Method for calibrating a transmitter

Abstract

The present application relates to a method for calibrating a transmitter having an oscillator, a first signal path, and a second signal path. The first signal path and the second signal path include a first calibration unit before a first low-pass filter and a second low-pass filter, and a second calibration unit after the first low-pass filter and the second low-pass filter. The calibration method includes: setting the first calibration unit and the second calibration unit and generating a transmission signal, and performing spectral analysis on the transmission signal to obtain a spectral analysis result to generate an optimal first compensation value for the first calibration unit and an optimal second compensation value for the second calibration unit.

Description

Technical Field

[0001] The present application relates to a calibration method, and more particularly to a method capable of calibrating the leakage of a local oscillator of a transmitter. Background Art

[0002] When the isolation between the local oscillator and the mixer and the low-noise amplifier at the transmission end is not perfect, it is possible for the local oscillation signal to leak, interfering with the transmitted signal. Generally known methods analyze the components mixed by the original signal and the leaked local oscillation signal in the real signal generated after the I and Q signals are self-mixed, and adjust the compensation value accordingly until an optimal result is obtained. However, this method also has the disadvantage of slow speed. Therefore, in communication systems, how to quickly and accurately compensate for the leakage of the local oscillation signal has become a quite important issue in this field. Summary of the Invention

[0003] The present application relates to a method for calibrating a transmitter, the transmitter having an oscillator, a first signal path, and a second signal path, one of the first signal path and the second signal path being a in-phase signal path, the other of the first signal path and the second signal path being a quadrature signal path, the first signal path including a first low-pass filter, the second signal path including a second low-pass filter, the oscillator forming a first local oscillator leakage for the portions of the first signal path and the second signal path before the first low-pass filter and the second low-pass filter, the oscillator forming a second local oscillator leakage for the portions of the first signal path and the second signal path after the first low-pass filter and the second low-pass filter, and the first signal path and the second signal path including a first calibration unit before the first low-pass filter and the second low-pass filter, the first calibration unit being settable to a first compensation value, and a second calibration unit after the first low-pass filter and the second low-pass filter, the second calibration unit being settable to a second compensation value, the calibration method including: setting the first compensation value to zero and the second compensation value to a first default value, and passing a single-frequency signal through the transmitter to generate a first transmitted signal; feeding back the first transmitted signal, and performing a spectral analysis on the first transmitted signal to obtain a first spectral analysis result; setting the first compensation value to zero and the second compensation value to a second default value, and passing the single-frequency signal through the transmitter to generate a second transmitted signal; feeding back the second transmitted signal, and performing a spectral analysis on the second transmitted signal to obtain a second spectral analysis result; controlling the gains of the first low-pass filter and the second low-pass filter to be positive-negative inverted, setting the first compensation value to zero and the second compensation value to the first default value, and passing a single-frequency signal through the transmitter to generate a third transmitted signal; feeding back the third transmitted signal, and performing a spectral analysis on the third transmitted signal to obtain a third spectral analysis result; controlling the gains of the first low-pass filter and the second low-pass filter to be positive-negative inverted, setting the first compensation value to zero and the second compensation value to the second default value, and passing the single-frequency signal through the transmitter to generate a fourth transmitted signal; feeding back the fourth transmitted signal, and performing a spectral analysis on the fourth transmitted signal to obtain a fourth spectral analysis result; and optimizing the second compensation value and generating an optimal second compensation value according to the first spectral analysis result, the second spectral analysis result, the third spectral analysis result, the fourth spectral analysis result, the first default value, and the second default value.

