System and method for measuring equivalent noise temperature of low-noise amplifier

Abstract

The invention discloses a system and method for measuring the equivalent noise temperature of a low-noise amplifier, and the system comprises a load assembly which is used for providing a thermal noise signal and comprises a first load and a second load, and the first load and the second load are respectively located in a first temperature region and a second temperature region which are different in temperature; the input end of the low-noise amplifier to be tested is electrically connected with the first load or the second load to receive a thermal noise signal; the second-stage amplification assembly is connected with the output end of the low-noise amplifier and amplifies an output signal of the low-noise amplifier, and the second-stage amplification assembly and the low-noise amplifier meet impedance matching; and the measuring equipment is used for measuring the signal output by the secondary amplification assembly and obtaining the equivalent noise temperature of the low-noise amplifier. The low-noise amplifier is connected with the switching of the end part of the load in different temperature zones, so that uncertain factors in measurement are reduced.

Description

Technical Field

[0001] The invention belongs to the field of low-temperature measurement, and in particular relates to a system and method for measuring the equivalent noise temperature of a low-noise amplifier. Background Art

[0002] In the field of low-temperature measurement, the real effective signal of the sample to be tested is very weak compared to the system environmental noise, and it is difficult to be directly collected and processed by the measuring instrument. Usually, the real signal of the sample to be tested can be effectively extracted by in-situ signal amplification and improving the signal-to-noise ratio of the output signal.

[0003] Taking quantum computers as an example, quantum computing tasks are run through quantum processors and calculation result signals are output. However, the control and reading signals of quantum chips are very weak, usually below -110dBm, which is difficult to be directly collected and processed by measuring instruments. The effective signals of the chip need to be properly amplified in situ. While amplifying the effective signal, it is also necessary to suppress noise to improve the signal-to-noise ratio. Usually, a low-temperature low-noise amplifier is set in a temperature zone adjacent to the quantum chip in the refrigerator system for in-situ signal amplification of the quantum chip. At the same time, the lower equivalent noise temperature of the amplifier itself maximizes noise suppression.

[0004] The noise factor is a measure of the messy signal added to the signal by the device under test (DUT) when the RF signal passes through it, mainly due to the irregular thermal motion of the electrons in the device. In order to measure the degree of deterioration of the control signal, the concept of noise factor NF (Noise Fi gure) is introduced. That is to say, the noise factor quantifies the degree to which the DUT reduces the signal-to-noise ratio of the signal. Usually when the noise is very small, the equivalent noise temperature is used. To measure the noise performance of a low noise amplifier, the equivalent noise temperature The relationship with the noise factor is as follows:

[0005]

[0006] In the formula, T0=290K, which represents the equivalent noise temperature at room temperature.

[0007] The noise figure is a quality factor used to describe the amount of excess noise in a system, so the smaller the noise figure, the better. Designers strive to optimize the signal-to-noise ratio (SNR) of the entire system. Generally speaking, there are two options: increasing signal power and reducing noise figure. Generally speaking, increasing signal power means greater heat load, as well as waste of cost and performance, while reducing noise figure is more economical and easier to achieve. Summary of the invention

[0008] In order to improve the measurement accuracy of equivalent noise temperature, the present invention provides a system and method for measuring the equivalent noise temperature of a low noise amplifier, and the technical solution is:

[0009] A system for measuring equivalent noise temperature of a low noise amplifier, comprising:

[0010] A load component, used for providing a thermal noise signal, comprises a first load and a second load, wherein the first load and the second load are respectively located in a first temperature zone and a second temperature zone with different temperatures; an input end of the low noise amplifier to be tested is electrically connected to the first load or the second load to receive the thermal noise signal;

[0011] A secondary amplifying component connected to the output end of the low noise amplifier to amplify the output signal of the low noise amplifier, wherein the secondary amplifying component and the low noise amplifier meet impedance matching;

[0012] A measuring device is used to measure the signal output by the secondary amplification component and obtain the equivalent noise temperature of the low noise amplifier.

[0013] Optionally, the temperature zone ratio between the temperature zones where the first load and the second load are located is at least one order of magnitude.

