Line noise measurement method and apparatus

Abstract

The application discloses a line noise measurement method and device, and belongs to the technical field of noise measurement. In the line noise measurement method, a bridge circuit is formed by using a first adjustable resistor, a second adjustable resistor, a first fixed resistor and a second fixed resistor, the first fixed resistor and / or the second fixed resistor is connected with a line to be measured, a bridge signal output by the bridge circuit is detected through a reference signal, a first noise spectrum containing thermal noise of the first fixed resistor and the second fixed resistor is obtained, and then the first noise spectrum is processed according to a theoretical value of the thermal noise of the first fixed resistor and the second fixed resistor, so that the line noise of the line to be measured is determined. The measurement method can accurately measure the line noise, and is beneficial to accurate evaluation of line performance.

Description

Technical Field

[0001] This invention belongs to the field of noise measurement technology, specifically a method and apparatus for measuring line noise. Background Technology

[0002] Noise is a common phenomenon in electronic devices and materials, and it can reflect defects and instabilities in the system.

[0003] Accurate measurement and analysis of line noise can help researchers optimize system circuit design and reduce system defects. However, current technologies do not yet provide accurate measurement of line noise.

[0004] Therefore, how to accurately measure line noise is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a Josephson junction noise measurement system to overcome the shortcomings of the prior art, which can accurately measure the noise of the Josephson junction.

[0006] The solution presented in this application is implemented through the following steps.

[0007] In a first aspect, examples of this application present a method for measuring line noise, the method comprising:

[0008] Construct a bridge circuit with a first bridge arm and a second bridge arm connected in parallel. The first bridge arm includes a first adjustable resistor and a first fixed resistor, and the second bridge arm includes a second adjustable resistor and a second fixed resistor. The first fixed resistor and / or the second fixed resistor are connected to the circuit under test.

[0009] Using a reference signal, the bridge signal output by the bridge circuit in response to the excitation signal is detected, and a first noise spectrum is generated;

[0010] The line noise of the circuit under test is determined based on the theoretical thermal noise values ​​of the first and second fixed resistors and the first noise spectrum.

[0011] According to some examples of this application, the resistance values ​​of the first adjustable resistor and the second adjustable resistor are adjusted according to the resistance values ​​of the first fixed resistor and the second fixed resistor to balance the bridge circuit.

[0012] According to some examples of this application, adjusting the resistance values ​​of the first adjustable resistor and the second adjustable resistor based on the resistance values ​​of the first fixed resistor and the second fixed resistor to balance the bridge circuit includes:

[0013] Based on a preset value of the resistance ratio between the first adjustable resistor and the first fixed resistor, the resistance value of the first adjustable resistor is determined according to the resistance value of the first fixed resistor.

[0014] Based on the preset bridge balance formula, the resistance value of the second adjustable resistor is determined according to the resistance values ​​of the first fixed resistor, the first adjustable resistor, and the second fixed resistor.

[0015] According to some examples of this application, the step of using a reference signal to detect the bridge signal output by the bridge circuit in response to the excitation signal and generating a first noise spectrum includes:

[0016] Based on the first detection link, the bridge signal is detected using the reference signal to obtain a first time-domain signal;

[0017] Based on the second detection link, the bridge signal is detected using the reference signal to obtain a second time-domain signal. The first link and the second link have the same structure.

[0018] Cross-spectral analysis is performed on the first time-domain signal and the second time-domain signal to remove link noise from the first detection link and the second detection link, thereby obtaining the first noise spectrum.

[0019] According to some examples of this application, the step of detecting the bridge signal using the reference signal based on the first detection link to obtain a first time-domain signal includes:

[0020] The bridge signal is amplified based on a preset gain to obtain an amplified signal;

[0021] The amplified signal and the reference signal are multiplied together to obtain the first time-domain signal.

[0022] According to some examples of this application, determining the line noise of the circuit under test based on the theoretical thermal noise values ​​of the first fixed resistor and the second fixed resistor, and the first noise spectrum, includes:

[0023] The sum of the theoretical noise values ​​of the first fixed resistor and the second fixed resistor is taken as the target theoretical noise value;

[0024] The target theoretical noise value is removed from the first noise spectrum to obtain the target noise spectrum used to determine the line noise.

