Orthogonal modulation device, method for spurious correction, and method for correcting orthogonal modulation

Abstract

To provide an orthogonal modulation device, a method for spurious correction, and a method for correcting orthogonal modulation that can measure spurious components of a modulated wave with high accuracy without being limited by circuit configuration.SOLUTION: In a quantum computer 10, an orthogonal modulation device 12 includes a modulation unit 17 and a measurement unit 18. The modulation unit 17 includes: a first orthogonal modulation unit 21 configured to output a TX1 signal orthogonally modulated; and a second orthogonal modulation unit 22 configured to output a TX2 signal orthogonally modulated. The TX1 signal and the TX2 signal each include a desired wave of the same frequency. When the image components and local leakage of the TX1 signal and the TX2 signal are measured by the measurement unit 18, the TX1 signal and the TX2 signal are adjusted such that the desired wave of the TX1 signal and the desired wave of the TX2 signal have the same amplitude and are in opposite phase to each other, and the image components and local leakage are measured from a composite wave of the TX1 signal and the TX2 signal. A downconverter 53 of the measurement unit 18 includes a mixer 53a and a third local oscillator 53b composed of a fractional-N PLL circuit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a quadrature modulation device, a spurious correction method, and a correction method for quadrature modulation. [Background technology]

[0002] A quadrature modulator (IQ modulator) is known that quadrature-modulates a carrier wave using an I (in-phase) signal and a Q (quadrature-phase) signal. In quadrature modulation, two carrier waves with the same frequency but a 90° phase difference are modulated, one with the I signal and the other with the Q signal, and then the resulting signal is output as a single modulated wave.

[0003] It is known that in quadrature modulators, image components and local leaks are included in the modulated waves as spurious (unwanted waves), and these are generated by phase errors and amplitude errors in the quadrature modulator. Since it is difficult to avoid their generation in a quadrature modulator, corrections are made to reduce the signal strength. For example, Patent Document 1 describes a configuration for correcting image components. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-208091 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, when correcting the image component and local leak contained in a quadrature-modulated modulated wave, it is necessary to sample the modulated wave in a measuring unit composed of a downconverter, an AD converter, etc., and quantify the image component and local leak, respectively. Meanwhile, the modulated wave also contains a desired wave with a much stronger signal strength than the image component and local leak, in addition to the image component and local leak. Therefore, in order to accurately quantify the image component and local leak, the detecting unit needs a high-performance circuit configuration, such as a downconverter with a wide dynamic range for signal power, and an AD converter with a high resolution and sampling frequency for signal strength, so as to cover even the desired wave with a high signal strength. AD converters with a high sampling frequency have the problem of high power consumption.

[0006] An object of the present invention is to provide a quadrature modulation device, a spurious correction method, and a quadrature modulation correction method that can measure spurious components of a modulated wave with high accuracy without being limited by the circuit configuration. [Means for solving the problem]

[0007] The quadrature modulation device of the present invention includes a modulation unit having a first quadrature modulation unit that outputs a first modulated wave obtained by quadrature-modulating a first carrier wave using a first I signal and a first Q signal, and a second quadrature modulation unit that quadrature-modulates a second carrier wave having a frequency different from that of the first carrier wave using a second I signal and a second Q signal, and outputs a second modulated wave in which the frequency of the desired wave coincides with the frequency of the desired wave of the first modulated wave and the frequency of the image component differs from the frequency of the image component of the first modulated wave, and a modulation unit that receives the first modulated wave, the second modulated wave, or a composite wave of the first modulated wave and the second modulated wave as a target wave, and reduces the frequency of the target wave. The modulation unit is provided with a measurement unit including a downconverter, an AD converter that digitally converts the signal output from the downconverter, and a signal processing unit that measures the target wave based on the output of the AD converter, and when the measurement unit measures the spurious of the first modulated wave from the composite wave, the modulation unit outputs a first modulated wave and a second modulated wave in which the amplitudes of the desired waves are equal and the desired waves are in opposite phase, and suppresses the desired waves of the first modulated wave and the second modulated wave in the composite wave, and the downconverter has a fractional N-type PLL circuit that outputs a local signal and a mixer that mixes the local signal with the target wave.

[0008] The spurious correction method of the present invention includes a first modulated wave output step of outputting a first modulated wave obtained by quadrature-modulating a first carrier wave using a first I signal and a first Q signal; a second modulated wave output step of quadrature-modulating a second carrier wave using a second I signal and a second Q signal to output a second modulated wave in which the desired wave matches the frequency of the desired wave of the first modulated wave but is in opposite phase and the frequency of the image component is different from the frequency of the image component of the first modulated wave; an amplitude increasing step of gradually increasing the amplitude of the desired wave of the second modulated wave until it reaches a normal amplitude; a desired wave correction step of correcting the first I signal and the first Q signal each time the amplitude of the desired wave of the second modulated wave increases so that the desired waves of the first modulated wave and the second modulated wave cancel each other out in a combined wave obtained by combining the first modulated wave and the second modulated wave; and a desired wave synchronization step of correcting the first I signal and the first Q signal each time the first I signal and the first Q signal are corrected in the desired wave correction step. The method includes a spurious measurement step of measuring the image component and local leak of the first modulated wave in the composite wave in which the image component and local leak are canceled out, and a correction value calculation step of determining, each time the image component and local leak are measured in the spurious measurement step, a correction value for correcting the first I signal and the first Q signal so as to reduce the signal intensity of the image component and local leak of the first modulated wave, based on the measurement results of the image component and local leak of the first modulated wave, and at least before the desired wave of the second modulated wave reaches a normal amplitude, each time a correction value is obtained, the first I signal and the first Q signal are corrected by the obtained correction value to output the first modulated wave, and the correction value obtained when the desired wave of the second modulated wave has a normal amplitude is used as the first correction value for correcting the first I signal and the first Q signal when the first modulated wave is output to the outside.

[0009] The quadrature modulation correction method of the present invention includes a correction step of correcting a first I signal and a first Q signal when outputting a first modulated wave to the outside, based on a first correction value obtained by the above-mentioned spurious correction method. [Effects of the Invention]

[0010] According to the quadrature modulation device of the present invention, when measuring spurious emissions from a quadrature-modulated first modulated wave, a second modulated wave having the same frequency but opposite phase as the desired wave of the first modulated wave is multiplexed with the first modulated wave to generate a composite wave in which the desired waves cancel each other out, and a local signal from a fractional-N PLL circuit is mixed with this composite wave, down-converted, and measured. Because the local signal can be made closer in frequency to the composite wave with a simple circuit configuration and the frequency of the composite wave after frequency conversion can be made lower, spurious emissions can be measured with high accuracy while saving power using an AD converter with a low sampling frequency.

[0011] Furthermore, according to the spurious response correction method and quadrature modulation correction method of the present invention, when measuring spurious responses of a quadrature-modulated first modulated wave, a second modulated wave having the same frequency as the desired wave of the first modulated wave but in opposite phase to the desired wave of the first modulated wave is multiplexed with the first modulated wave to generate a composite wave in which the desired waves cancel each other out, and the spurious responses are measured from this composite wave, thereby enabling spurious responses to be measured with high accuracy.Furthermore, since the measurement is performed while gradually changing the amplitude of the first modulated wave toward the amplitude in normal mode, a first correction value that effectively suppresses spurious responses can be obtained. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a block diagram showing the configuration of a quantum computer including an orthogonal modulation device according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a quadrature modulator. [Figure 3] FIG. 1 is an explanatory diagram showing the transition of operation modes of a quantum computer. [Figure 4] FIG. 10 is an explanatory diagram schematically showing the frequency spectrum of a composite wave in which a desired wave is suppressed. [Figure 5] 10 is a flowchart showing an outline of a procedure for the TX1 signal in an example in which adjustment is performed by gradually increasing the amplitudes of the TX1 signal and the TX2 signal until they reach a normal magnitude. [Figure 6] 10 is a graph showing the distribution of frequency components of the TX1 signal before adjustment. [Figure 7]10 is a graph showing the distribution of frequency components of the adjusted TX1 signal. [Figure 8] 10 is a graph showing the distribution of frequency components of the TX1 signal during adjustment. DETAILED DESCRIPTION OF THE INVENTION

[0013] 1, quantum computer 10 includes quantum computer main body 11 (hereinafter simply referred to as main body) 11, quadrature modulation device 12 as a transmitter, receiver 13, and control unit 14 that controls each part of quantum computer 10 including quadrature modulation device 12. Quantum computer 10 provides control signals such as calculation instructions from control unit 14 to main body 11 via a transceiver consisting of quadrature modulation device 12 and receiver 13, and control unit 14 obtains calculation results and the like from main body 11 via receiver 13. Quadrature modulation device 12 includes modulation unit 17, measurement unit 18, and selector 19.

