Measurement system and related methods

Abstract

This application provides a measurement system and related method for measuring the phase of an IMD3 signal generated by a power amplifier. The method includes: performing a phase estimation operation, including multiple sub-operations, each sub-operation including: generating a first main signal, a second main signal, and a first adjustable signal, wherein the frequencies of the first main signal, the second main signal, and the first adjustable signal are f1, f2, and 2f1-f2, respectively; and correspondingly measuring a first power at the frequency of 2f1-f2; and estimating the phase of the IMD3 signal generated by the first main signal and the second main signal through the power amplifier at the frequency of 2f1-f2 based on the multiple first powers obtained from the multiple sub-operations; wherein the phase of the first adjustable signal in each sub-operation is different from that in the other sub-operations.

Description

Technical Field

[0001] This application relates to systems, and more particularly to a measurement system and related methods. Background Technology

[0002] When the output power of a power amplifier approaches its designed saturation power, distortion intensifies, generating inter-modulation distortion (IMD) signals at the output. This reduces the signal-to-noise ratio and may cause IMD signals to occupy other users' bandwidth, making the system non-compliant. Current technologies typically measure and calibrate the power amplifier after it has been integrated into the system, but this increases the overall system cost. Summary of the Invention

[0003] This application provides a measurement system for measuring the phase of an IMD3 signal generated by a power amplifier. The system includes: a signal generator coupled to the input of the power amplifier; a spectrum analyzer coupled to the output of the power amplifier; and a controller for performing phase estimation operations, including multiple sub-operations, each sub-operation including: controlling the signal generator to generate a first main signal, a second main signal, and a first adjustable signal, wherein the frequencies of the first main signal, the second main signal, and the first adjustable signal are f1, f2, and 2f1-f2, respectively; and controlling the spectrum analyzer. The analyzer measures the first power at a frequency of 2f1-f2; wherein the power of the first adjustable signal in each sub-operation is the same as that of the other sub-operations, but the phase is different from that of the other sub-operations; the phase and power of the first main signal in each sub-operation are the same as those of the other sub-operations; the phase and power of the second main signal in each sub-operation are the same as those of the other sub-operations; the controller estimates the phase of the IMD3 signal generated by the first main signal and the second main signal through the power amplifier at a frequency of 2f1-f2 based on the multiple first powers obtained from the multiple sub-operations.

[0004] This application provides a measurement method for measuring the phase of an IMD3 signal generated by a power amplifier. The method includes: performing a phase estimation operation, comprising multiple sub-operations, each sub-operation including: generating a first main signal, a second main signal, and a first adjustable signal, wherein the frequencies of the first main signal, the second main signal, and the first adjustable signal are f1, f2, and 2f1-f2, respectively; and correspondingly measuring a first power at the frequency of 2f1-f2; and estimating the phase of the IMD3 signal at the frequency of 2f1-f2 after the first main signal and the second main signal pass through the power amplifier based on the multiple first powers obtained from the multiple sub-operations; wherein the power of the first adjustable signal in each sub-operation is the same as that in the other sub-operations, but the phase is different from that in the other sub-operations; the phase and power of the first main signal in each sub-operation are the same as those in the other sub-operations; and the phase and power of the second main signal in each sub-operation are the same as those in the other sub-operations.

[0005] The method of this application can determine the characteristics of the power amplifier at an early stage, avoiding measurement after the power amplifier has been integrated into the system, thereby reducing costs. Attached Figure Description

[0006] A thorough understanding of the various embodiments of this application can be achieved by reading the detailed description and accompanying drawings below. It should be noted that, in accordance with standard practice in the art, the various features in the figures are not drawn to scale. In fact, the dimensions of certain features may be intentionally enlarged or reduced for clarity of description.

[0007] Figure 1 An embodiment of the measurement system of this application is shown.

[0008] Figure 2 A schematic diagram of the spectrum of the main signal S1 and the main signal S2 is shown.

[0009] Figure 3 The diagram shows the spectrum of the main signals S1 and S2 after passing through the power amplifier.

[0010] Figure 4 A flowchart of a first embodiment of the measurement method of this application is shown.

[0011] Figure 5 A flowchart of a second embodiment of the measurement method of this application is shown.

[0012] Figure 6 The power of the IMD3 signal IMD3L and IMD3 signal IMD3R obtained by adjusting the IMD3CL and IMD3CR at different phases is shown.

