuracy is high, easy to spread.The present invention uses temperature sensor to monitor the physical temperature of each link of microwave path the equivalent output noise temperature calculating and calibrating the output port to noise source in real time.Its value quantifies in real time, it is ensured that the accuracy of noise source output value and reliability.Temperature monitor and control circuit carries out reaction type closed-loop control to temperature in Dewar, it is ensured that the stability of noise temperature output.Can arbitrarily export multiple noise temperature value in the range of 50K～200K, the method for available mathematical statistics improves the degree of accuracy when noise-factor measurement, reduces the accuracy requirement of noise source simultaneously, it is simple to through engineering approaches realizes and application.Solve prior art alternating temperature noise source output port and tested microwave ultra-low noise amplifier is intended to be under low temperature, noise-factor measurement can not be carried out to the ultra-low noise amplifier with normal temperature input port and the physical temperature distribution of microwave pad and microwave insulated delivery line and microwave coaxial port, and the problem of the equivalent output noise temperature value of further Registration microwave coaxial port cannot be monitored in real time.
2) alternating temperature noise source output port works in normal temperature, and application is wide.When the alternating temperature noise source output port of the present invention works, physical temperature is normal temperature, targeted measured piece type is more extensive, can be applied not only to the noise figure of amplifier measurement with normal temperature input port using low temperature or superconductor electronic technology to make, also can directly measure common normal temperature low-noise amplifier widely used on market, apply also for the linearity of all types of Microwave Low-Noise receiver or microwave radiometer, sensitivity, the calibration fields of measurement of brightness temperature simultaneously.
Accuracy of measurement of the present invention is high, is particularly well-suited to the measurement with the ultra-low noise coefficient close to the noise coefficient parameter quantities limit.
Brief description
Fig. 1 is the principle schematic of normal temperature output port microwave alternating temperature noise source of the present invention.
Fig. 2 is the embodiment schematic diagram of Fig. 1.
In figure: 1 refrigeration machine, 2 cryocooler cold head, 3 temperature monitor and control circuit, 4 cooled cryostats, 5 microwave pads, 6 microwave insulated delivery lines, 7 temperature sensors, 8 normal temperature microwave coaxial output ports, 9 vavuum pumps, 10 vacuum leads, 11 temperature monitor and control lines, 12 racks.
Detailed description of the invention
Refering to Fig. 1, Fig. 2.A kind of in Fig. 1 description has in the microwave alternating temperature noise source embodiment of normal temperature output port for the test of ultralow microwave noise, and this alternating temperature noise source mainly includes that the 1st, the refrigeration machine that top is under vacuum environment in cooled cryostat 4 is connected to radiate the microwave pad 5 producing thermal noise on the cold head 2 on refrigeration machine 1 main shaft.Refrigeration machine 1 uses sterlin refrigerator.The temperature sensor 7 of distribution monitoring microwave path physical temperature is installed on the microwave pad 5 of noise source and microwave insulated delivery line 6 and microwave coaxial output port 8, temperature sensor 7 linear array is arranged on microwave insulated delivery line 6, is built low temperature environment by refrigeration machine 1 and cooled cryostat 4.Microwave pad 5 is radially fixedly connected with one end and is connected on the microwave insulated delivery line 6 of the outer normal temperature microwave coaxial output port 8 of vacuum tank wall, the connection of microwave insulated delivery line 6 carries out the microwave pad of alternating temperature to the microwave coaxial output port 8 being under normal temperature in being in low temperature range, the temperature sensor 7 of distribution monitoring microwave path physical temperature is installed, microwave pad 5 in noise source is under low temperature, and alternating temperature can be carried out in 50K～200K temperature range, the physical temperature of the microwave coaxial output port 8 of noise source is then normal temperature.The cold head 2 connecting firmly on refrigeration machine 1 main shaft is sealed in cooled cryostat 4 together with the temperature sensor that linear array is arranged on microwave insulated delivery line 6, cold head 2 in cooled cryostat 4 is connected Monitoring and Controlling circuit 3 by temperature monitor and control line, and microwave insulated delivery line 6 is radial through cooled cryostat wall the normal temperature microwave coaxial output port 8 being installed on rack 12.Air in Dewar and transmission line is extracted out by vavuum pump 9 by vacuum lead 10 is real-time so that it is be in vacuum state, to avoid the internal frosting of Dewar.Noise source each several part is arranged on rack 12.Noise source operation is all carried out on temperature monitoring and control circuit 3.Microwave pad 5 radiation being on cryocooler cold head 2 produces noise temperature equivalence output to normal temperature microwave coaxial output port 8.Temperature monitor and control circuit 3 carries out reaction type closed-loop control to temperature in Dewar, according to calibration calculation procedure, instruction and the temperature monitoring numerical value of series of temperature sensor 7 feedback are set, it is controlled by the temperature to refrigeration machine for the temperature monitor and control line 11, thus controlling the physical temperature of microwave pad 5, the equivalent output noise temperature of microwave pad then changes with the change of the physical temperature controlling.Microwave insulated delivery line 6 connects microwave pad 5 to the normal temperature microwave coaxial output port 8 under low temperature.Temperature monitor and control circuit 3 is integrated with the working procedure of whole noise source, and includes the calibration calculation procedure of noise source equivalence output noise temperature.This equivalence output noise temperature value will be used for the calculating to ultra-low noise amplifier noise-factor measurement.