[0014] The modulation unit 17 is composed of a first quadrature modulation unit 21, a second quadrature modulation unit 22, a correction unit 23, and a calibration signal generation unit 24. The first quadrature modulation unit 21 outputs a TX1 signal as a first modulated wave obtained by quadrature modulating a first carrier wave with an I1 signal as a first I signal and a Q1 signal as a first Q signal. The second quadrature modulation unit 22 outputs a TX2 signal as a second modulated wave obtained by quadrature modulating a second carrier wave with an I2 signal as a second I signal and a Q2 signal as a second Q signal.

[0015] The quadrature modulation device 12 has two operating modes: a normal mode and an adjustment mode. In the normal mode, the control unit 14 issues a calculation instruction to the main unit 11, and the main unit 11 reads out the calculation result. In this normal mode, the control unit 14 outputs the I1 signal, the Q1 signal, the I2 signal, and the Q2 signal, and the I1 signal and the Q1 signal are input to the first quadrature modulation unit 21 and the I2 signal and the Q2 signal are input to the second quadrature modulation unit 22 via the correction unit 23. In the normal mode, the TX1 signal and the TX2 signal output from the modulation unit 17 are output to the main unit 11, which is external to the modulation unit 17.

[0016] On the other hand, the adjustment mode is a mode in which the image components and local leaks contained as spurious components in the TX1 signal and the TX2 signal are measured, and correction values ​​for reducing the image components and local leaks are calculated. In this adjustment mode, the calibration signal generating unit 24 outputs the I1 signal, Q1 signal, I2 signal, and Q2 signal for calibration, and of these, the I1 signal and Q1 signal are input to the first quadrature modulation unit 21, and the I2 signal and Q2 signal are input to the second quadrature modulation unit 22. In the adjustment mode, the TX1 signal and TX2 signal output from the modulation unit 17 are output to the measurement unit 18.

[0017] In the adjustment mode, the image components and local leak of the TX1 and TX2 signals are measured from the composite wave (described later), and compensation processing is performed to calculate correction values ​​for suppressing the image components and local leak of the TX1 and TX2 signals output in normal mode based on the measurement results, including the measured values. Furthermore, in the initial (first) adjustment mode immediately after startup, prior to the compensation processing, an adjustment (hereinafter referred to as initial adjustment) is performed to suppress the desired wave in the composite wave, i.e., to superimpose the desired wave of the TX1 signal and the TX2 signal, which is in opposite phase to the TX1 signal, so that they cancel each other out. In the second and subsequent adjustment modes, the correction values ​​for suppressing the image components and local leak are updated in response to temperature changes, etc.

[0018] The selector 19 switches the output destination of the TX1 signal and the TX2 signal from the modulation unit 17 between the main unit 11 and the measurement unit 18 depending on the operation mode. That is, the selector 19 outputs the TX1 signal and the TX2 signal to the main unit 11 in the normal mode, and outputs the TX1 signal and the TX2 signal to the measurement unit 18 in the adjustment mode.

[0019] The control unit 14 outputs digital signals I1 signal and Q1 signal, I2 signal and Q2 signal. The I1 signal output from the control unit 14 is obtained by modulating I1 channel bit information with the I1 channel carrier signal, and the Q1 signal is obtained by modulating Q1 channel bit information with the Q1 channel carrier signal. The Q1 channel carrier signal has the same frequency as the I1 channel carrier signal but is phase shifted (delayed) by 90°. The same is true for the I2 signal and Q2 signal from the control unit 14: the I2 signal is obtained by modulating I2 channel bit information with the I2 channel carrier signal, and the Q2 signal is obtained by modulating Q2 channel bit information with the Q2 channel carrier signal which has the same frequency as the I2 channel carrier signal but is phase shifted by 90°.

[0020] I1 channel carrier signal to I 01 , Q1 channel carrier signal Q 01 , I2 channel carrier signal I 02 , Q2 channel carrier signal Q 02 The frequencies of the I1 channel carrier signal and the Q1 channel carrier signal are f IQ1 , the frequencies of the I2 channel carrier signal and the Q2 channel carrier signal are f IQ2 When this is set, the I1 channel carrier signal, the Q1 channel carrier signal, the I2 channel carrier signal, and the Q2 channel carrier signal are expressed as in equation (1). Note that the value P in equation (1) is a constant indicating the amplitude of the channel carrier signal. In this example, the amplitudes of the I1 channel carrier signal, the Q1 channel carrier signal, and the I2 channel carrier signal, and the Q2 channel carrier signal are set to be the same, but they may be different.

[0021]

number

[0022] Digital signals I1 signal, Q1 signal, I2 signal, and Q2 signal are also output from the calibration signal generating unit 24. Details of the I1 signal, Q1 signal, I2 signal, and Q2 signal output from the calibration signal generating unit 24 will be described later.

[0023] The first quadrature modulation unit 21 is composed of a selector 31, DA converters 32a and 32b, a first local oscillator 33, and a first quadrature modulator 34. The selector 31 selects either the correction unit 23 or the calibration signal generation unit 24, and inputs the I1 signal and Q1 signal from the selected circuit to the DA converters 32a and 32b. The selector 31 selects the correction unit 23 in normal mode and selects the calibration signal generation unit 24 in adjustment mode. The DA converter 32a converts the I1 signal, which is an input digital signal, into an analog signal, and the DA converter 32b converts the Q1 signal, which is an input digital signal, into an analog signal. The I1 signal and Q1 signal output from the DA converters 32a and 32b are input to the first quadrature modulator 34.

[0024] The first local oscillator 33 generates a first carrier wave and inputs it to the first quadrature modulator 34. As shown in FIG. 2, the first quadrature modulator 34 is composed of multipliers 34a and 34b, an adder 34c, and a 90° phase shifter 34d that delays the phase of the first carrier wave by 90°. In the first quadrature modulator 34, the multiplier 34a multiplies the I1 signal by the first carrier wave to generate an I1 channel modulated signal by modulating the first carrier wave with the I1 signal, and the multiplier 34b multiplies the Q1 signal by the first carrier wave from the 90° phase shifter 34d to generate a Q1 channel modulated signal by modulating the first carrier wave with the Q1 signal. The I1 channel modulated signal and the Q1 channel modulated signal are added together in the adder 34c to generate the TX1 signal, in which the first carrier wave is quadrature modulated using the I1 signal and Q1 signal.

[0025] As shown in FIG. 1, the second quadrature modulation unit 22 is composed of a selector 41, DA converters 42a and 42b, a second local oscillator 43, and a second quadrature modulator 44. The second quadrature modulation unit 22 has the same configuration as the first quadrature modulation unit 21. That is, the selector 41 selects the correction unit 23 in normal mode and selects the calibration signal generation unit 24 in adjustment mode, and outputs the I2 signal and Q2 signal from the selected circuit to the DA converters 42a and 42b. The DA converters 42a and 42b convert the input I2 signal and Q2 signal into analog signals and input them to the second quadrature modulator 44. The second local oscillator 43 generates a second carrier wave and inputs it to the second quadrature modulator 44.