[0013] Explanation of reference numerals in the attached figures:

[0014] 100: Measurement system; 102: Power amplifier; 104: Spectrum analyzer

[0015] 106: Controller; 108: Signal Generator; 200: Measurement Method

[0016] 300: Measurement Method; 202-210: Procedure; 301: Procedure

[0017] 302: Steps Detailed Implementation

[0018] Figure 1 This is a schematic diagram of an embodiment of the measurement system 100 of this application, used to measure the phase of the IMD3 signal generated by the power amplifier 102. The signal generator 108 is coupled to the input of the power amplifier 102; the spectrum analyzer 104 is coupled to the output of the power amplifier 102. The controller 106 controls the signal generator 108 and the spectrum analyzer 104 to perform phase estimation operations. In this embodiment, the controller 106 can be implemented using firmware or software in conjunction with a processor.

[0019] When the input terminal of power amplifier 102 receives, such as Figure 2 When the main signal S1 with frequency f1 and power P1 and the main signal S2 with frequency f2 and power P2 are shown, the output of the power amplifier 102 will receive the following: Figure 3 The diagram shows a main signal S1 with frequency f1 and power P1*G, and a main signal S2 with frequency f2 and power P2*G, where G is the gain of power amplifier 102. Simultaneously, an IMD3 signal IMD3L with power P3 is generated at frequency 2f1-f2, and an IMD3 signal IMD3R with power P4 is generated at frequency 2f2-f1. Note that this application only discusses the most influential IMD3 signals IMD3L and IMD3R, ignoring other IMD signals.

[0020] The spectrum analyzer 104 can easily determine the power of signals IMD3L and IMD3R, but it cannot determine their phase information. When the power amplifier 102 is integrated into a communication system, it may be necessary to know the relationship between the phase of the input signal to the power amplifier 102 and the phase of the output IMD3 signal for system calibration. Therefore, the purpose of this application is to estimate the phase of signals IMD3L and IMD3R before integrating the power amplifier 102 into the communication system.

[0021] Please refer to this as well. Figure 4The flowchart below shows a first embodiment of the measurement method 200 of this application. Steps 202 to 210 are phase estimation operations, which include multiple sub-operations (steps 202, 204, 206, and 210 constitute a single sub-operation). In step 202, the controller 106 controls the signal generator 108 to generate a main signal S1, a main signal S2, an adjustable signal IMD3CL, and an adjustable signal IMD3CR at the input of the power amplifier 102, wherein the frequencies of the main signal S1, the main signal S2, the adjustable signal IMD3CL, and the adjustable signal IMD3CR are f1, f2, 2f1-f2, and 2f2-f1, respectively. Next, in step 204, the controller 106 controls the spectrum analyzer 104 to measure and record the power at frequencies 2f1-f2 and 2f2-f1 at the output of the power amplifier 102.

[0022] Since the frequencies of the adjustable signals IMD3CL and IMD3CR are located at 2f1-f2 and 2f2-f1 respectively, it will affect... Figure 3 The power of the IMD3 signals IMD3L and IMD3R in the system is affected. Specifically, if the adjustable signals IMD3CL and... Figure 3 If the phase difference between the IMD3 signal IMD3L and the IMD3 signal is 0°, then the power of the adjustable signal IMD3CL will be completely positively summed. Figure 3 The IMD3 signal IMD3L is used in the IMD3 signal; conversely, if the adjustable signal IMD3CL and Figure 3 If the phase difference between the IMD3 signal IMD3L and the IMD3 signal is 180°, then the power of the adjustable signal IMD3CL will be completely reversed and summed. Figure 3 The IMD3 signal is IMD3L. The relationship between the adjustable signals IMD3CR and IMD3R is similar, so details will not be described further.

[0023] Therefore, in multiple sub-operations, this application sets the phases of the adjustable signals IMD3CL and IMD3CR to different values, and obtains the power at frequencies between 2f1-f2 and between 2f2-f1. In this embodiment, the phases of the adjustable signals IMD3CL and IMD3CR are equally distributed between 0° and 360° in each sub-operation. For example, 100 sub-operations are performed, and the 360° is divided into 100 phases, namely 0°, 3.6°, 7.2°, ..., 356.4°, as the phases of the adjustable signals IMD3CL and IMD3CR in each sub-operation.