[0014] Optionally, the low noise amplifier is respectively connected to the first load and the second load through the same first cable, and the measuring device obtains two corresponding measurement signals.

[0015] Optionally, the first load and the second load are the same load.

[0016] Optionally, the low noise amplifier and the secondary amplifier assembly are arranged in a lowest temperature zone corresponding to the working environment temperature requirement.

[0017] Optionally, the gain of the secondary amplification component and the low-noise amplifier as a whole is greater than the background noise of the measuring device.

[0018] A method for measuring an equivalent noise temperature of a low noise amplifier, comprising:

[0019] A measurement system of the low noise amplifier is constructed, wherein the load as a noise source is located in the first temperature zone and the second temperature zone respectively, and the measuring device measures the first noise signal and the second noise signal correspondingly, and obtains the first relationship and the second relationship corresponding to the fixed parameters of the components in the measurement system; the components include a load component, a low noise amplifier, a secondary amplification component, a measuring device, a first cable, and a second cable;

[0020] determining a third relationship representing an equivalent noise temperature of the low noise amplifier based on the first relationship, the second relationship, and a Y factor, wherein the Y factor is a ratio of the first noise signal to the second noise signal;

[0021] According to the loads in different temperature zones, the noise after being amplified by the low-noise amplifier and the secondary amplifier component is much greater than the background noise of the measuring device, and the third relationship is simplified to obtain the fourth relationship;

[0022] The equivalent noise temperature of the low noise amplifier is obtained according to the fourth relationship.

[0023] Optionally, a first relationship and a second relationship between the first noise signal and the second noise signal and a fixed parameter of an element in the measurement system are obtained, wherein the first relationship and the second relationship are respectively:

[0024]

[0025]

[0026] Among them, T 4K 、T 50K are the equivalent noise temperatures of the first load and the second load as source noise, G L1 , G L2 The first cable G L1 The attenuation factor and the loss of the second cable, is the gain multiple and equivalent noise temperature of the low noise amplifier, G2 and T2 are the gain and equivalent noise temperature of the secondary amplifier component, P noise is the noise floor of the measurement device, k is the Boltzmann constant, and B is the resolution bandwidth.

[0027] Optionally, determining a third relationship representing an equivalent noise temperature of the low noise amplifier based on the first relationship, the second relationship, and the Y factor specifically includes: the equivalent noise temperature and the Y factor of the low noise amplifier are respectively determined as:

[0028]

[0029]

[0030] Among them, Y is the Y factor, which is used to characterize the amplification factor.

[0031] Optionally, according to the fact that the noise of the first load and the second load after being amplified by the low-noise amplifier and the secondary amplification component is much greater than the background noise of the measuring device, the third relationship is simplified to obtain the fourth relationship, wherein the

[0032] The four relationships are:

[0033]

[0034] Optionally, the equivalent noise temperature of the low noise amplifier is obtained according to the fourth relationship:

[0035]

[0036] The beneficial effects of the present invention are:

[0037] (1) The present application reduces the uncertain interference factors of the front end of the low noise amplifier to be tested; for example, the front end of the low noise amplifier to be tested uses the same section of cable and 50 ohm impedance to ensure the consistency of impedance matching, which greatly reduces the uncertain factors. In addition, the first load and the second load can use the same load, so that only the same load needs to be moved in different temperature zones, which minimizes the uncertain factors.

[0038] (2) The two-stage amplification component of the present application and the low-noise amplifier to be tested have a relatively large gain as a whole, so that the system noise power after two-stage amplification is much larger than the spectrum analyzer noise floor, thereby ensuring the accuracy of the measurement data. At the same time, for the two-stage amplification component, more stages of amplification can also be used to ensure the accuracy of the measurement data.

[0039] (3) For the first cable G L1 and the second cable G L2 In order to reduce the impact of the measurement system, the line loss is also introduced into the calculation of the measurement system to further improve the accuracy of the measurement system.