[0026] The second quadrature modulator 44 has the same configuration as the first quadrature modulator 34, and is therefore not shown in the figures. The second quadrature modulator 44 generates an I2 channel modulated signal by modulating the second carrier wave with the I2 signal, generates a Q2 channel modulated signal by modulating the second carrier wave delayed in phase by 90 degrees with the Q2 signal, and adds these I2 channel modulated signal and Q2 channel modulated signal together. This generates a TX2 signal by quadrature modulating the second carrier wave using the I2 signal and Q2 signal.

[0027] The frequencies of the first carrier wave, the second carrier wave, the I1 channel carrier signal and the Q1 channel carrier signal, and the I2 channel carrier signal and the Q2 channel carrier signal are determined so that the frequencies of the desired waves of the TX1 signal and the TX2 signal match, the frequencies of the local leaks differ from each other, and the frequencies of the image components differ from each other.

[0028] Therefore, the frequency of the first carrier is f LO1 , the frequency of the second carrier is f LO2 When these frequencies f LO1 , f LO2 and the frequency f of the I1 channel carrier signal and the Q1 channel carrier signal IQ1 , the frequency f of the I2 channel carrier signal and the Q2 channel carrier signal IQ2 is "f LO1 -f IQ1 =f LO2 -fIQ2 " is satisfied. In other words, the desired wave of the TX1 signal and the desired wave of the TX2 signal are set to the same frequency. This is because, when measuring the image component and local leak in the measuring unit 18, the desired waves of the TX1 signal and the TX2 signal, which are in opposite phase, are superimposed and cancel each other out. Also, in order to be able to measure each image component and each local leak without the image components of the TX1 signal and the TX2 signal interfering with each other and the local leaks interfering with each other, "f LO1 ≠f LO2 " "f LO1 +f IQ1 ≠f LO2 +f IQ2 " is determined to be satisfied.

[0029] In this example, the phase of the Q1 channel carrier signal is delayed by 90° from the I1 channel carrier signal, and the phase of the Q2 channel carrier signal is delayed by 90° from the I2 channel carrier signal. The frequencies of the desired waves of the TX1 signal and TX2 signal are "f LO1 -f IQ1 ", "f LO2 -f IQ2 The above frequency conditions are also for such a case. The frequency of the desired wave of the TX1 signal and the TX2 signal is set to "f LO1 +f IQ1 ", "f LO2 +f IQ2 ", that is, when the phase of the Q1 channel carrier signal is advanced by 90° relative to the I1 channel carrier signal, and the phase of the Q2 channel carrier signal is advanced by 90° relative to the I2 channel carrier signal, "f LO1 +f IQ1 =f LO2 +f IQ2 ", "f LO1 ≠f LO2 " "f LO1 -f IQ1 ≠f LO2 -f IQ2 Each frequency is determined so as to satisfy the following condition.

[0030] The phase of the Q1 channel carrier signal is advanced by 90° relative to the I1 channel carrier signal, and the frequency of the desired wave of the TX1 signal is set to "f LO1 +f IQ1 ", and the phase of the Q2 channel carrier signal is delayed by 90° relative to the I2 channel carrier signal, and the frequency of the desired wave of the TX2 signal is set to "f LO2 -f IQ2 " as "f LO1 +f IQ1 =f LO2 -f IQ2 ", "f LO1 ≠f LO2 " "f LO1 -f IQ1 ≠f LO2 +f IQ2 ". Also, the phase of the Q1 channel carrier signal may be delayed by 90° relative to the I1 channel carrier signal, and the frequency of the desired wave of the TX1 signal may be set to "f LO1 -f IQ1 ", and the phase of the Q2 channel carrier signal is advanced by 90° relative to the I2 channel carrier signal, and the frequency of the desired wave of the TX2 signal is set to "f LO2 +f IQ2 " as "f LO1 -f IQ1 =f LO2 +f IQ2 ", "f LO1 ≠f LO2 " "f LO1 +f IQ1 ≠f LO2 -f IQ2 Each frequency may be determined so that

[0031] In the normal mode, the correction unit 23 receives the I1 signal, Q1 signal, I2 signal, and Q2 signal (hereinafter referred to as I I1 Signal, Q Q1 Signal, I I2 Signal, Q Q2 The corrected I1 signal, Q1 signal, I2 signal, and Q2 signal are input to the DA converters 32a, 32b, 42a, and 42b via the selectors 31 and 41. In the adjustment mode, the corrector 23 is set with a first correction value and a second correction value by the measuring unit 18. The corrector 23 corrects the I signal from the control unit 14 based on the first correction value.I1 Signal, Q Q1 The signal is corrected and the I from the control unit 14 is output based on the second correction value. I2 Signal, Q Q2 The first and second correction values ​​each include an image correction value for suppressing image components and an offset value for suppressing local leaks. This reduces amplitude and phase errors in quadrature modulation, effectively suppressing the image components and local leaks of the TX1 and TX2 signals.

[0032] The correction by the correction unit 23 is expressed as in equation (2). 1,N+1 ", "OF 1,N+1 " is a matrix indicating the image correction value and offset value of the first correction value obtained in the N+1th (N is 0, 1, 2, . . . ) compensation process. 2,N+1 ", "OF 2,N+1 " is a matrix showing the image correction value and offset value of the second correction value obtained in the N+1th compensation process. Note that the image correction value H 1,N+1 , H 2,N+1 is a 4x4 matrix, and the offset value OF 1,N+1 , OF 2,N+1 is a 2-by-1 matrix.

[0033]

number

[0034] In the adjustment mode, the calibration signal generator 24 outputs the I1 signal, Q1 signal, I2 signal, and Q2 signal with adjusted phase, amplitude, etc. As will be described in detail later, the calibration signal generator 24 has functions to prevent the signal strength from over-ranging in the measurement unit 18, i.e., to reduce the amplitude (signal strength) of the I1 signal, Q1 signal, I2 signal, and Q2 signal so that the input signal strength and signal power fall within the measurement range of the measurement unit 18, to intentionally emphasize (not suppress) image components, and to adjust the phase of the I1 signal, Q1 signal, I2 signal, and Q2 signal or make them DC (direct current component) so as to intentionally generate local leak. For example, when measuring the image component and local leak of the composite wave of the TX1 signal and the TX2 signal, the calibration signal generator 24 outputs the I1 signal, Q1 signal, I2 signal, and Q2 signal adjusted so that the desired waves of the TX1 signal and the TX2 signal cancel each other out. The amplitudes of the I1 signal, Q1 signal, I2 signal, and Q2 signal are reduced to be smaller than the maximum amplitude in the normal mode.

[0035] The measurement unit 18 includes a combiner 51, an amplifier 52, a downconverter 53, an AD converter 54, and a signal processing unit 55. The combiner 51 combines the TX1 signal and the TX2 signal from the first quadrature modulation unit 21 and the second quadrature modulation unit 22 while achieving impedance matching for each of them. In this example, the combiner 51 has two input ports connected to resistors 51a, respectively, and the connection point of the two resistors 51a forms an output port. In this example, the resistor 51a has a resistance value of 50Ω.

[0036] The two input ports of the combiner 51 are connected to a first quadrature modulation unit 21 and a second quadrature modulation unit 22 via a selector 19. The combiner 51 receives a TX1 signal at one of the two input ports and a TX2 signal at the other, and outputs a composite wave (combined signal) obtained by combining (combining) the TX1 signal and the TX2 signal from the output port. Note that when only one of the TX1 signal and the TX2 signal is input to the combiner 51, only that input signal is output from the output port. Hereinafter, when there is no particular need to distinguish between the signals (combined wave, TX1 signal, TX2 signal) output from the combiner 51, they will be collectively referred to as target waves.

[0037] An amplifier 52 is connected to the output port of the combiner 51. The amplifier 52 amplifies the target wave output from the combiner 51 and outputs the amplified signal to a downconverter 53. The downconverter 53 is composed of a mixer 53a, a third local oscillator 53b, etc., and converts the target wave to a lower frequency by mixing the target wave with a local signal for downconversion from the third local oscillator 53b in the mixer 53a. An AD converter 54 converts the target wave, frequency-converted by the downconverter 53, into a digital signal. The target wave digitized by the AD converter 54 is sent to a signal processing unit 55.