[0024] In step 206, the controller 106 determines whether the preset number of sub-operations has been completed. If not, it sets the phases of the adjustable signals IMD3CL and IMD3CR to different values ​​and performs the sub-operation again; if yes, it proceeds to step 208. Step 208 estimates the power values ​​at frequencies between 2f1 and f2 and at frequencies between 2f2 and f1 obtained from the multiple sub-operations. Figure 3 The IMD3 signal IMD3L and the phase of IMD3L in the signal.

[0025] For example, the information recorded by controller 106 is as follows: Figure 6 As shown, the horizontal axis corresponding to the curve containing the circle represents the phase of the adjustable signal IMD3CL applied to the input of power amplifier 102, and the vertical axis represents the power measured at the output of power amplifier 102 at frequencies 2f1-f2. The horizontal axis corresponding to the curve containing the dashed line represents the phase of the adjustable signal IMD3CR applied to the input of power amplifier 102, and the vertical axis represents the power measured at the output of power amplifier 102 at frequencies 2f2-f1. Therefore, the phase corresponding to the highest point of the curve containing the circle (approximately 240°) can be taken as... Figure 3 The estimated phase value of the IMD3 signal IMD3L in the data; and the phase corresponding to the highest point of the curve containing the dashed line (approximately 270°) as... Figure 3 The phase estimate of the IMD3 signal IMD3R in the data. Alternatively, the phase opposite to the phase (approximately 240°) corresponding to the lowest point of the curve containing the circle can be used as the phase estimate. Figure 3 The phase estimate of the IMD3 signal IMD3L in the data; and the out-of-phase phase (approximately 270°) corresponding to the lowest point of the curve containing the dashed line (approximately 110°), as... Figure 3 The estimated phase value of the IMD3 signal IMD3R in the data.

[0026] In this embodiment, for Figure 3 Phase estimation is performed on both IMD3L and IMD3R signals in the IMD3 signal, but in some embodiments, it may be performed only on the IMD3 signals. Figure 3 Phase estimation is performed on the IMD3 signal IMD3L or IMD3 signal IMD3R.

[0027] Figure 5 This is a flowchart of a second embodiment of the measurement method 300 of this application. The difference between measurement method 300 and measurement method 200 is that measurement method 300 first measures the... Figure 3The powers P3 and P4 of the IMD3 signals IMD3L and IMD3R are measured. Next, step 302 of measurement method 300 is similar to step 202 of measurement method 200, except that the powers of the adjustable signals IMD3CL and IMD3CR are specifically set to P3 / G and P4 / G, respectively. This ensures that the power of the adjustable signal IMD3CL after passing through power amplifier 102 is the same as that of the IMD3 signal IMD3L. When the phase of the adjustable signal IMD3CL is opposite to that of the IMD3 signal IMD3L, they completely cancel each other out, causing the power measured by the spectrum analyzer 104 at the output of power amplifier 102 at frequencies 2f1-f2 to be 0. Therefore, it is more convenient for controller 106 to determine the minimum power in step 208. The relationship between the adjustable signals IMD3CR and IMD3R is similar, so details will not be described further.

[0028] The foregoing description briefly outlines the features of certain embodiments of this application, enabling those skilled in the art to more fully understand the various implementations of this application. Those skilled in the art should understand that other programs and structures can be easily designed or modified based on this application to achieve the same purpose and / or the same effect as the embodiments described herein. Those skilled in the art should know that equivalent implementations still fall within the spirit and scope of this application, and various changes, substitutions, and corrections can be made without departing from the spirit and scope of this application.

Claims

1. A measurement system for measuring the phase of an IMD3 signal produced by a power amplifier, characterized by, The measurement system includes: A signal generator is coupled to the input terminal of the power amplifier; A spectrum analyzer is coupled to the output of the power amplifier; The controller is used to perform phase estimation operations, which include multiple sub-operations, each of which includes: The signal generator is controlled to generate a first main signal, a second main signal, and a first adjustable signal, wherein the frequencies of the first main signal, the second main signal, and the first adjustable signal are f1, f2, and 2f1-f2, respectively; and The spectrum analyzer is controlled to measure the first power at frequencies 2f1-f2. The power of the first adjustable signal in each sub-operation is the same as that of the other sub-operations, but the phase is different from that of the other sub-operations. The phase and power of the first main signal in each sub-operation are the same as those of the other sub-operations. The phase and power of the second main signal in each sub-operation are the same as those of the other sub-operations. The controller estimates the phase of the IMD3 signal generated by the first main signal and the second main signal through the power amplifier at a frequency of 2f1-f2 based on the maximum or minimum value of the multiple first powers obtained from the multiple sub-operations.