[0040] (4) The present invention provides a method for measuring the equivalent noise temperature of a low noise amplifier, which uses the above-mentioned measurement system and thus has the same beneficial effects, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the structure of an amplifier equivalent noise temperature characterization system in the prior art;

[0042] Figure 2 It is a structural schematic diagram of a measurement system for the equivalent noise temperature of a low noise amplifier DUT in the present invention;

[0043] Figure 3 A table comparing the measured equivalent noise temperature with the data in the data sheet using two identical commercial cryogenic low noise amplifier DUTs according to the present invention. DETAILED DESCRIPTION

[0044] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present application, and cannot be interpreted as limitations on the present application.

[0045] In the description of the present invention, it is necessary to understand that the terms "center", "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0047] In the field of low-temperature measurement, the real effective signal of the sample to be measured is very weak compared to the system environmental noise, and it is difficult to be directly collected and processed by the measuring instrument. Usually, the real signal of the sample to be measured can be effectively extracted after in-situ signal amplification and improving the signal-to-noise ratio of the output signal. In the existing technology, the mainstream methods of noise measurement are the Y factor method and the cold source method. Taking quantum computers as an example, as shown in the attached Figure 1 As shown, an existing amplifier equivalent noise temperature characterization system includes a signal amplifier D to be measured and located in the first temperature zone of the refrigeration equipment, a microwave switch K, and a first load Z1, a second load Z2 located in the second temperature zone of the refrigeration equipment, and a measuring device 21 located in the third temperature zone. The input end of the signal amplifier D is connected to the first load Z1 or the second load Z2 through the microwave switch K, and the output end of the signal amplifier D is connected to the measuring device 21; the first temperature zone and the second temperature zone are both preset temperature zones in the refrigeration equipment. The microwave switch K is used to switch between different thermal noise sources. This method can achieve fast measurement, but the measurement accuracy is not high enough and has the following defects:

[0048] 1) Microwave switch K is an active device and can introduce certain noise into the test system;

[0049] 2) When the microwave switch K is switched to different temperature zones, the cables connected to different temperature zones are not exactly the same, and the impedance matching before and after the switching is also different. Impedance mismatch will greatly affect the measurement accuracy;

[0050] 3) This scheme adopts one-stage amplification. If the amplifier gain is not enough to make the effective signal of the thermal noise source after amplification much larger than the background noise of the measuring instrument, the test data will lose its meaning and the equivalent noise temperature cannot be effectively calculated.

[0051] In summary, in the measurement of quantum chips, the signal is very weak and difficult to enhance, and it is easy to be drowned by the system noise. Therefore, an excellent low-temperature low-noise amplifier can achieve in-situ signal amplification while reducing system noise and improving the signal-to-noise ratio of the measurement system. Improving the measurement accuracy of the noise factor can refine the system model during product development and better optimize system performance.

[0052] To improve the measurement accuracy, Figure 2 As shown: The embodiment of the present application discloses a system for measuring the equivalent noise temperature of a low noise amplifier, comprising:

[0053] A load component, used for providing a thermal noise signal, comprises a first load Z1 and a second load Z2, wherein the first load Z1 and the second load Z2 are respectively located in a first temperature zone and a second temperature zone with different temperatures; an input end of a low noise amplifier DUT to be tested is electrically connected to the first load Z1 or the second load Z2 to receive the thermal noise signal; the test frequency band of the low noise amplifier DUT of the present invention is wide, and the applicable field is not limited.

[0054] The secondary amplifier component is connected to the output end of the low-noise amplifier DUT to amplify the output signal of the low-noise amplifier DUT. The secondary amplifier component and the low-noise amplifier DUT meet impedance matching. In order to test the effect, in this solution, each secondary amplifier in the secondary amplifier component has the same model and specification as the low-noise amplifier DUT.

[0055] A measuring device is used to measure the signal output by the secondary amplification component and obtain the equivalent noise temperature of the low noise amplifier.

[0056] Preferably, the temperature ratio of the two temperature zones in the present application is at least one order of magnitude, and compared with the prior art where the first temperature zone is 4K and the second temperature zone is 1K, the greater the temperature difference between the first temperature zone and the second temperature zone in the present application, the closer the equivalent noise temperature obtained is to the true value. The temperature of the first temperature zone where the first load Z1, the low noise amplifier DUT, and the secondary amplification component are located is 4K, and the temperature of the second temperature zone where the second load Z2 is located is 50K.