[0038] As third local oscillator 53b, for example, a PLL (Phase-Locked Loop) is used, and in this example, a fractional N-type PLL circuit (fractional frequency division type PLL circuit) is used. The fractional N-type PLL circuit feedback controls the output signal based on the phase difference between the reference signal and a feedback signal obtained by fractionally frequency dividing the output signal (local signal) using a fractional frequency divider, thereby generating an output signal in which the frequency of the reference signal is multiplied with decimal precision.

[0039] By using a fractional-N PLL circuit for the third local oscillator 53b, the frequency of the local signal mixed with the target wave in the mixer 53a can be adjusted with high resolution. Therefore, with a simple circuit configuration, the frequency of the local signal can be made closer to the spurious frequency of the target wave. This effectively reduces the frequency of the spurious after downconversion, allowing the spurious to be measured with high accuracy using an AD converter 54 that operates at a slower speed, i.e., has a lower sampling frequency, as described below. Using a slow-operating AD converter 54 is advantageous in terms of reducing cost and power consumption, and is also suitable for a quantum computer 10 with a large number of quantum bits.

[0040] The integer division ratio of the fractional divider is N, the fractional division ratio is F / M, and the frequency of the reference signal input to the phase comparator is F. ref , the frequency of the high frequency signal output from the PLL circuit (voltage controlled oscillator) is f out If you set "f out =(N+F / M) F ref " is established. Also, the frequency of the signal input to the AD converter 54 is set to f ADC , the spurious frequency before conversion is f S Then, "f ADC =f S -f out For example, if the spurious frequency of the desired wave is 8.912 GHz and the frequency of the reference signal is 100 MHz, the spurious frequency can be reduced to about 15 MHz by setting the integer division ratio N to "88" and the fractional division ratio F / M to "31 / 32." As a result, spurious can be measured with good accuracy using an AD converter 54 with a sampling frequency of about 100 MHz, for example.

[0041] The fractional-N PLL circuit used as the third local oscillator 53b may be either an analog PLL circuit or a digital PLL circuit. Furthermore, the quadrature modulation device 12 suppresses the desired wave and performs compensation to suppress spurious signals, ultimately bringing the target wave to zero voltage, so that the generation of fractional spurious signals from the fractional-N PLL circuit can be tolerated. Therefore, a fractional-N PLL circuit that is space-saving, inexpensive, and low-power-consumption and can generate frequencies with fine resolution while generating fractional spurious signals can be used as the third local oscillator 53b.

[0042] When measuring the local leak and image components of the composite wave, the calibration signal generator 24 adjusts and outputs the I1 signal, Q1 signal, I2 signal, and Q2 signal so that the desired waves of the TX1 signal and the TX2 signal cancel each other out, as described above. Furthermore, when selectively outputting the TX1 signal and the TX2 signal to measure the individual desired waves, local leak, and image components, the calibration signal generator 24 adjusts the I1 signal, Q1 signal, I2 signal, and Q2 signal so as to reduce the amplitude of the TX1 signal and the TX2 signal. Therefore, the downconverter 53 does not need to convert target waves containing desired waves with high signal strength, i.e., high signal power, and can use one with a narrow dynamic range for signal power. Furthermore, because the AD converter 54 does not digitally convert target waves containing desired waves with high signal strength, the resolution required for the required conversion accuracy can be reduced compared to when converting target waves containing normal desired waves.

[0043] As described above, in this quadrature modulation device 12, spurious emissions can be measured with high accuracy without being limited by the performance of the downconverter 53 and the AD converter 54. Furthermore, using a downconverter 53 with a narrow dynamic range and an AD converter 54 with low resolution and a low sampling rate is advantageous in terms of simplifying the circuit configuration and saving power, as well as reducing manufacturing costs.

[0044] Furthermore, a wide dynamic range of the downconverter means a large difference between the noise floor level, which is mainly caused by circuit thermal noise, and the maximum signal level (a high S / N ratio). Conventionally, for example, noise is averaged by integrating the signal to be measured over a predetermined integration time, thereby reducing the influence of circuit thermal noise and improving measurement accuracy. When the S / N ratio is high, a predetermined measurement accuracy can be achieved even if the integration time is reduced. In contrast, in this example, the desired wave in the composite wave is suppressed, and therefore, as described above, highly accurate measurement of spurious signals is achieved even with a simple circuit configuration consisting of a downconverter 53 with a narrow dynamic range and an AD converter 54 with a low resolution.

[0045] The signal processing unit 55 performs various processes, including synchronous detection, on the input target wave to measure the amplitude and phase angle of the desired wave, image component, and local leak in the target wave. The measurement values ​​measured by the signal processing unit 55 during initial adjustment include the amplitude A1 and phase angle θ of the desired wave for the TX1 signal. 1d , the phase angle θ of the image component of the TX1 signal when the image component is intentionally emphasized 1i , the amplitude A2 and phase angle θ of the desired wave for the TX2 signal 2d , the phase angle θ of the image component of the TX2 signal when the image component is intentionally emphasized 2i The amplitude β1 and phase angle ζ1 of the local leak of the TX1 signal, in which local leak is intentionally generated, and the amplitude β2 and phase angle ζ2 of the local leak of the TX2 signal are shown. Note that the phase angles measured by the signal processing unit 55 are relative to a single invariant reference determined by the measurement unit 18.

[0046] The signal processing unit 55 measures the amplitude γ of the image component of the TX1 signal in the (N+1)th compensation process. 1,N , phase angle η 1,N , the amplitude of the image component of the TX2 signal γ 2,N , phase angle η 2,N , the amplitude of the local leakage of the TX1 signal a 1,N , phase angle λ 1,N , the amplitude of the image component of the TX2 signal a2,N , phase angle λ 2,N These are measured from a composite wave in which the desired wave is suppressed.

[0047] In the initial adjustment, the signal processing unit 55 determines, based on the measurement values, desired wave suppression correction values ​​that correct the I1 signal, Q1 signal, I2 signal, and Q2 signal for suppressing the desired wave of the composite wave, and sets these values ​​in the calibration signal generating unit 24. When generating a composite wave, the calibration signal generating unit 24 generates and outputs the I1 signal, Q1 signal, I2 signal, and Q2 signal based on the set desired wave suppression correction values.

[0048] In the compensation process, the signal processor 55 calculates the image correction value and the offset value from the controller 14 based on the measured value. 01 Signal and Q 01 The first correction value for the signal, I 02 Signal and Q 02 The second correction value for the signal is calculated. The first correction value and the second correction value are set in the correction unit 23.

[0049] The receiving unit 13 is composed of a bandpass filter (BPF) 61, an amplifier 62, a demodulation unit 63, a fourth local oscillator 64, etc. The receiving unit 13 is, for example, an IF (intermediate frequency) demodulation circuit that mixes a high-frequency signal from the fourth local oscillator 64 with the received signal from the main unit 11 in the demodulation unit 63, converts the received signal to an intermediate frequency, and demodulates it. The demodulation unit 63 extracts bit information, which is the result of calculation, from the received signal from the main unit 11 and outputs it to the control unit 14. Note that in this example, an IF type is used as the receiving unit 13, but the demodulation method is not limited to this.

[0050] Next, the operation of the above configuration will be described. Note that the order of measuring the measurement values ​​and calculating the correction values ​​described below is an example and is not limited to this. In the quantum computer 10, the adjustment mode and the normal mode are repeatedly switched alternately, as shown in FIG. 3. In the first adjustment mode (N=0) immediately after starting up the quantum computer 10, an initial adjustment is performed followed by a compensation process. In the second and subsequent adjustment modes (N=1, 2, 3, etc.), only the compensation process is performed.