[0004] The present application relates to a method for calibrating a transmitter, the transmitter having an oscillator, a first signal path, and a second signal path, one of the first signal path and the second signal path being a in-phase signal path, the other of the first signal path and the second signal path being a quadrature signal path, the first signal path including a first low-pass filter, the second signal path including a second low-pass filter, the oscillator forming a first local oscillator leakage for the portions of the first signal path and the second signal path before the first low-pass filter and the second low-pass filter, the oscillator forming a second local oscillator leakage for the portions of the first signal path and the second signal path after the first low-pass filter and the second low-pass filter, and the first signal path and the second signal path including a first calibration unit before the first low-pass filter and the second low-pass filter, the first calibration unit being settable to a first compensation value, and a second calibration unit after the first low-pass filter and the second low-pass filter, the second calibration unit being settable to a second compensation value, the calibration method including: setting the first compensation value to a first default value and the second compensation value to zero, and passing a single-frequency signal through the transmitter to generate a first transmitted signal; looping back the first transmitted signal, and performing spectral analysis on the first transmitted signal to obtain a first spectral analysis result; setting the first compensation value to a second default value and the second compensation value to zero, and passing the single-frequency signal through the transmitter to generate a second transmitted signal; looping back the second transmitted signal, and performing spectral analysis on the second transmitted signal to obtain a second spectral analysis result; controlling the gains of the first low-pass filter and the second low-pass filter to be positive and negative in opposite phases, setting the first compensation value to the first default value and the second compensation value to zero, and passing a single-frequency signal through the transmitter to generate a third transmitted signal; looping back the third transmitted signal, and performing spectral analysis on the third transmitted signal to obtain a third spectral analysis result; controlling the gains of the first low-pass filter and the second low-pass filter to be positive and negative in opposite phases, setting the first compensation value to the second default value and the second compensation value to zero, and passing the single-frequency signal through the transmitter to generate a fourth transmitted signal; looping back the fourth transmitted signal, and performing spectral analysis on the fourth transmitted signal to obtain a fourth spectral analysis result; and optimizing the first compensation value based on the first spectral analysis result, the second spectral analysis result, the third spectral analysis result, the fourth spectral analysis result, the first default value, and the second default value to generate an optimal first compensation value.

[0005] The present application relates to a method for calibrating a transmitter, the transmitter having an oscillator, a first signal path, and a second signal path, one of the first signal path and the second signal path being an in-phase signal path, the other of the first signal path and the second signal path being a quadrature signal path, the first signal path including a first low-pass filter, the second signal path including a second low-pass filter, the oscillator forming a first local oscillator leakage for the portions of the first signal path and the second signal path before the first low-pass filter and the second low-pass filter, the oscillator forming a second local oscillator leakage for the portions of the first signal path and the second signal path after the first low-pass filter and the second low-pass filter, and the first signal path and the second signal path including a first calibration unit before the first low-pass filter and the second low-pass filter, the first calibration unit being configurable with a first compensation value, and a second calibration unit after the first low-pass filter and the second low-pass filter, the second calibration unit being configurable with a second compensation value, the calibration method including: controlling the gains of the first low-pass filter and the second low-pass filter to a first gain, setting the first compensation value to zero and the second compensation value to a first default value, and passing a single-frequency signal through the transmitter to generate a first transmitted signal; feeding back the first transmitted signal, and performing a spectral analysis on the first transmitted signal to obtain a first spectral analysis result; controlling the gains of the first low-pass filter and the second low-pass filter to the first gain, setting the first compensation value to zero and the second compensation value to a second default value, and passing a single-frequency signal through the transmitter to generate a second transmitted signal; feeding back the second transmitted signal, and performing a spectral analysis on the second transmitted signal to obtain a second spectral analysis result; and optimizing the second compensation value based on the first spectral analysis result, the second spectral analysis result, the first default value, and the second default value to generate a first pre-optimal value.

[0006] The above calibration method can calibrate the local oscillator leakage of the fundamental frequency circuit and the front-end modulation circuit of the transmitter respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of an embodiment of the transmitter of the present invention.

[0008] Figure 2 It is a schematic diagram for calculating the optimal compensation value by using the principle of linear extrapolation or linear interpolation. DETAILED DESCRIPTION

[0009] Figure 1Schematic diagram of an embodiment of a transmitter according to the present invention. The transmitter 100 has a first signal path and a second signal path, one of which is an in-phase (I) signal path, and the other of the first signal path and the second signal path is a quadrature (Q) signal path.

[0010] As Figure 1 shown, the transmitter 100 includes: a transmission end 104, a power amplifier 106, a self-mixer 108, an analog-to-digital converter (DAC) 110, a spectrum analysis unit 112, a correction coefficient calculation unit 114, and a control unit 116. The transmission end 104 includes a first signal path, a second signal path, and an adder 1056. For example, the first signal path is an in-phase signal path, passing through a first digital-to-analog converter 1042, a first low-pass filter 1046, and a first mixer 1050; the second signal path is a quadrature signal path, passing through a second digital-to-analog converter 1044, a second low-pass filter 1048, and a second mixer 1052.