[0025] According to some examples of this application, the circuit under test includes a main circuit and multiple sub-circuits, the main circuit and the multiple sub-circuits are connected by a preset switch, and the method further includes:

[0026] Among the multiple sub-lines, select the target sub-line;

[0027] The preset switch is set so that the main line is only connected to the target sub-line.

[0028] According to some examples of this application, the circuit under test operates in a preset temperature environment, and the first fixed resistor and / or the second fixed resistor are both set in the preset temperature environment.

[0029] According to some examples of this application, the reference signal and the excitation signal are the same.

[0030] Secondly, examples of this application provide a line noise measuring device, the measuring device comprising:

[0031] A construction module is used to construct a bridge circuit with a first bridge arm and a second bridge arm connected in parallel. The first bridge arm includes a first adjustable resistor and a first fixed resistor, and the second bridge arm includes a second adjustable resistor and a second fixed resistor. The first fixed resistor and / or the second fixed resistor are connected to the circuit under test.

[0032] The detection module is used to detect the bridge signal output by the bridge circuit in response to the excitation signal using a reference signal, and generate a first noise spectrum;

[0033] The determination module is used to determine the line noise of the circuit under test based on the theoretical thermal noise values ​​of the first fixed resistor and the second fixed resistor, as well as the first noise spectrum.

[0034] In the line noise measurement method described in the foregoing example of this application, a bridge circuit is constructed using a first adjustable resistor, a second adjustable resistor, a first fixed resistor, and a second fixed resistor. The first fixed resistor and / or the second fixed resistor are connected to the line under test. The bridge signal output by the bridge circuit is detected using a reference signal to obtain a first noise spectrum containing the thermal noise of the first and second fixed resistors. Then, based on the theoretical values ​​of the thermal noise of the first and second fixed resistors, the first noise spectrum is processed to determine the line noise of the line under test. This measurement method can accurately measure line noise, facilitating accurate evaluation of line performance. Attached Figure Description

[0035] To illustrate this more clearly, the accompanying drawings used in the description will be briefly introduced below.

[0036] Figure 1 This is a flowchart illustrating a line noise measurement method in one example of this application;

[0037] Figure 2 This is a schematic diagram of the bridge circuit and signal processing device in one example of this application;

[0038] Figure 3 This is a schematic diagram of the structure of a line noise measurement system in another example of this application;

[0039] Figure 4 This is a flowchart illustrating a line noise measurement method in one example of this application;

[0040] Figure 5 This is a block diagram of a line noise measurement device in one example of this application. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of this application. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0042] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0044] Accurate measurement and analysis of line noise can help researchers optimize system circuit design and reduce system defects. However, current technologies do not yet provide accurate measurement of line noise.

[0045] Based on this, such as Figure 1 As shown in the illustration, one embodiment of the present invention provides a method for measuring line noise. The method includes:

[0046] Step S110: Construct a bridge circuit 210 with a first bridge arm and a second bridge arm connected in parallel. The first bridge arm includes a first adjustable resistor 211 and a first fixed resistor 212. The second bridge arm includes a second adjustable resistor 213 and a second fixed resistor 214. The first fixed resistor 212 and / or the second fixed resistor 214 are connected to the circuit under test 215.

[0047] Step S120: Using the reference signal, detect the bridge signal output by the bridge circuit 210 in response to the excitation signal, and generate a first noise spectrum;

[0048] Step S130: Determine the line noise of the circuit under test 215 based on the theoretical thermal noise values ​​of the first fixed resistor 212 and the second fixed resistor 214, as well as the first noise spectrum.