[0057] In this solution, the resistance of the first load Z1 and the second load Z2 are both 50 ohms. The 50 ohm impedance is used for optimal matching of the amplifier, and as a passive device, its echo characteristics are insensitive to temperature changes, which also helps to improve the measurement accuracy.

[0058] In order to achieve the measurement environment, the system is set in the refrigeration device 1. Optionally, the refrigeration device 1 is a dilution refrigerator, and multiple temperature zones are arranged inside. Each temperature zone is isolated from each other. The temperature of each temperature zone is achieved by a refrigeration plate, and the first load Z1 and the second load Z2 are respectively set on the refrigeration plate of the corresponding temperature zone. The refrigeration device 1 of this solution is not limited to a dilution refrigerator, and it only needs to meet the difference setting of the temperature zones and stable temperature control in this application.

[0059] Optionally, the low noise amplifier DUT is connected via a first cable G L1 Connected to the first load Z1 and the second load Z2 respectively, using the first cable G L1 It is convenient for the end connected to the load to switch in different temperature zones. In addition, the low noise amplifier DUT uses the same first cable G L1 Alternating the connection between the first load Z1 and the second load Z2 can reduce the uncertainty in the measurement. When two cables are used to connect the corresponding loads and the low noise amplifier DUT through a microwave switch K, the materials and lengths of the two cables cannot be guaranteed to be exactly the same, so they will affect the calculation of the equivalent noise temperature as an uncertainty factor.

[0060] Preferably, the first load Z1 and the second load Z2 are the same load. After obtaining the first measurement result, it is only necessary to move the load connected to the cable to another temperature zone. This process minimizes uncertainties, including: the two different loads cannot be completely consistent due to the process, the structure of the cable connecting the two loads is different, etc.

[0061] Optionally, the first cable G L1 The length of the first cable G is as short as possible, reducing L1 The impact on the measurement makes the data measured by the measuring device closer to the true value of the equivalent noise temperature of the low noise amplifier DUT.

[0062] Optionally, the secondary amplifier component uses multi-stage amplification to ensure the accuracy of the measurement data. The setting of the secondary amplifier component can reduce the introduction of other noises. The secondary amplifier component includes at least one secondary amplifier. For the convenience of description, the secondary amplifier component uses a secondary amplifier LNA2. It should be noted that the present application is not limited to the use of one secondary amplifier LNA2. The secondary amplifier LNA2 satisfies the impedance matching with the low-noise amplifier DUT. The gain of the secondary amplifier component and the low-noise amplifier as a whole is greater than the background noise of the measuring device. In order to improve the accuracy of the measurement, the overall gain is at least 10dB greater than the background noise of the measuring device. In detail, the greater the gain of the secondary amplifier LNA2 and the overall gain of the low-noise amplifier DUT, the smaller the noise impact of the amplifier back end, the smaller the error caused by its own low noise, and the closer the data measured by the measuring device is to the true value.

[0063] Optionally, the low noise amplifier and the secondary amplifier components are set in the lowest temperature zone corresponding to the working environment temperature requirement. In this embodiment, the low noise amplifier DUT and the secondary amplifier LNA2 are set in the first temperature zone (the temperature zone corresponding to 4K in this solution). Compared with being placed in the second temperature zone (the temperature zone corresponding to 50K in this solution), it can ensure that the system measures the minimum equivalent noise temperature.

[0064] Optionally, the output end of the secondary amplifier LNA2 is connected to the output end of the secondary amplifier LNA2 through a second cable G L2 The measuring device 21 is connected to the input end of the measuring device 21. The measuring device 21 is a spectrum analyzer in this solution, and may be other measuring devices in other solutions, such as a high-precision power meter.

[0065] Optionally, the present application uses a cascade system so that the amplified noise is much greater than the background noise of the measuring device, thereby ensuring the accuracy of the measured data.

[0066] In addition, the measurement system further includes a power supply for the low noise amplifier DUT and the secondary amplifier LNA2, so as to support the normal operation of the low noise amplifier DUT and the secondary amplifier LNA2 as active devices.