[0011] In this embodiment, each time the transmitter 100 is restarted (such as after power-on or system reset), and before the general data transmission mode officially starts, in order to reduce the local oscillator leakage formed by the oscillator 1054 and reduce the interference received by the transmitted signal, the transmitter 100 will first enter the correction parameter calculation mode; in other words, in the correction parameter calculation mode, the transmitted signal of the transmitter 100 will be sent back to the self-mixer 108, passing through the DAC 110, the spectrum analysis unit 112, and the correction coefficient calculation unit 114 to perform optimized correction parameter calculation for the leakage problem of the oscillator 1054. After that, the transmission end 104 will enter the general data transmission mode. In the general data transmission mode, the transmitted signal will no longer be sent back to the self-mixer 108, and the correction parameters obtained in the correction parameter calculation mode will be used to start the formal data transmission and reception.

[0012] Specifically, in this embodiment, a first calibration unit 102 and a second calibration unit 103 are additionally added to the transmission end 104 of the transmitter 100. The first calibration unit 102 includes adders 1024 and 1026, which use the compensation value DBC to compensate for the leakage DB generated by the circuit (i.e., the corresponding fundamental frequency circuit) of the oscillator 1054 before the first low-pass filter 1046 and the second low-pass filter 1048; the second calibration unit 103 includes adders 1034 and 1036, which use the compensation value DMC to compensate for the leakage DM generated by the circuit (i.e., the corresponding front-end modulation circuit) of the oscillator 1054 after the first low-pass filter 1046 and the second low-pass filter 1048. It should be noted that the adders 1024, 1026, 1034, and 1036 can be implemented in practical applications by means such as current digital-to-analog converters (IDACs), and the leakage and compensation values mentioned throughout the text are complex numbers, and their real and imaginary parts correspond to the I path and the Q path, respectively.

[0013] The advantage of this application compensating for the oscillator leakage of the circuits before and after the first low-pass filter 1046 and the second low-pass filter 1048 respectively is that the signal generated by the fundamental frequency circuit can enter the front-end modulation circuit under the condition that the leakage DB has been compensated. Therefore, the leakage DM in the front-end modulation circuit does not contain the component of the leakage DB, and the leakage DB will not be amplified by the gain of the front-end modulation circuit. The methods for obtaining the optimal value DMCT of the compensation value DMC and the optimal value DBCT of the compensation value DBC will be described as follows.

[0014] Steps 202 to 216 are the first embodiment of this application for calculating DMCT and DBCT in the calibration parameter calculation mode. Please refer to Figure 1 , in step 202, the control unit 116 sets the compensation value DBC of the first calibration unit 102 to 0, and sets the compensation value DMC of the second calibration unit 103 to DMC1. Then, after the control unit 116 inputs a single-frequency test signal with a frequency of w, the result P1 of the Fourier transform performed by the spectrum analysis unit 112 for -w (i.e., the energy power at the frequency -w) can be expressed as:

[0015] P1 ∝ G * DB + (DM + DMC1) (1)

[0016] where G is the gain formed by the first low-pass filter 1046 and the second low-pass filter 1048 for the single-frequency test signal, and the symbol ∝ represents proportional.

[0017] In step 204, after the control unit 116 sets the compensation value DBC of the first correction unit 102 to 0 and sets the compensation value DMC of the second correction unit 103 to DMC2 different from DMC1, and then the control unit 116 inputs a single-frequency test signal with a frequency of w, the result P2 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0018] P2 ∝ G*DB + (DM + DMC2) (2)

[0019] In step 206, the signs of the gains of the first low-pass filter 1046 and the second low-pass filter 1048 are inverted (for example, by swapping the differential pair signals on the first signal path and swapping the differential pair signals on the second signal path), and step 202 is repeated. Then, the result P3 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0020] P3 ∝ -G*DB + (DM + DMC1) (3)

[0021] In step 208, the signs of the gains of the first low-pass filter 1046 and the second low-pass filter 1048 are inverted, and step 204 is repeated. Then, the result P4 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0022] P4 ∝ -G*DB + (DM + DMC2) (4)

[0023] In step 210, the correction coefficient calculation unit 114 adds P1 and P3, and adds P2 and P4, respectively, to obtain:

[0024] (P1 + P3) ∝ (DM + DMC1) (5)