[0051] In normal mode, quantum control operation, read operation, and active reset operation are performed. In quantum control operation, a TX1 signal from the first orthogonal modulation unit 21 is sent to the main unit 11 to control the quantum bit. In read operation, a TX2 signal from the second orthogonal modulation unit 22 is sent to the main unit 11 to instruct the quantum bit to read, and the receiver 13 receives a reception signal from the main unit 11 as a response from the quantum bit and demodulates it. In active reset operation, the TX1 signal is sent to the main unit 11 to reset the quantum bit, a TX2 signal is sent for readout, and the reception signal from the main unit 11 is received, in sequence.

[0052] The quantum control operation, read operation, and active reset operation are performed in sequence over a time period of, for example, several tens of microseconds, several microseconds, or less than 1 microsecond. While there is no particular time limit for the initial adjustment in the adjustment mode, it is preferable that the compensation process be performed over a time period of, for example, less than 1 microsecond in order to achieve high-speed operation of the quantum computer 10.

[0053] When quantum computer 10 is started, it enters the first adjustment mode (N=0) and performs initial adjustment first. For this reason, selector 19 is switched to the side of measurement unit 18. As a result, the TX1 signal and TX2 signal output from modulation unit 17 are input to measurement unit 18 via selector 19. In addition, selectors 31 and 41 are switched to the side of calibration signal generation unit 24, so that the I1 signal and Q1 signal from calibration signal generation unit 24 are input to first quadrature modulator 34 via DA converters 32a and 32b, and the I2 signal and Q2 signal are input to second quadrature modulator 44 via DA converters 42a and 42b.

[0054] After this, only the TX1 signal is output from the modulation unit 17, and the amplitude A1 and phase angle θ of the desired wave of the TX1 signal are 1d To this end, the calibration signal generating unit 24 outputs, as the I1 signal and the Q1 signal, the I1 channel carrier signal and the Q1 channel carrier signal whose amplitudes have been reduced to prevent over-range in the measuring unit 18. In other words, it outputs unmodulated I1 and Q1 signals whose amplitudes are smaller than the maximum amplitude in normal mode. In this example, the amplitudes of the I1 and Q1 signals when measuring the amplitude and phase angle of the desired wave are set to 1 / 100 of the maximum amplitude in normal mode.

[0055] At this time, the I1 signal and Q1 signal output from the calibration signal generator 24 are 01 , Q 01 It is expressed as in equation (3) using the matrix H 1d is intended to reduce the amplitude of the I1 signal and the Q1 signal, and the magnitude (absolute value) of each component in the first row, first column and the fourth row, fourth column is set to a value according to the ratio of the amplitude of the I1 signal and the Q1 signal to the maximum amplitude in normal mode.

[0056]

number

[0057] The I1 signal and Q1 signal from the calibration signal generator 24 are converted into analog signals by the DA converters 32a and 32b, respectively, and input to the first quadrature modulator 34. Then, the I1 signal and the Q1 signal are used to generate a frequency F Lo1 The TX1 signal, which is obtained by quadrature-modulating the first carrier wave, is output from the first quadrature modulator 34. Since the amplitudes of the I1 signal and Q1 signal are reduced, the amplitude of the output TX1 signal is also reduced, and in this example, it is 1 / 100 of the maximum amplitude in normal mode. Note that the second quadrature modulator 44 is stopped so that the TX2 signal is not generated.

[0058] The TX1 signal from the first quadrature modulator 34 is input to the measurement unit 18. In the measurement unit 18, the TX1 signal is input to a downconverter 53 via a combiner 51 and an amplifier 52, and is converted to a lower frequency by this downconverter 53. The downconverted TX1 signal is converted to a digital signal by an AD converter 54 and then input to a signal processing unit 55. As described above, the TX1 signal input to the measurement unit 18 has a reduced amplitude, so that its signal strength and signal power do not exceed the measurement range of the measurement unit 18, and signal processing can be performed normally. The signal processing unit 55 synchronously detects the desired wave using a reference signal of the same frequency as the desired wave of the TX1 signal, and detects the amplitude A1 and phase angle θ of the extracted desired wave. 1d Measure (calculate).

[0059] Next, the TX1 signal, in which the image component is intentionally emphasized, is output from the modulation unit 17, and the phase angle θ of the image component is 1i At this time, the TX2 signal is not generated, so the second quadrature modulator 44 remains stopped.

[0060] The calibration signal generator 24 calculates the amplitude A1 and phase angle θ of the desired wave for the I1 signal. 1d As with the measurement of the amplitude and phase angle of the desired wave, the amplitude of the I1 channel carrier signal is reduced and output. On the other hand, for the Q1 signal, the amplitude is reduced and the Q1 channel carrier signal is shifted in phase by 180° relative to the I1 channel carrier signal, i.e., the sign of the Q1 channel carrier signal is inverted and output. This intentionally emphasizes the image component in the TX1 signal. In this example, as with the measurement of the amplitude and phase angle of the desired wave, the amplitudes of the I1 and Q1 signals are set to 1 / 100 of the maximum amplitude in normal mode.

[0061] Phase angle θ of the image component 1i The I1 signal and Q1 signal output from the calibration signal generator 24 when measuring the channel carrier signal I 01 , Q 01 It is expressed as in equation (4) using the matrix H 1iis intended to reduce the amplitude of the I1 signal and the Q1 signal and invert the sign of the Q1 signal. The magnitude (absolute value) of each component in the first row, first column and the fourth row, fourth column is set to a value that corresponds to the ratio of the amplitude of the I1 signal and the Q1 signal to the maximum amplitude in normal mode.

[0062]

number

[0063] The I1 signal and Q1 signal are input to the first quadrature modulator 34 via the DA converters 32a and 32b, respectively, and the TX1 signal, in which the first carrier wave is quadrature-modulated using the I1 signal and Q1 signal, is output from the first quadrature modulator 34. In this case, too, the amplitude of the I1 signal and Q1 signal is reduced, so the amplitude of the output TX1 signal is reduced. Also, because the phase of the Q1 signal is changed as described above, the image component of the TX1 signal is not suppressed, and its signal strength is increased. In this case, the desired wave of the TX1 signal is suppressed, so the signal strength is reduced.

[0064] The TX1 signal from the first quadrature modulator 34 is input to the measurement unit 18 via the selector 19, and is then input to the signal processing unit 55 via the combiner 51, amplifier 52, downconverter 53, and AD converter 54. The signal processing unit 55 then performs synchronous detection using a reference signal with the same frequency as the image component of the TX1 signal, and calculates the phase angle θ of the extracted image component. 1i In this case, the TX1 signal input to the measuring unit 18 has a small amplitude, so that the signal strength and signal power do not exceed the measurement range of the measuring unit 18, and signal processing can be performed normally.

[0065] Phase angle θ of the image component of the TX1 signal 1i After measuring the amplitude A2 and phase angle θ of the desired wave of the TX2 signal, just like the TX1 signal, output the TX2 signal. 2dThe calibration signal generating unit 24 outputs the I2 channel carrier signal and Q2 channel carrier signal with reduced amplitude as the I2 signal and Q2 signal. In this case, the amplitude of the I2 signal and Q2 signal is also set to 1 / 100 of the maximum amplitude in normal mode.

[0066] The I2 signal and Q2 signal output from the calibration signal generator 24 are 02 , Q 02 It is expressed as in equation (5) using the matrix H 2d is the matrix H 1d and is used to reduce the amplitude of the I2 signal and the Q2 signal. The magnitude (absolute value) of each component in the first row, first column and the fourth row, fourth column is set to a value that corresponds to the ratio of the amplitude of the I2 signal and the Q2 signal to the maximum amplitude in normal mode.