[0067] The measurement system of the present application will greatly improve the measurement accuracy of the system, which is of great significance for characterizing low-temperature low-noise amplifiers with better performance.

[0068] The measuring method of the measuring system of the equivalent noise temperature of a low noise amplifier comprises:

[0069] S10. Build a measurement system for the above-mentioned low-noise amplifier DUT, where the first load and the second load as noise sources in the measurement system are located in the first temperature zone and the second temperature zone respectively, and the measuring device 21 measures the first noise signal and the second noise signal correspondingly, and obtains the first relationship and the second relationship between the first noise signal and the second noise signal and the fixed parameters of the components in the measurement system; wherein the first noise signal is the total noise of the output signal when the input end of the low-noise amplifier DUT is connected to the first load Z1, and the second noise signal is the total noise of the output signal when the input end of the low-noise amplifier DUT is connected to the second load Z2; the components include a load component, a low-noise amplifier, a secondary amplification component, a measuring device, a first cable, and a second cable; the first load and the second load in the load component are the same load.

[0070] S20. Determine a third relationship representing an equivalent noise temperature of the low noise amplifier DUT based on the first relationship, the second relationship, and a Y factor, wherein the Y factor is a ratio of the first noise signal to the second noise signal.

[0071] Among them, the first relationship and the second relationship are the relative relationship between the noise signal in the output signal of the measurement system and the fixed parameters of each component in the measurement system, using two loads located in an area with a large temperature difference as noise sources, and the first relationship and the second relationship are converted in combination with the ratio Y factor of the first noise signal and the second noise signal to obtain a third relationship between the equivalent noise temperature of the low-noise amplifier DUT to be measured and the fixed parameters of each component in the measurement system and the Y factor.

[0072] Wherein, the first relationship and the second relationship are the relative relationship between the noise signal of the output signal of the measurement system and the fixed parameters of the low noise amplifier DUT and the secondary amplification component. The first relationship and the second relationship are converted to obtain the third relationship between the equivalent noise temperature of the low noise amplifier DUT and the fixed parameters of the secondary amplification component in the measurement system. Wherein, the fixed parameters of each component in the measurement system correspond to the first noise signal and the second noise signal, so the third relationship can also be expressed as a function of the first noise signal and the second noise signal. For low-gain amplifiers, the secondary amplification component uses multi-stage amplification to ensure the accuracy of the measurement data. The secondary amplification component includes at least one secondary amplifier LNA2. For the convenience of description, the secondary amplification component uses one secondary amplifier LNA2. It should be noted that the present application is not limited to the use of one secondary amplifier LNA2.

[0073] S30: Simplifying the third relationship to obtain a fourth relationship according to the fact that the noise of the first load Z1 and the second load Z2 as thermal noise sources after being amplified by the low noise amplifier DUT and the secondary amplifier LNA2 is much greater than the background noise of the measuring device 2;

[0074] S40: Obtaining an equivalent noise temperature of the low noise amplifier DUT according to the fourth relationship.

[0075] As an implementation method of the present application, in step S10, a measurement system for a low noise amplifier DUT is constructed. The first cable G L1 The first load Z1 or the second load Z2 is connected respectively, and the measuring device 21 measures the first noise signal and the second noise signal accordingly. L1 First connect the second load Z2 and then connect the first load Z1 as an example. You can also use the first cable G L1 The first load Z1 is connected first and then the second load Z2 is connected, which will not be described in detail here.

[0076] The above system is used to measure the equivalent noise temperature of the low noise amplifier DUT with the first cable G L1 The steps of connecting the second load Z2 first and then the first load Z1 are as follows:

[0077] S11, through the first cable G L1 Connect the input end of the low noise amplifier DUT to the second load Z2 on the 50K plate (second temperature zone);

[0078] S12, directly connecting the output end of the low noise amplifier DUT to the input end of the secondary amplifier LNA2, and the impedance of the low noise amplifier DUT and the secondary amplifier LNA2 are matched, thereby reducing the introduction of other noises;

[0079] S13, placing the low noise amplifier DUT and the secondary amplifier LNA2 on a 4K tray (first temperature zone), and connecting them via a second cable G L2 Connect the output end of the secondary amplifier LNA2 and the input end of the spectrum analyzer;

[0080] S14, complete the second noise signal power P through the measurement device 50K Measurement of

[0081] S15, connect the first cable G L1 The end located in the second temperature zone moves to the 4K disk (first temperature zone) and is connected to the first load Z1;

[0082] S16, completing the first noise signal power P through the spectrum analyzer 4K measurement.