[0025] (P2 + P4) ∝ (DM + DMC2) (6)

[0026] Since the leakage DM formed in the front-end modulation circuit by the oscillator 1054 is a fixed value, in equations (5) and (6), DMC1, DMC2 and (P1 + P3), (P2 + P4) are in a linear relationship. Therefore, the correction coefficient calculation unit 114 can calculate the optimal compensation value DMCT using the principle of linear extrapolation or linear interpolation. As Figure 2 shown, after connecting the two points obtained by DMC1, DMC2, (P1 + P3) and (P2 + P4) on the two-dimensional coordinate to form a straight line, the intersection point of the extension of the straight line and the X-axis is DMCT. It should be noted that in Figure 2 this embodiment, the concept is simplified to two dimensions for easy understanding, and the actual situation is four dimensions.

[0027] In step 212, the control unit 116 sets the compensation value DMC of the second correction unit 103 to DMCT so that the leakage DM in the front-end modulation circuit is perfectly compensated, sets the compensation value DBC of the first correction unit 102 to DBC1, and then the control unit 116 inputs a single-frequency test signal with a frequency of w. Then, the result P5 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0028] P5 ∝ G * (DB + DBC1) (7)

[0029] In step 214, the control unit 116 sets the compensation value DMC of the second correction unit 103 to DMCT, sets the compensation value DBC of the first correction unit 102 to DBC2 different from DBC1, and then the control unit 116 inputs a single-frequency test signal with a frequency of w. Then, the result P1 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0030] P6 ∝ G * (DB + DBC2) (8)

[0031] In step 216, since the leakage DB formed in the fundamental frequency circuit by the oscillator 1054 is a fixed value, in equations (7) and (8), DBC1, DBC2 and P5, P6 have a linear relationship. The correction coefficient calculation unit 114 can deduce the optimal compensation value DBCT using the principle of linear extrapolation or linear interpolation.

[0032] Steps 302 to 316 are the second embodiment for calculating DMCT and DBCT in the correction parameter calculation mode described in this application. The difference from the first embodiment is that in the second embodiment, DBCT is calculated first and then DMCT. Please refer to Figure 1 , in step 302, the control unit 116 sets the compensation value DMC of the second correction unit 103 to 0, sets the compensation value DBC of the first correction unit 102 to DBC3, and then the control unit 116 inputs a single-frequency test signal with a frequency of w. Then, the result P7 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0033] P7 ∝ G * (DB + DBC3) + DM (9)

[0034] In step 304, the control unit 116 sets the compensation value DMC of the second correction unit 103 to 0, sets the compensation value DBC of the first correction unit 102 to DBC4 different from DBC3, and then the control unit 116 inputs a single-frequency test signal with a frequency of w. Then, the result P8 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0035] P8 ∝ G * (DB + DBC4) + DM (10)

[0036] In step 306, the signs of the gains of the first low-pass filter 1046 and the second low-pass filter 1048 are inverted, and step 302 is repeated. Then, the result P9 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0037] P9 ∝ -G * (DB + DBC3) + DM (11)

[0038] In step 308, the signs of the gains of the first low-pass filter 1046 and the second low-pass filter 1048 are inverted, and step 304 is repeated. Then, the result P4 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0039] P10 ∝ -G * (DB + DBC4) + DM (12)

[0040] In step 310, the correction coefficient calculation unit 114 subtracts P9 from P7 and subtracts P10 from P8, respectively, to obtain:

[0041] (P7 - P9) ∝ 2G(DB + DBC3) (13)

[0042] (P8 - P10) ∝ 2G(DB + DBC4) (14)

[0043] The correction coefficient calculation unit 114 can estimate the optimal compensation value DBCT by using the principle of linear extrapolation or linear interpolation.

[0044] In step 312, the control unit 116 sets the compensation value DBC of the first correction unit 102 to DBCT so that the leakage DB in the fundamental frequency circuit is perfectly compensated, sets the compensation value DMC of the second correction unit 103 to DMC3, and then the control unit 116 inputs a single-frequency test signal with a frequency of w. Then, the result P11 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0045] P11 ∝ (DM + DMC3) (15)

[0046] In step 314, the control unit 116 sets the compensation value DBC of the first correction unit 102 to DBCT so that the leakage DB in the fundamental frequency circuit is perfectly compensated, sets the compensation value DMC of the second correction unit 103 to DMC4 different from DMC3, and then the control unit 116 inputs a single-frequency test signal with a frequency of w. Then, the result P12 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0047] P12 ∝ (DM + DMC4) (16)

[0048] In step 316, the correction coefficient calculation unit 114 can deduce the optimal compensation value DMCT by using the principle of linear extrapolation or linear interpolation.