Claims (8)
- null1. a normal temperature output port microwave alternating temperature noise source，Including upper end is placed in the refrigeration machine (1) in cooled cryostat (4) vacuum environment、The cold head (2) being connected on refrigeration machine (1) main shaft and the microwave pad (5) being positioned at cold head (2) top radiation generation thermal noise source，It is characterized in that，On microwave insulated delivery line (6) that microwave pad (5) radially connects firmly，The temperature sensor (7) of distribution monitoring microwave path physical temperature is installed，Connected by microwave insulated delivery line (6) in being in low temperature range and carry out the microwave pad (5) of alternating temperature to the microwave coaxial output port (8) being under normal temperature，By microwave pad (5)、Microwave insulated delivery line (6) and microwave coaxial output port (8) are mounted on a series of temperature sensor (7) and carry out real-time physical temperature distribution monitoring，And the microwave pad (5) of alternating temperature can be carried out in 50K～200K temperature range、A series of temperature sensor (7) and microwave insulated delivery line (6) are placed in the low temperature environment that sterlin refrigerator and cooled cryostat build，Wherein，Microwave pad (5) radiation being on cryocooler cold head (2) produces noise temperature equivalence output to normal temperature microwave coaxial output port (8)，The arrangement of temperature sensor (7) linear array is connected Monitoring and Controlling circuit (3) by temperature monitor and control line，Temperature monitor and control circuit (3) is carried out the noise source working procedure of reaction type closed-loop control and the calibration calculation procedure of noise source equivalence output noise temperature by the integrated interior temperature to cooled cryostat (40)，According to calibration calculation procedure, instruction is set，The equivalent output noise temperature of scaled noise source output terminal mouth，Application equivalence output noise temperature value calculates the noise coefficient of low-noise amplifier measurement，Monitor the physical temperature of each link of microwave path in real time，The temperature monitoring numerical value feeding back according to the upper temperature sensor (7) of microwave insulated delivery line (6)，By temperature monitor and control line (11), the physical temperature of microwave pad (5) and the temperature of refrigeration machine are controlled，The noise temperature of the microwave pad changing changing with control temperature in noise source，Equivalence exports the microwave coaxial output port (8) to normal temperature，Multiple noise temperature value is arbitrarily exported in the range of 50K～200K.
- 2. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterised in that: the physical temperature of the microwave pad (5) of noise source and the upper temperature sensor (7) installed of microwave insulated delivery line (6) real-time distribution monitoring microwave path during measurement.
- 3. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterised in that: normal temperature microwave coaxial output port (8) of noise source is in normal temperature environment, and which is coaxial interface mode.
- 4. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterised in that: noise source operation is all carried out on temperature monitor and control circuit (3).
- 5. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterized in that: cold head (2) and the linear array connecting firmly on refrigeration machine (1) main shaft be arranged in the temperature sensor on microwave insulated delivery line (6) together be sealed in cooled cryostat (4), cold head (2) in cooled cryostat (4) is connected Monitoring and Controlling circuit (3) by temperature monitor and control line, and microwave insulated delivery line (6) is radial through cooled cryostat wall normal temperature microwave coaxial output port (8) being installed on rack (12).
- 6. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterised in that: the air in cooled cryostat (4) and transmission line, extracted out by vavuum pump (9) vacuum lead (10) so that it is be in vacuum state.
- 7. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterised in that: the physical temperature of the microwave coaxial output port (8) of noise source is normal temperature.
- 8. normal temperature output port microwave alternating temperature noise source as claimed in claim 1, it is characterized in that: the physical temperature distribution of microwave pad (5) and microwave insulated delivery line (6) and microwave coaxial output port (8) monitored in real time by temperature sensor (7), determines the equivalent output noise temperature value of mark microwave coaxial port.
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| CN107727267A (en) * | 2017-09-28 | 2018-02-23 | 北京无线电计量测试研究所 | A kind of coaxial standard cryogenic noise source |
| CN110231516B (en) * | 2019-06-14 | 2021-05-11 | 北京无线电计量测试研究所 | Quick variable temperature microwave noise source |
| CN110411555A (en) * | 2019-07-05 | 2019-11-05 | 北京无线电计量测试研究所 | A kind of high temperature noise source |
| CN113258882A (en) * | 2021-03-31 | 2021-08-13 | 北京无线电计量测试研究所 | System and method for improving equivalent output noise temperature stability |
| CN113589053B (en) * | 2021-08-20 | 2023-04-25 | 中国科学院新疆天文台 | K wave band radio astronomical refrigeration receiver noise source device |
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