[0083] As an implementation method of the present application, the first noise signal P of the measurement system output signal 4K and the second noise signal P 50K The first relationship and the second relationship with the fixed parameters of the elements in the measurement system are respectively:

[0084]

[0085]

[0086] Among them, T 4K 、T 50K are the equivalent noise temperatures of the first load Z1 and the second load Z2 as source noise, G L1 , G L2 The first cable G L1 The attenuation factor and the loss of the second cable, is the gain multiple and equivalent noise temperature of the low noise amplifier DUT, G2 and T2 are the gain and equivalent noise temperature of the secondary amplifier LNA2, P noise is the noise floor of the spectrum analyzer used as the measurement device, k is the Boltzmann constant, and B represents the bandwidth. L1 The attenuation factor G L1 , the gain multiple of the low noise amplifier DUT The attenuation loss G′ in dB is required L1 and gain value Converted into the corresponding multiple relationship, the conversion formula is: The gains of the low noise amplifier DUT and the secondary amplifier LNA2 are positive values, and the cable attenuation should be recorded as -0.1dB gain instead of 0.1dB.

[0087] As an implementation method of the embodiment of the present application, a third relationship representing the equivalent noise temperature of the low noise amplifier is determined based on the first relationship, the second relationship, and the Y factor, specifically including: the equivalent noise temperature and the Y factor of the low noise amplifier are respectively determined as:

[0088]

[0089]

[0090] Among them, Y can be understood as the Y factor, which can be used to characterize the amplification factor. The Y factor is the ratio of the first noise signal to the second noise signal. By combining the first relationship and the second relationship, the equivalent noise temperature of the low noise amplifier to be tested can be obtained. It can be found from the above formula that the equivalent noise temperature of the low noise amplifier DUT is related to the fixed parameters of each component of the measurement system and Y. In this application, the first cable G is introduced in the calculation of the equivalent noise temperature L1 and the second cable G L2 The noise calculation brought by the first cable G L1 and the second cable G L2The noise error caused.

[0091] As an implementation method of the present application, according to the noise of the first load and the second load after being amplified by the low-noise amplifier and the secondary amplification component is much greater than the background noise of the measuring device, the third relationship is simplified to obtain the fourth relationship, and the fourth relationship is:

[0092]

[0093] As an implementation method of the embodiment of the present application, the equivalent noise temperature of the low noise amplifier is obtained according to the fourth relationship:

[0094]

[0095] Different schemes in the above measurement systems and measurement methods can achieve measurement effects in different combinations.

[0096] Based on the above measurement system and measurement method, it can be obtained Figure 3 Corresponding to the measured data and calculated results in the table, this test uses two identical commercial low-temperature low-noise amplifier DUTs, and compares the measured equivalent noise temperature with the data in the specification sheet. The sixth column represents the nominal value of the equivalent noise temperature in the specification sheet of the commercial secondary amplifier LNA2, and the last column represents the laboratory measured value of the equivalent noise temperature of the commercial secondary amplifier LNA2. Since the secondary amplifier LNA2 and the low-noise amplifier DUT to be tested have the same model specifications, the measured value of the secondary amplifier LNA2 in the table is the measured value of the low-noise amplifier DUT.

[0097] (1) The frequency range of this measurement is 0.1 GHz to 2 GHz.

[0098] 0.1 / 0.3 / 0.5 / 0.7 / 0.9 / 1.1 / 1.3 / 1.5 / 1.7 / 1.9GHz points;

[0099] (2) The actual temperature in the 50K temperature zone is 48.31K, and the actual temperature in the 4K temperature zone is 3.59K;

[0100] (3) Measure the noise power in different temperature zones at different frequencies and calculate the corresponding Y factor;

[0101] (4) According to the formula Calculate the equivalent noise temperature at different frequencies

[0102] (5) According to data comparison, the difference between the test data and the nominal data is about 1 to 2K.