[0049] Steps 402 to 416 are the third embodiment for calculating DMCT and DBCT in the correction parameter calculation mode described in this application. Please refer to Figure 1 , in step 402, after the control unit 116 sets the gains of the first low-pass filter 1046 and the second low-pass filter 1048 to G1, sets the compensation value DBC of the first correction unit 102 to 0, and sets the compensation value DMC of the second correction unit 103 to DMC5, and then inputs a single-frequency test signal with a frequency of w by the control unit 116, the result P13 of the Fourier transform of the spectrum analysis unit 112 for -w can be expressed as:

[0050] P13 ∝ G1 * DB + DM + DMC5 (17)

[0051] In step 404, after the control unit 116 sets the gains of the first low-pass filter 1046 and the second low-pass filter 1048 to G1, sets the compensation value DBC of the first correction unit 102 to 0, and sets the compensation value DMC of the second correction unit 103 to DMC6 different from DMC5, and then inputs a single-frequency test signal with a frequency of w by the control unit 116, the result P14 of the Fourier transform of the spectrum analysis unit 112 for -w can be expressed as:

[0052] P14 ∝ G1 * DB + DM + DMC6 (18)

[0053] In step 406, since DM and DB formed by the oscillator 1054 are fixed values, in equations (17) and (18), DMC5, DMC6 and P13, P14 are in a linear relationship. Therefore, the correction coefficient calculation unit 114 can use the principle of linear extrapolation or linear interpolation to find the compensation value DM that can compensate both DB and DM when the gains of the first low-pass filter 1046 and the second low-pass filter 1048 are G1. Here, it is called the pre-optimal value DMPT1, so that:

[0054] G1 * DB + (DM + DMPT1) = 0 (19)

[0055] In step 408, the control unit 116 sets the gains of the first low-pass filter 1046 and the second low-pass filter 1048 to G2, and the remaining steps are the same as those in step 402. Then, the result P15 of the Fourier transform of the spectrum analysis unit 112 for -w can be expressed as:

[0056] P15 ∝ G2 * DB + DM + DMC5 (20)

[0057] In step 410, the control unit 116 sets the gains of the first low-pass filter 1046 and the second low-pass filter 1048 to G2, and the remaining steps are the same as those in step 404. Then, the result P16 of the Fourier transform performed by the spectrum analysis unit 112 for -w can be expressed as:

[0058] P16 ∝ G2 * DB + DM + DMC6 (21)

[0059] In step 412, the correction coefficient calculation unit 114 can find the compensation value DM that can simultaneously compensate for DB and DM, herein referred to as the pre-optimal value DMPT2, when the gains of the first low-pass filter 1046 and the second low-pass filter 1048 are G2, by using the principle of linear extrapolation or linear interpolation, such that:

[0060] G2 * DB + (DM + DMPT2) = 0 (22)

[0061] In step 414, the correction coefficient calculation unit 114 can obtain according to equations (19) and (22):

[0062]

[0063]

[0064] That is:

[0065]

[0066]

[0067] The above description briefly discloses the features of some embodiments of the present application, enabling those of ordinary skill in the art to which the present application pertains to more comprehensively understand various forms of the content of the present application. Those of ordinary skill in the art to which the present application pertains should understand that they can easily use the content of the present application as a basis to design or change other processes and structures to achieve the same purpose and / or the same advantages as those described in the embodiments herein. It should be understood that in the method flowcharts of the present application, the steps mentioned, except for those with a specifically described order, can be adjusted in their order before and after according to actual needs, and can even be executed simultaneously or partially simultaneously. In addition, the above-mentioned various modules or method steps can be implemented by hardware, software, or firmware according to the needs of the designer. Those of ordinary skill in the art to which the present application pertains should understand that these equivalent embodiments still fall within the spirit and scope of the content of the present application, and they can be subject to various changes, substitutions, and modifications without departing from the spirit and scope of the content of the present application.