[0049] like Figure 2 As shown, the bridge circuit 210 includes a first adjustable resistor 211, a first fixed resistor 212, a second adjustable resistor 213, and a second fixed resistor 214. The first terminal of the first adjustable resistor 211 is connected to the first terminal of the second adjustable resistor 213. The second terminal of the first adjustable resistor 211 is connected to the first terminal of the first fixed resistor 212, and the second terminal of the first fixed resistor 212 is grounded. The second terminal of the second adjustable resistor 213 is connected to the first terminal of the second fixed resistor 214, and the second terminal of the second fixed resistor 214 is grounded. The first terminals of the first adjustable resistor 211 and the second adjustable resistor 213 jointly receive the excitation signal. The first terminal of the first fixed resistor 212 serves as the first output port, outputting the first branch signal. The first terminal of the second fixed resistor 214 serves as the second output port, outputting the second branch signal. The first branch signal and the second branch signal are differential signals, and together they constitute the bridge signal.

[0050] In one embodiment of this application, such as Figure 2 As shown, the second terminal of the first fixed resistor 212 is directly grounded, and the second terminal of the second fixed resistor 214 is grounded through the circuit under test 215. In one embodiment of this application, the second terminal of the second fixed resistor 214 is directly grounded, and the second terminal of the first fixed resistor 212 is grounded through the circuit under test 215. In one embodiment of this application, the circuit under test 215 includes a first sub-circuit and a second sub-circuit. The second terminal of the first fixed resistor 212 is grounded through the first sub-circuit, and the second terminal of the second fixed resistor 214 is grounded through the second sub-circuit. The first sub-circuit and the second sub-circuit can be of the same type or different types.

[0051] The excitation signal serves as the carrier signal, and the noise signal of the bridge circuit 210 serves as the baseband signal. This noise signal includes the thermal noise of the first fixed resistor 212 and the second fixed resistor 214, as well as the noise of the circuit under test 215. In response to the excitation signal, the bridge circuit 210 modulates the baseband signal onto the carrier signal, which becomes the bridge signal output by the bridge circuit 210.

[0052] Specifically, a signal processing device can be used to detect the bridge signal output by the bridge circuit 210 in response to the excitation signal using a reference signal, thereby generating a first noise spectrum. For example, the bridge signal can be amplified using a preamplifier 220 to ensure that it can be detected by a lock-in amplifier 230. Then, the phase-sensitive detector in the lock-in amplifier 230 multiplies the reference signal and the bridge signal. Since the excitation signal and the reference signal are two signals with only a phase difference, and the phase difference can be zero, the noise signal can be demodulated from the amplified bridge signal using the reference signal through the phase-sensitive detector. Finally, the first noise spectrum corresponding to the noise signal can be generated using a spectrum analyzer 240.

[0053] The noise signal includes the thermal noise of the first fixed resistor 212 and the second fixed resistor 214, as well as the noise of the circuit under test 215. Therefore, the theoretical thermal noise of the first fixed resistor 212 and the second fixed resistor 214 can be determined according to the theoretical calculation formula of the thermal noise of the fixed resistor, and then the line noise of the circuit under test 215 can be determined according to the first noise spectrum.

[0054] The theoretical formula for calculating thermal noise is:

[0055] S v =4kTR

[0056] Among them, S v Here, represents the noise power spectrum, k is a constant coefficient, T is the ambient temperature of the fixed resistor, and R is the resistance value of the fixed resistor.

[0057] It should be noted that the circuit under test 215 can be a circuit that operates at low temperature or at room temperature. The circuit under test 215 has an operating ambient temperature. Only the fixed resistors connected to the circuit under test 215 (the first fixed resistor 212 and / or the second fixed resistor 214) are also set at the operating ambient temperature of the circuit under test 215. Other measuring components (such as the first adjustable resistor 211, the second adjustable resistor 213, the preamplifier 220, the lock-in amplifier 230, the spectrum analyzer 240, etc.) are all set at room temperature.

[0058] In the line noise measurement method described in the foregoing example of this application, a bridge circuit 210 is constructed using a first adjustable resistor 211, a second adjustable resistor 213, a first fixed resistor 212, and a second fixed resistor 214. The first fixed resistor 212 and / or the second fixed resistor 214 are connected to the line under test 215. The bridge signal output from the bridge circuit 210 is detected using a reference signal to obtain a first noise spectrum containing the thermal noise of the first fixed resistor 212 and the second fixed resistor 214. Then, based on the theoretical values ​​of the thermal noise of the first fixed resistor 212 and the second fixed resistor 214, the first noise spectrum is processed to determine the line noise of the line under test 215. This measurement method can accurately measure line noise, which is beneficial for accurate evaluation of line performance.