[0103] In the description of this specification, the description with reference to the terms "some embodiments" or "examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0104] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A system for measuring equivalent noise temperature of a low noise amplifier, characterized in that: include: A load component, used for providing a thermal noise signal, comprises a first load and a second load, wherein the first load and the second load are respectively located in a first temperature zone and a second temperature zone with different temperatures; an input end of the low noise amplifier to be tested is electrically connected to the first load or the second load to receive the thermal noise signal; A secondary amplifying component connected to the output end of the low noise amplifier to amplify the output signal of the low noise amplifier, wherein the secondary amplifying component and the low noise amplifier meet impedance matching; A measuring device is used to measure the signal output by the secondary amplification component and obtain the equivalent noise temperature of the low noise amplifier.

2. The measuring system according to claim 1, characterized in that The temperature zone ratio between the temperature zones where the first load and the second load are located is at least one order of magnitude.

3. The measuring system according to claim 1, characterized in that The low noise amplifier is connected to the first load and the second load respectively through the same first cable, and the measuring device obtains two corresponding measurement signals.

4. The measuring system according to claim 1, characterized in that The first load and the second load are the same load.

5. The measuring system according to claim 1, characterized in that The low noise amplifier and the secondary amplifier assembly are arranged in the lowest temperature zone corresponding to the working environment temperature requirement.

6. The measuring system according to claim 1, characterized in that The gain of the secondary amplification component and the low noise amplifier as a whole is greater than the background noise of the measuring device.

7. A method for measuring the equivalent noise temperature of a low noise amplifier, characterized in that: include: A measurement system for a low noise amplifier as described in any one of claims 1 to 6 is constructed, wherein the load as a noise source is located in a first temperature zone and a second temperature zone respectively, and a measuring device measures a first noise signal and a second noise signal correspondingly, and obtains a first relationship and a second relationship between the first noise signal and the second noise signal and fixed parameters of components in the measurement system; the components include a load component, a low noise amplifier, a secondary amplification component, a measuring device, a first cable, and a second cable; determining a third relationship representing an equivalent noise temperature of the low noise amplifier based on the first relationship, the second relationship, and a Y factor, wherein the Y factor is a ratio of the first noise signal to the second noise signal; According to the loads in different temperature zones, the noise after being amplified by the low-noise amplifier and the secondary amplifier component is much greater than the background noise of the measuring device, and the third relationship is simplified to obtain the fourth relationship; The equivalent noise temperature of the low noise amplifier is obtained according to the fourth relationship.

8. The measuring method according to claim 7, characterized in that: A first relationship and a second relationship between the first noise signal and the second noise signal and a fixed parameter of an element in the measurement system are obtained, wherein the first relationship and the second relationship are respectively: Among them, T 4K , T 50K are the equivalent noise temperatures of the first load and the second load as source noise, G L1 , G L2 The first cable G L1 The attenuation factor and the loss of the second cable, is the gain multiple and equivalent noise temperature of the low noise amplifier, G2 and T2 are the gain and equivalent noise temperature of the secondary amplifier component, P noise is the noise floor of the measurement device, k is the Boltzmann constant, and B is the resolution bandwidth.

9. The method according to claim 8, characterized in that Determining a third relationship representing the equivalent noise temperature of the low noise amplifier based on the first relationship, the second relationship, and the Y factor specifically includes: the equivalent noise temperature and the Y factor of the low noise amplifier are respectively determined as: Among them, Y is the Y factor, which is used to characterize the amplification factor.

10. The method according to claim 9, characterized in that According to the fact that the noise of the first load and the second load after being amplified by the low-noise amplifier and the secondary amplification component is much greater than the background noise of the measuring device, the third relationship is simplified to obtain the fourth relationship, which is:

11. The method according to claim 10, characterized in that The equivalent noise temperature of the low noise amplifier is obtained according to the fourth relationship:

Images