[0067]

number

[0068] The I2 signal and Q2 signal from the calibration signal generator 24 are input to the second quadrature modulator 44 via the DA converters 42a and 42b, respectively, and the I2 signal and Q2 signal are used to generate a frequency F Lo2 The TX2 signal, in which the second carrier wave is quadrature-modulated, is output from the second quadrature modulator 44. The TX2 signal from the second quadrature modulator 44 is input to the measurement unit 18 via the selector 19, and is then input to the signal processing unit 55 via the combiner 51, the amplifier 52, the down-converter 53, and the AD converter 54. The signal processing unit 55 then performs synchronous detection on the input TX2 signal using a reference signal having the same frequency as the desired wave, and extracts the amplitude A2 and phase angle θ of the extracted desired wave. 2d Measure.

[0069] Next, in the same way as with the TX1 signal, the TX2 signal, in which the image component is intentionally emphasized, is output from the second quadrature modulation unit 22, and the phase angle θ of the image component is 2iThe calibration signal generator 24 outputs the I2 channel carrier signal with reduced amplitude for the I2 signal, but outputs the Q2 channel carrier signal with reduced amplitude and inverted sign for the Q2 signal. This intentionally emphasizes the image component in the TX2 signal.

[0070] Phase angle θ of the image component 2i The I2 signal and Q2 signal output from the calibration signal generator 24 when measuring the channel carrier signal I 02 , Q 02 It is expressed as in equation (6) using the matrix H 2i decreases the amplitude of the I2 signal and the Q2 signal and inverts the sign of the Q2 signal. The magnitude (absolute value) of each component in the first row, first column and the fourth row, fourth column is set to a value that corresponds to the ratio of the amplitude of the I2 signal and the Q2 signal to the maximum amplitude in normal mode.

[0071]

number

[0072] The I2 signal and Q2 signal are input to the second quadrature modulator 44 via the DA converters 42a and 42b, respectively, and the TX2 signal, in which the second carrier wave is quadrature-modulated using the I2 signal and Q2 signal, is output from the second quadrature modulator 44. Because the phase of the Q2 signal is changed as described above, the image component of the TX2 signal is not suppressed and its signal strength increases, but the desired wave is suppressed and its signal strength decreases.

[0073] The TX2 signal from the second quadrature modulator 44 is input to a signal processing unit 55 via a selector 19, a combiner 51, an amplifier 52, a downconverter 53, and an AD converter 54. The signal processing unit 55 then extracts the image component of the input TX2 signal by synchronous detection, and calculates the phase angle θ of the extracted image component. 2i Measure (calculate).

[0074] Amplitude A2 and phase angle θ of the desired wave of the TX2 signal 2dand the phase angle θ of the image component 2i Even when measuring the amplitude A2 and phase angle θ of the desired wave of the TX2 signal, the amplitude of the TX2 signal input to the measurement unit 18 is reduced, so that the signal strength and signal power do not exceed the measurement range of the measurement unit 18, and signal processing can be performed normally. When performing these measurements, the amplitudes of the I2 signal and Q2 signal are set to 1 / 100 of the maximum amplitude in normal mode. Also, the amplitude A2 and phase angle θ of the desired wave of the TX2 signal are set to 1 / 100 of the maximum amplitude in normal mode. 2d Measurement of the phase angle θ of the image component 2i In either case of the measurements, the first quadrature modulator 34 is in a stopped state so as not to generate the TX1 signal.

[0075] In this example, the amplitude of the desired wave is assumed to be equal to the amplitude of the image component in the above measurement, and the amplitude of the desired wave is taken as the amplitude of the image component. Therefore, measurement of the amplitude of the image component is omitted for both the TX1 signal and the TX2 signal, but the amplitude of the image component may also be measured. In addition, the phase angle θ of each image component of the TX1 signal and the TX2 signal 1i , θ 2i When measuring 、 The TX1 signal and the TX2 signal may be output simultaneously and measured from the composite wave. From the viewpoint of shortening the time required for the initial adjustment, the TX1 signal and the TX2 signal may be output simultaneously and the phase angle θ of each image component may be measured. 1i , θ 2i It is preferable to measure

[0076] Furthermore, the TX1 signal and the TX2 signal, in which local leaks have been intentionally generated, are simultaneously generated, and the amplitude β1 and phase angle ζ1 of the local leak in the TX1 signal, and the amplitude β2 and phase angle ζ2 of the local leak in the TX2 signal are measured. In this measurement, the calibration signal generating unit 24 outputs constant values ​​of the I1 signal and the I2 signal, and zero values ​​of the Q1 signal and the Q2 signal. In this case, the magnitudes of the I1 signal and the I2 signal are reduced to prevent over-range in the measuring unit 18. In this example, the magnitudes are set to 1 / 100 of the maximum amplitude in normal mode. The I1 signal, the Q1 signal, the I2 signal, and the Q2 signal output by the calibration signal generating unit 24 are expressed as shown in Equation (7).

[0077]

number

[0078] The TX1 signal and the TX2 signal, in which local leaks have been intentionally generated, are input from the modulator 17 to a combiner 51 via a selector 19, and are combined by the combiner 51 to form a composite wave. The composite wave is input to a signal processor 55 via an amplifier 52, a down converter 53, and an AD converter 54. Because the I1 signal and the I2 signal are constant (DC) as described above, the composite wave contains only the local leaks of the TX1 signal and the TX2 signal, and does not contain any desired wave or image components. The composite wave is appropriately processed by the down converter 53 and the AD converter 54 and then input to the signal processor 55.

[0079] The signal processing unit 55 performs synchronous detection on the input composite wave, extracts the local leak of the TX1 signal, and measures its amplitude β1 and phase angle ζ1, and extracts the local leak of the TX2 signal, and measures its amplitude β2 and phase angle ζ2. When measuring the amplitude β1, phase angle ζ1, amplitude β2, and phase angle ζ2 of the local leaks of the TX1 signal and the TX2 signal, the TX1 signal and the TX2 signal may be input separately to the measuring unit 18 for measurement. From the viewpoint of shortening the time required for initial adjustment, it is preferable to output the TX1 signal and the TX2 signal simultaneously and measure each local leak.

[0080] After acquiring the measured values ​​in the initial adjustment as described above, the signal processing unit 55 determines a desired wave suppression correction value for causing the desired wave of the TX1 signal and the desired wave of the TX2 signal to cancel each other out, and sets this value in the calibration signal generating unit 24. In this example, the I1 signal and Q1 signal on the TX1 signal side are used as references, i.e., the I1 channel carrier signal and Q1 channel carrier signal are used as they are, and the I2 channel carrier signal and Q2 channel carrier signal on the TX2 signal side are corrected to become the I2 signal and Q2 signal, and a desired wave suppression correction value is determined and set in the calibration signal generating unit 24. Note that it is only necessary to correct the I1 signal and Q1 signal and the I2 signal and Q2 signal relatively, and therefore the I1 signal and Q1 signal may be corrected using the I2 signal and Q2 signal as reference, or both may be corrected.

[0081] The I1 signal, Q1 signal, I2 signal, and Q2 signal output by the calibration signal generating unit 24 when suppressing the desired wave in the composite wave are expressed as in equation (8), where the desired wave suppression correction value for the I1 signal and Q1 signal is H1 and the desired wave suppression correction value for the I2 signal and Q2 signal is H2. In this case, the desired wave suppression correction value H1 for the I1 signal and Q1 signal and the desired wave suppression correction value H2 for the I2 signal and Q2 signal in the first adjustment mode are determined by the amplitude ratio (A1 / A2) and phase angle difference (θ 1d -θ 2d ) is used to express it as in equation (9). The reason why the sign of the desired wave suppression correction value H2 is negative is to make the desired wave of the TX2 signal have an opposite phase to the desired wave of the TX1 signal.

[0082]

number

[0083]

number

[0084] Setting the desired wave suppression correction values ​​H1 and H2 completes the initial adjustment, followed by the first compensation process (N=0). Both the first quadrature modulator 34 and the second quadrature modulator 44 are activated. The calibration signal generator 24 applies the set desired wave suppression correction value H1 to the I1 channel carrier signal and the Q1 channel carrier signal to generate the I1 signal and the Q1 signal, and applies the desired wave suppression correction value H2 to the I2 channel carrier signal and the Q2 channel carrier signal to generate and output the corrected I2 signal and the Q2 signal. The TX1 signal, quadrature-modulated using the I1 signal and the Q1 signal, is then output from the first quadrature modulator 34, and the TX2 signal, quadrature-modulated using the I2 signal and the Q2 signal, is then output from the second quadrature modulator 44.