[0059] In one embodiment of this application, the resistance values ​​of the first adjustable resistor 211 and the second adjustable resistor 213 are adjusted according to the resistance values ​​of the first fixed resistor 212 and the second fixed resistor 214 to balance the bridge circuit 210.

[0060] When the bridge circuit 210 is balanced, the condition R1r2=R2r1 must be satisfied, where R1 is the resistance value of the first adjustable resistor 211, r1 is the resistance value of the first fixed resistor 212, R2 is the resistance value of the second adjustable resistor 213, and r2 is the resistance value of the second fixed resistor 214.

[0061] Therefore, the resistance values ​​of the first adjustable resistor 211 and the second adjustable resistor 213 can be determined based on the first fixed resistor 212 and the second fixed resistor 214, so that the first fixed resistor 212, the second fixed resistor 214, the first adjustable resistor 211 and the second adjustable resistor 213 satisfy the above balance formula, thereby achieving the balance of the bridge circuit 210.

[0062] In one embodiment of this application, the resistance values ​​of the first adjustable resistor 211 and the second adjustable resistor 213 are adjusted according to the resistance values ​​of the first fixed resistor 212 and the second fixed resistor 214 to balance the bridge circuit 210, including:

[0063] Based on the preset value of the resistance ratio of the first adjustable resistor 211 and the first fixed resistor 212, the resistance value of the first adjustable resistor 211 is determined according to the resistance value of the first fixed resistor 212.

[0064] Based on the preset bridge balance formula, the resistance value of the second adjustable resistor 213 is determined according to the resistance values ​​of the first fixed resistor 212, the first adjustable resistor 211, and the second fixed resistor 214.

[0065] Specifically, the resistance ratio of the first adjustable resistor 211 to the first fixed resistor 212 can be preset, and then the resistance value of the first adjustable resistor 211 can be determined based on the preset ratio and the first fixed resistor 212; the resistance value of the second adjustable resistor 213 can be determined based on the bridge balance condition R1r2 = R2r1. Alternatively, the resistance ratio of the second adjustable resistor 213 to the second fixed resistor 214 can be preset, and then the resistance value of the second adjustable resistor 213 can be determined based on the preset ratio and the second fixed resistor 214; the resistance value of the first adjustable resistor 211 can be determined based on the bridge balance condition R1r2 = R2r1.

[0066] In one embodiment of this application, step S120, which uses a reference signal to detect the bridge signal output by the bridge circuit 210 in response to the excitation signal and generates a first noise spectrum, includes:

[0067] Based on the first detection link 310, the bridge signal is detected using the reference signal to obtain the first time domain signal;

[0068] Based on the second detection link 320, the bridge signal is detected using the reference signal to obtain the second time domain signal. The first link and the second link have the same structure.

[0069] Cross-spectral analysis is performed on the first time-domain signal and the second time-domain signal to remove link noise from the first detection link and the second detection link, thus obtaining the first noise spectrum.

[0070] like Figure 3 As shown, the first detection link 310 may include a first amplifier 311 and a first lock-in amplifier 312, and the second detection link 320 may include a second amplifier 312 and a second lock-in amplifier 322. A target spectrum analyzer 330 can be used to perform cross-spectrum analysis on the first time-domain signal and the second time-domain signal to obtain the first noise spectrum. The bridge circuit 210, the first detection link 310, the second detection link 320, and the target spectrum analyzer 330 constitute a line noise measurement system.

[0071] The first detection link and the second detection link have the same structure and receive the same input signal. The first detection link is connected to the first end of the first fixed resistor 212 and the first end of the second fixed resistor 214, respectively. The second detection link is connected to the first end of the first fixed resistor 212 and the first end of the second fixed resistor 214, respectively.