2. The measurement system according to claim 1, characterized in that, The controller takes the inverted phase of the first adjustable signal corresponding to the minimum value among the multiple first powers obtained from the multiple sub-operations as the estimated phase result of the IMD3 signal with a frequency of 2f1-f2 after the first main signal and the second main signal pass through the power amplifier.

3. The measurement system according to claim 1, characterized in that, Each sub-operation also includes: The signal generator is controlled to generate a second adjustable signal, wherein the frequency of the second adjustable signal is 2f2-f1; and The spectrum analyzer is controlled to measure the second power at frequencies between 2f2 and f1. The power of the second adjustable signal in each sub-operation is the same as that of the other sub-operations, but the phase is different from that of the other sub-operations. The controller estimates the phase of the IMD3 signal with a frequency of 2f2-f1 after the first main signal and the second main signal pass through the power amplifier based on the multiple second powers obtained from the multiple sub-operations.

4. The measurement system according to claim 3, characterized in that, The controller takes the inverted phase of the second adjustable signal corresponding to the minimum value among the multiple second powers obtained from the multiple sub-operations as the estimated phase result of the IMD3 signal with a frequency of 2f2-f1 after the first main signal and the second main signal pass through the power amplifier.

5. The measurement system according to claim 1, characterized in that, Before performing the phase estimation operation, the controller also performs a power estimation operation, wherein in the power estimation operation, the controller controls the signal generator to generate the first main signal, the second main signal and measures the third power at a frequency of 2f1-f2.

6. The measurement system according to claim 3, characterized in that, Before performing the phase estimation operation, the controller also performs a power estimation operation, wherein in the power estimation operation, the controller controls the signal generator to generate the first main signal, the second main signal and measures the fourth power at a frequency of 2f2-f1.

7. A measurement method for measuring the phase of an IMD3 signal generated by a power amplifier, characterized in that, The method includes: The phase estimation operation is performed, which includes multiple sub-operations, each of which includes: Generate a first main signal, a second main signal, and a first adjustable signal, wherein the frequencies of the first main signal, the second main signal, and the first adjustable signal are f1, f2, and 2f1-f2, respectively; and Correspondingly, the first power at frequencies 2f1-f2 was measured; and The phase of the IMD3 signal at frequency 2f1-f2 after the first main signal and the second main signal pass through the power amplifier is estimated based on the maximum or minimum value of the multiple first powers obtained from the multiple sub-operations. The first adjustable signal has the same power as the other sub-operations in each sub-operation, but its phase is different from the other sub-operations. The first main signal has the same phase and power as the other sub-operations in each sub-operation. The second main signal has the same phase and power as the other sub-operations in each sub-operation.

8. The measurement method according to claim 7, characterized in that, The steps for estimating the phase of the IMD3 signal at frequencies between 2f1 and f2 include: The phase of the first adjustable signal corresponding to the minimum value among the multiple first powers obtained from the multiple sub-operations is used as the estimated phase of the IMD3 signal at frequency 2f1-f2 after the first main signal and the second main signal pass through the power amplifier.

9. The measurement method according to claim 7, characterized in that, Each sub-operation also includes: Generate a second adjustable signal, wherein the frequency of the second adjustable signal is 2f2-f1; and Correspondingly, the second power at the frequency 2f2-f1 was measured; and The method further includes: The phase of the IMD3 signal at frequency 2f2-f1 after the first main signal and the second main signal pass through the power amplifier is estimated based on the multiple second powers obtained from the multiple sub-operations. The power of the second adjustable signal in each sub-operation is the same as that in the other sub-operations, but the phase is different from that in the other sub-operations.

10. The measurement method according to claim 9, characterized in that, The steps for estimating the phase of the IMD3 signal at frequencies between 2f2 and f1 include: The phase of the second adjustable signal corresponding to the minimum value among the multiple second powers obtained from the multiple sub-operations is used as the estimated phase of the IMD3 signal with a frequency of 2f2-f1 after the first main signal and the second main signal pass through the power amplifier.

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