[0085] The TX1 signal and the TX2 signal are input to the combiner 51 via the selector 19, and are combined by the combiner 51 to form a composite wave. In the composite wave, the desired wave of the TX2 signal, which is generated using the desired wave suppression correction value H2 as described above, has the same amplitude as the desired wave of the TX1 signal and is in the opposite phase to the desired wave of the TX1 signal. Also, as described above, the frequency f of the first carrier wave LO1 and the frequency of the second carrier wave f LO2 Although it is different from (f LO1 ≠f LO2 ), the frequency of the desired wave of the TX1 signal and the frequency of the desired wave of the TX2 signal are the same, that is, "f LO1 -f IQ1 =f LO2 -f IQ2 ", the frequency f of the I1 channel carrier signal and the Q1 channel carrier signal is set to IQ1 and the frequency f of the I2 channel carrier signal and the Q2 channel carrier signal IQ2 Therefore, the TX1 signal and the TX2 signal are input to the measuring unit 18 and combined in a state where the frequencies of the desired waves thereof match each other and are in opposite phases.

[0086] In addition, the frequency of the image component of the TX1 signal in the composite wave is "f LO1 +f IQ1 " and the frequency of the image component of the TX2 signal is "fLO2 +f IQ2 ", but as mentioned above, "f LO1 +f IQ1 ≠f LO2 +f IQ2 "

[0087] That is, a composite wave is generated from the TX1 and TX2 signals that satisfy the suppression conditions that the frequencies of the desired waves are the same, their amplitudes are equal, and their phases are opposite, and the frequencies of the image components of the TX1 and TX2 signals are different from each other.

[0088] As a result, as shown in the frequency spectrum of the composite wave in Figure 4, the frequencies of the desired waves of the TX1 signal and the TX2 signal match each other (f LO1 -f IQ1 =f LO2 -f IQ2 ), the amplitudes of the desired waves are equal and the phases are opposite, so the desired waves cancel each other out. Also, in the composite wave, the frequencies of the image components are different from each other (f LO1 +f IQ1 ≠f LO2 +f IQ2 ), they appear without overlapping. Furthermore, the local leak has the same frequency as the carrier wave in quadrature modulation, but the frequency f of the first carrier wave LO1 and the frequency of the second carrier wave f LO2 are different from each other, the local leaks appear in the composite wave without overlapping with each other.

[0089] The composite wave output from the combiner 51 is input to the signal processing unit 55 via the amplifier 52, the downconverter 53, and the AD converter 54. In this compensation process, the amplitudes of the TX1 signal and the TX2 signal are not reduced, but the desired waves of the TX1 signal and the TX2 signal cancel each other out and disappear in the composite wave as described above. Therefore, even when the composite wave is input to the downconverter 53, signal power exceeding the measurement range is not input, and the composite wave is appropriately converted to a lower frequency. Furthermore, even if the AD converter 54 has a low resolution, even if the resolution is small enough to match the relatively small signal strength of the image component and local leak, the required conversion accuracy can be achieved. Furthermore, even if the resolution is high enough to achieve the required conversion accuracy for such image components and local leak, the desired wave with a high signal strength is not input, so the output is appropriately converted to a digital signal without saturating.

[0090] When the composite wave is input from the AD converter 54, the signal processing unit 55 sequentially changes the frequency of the reference signal to synchronously detect and extract the image component and local leak of the TX1 signal and the image component and local leak of the TX2 signal, respectively. 1,0 and phase angle η 1,0 , the amplitude of the image component of the TX2 signal γ 2,0 and phase angle η 2,0 , the amplitude of the local leakage of the TX1 signal a 1,0 and phase angle λ 1,0 , the amplitude of the local leakage of the TX2 signal a 2,0 and phase angle λ 2,0 are measured respectively.

[0091] After the above measurement, the signal processing unit 55 calculates the image correction value H 1,1 and the image correction value H of the second correction value 2,1 and set them in the correction unit 23. The image correction value H 1,1 and image correction value H 2,1 is the amplitude γ of the image component measured in the compensation process. 1,0 , γ2,0 , phase angle η 1,0 , η 2,0 , amplitudes A1, A2, and phase angle θ measured in the initial adjustment 1i , θ 2i Using the above, it is expressed as in equation (10). Note that the amplitudes A1 and A2 in equation (10) are measured as the amplitudes of the desired wave and are regarded as the amplitudes of the image components.

[0092]

number

[0093] The signal processing unit 55 also calculates the amplitude a 1,0 and phase angle λ 1,0 Offset value OF to cancel local leakage of TX1 signal 1,1 and amplitude a 2,0 and phase angle λ 2,0 Offset value OF to cancel local leakage of TX2 signal 2,1 These are then used as the offset value OF 1,1 , OF 2,1 are set in the correction unit 23. 1,1 , OF 2,1 is the amplitude a of the local leak measured in the compensation process. 1,0 , a 2,0 , phase angle λ 1,0 , λ 2,0 Using the amplitudes β1, β2 and phase angles ζ1, ζ2 of the local leaks measured in the initial adjustment, it can be expressed as in equation (11).

[0094]

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[0095] As described above, when the compensation process in the first adjustment mode is completed and the normal mode is entered, the selector 19 is switched to select the main body 11. Also, the selectors 31 and 41 are switched to select the correction unit 23. After this, the control unit 14 sends II1 Signal, Q Q1 Signal, I I2 Signal, Q Q2 The output of signals starts, and these signals are input to the correction unit 23. The correction unit 23 corrects the input I I1 Signal, Q Q1 The signal is adjusted to the set image correction value H 1,1 and offset value OF 1、1 The I1 signal and the Q1 signal corrected using the above are input to the first quadrature modulator 34 via the DA converters 32a and 32b. That is, the corrector 23 sets "N=0" and the image correction value H 1,1 and offset value OF 1、1 Based on the equation (2) applied, I I1 Signal, Q Q1 The signal is converted into an I1 signal and a Q1 signal.

[0096] Similarly, the correction unit 23 corrects the input I I2 Signal, Q Q2 The signal is calculated by the image correction value H 1,2 and offset value OF 1、2 The I2 signal and the Q2 signal corrected using the above are input to the second quadrature modulator 44 via the DA converters 42a and 42b. That is, the corrector 23 sets "N=0" and the image correction value H 2,1 and offset value OF 2、1 Based on the equation (2) applied, I I2 Signal, Q Q2 The signal is converted into I2 signal and Q2 signal.

[0097] The TX1 signal, in which the first carrier wave is quadrature-modulated using the I1 signal and Q1 signal corrected by the correction unit 23 as described above, and the TX2 signal, in which the second carrier wave is quadrature-modulated using the I2 signal and Q2 signal, are transmitted to the main body unit 11.

[0098] When the first normal mode ends, the second (N=1) adjustment mode begins. In the second adjustment mode, only the compensation process is performed. In this compensation process, the amplitude γ of the image component of the TX1 signal is adjusted by the same procedure as in the first adjustment mode. 1,1 , phase angle η 1,1Measurement of the amplitude of the image component of the TX2 signal γ 2,1 , phase angle η 2,1 Measurement of the amplitude of the local leak of the TX1 signal a 1,1 , phase angle λ 1,1 Measurement of the amplitude of the local leak of the TX2 signal a 2,1 , phase angle λ 2,1 When generating a composite wave in which each desired wave is canceled out in the measurement in this second adjustment mode, the image correction value H calculated in the compensation process in the previous (first) adjustment mode is used. 1,1 is the correction value for suppressing the desired wave H1, and the image correction value H 2,1 is the correction value H2 (=-H 2,1 ) and generates the I1 signal, the Q1 signal, the I2 signal, and the Q2 signal based on the equation (8).