[0072] Specifically, when the first detection link receives the bridge signal, the bridge signal is amplified by the first amplifier 311, and the phase-sensitive detector in the first lock-in amplifier 312 is used to obtain the first time-domain signal. When the second detection link receives the bridge signal, the bridge signal is amplified by the second amplifier 321, and the phase-sensitive detector in the second lock-in amplifier 322 is used to obtain the second time-domain signal. Finally, the target spectrum analyzer 330 with cross-spectrum analysis function is used to perform cross-spectrum analysis on the first time-domain signal and the second time-domain signal to obtain the first noise spectrum after removing link noise.

[0073] In one embodiment of this application, based on a first detection link, a first time-domain signal is obtained by detecting the bridge signal using a reference signal, including:

[0074] Based on the preset gain, the bridge signal is amplified to obtain the amplified signal;

[0075] The amplified signal and the reference signal are multiplied to obtain the first time-domain signal.

[0076] Specifically, such as Figure 3 As shown, the bridge signal can be amplified using the first amplifier 311. The first amplifier 311 may have a filter, which can retain the bridge signal output by the bridge circuit 210 while filtering out the inherent noise of the first amplifier 311 itself, thereby reducing the influence of the inherent noise of the first amplifier 311 on the measurement results. Furthermore, by amplifying the bridge signal through the first amplifier 311, it is ensured that the bridge signal can be detected by the lock-in amplifier 230. Then, using the phase-sensitive detector in the first lock-in amplifier 312, the reference signal and the bridge signal are multiplied. Since the excitation signal and the reference signal are two signals with only a phase difference, and the phase difference can be zero, the noise signal can be demodulated from the amplified bridge signal using the reference signal through the phase-sensitive detector to obtain the noise signal in the time domain.

[0077] like Figure 4 As shown, in one embodiment of this application, step S130, which determines the line noise of the circuit under test 215 based on the theoretical thermal noise values ​​of the first fixed resistor 212 and the second fixed resistor 214, and the first noise spectrum, includes:

[0078] S410, take the sum of the theoretical noise values ​​of the first fixed resistor 212 and the second fixed resistor 214 as the target theoretical noise value;

[0079] S420: Remove the target theoretical noise value from the first noise spectrum to obtain the target noise spectrum used to determine the line noise.

[0080] Specifically, according to the thermal noise theory calculation formula S v=4kTR, calculate the sum of the theoretical noise values ​​of the first fixed resistor 212 and the second fixed resistor 214. At this point, the connection status between the first fixed resistor 212 and the second fixed resistor 214 and the circuit under test 215, as well as the operating temperature of the circuit under test 215, need to be considered. Since the measured first noise spectrum includes the thermal noise of the first fixed resistor 212 and the second fixed resistor 214, subtracting the sum of the theoretical noise values ​​of the first fixed resistor 212 and the second fixed resistor 214 from the first noise spectrum yields the target noise spectrum of the circuit.

[0081] In one embodiment of this application, the circuit under test 215 includes a main circuit and multiple sub-circuits, which are connected by a preset switch. The method further includes:

[0082] Filter the target sub-line from multiple sub-lines;

[0083] Set a preset switch to ensure that the main line is connected only to the target sub-line.

[0084] The preset switch can be a single-pole double-throw switch. The first end of the main line is connected to the second end of the first fixed resistor 212. The first end of the main line is connected to the first end of the single-pole double-throw switch. The first end of each sub-line is connected to the second end of the single-pole double-throw switch. The first end of each sub-line is connected to ground.

[0085] Specifically, according to preset requirements, one sub-circuit is selected as the target sub-circuit among multiple sub-circuits. By controlling a preset switch, only the main circuit and the target sub-circuit are turned on, so that the main circuit and the target sub-circuit are used as the circuit under test 215 and connected to the bridge circuit 210, thereby measuring the noise of the main circuit and the target sub-circuit.

[0086] In one embodiment of this application, the circuit under test 215 operates in a preset temperature environment, and the first fixed resistor 212 and / or the second fixed resistor 214 are both set in the preset temperature environment.