[0068] Description of the Reference Numerals

[0069] 100: Transmitter

[0070] 102: First correction unit

[0071] 103: Second correction unit

[0072] 104: Transmission end

[0073] 106: Power amplifier

[0074] 108: Self - mixer

[0075] 110: Analog - to - digital converter

[0076] 112: Spectrum analysis unit

[0077] 114: Correction coefficient calculation unit

[0078] 116: Control unit

[0079] 1024, 1024, 1034, 1036, 1056: Adder

[0080] 1042: First digital - to - analog converter

[0081] 1044: Second digital - to - analog converter

[0082] 1046: First low - pass filter

[0083] 1048: Second low - pass filter

[0084] 1050: First mixer

[0085] 1052: Second mixer

Claims

1. A method for calibrating a transmitter, the transmitter having an oscillator, a first signal path, and a second signal path, one of the first signal path and the second signal path being an in-phase signal path, the other of the first signal path and the second signal path being a quadrature signal path, the first signal path including a first low-pass filter, the second signal path including a second low-pass filter, the oscillator forming a first local oscillator leakage for portions of the first signal path and the second signal path before the first low-pass filter and the second low-pass filter, the oscillator forming a second local oscillator leakage for portions of the first signal path and the second signal path after the first low-pass filter and the second low-pass filter, and the first signal path and the second signal path including a first calibration unit before the first low-pass filter and the second low-pass filter, the first calibration unit being settable to a first compensation value, and a second calibration unit after the first low-pass filter and the second low-pass filter, the second calibration unit being settable to a second compensation value, the method comprising: Setting the first compensation value to zero and the second compensation value to a first default value, and passing a single-frequency signal through the transmitter to generate a first transmitted signal; Feeding back the first transmitted signal, and performing spectral analysis on the first transmitted signal to obtain a first spectral analysis result; Setting the first compensation value to zero and the second compensation value to a second default value, and passing the single-frequency signal through the transmitter to generate a second transmitted signal; Feeding back the second transmitted signal, and performing spectral analysis on the second transmitted signal to obtain a second spectral analysis result; Controlling the gains of the first low-pass filter and the second low-pass filter to be inverted in sign, setting the first compensation value to zero and the second compensation value to the first default value, and passing a single-frequency signal through the transmitter to generate a third transmitted signal; Feeding back the third transmitted signal, and performing spectral analysis on the third transmitted signal to obtain a third spectral analysis result; Controlling the gains of the first low-pass filter and the second low-pass filter to be inverted in sign, setting the first compensation value to zero and the second compensation value to the second default value, and passing the single-frequency signal through the transmitter to generate a fourth transmitted signal; Feeding back the fourth transmitted signal, and performing spectral analysis on the fourth transmitted signal to obtain a fourth spectral analysis result; And Optimizing the second compensation value based on the first spectral analysis result, the second spectral analysis result, the third spectral analysis result, the fourth spectral analysis result, the first default value, and the second default value to generate an optimal second compensation value, wherein the first default value and the second default value are non-zero values.

2. The method according to claim 1, wherein The optimal second compensation value compensates for the second local oscillator leakage and does not compensate for the first local oscillator leakage.

3. The method according to claim 1, characterized in that, In the step of performing the spectrum analysis on the first transmission signal, the second transmission signal, the third transmission signal, and the fourth transmission signal, Fourier transform is performed on the negative first harmonic of the first transmission signal, the second transmission signal, the third transmission signal, and the fourth transmission signal at a specific frequency.

4. The method according to claim 1, wherein The step of optimizing the second compensation value generates the optimal second compensation value based on linear extrapolation or linear interpolation.

5. The method according to claim 1, wherein Further included: Setting the first compensation value to a third default value and the second compensation value to the optimal second compensation value, and passing the single-frequency signal through the transmitter to generate a fifth transmission signal; Returning the fifth transmission signal, and performing spectrum analysis on the fifth transmission signal to obtain a fifth spectrum analysis result; Setting the first compensation value to a fourth default value and the second compensation value to the optimal second compensation value, and passing the single-frequency signal through the transmitter to generate a sixth transmission signal; Returning the sixth transmission signal, and performing spectrum analysis on the sixth transmission signal to obtain a sixth spectrum analysis result; And Optimizing the first compensation value and generating an optimal first compensation value according to the fifth spectrum analysis result, the sixth spectrum analysis result, the third default value, and the fourth default value.