[0087] The circuit under test 215 can be a circuit that operates at low temperature or at room temperature. The circuit under test 215 has an operating ambient temperature. Only the fixed resistors (first fixed resistor 212 and / or second fixed resistor 214) connected to the circuit under test 215 are also set at the operating ambient temperature of the circuit under test 215. All other measuring components are set at room temperature.

[0088] In one embodiment of this application, the reference signal and the excitation signal are the same.

[0089] The reference signal and the excitation signal can be the same signal or signals that differ only in phase.

[0090] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0091] Based on the same inventive concept, this application also provides a line noise measuring device for implementing the line noise measuring method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more line noise measuring device embodiments provided below can be found in the limitations of the line noise measuring method described above, and will not be repeated here.

[0092] like Figure 5 As shown, this application also provides a line noise measuring device 500, comprising:

[0093] The construction module 510 is used to construct a bridge circuit with a first bridge arm and a second bridge arm connected in parallel. The first bridge arm includes a first adjustable resistor and a first fixed resistor, and the second bridge arm includes a second adjustable resistor and a second fixed resistor. The first fixed resistor and / or the second fixed resistor are connected to the circuit under test.

[0094] Detection module 520 is used to detect the bridge signal output by the bridge circuit in response to the excitation signal using a reference signal, and generate a first noise spectrum;

[0095] The determination module 530 is used to determine the line noise of the circuit under test based on the theoretical thermal noise values ​​of the first and second fixed resistors and the first noise spectrum.

[0096] In one embodiment of this application, the line noise measuring device 500 further includes:

[0097] The balancing module is used to adjust the resistance values ​​of the first adjustable resistor and the second adjustable resistor according to the resistance values ​​of the first fixed resistor and the second fixed resistor, so as to balance the bridge circuit.

[0098] In one embodiment of this application, the balancing module is specifically used for:

[0099] Based on the preset value of the resistance ratio of the first adjustable resistor and the first fixed resistor, the resistance value of the first adjustable resistor is determined according to the resistance value of the first fixed resistor.

[0100] Based on the preset bridge balance formula, the resistance value of the second adjustable resistor is determined according to the resistance values ​​of the first fixed resistor, the first adjustable resistor, and the second fixed resistor.

[0101] In one embodiment of this application, the detection module 520 is specifically used for:

[0102] Based on the first detection link, the bridge signal is detected using the reference signal to obtain the first time domain signal;

[0103] Based on the second detection link, the bridge signal is detected using a reference signal to obtain the second time-domain signal. The first link and the second link have the same structure.

[0104] Cross-spectral analysis is performed on the first time-domain signal and the second time-domain signal to remove link noise from the first detection link and the second detection link, thus obtaining the first noise spectrum.

[0105] In one embodiment of this application, the detection module 520 is specifically used for:

[0106] Based on the preset gain, the bridge signal is amplified to obtain the amplified signal;

[0107] The amplified signal and the reference signal are multiplied to obtain the first time-domain signal.

[0108] In one embodiment of this application, the determining module 530 is specifically used for:

[0109] The sum of the theoretical noise values ​​of the first fixed resistor and the second fixed resistor is taken as the target theoretical noise value.

[0110] The target theoretical noise value is removed from the first noise spectrum to obtain the target noise spectrum used to determine the line noise.

[0111] In one embodiment of this application, the circuit under test includes a main circuit and multiple sub-circuits, which are connected by a preset switch. The circuit noise measuring device 500 further includes:

[0112] Filter the target sub-line from multiple sub-lines;

[0113] Set a preset switch to ensure that the main line is connected only to the target sub-line.

[0114] In one embodiment of this application, the circuit under test operates in a preset temperature environment, and the first fixed resistor and / or the second fixed resistor are both set in the preset temperature environment.

[0115] In one embodiment of this application, the reference signal and the excitation signal are the same.

[0116] In this specification, references to terms such as "some embodiments" or "example" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0117] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.

Claims

1. A method for measuring line noise, characterized in that, The measurement method includes: Construct a bridge circuit with a first bridge arm and a second bridge arm connected in parallel. The first bridge arm includes a first adjustable resistor and a first fixed resistor, and the second bridge arm includes a second adjustable resistor and a second fixed resistor. The first fixed resistor and / or the second fixed resistor are connected to the circuit under test. Using a reference signal, the bridge signal output by the bridge circuit in response to the excitation signal is detected, and a first noise spectrum is generated; The line noise of the circuit under test is determined based on the theoretical thermal noise values ​​of the first and second fixed resistors and the first noise spectrum.

2. The line noise measurement method according to claim 1, characterized in that, Before detecting the bridge signal output by the bridge circuit in response to the excitation signal using the reference signal, the measurement method further includes: The resistance values ​​of the first fixed resistor and the second fixed resistor are adjusted according to their resistance values ​​to balance the bridge circuit.

3. The line noise measurement method according to claim 2, characterized in that, The step of adjusting the resistance values ​​of the first adjustable resistor and the second adjustable resistor based on the resistance values ​​of the first fixed resistor and the second fixed resistor to balance the bridge circuit includes: Based on a preset value of the resistance ratio between the first adjustable resistor and the first fixed resistor, the resistance value of the first adjustable resistor is determined according to the resistance value of the first fixed resistor. Based on the preset bridge balance formula, the resistance value of the second adjustable resistor is determined according to the resistance values ​​of the first fixed resistor, the first adjustable resistor, and the second fixed resistor.

4. The line noise measurement method according to claim 1, characterized in that, The step of using a reference signal to detect the bridge signal output by the bridge circuit in response to the excitation signal and generating a first noise spectrum includes: Based on the first detection link, the bridge signal is detected using the reference signal to obtain a first time-domain signal; Based on the second detection link, the bridge signal is detected using the reference signal to obtain a second time-domain signal. The first link and the second link have the same structure. Cross-spectral analysis is performed on the first time-domain signal and the second time-domain signal to remove link noise from the first detection link and the second detection link, thereby obtaining the first noise spectrum.

5. The line noise measurement method according to claim 4, characterized in that, The step of detecting the bridge signal using the reference signal based on the first detection link to obtain the first time-domain signal includes: The bridge signal is amplified based on a preset gain to obtain an amplified signal; The amplified signal and the reference signal are multiplied together to obtain the first time-domain signal.

6. The line noise measurement method according to claim 1, characterized in that, The step of determining the line noise of the circuit under test based on the theoretical thermal noise values ​​of the first and second fixed resistors and the first noise spectrum includes: The sum of the theoretical noise values ​​of the first fixed resistor and the second fixed resistor is taken as the target theoretical noise value; The target theoretical noise value is removed from the first noise spectrum to obtain the target noise spectrum used to determine the line noise.

7. The line noise measurement method according to claim 1, characterized in that, The circuit under test includes a main circuit and multiple sub-circuits, the main circuit and the multiple sub-circuits are connected by a preset switch, and the method further includes: Among the multiple sub-lines, select the target sub-line; The preset switch is set so that the main line is only connected to the target sub-line.

8. The line noise measurement method according to claim 1, characterized in that, The circuit under test operates in a preset temperature environment, and the first fixed resistor and / or the second fixed resistor are both set in the preset temperature environment.

9. The line noise measurement method according to claim 1, characterized in that, The reference signal and the excitation signal are the same.

10. A line noise measuring device, characterized in that, The measuring device includes: A construction module is used to construct a bridge circuit with a first bridge arm and a second bridge arm connected in parallel. The first bridge arm includes a first adjustable resistor and a first fixed resistor, and the second bridge arm includes a second adjustable resistor and a second fixed resistor. The first fixed resistor and / or the second fixed resistor are connected to the circuit under test. The detection module is used to detect the bridge signal output by the bridge circuit in response to the excitation signal using a reference signal, and generate a first noise spectrum; The determination module is used to determine the line noise of the circuit under test based on the theoretical thermal noise values ​​of the first fixed resistor and the second fixed resistor, as well as the first noise spectrum.

Images