6. The method according to claim 5, wherein The optimal first compensation value compensates for the first local oscillator leakage and does not compensate for the second local oscillator leakage.

7. The method according to claim 5, wherein The step of optimizing the first compensation value generates the optimal first compensation value based on linear extrapolation or linear interpolation.

8. A method for calibrating a transmitter, the transmitter having an oscillator, a first signal path, and a second signal path, one of the first signal path and the second signal path being a in-phase signal path, the other of the first signal path and the second signal path being a quadrature signal path, the first signal path including a first low-pass filter, the second signal path including a second low-pass filter, the oscillator forming a first local oscillator leakage for the portions of the first signal path and the second signal path before the first low-pass filter and the second low-pass filter, the oscillator forming a second local oscillator leakage for the portions of the first signal path and the second signal path after the first low-pass filter and the second low-pass filter, and the first signal path and the second signal path including a first calibration unit before the first low-pass filter and the second low-pass filter, the first calibration unit being configurable with a first compensation value, and a second calibration unit after the first low-pass filter and the second low-pass filter, the second calibration unit being configurable with a second compensation value, the method including: Setting the first compensation value to a first default value and the second compensation value to zero, and passing a single-frequency signal through the transmitter to generate a first transmission signal; Returning the first transmission signal, and performing spectrum analysis on the first transmission signal to obtain a first spectrum analysis result; Set the first compensation value to a second default value and the second compensation value to zero, and pass the single-frequency signal through the transmitter to generate a second transmitted signal; Loop back the second transmitted signal, and perform spectral analysis on the second transmitted signal to obtain a second spectral analysis result; Control the gains of the first low-pass filter and the second low-pass filter to be inverted in sign, set the first compensation value to the first default value and the second compensation value to zero, and pass the single-frequency signal through the transmitter to generate a third transmitted signal; Loop back the third transmitted signal, and perform spectral analysis on the third transmitted signal to obtain a third spectral analysis result; Control the gains of the first low-pass filter and the second low-pass filter to be inverted in sign, set the first compensation value to the second default value and the second compensation value to zero, and pass the single-frequency signal through the transmitter to generate a fourth transmitted signal; Loop back the fourth transmitted signal, and perform spectral analysis on the fourth transmitted signal to obtain a fourth spectral analysis result; And Optimize the first compensation value based on the first spectral analysis result, the second spectral analysis result, the third spectral analysis result, the fourth spectral analysis result, the first default value, and the second default value to generate an optimal first compensation value, wherein the first default value and the second default value are non-zero values.

9. A method for calibrating a transmitter, the transmitter having an oscillator, a first signal path, and a second signal path, one of the first signal path and the second signal path being a in-phase signal path, the other path of the first signal path and the second signal path being a quadrature signal path, the first signal path including a first low-pass filter, the second signal path including a second low-pass filter, the oscillator forming a first local oscillator leakage for portions of the first signal path and the second signal path before the first low-pass filter and the second low-pass filter, the oscillator forming a second local oscillator leakage for portions of the first signal path and the second signal path after the first low-pass filter and the second low-pass filter, and the first signal path and the second signal path including a first calibration unit before the first low-pass filter and the second low-pass filter, the first calibration unit being configurable with a first compensation value, and a second calibration unit after the first low-pass filter and the second low-pass filter, the second calibration unit being configurable with a second compensation value, the method comprising: Control the gains of the first low-pass filter and the second low-pass filter to be a first gain, set the first compensation value to zero and the second compensation value to a first default value, and pass the single-frequency signal through the transmitter to generate a first transmitted signal; Loop back the first transmitted signal, and perform spectral analysis on the first transmitted signal to obtain a first spectral analysis result; Control the gains of the first low-pass filter and the second low-pass filter to be the first gain, set the first compensation value to zero and the second compensation value to a second default value, and pass a single-frequency signal through the transmitter to generate a second transmission signal; Loop back the second transmission signal and perform spectral analysis on the second transmission signal to obtain a second spectral analysis result; and Optimize the second compensation value according to the first spectral analysis result, the second spectral analysis result, the first default value and the second default value to generate a first pre-optimal value, wherein, the first default value and the second default value are non-zero values.

10. The method according to claim 9, characterized in that, The first pre-optimal value is for compensating the first local oscillator leakage and the second local oscillator leakage.

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