[0099] In the second compensation process, after the above measurement, the signal processing unit 55 calculates the image correction value H 1,2 and the image correction value H of the second correction value 2,2 and set them in the correction unit 23. Image correction value H 1,2 As shown in equation (12), the image correction value H 1,1 The amplitude γ of the TX1 signal measured in the second compensation process 1,1 , phase angle η 1,1 Similarly, the image correction value H 2,2 As shown in equation (12), the image correction value H 2,1 The amplitude γ of the TX2 signal measured in the second compensation process 2,1 , phase angle η 2,1 A correction value that cancels the image component of

[0100]

number

[0101] In addition, the offset value OF calculated in the second compensation process 1,2 , OF2,2 is the amplitude a of the TX1 signal measured in the second compensation process. 1,1 , phase angle λ 1,1 The local leakage of the TX2 signal, amplitude a 2,1 , phase angle λ 2,1 It can be expressed as equation (13).

[0102]

number

[0103] When the compensation process in the second adjustment mode is completed and the second normal mode is entered, the correction unit 23 calculates and sets the image correction value H 1,2 and offset value OF 1,2 The correction unit 23 generates the corrected I1 signal and Q1 signal using the image correction value H 2,2 and offset value OF 2,2 Then, the correction unit 23 generates a TX1 signal, in which the first carrier wave is quadrature-modulated using the I1 signal and Q1 signal corrected by the correction unit 23, and a TX2 signal, in which the second carrier wave is quadrature-modulated using the I2 signal and Q2 signal, which are transmitted to the main body 11.

[0104] Similarly, in the third and subsequent (N+1)th adjustment modes, only the compensation process is performed. In this compensation process, the amplitude γ of the image component of the TX1 signal is adjusted by the same procedure. 1,N , phase angle η 1,N Measurement of the amplitude of the image component of the TX2 signal γ 2,N , phase angle η 2,N Measurement of the amplitude of the local leak of the TX1 signal a 1,N , phase angle λ 1,N Measurement of the amplitude of the local leak of the TX2 signal a 2,N , phase angle λ 2,N Then, based on these measurements, the image correction value H 1,N , H 2,N and offset value OF1,N , OF 2,N The image correction value H calculated in the compensation process in the N+1th adjustment mode is determined. 1,N+1 , H 2,N+1 and offset value OF 1,N+1 , OF 2,N+1 is expressed as in equation (14). When generating a composite wave in which each desired wave is canceled out in the measurement in the N+1th adjustment mode, the image correction value H calculated in the compensation process in the Nth adjustment mode is 1,N is the correction value for suppressing the desired wave H1, and the image correction value H 2,N is the correction value H2 (=-H 2,N ) and generates the I1 signal, the Q1 signal, the I2 signal, and the Q2 signal based on the equation (8).

[0105]

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[0106] As described above, the TX1 signal and the TX2 signal in which the image component and the local leak have been effectively suppressed are transmitted from the quadrature modulation device 12 to the main unit 11.

[0107] As described above, the adjustment mode is repeated and the AD converter 54 outputs a digital signal for measurement by the measuring unit 18. However, by using a fractional N-type PLL circuit as the third local oscillator 53b of the downconverter 53, the frequency of the spurious signals after downconversion can be effectively reduced, allowing the AD converter 54 to have a low sampling frequency, enabling the spurious signals to be measured with good accuracy and operating with low power consumption.

[0108] In the above example, the amplitude A1 of the desired wave of the TX1 signal and the phase angle θ of the image are measured in the initial adjustment. 1i , amplitude β1 of local leak, phase angle ζ1, amplitude A2 of desired wave of TX2 signal, phase angle θ of image 2iThe amplitude β2 and phase angle ζ2 of the local leak are used in the compensation process in the first adjustment mode and in the second and subsequent adjustment modes, but these measured values ​​may also fluctuate. If these measured values ​​fluctuate, the accuracy of suppressing the image components and local leak may decrease, so it is preferable to perform initial adjustment and re-measurement every certain number of adjustment modes (for example, 100 times).

[0109] As shown in the example of Fig. 5, in the compensation process in the first adjustment mode, the amplitude may be increased stepwise, spurious measurements may be performed for each increase, and an image correction value and offset value for the amplitude in the normal mode may be determined. Note that Fig. 5 shows an outline of an example of a procedure for determining the first correction value (image correction value, offset value) for the TX1 signal in the first adjustment mode, but the second correction value for the TX2 signal can also be determined using a similar procedure. Furthermore, compensation processes for the TX1 signal and the TX2 signal may be performed simultaneously.

[0110] When the quantum computer 10 enters the first adjustment mode immediately after startup, compensation processing is performed for the TX1 signal, followed by compensation processing for the TX2 signal. The compensation processing for the TX1 signal involves a first correction value determination processing that determines a first correction value for reducing (suppressing) the image component and local leak. The first correction value determination processing involves multiple sub-processes (100 times in this example). Note that in this example, after the first correction value determination processing, a calibration processing is performed to return the amplitude and phase angle of the TX1 signal to their intended values, but a description of this calibration processing will be omitted.

[0111] Prior to the first sub-processing (M=1), an initial measurement is performed. In this initial measurement, the amplitudes of the I1 and Q1 signals of the TX1 signal are set to 1 / 100 of those in the normal mode (step ST1), and the measurement is performed in the same manner as in the initial adjustment described above. First, the TX1 signal is output from the first quadrature modulator 34, and the amplitude A1 and phase angle θ of the desired wave of the TX1 signal are set. 1d is measured by the measuring unit 18 (step ST2). Next, the TX1 signal in which the image component is intentionally emphasized is output from the modulation unit 17, and the phase angle θ of the image component is measured.1i Furthermore, a TX1 signal in which a local leak is intentionally generated is output from the modulation unit 17, and the amplitude β1 and phase angle ζ1 of the local leak are measured (step ST4).

[0112] As described above, after the initial measurement, 100 sub-processes are performed. In the Mth (M is 1, 2, . . . , 100) sub-process, first, the correction value H 1(0) is set in the calibration signal generator 24, the intentional generation of local leak and the emphasis of image components are cancelled, the amplitudes of the I1 signal and Q1 signal are corrected, and output of the TX1 signal with the amplitude reduced to 1 / 100 of that in normal mode is started (step ST5). After starting output of this TX1 signal, TX2 signal output processing (step ST6), desired wave measurement processing (step ST7), desired wave suppression processing (step ST8), spurious measurement processing (step ST9), and spurious correction processing (step ST10) are sequentially performed.

[0113] In the TX2 signal output processing, for example, the correction value H 2(M) is set in the calibration signal generator 24, and the amplitude of the desired wave is "M / 100" in normal mode. The TX2 signal is generated from the I2 signal and Q2 signal, which have been corrected so that the desired wave is in opposite phase relative to the desired wave of the TX1 signal, and output from the modulator 17. That is, in the TX2 signal output process, the TX2 signal is output, and the TX2 signal is increased as the number of sub-processes increases. The TX2 signal output in this TX2 signal output process is not corrected for image components or local leaks. By outputting the TX2 signal, a composite wave (combined signal) in which the TX1 signal and the TX2 signal are combined is input to the measurement unit 18. In this example, the TX2 signal output process corresponds to the second modulated wave output step and the amplitude increasing step. Note that in this example, the desired waves of the TX1 signal and the TX2 signal are in opposite phase to each other by adjusting the phase of the TX1 signal.

[0114] In the subsequent desired wave measurement process, the amplitude A of the desired wave in the composite wave is 1,M and phase θ 1d,MIn the composite wave, the desired wave of the TX1 signal and the desired wave of the TX2 signal are in opposite phases and therefore cancel each other out, but this cancellation is incomplete in the first sub-processing due to, for example, variations in the characteristics of the first quadrature modulator 34 and the second quadrature modulator 44. Furthermore, in the second and subsequent sub-processing, the amplitude of the TX2 signal is increased, which causes the desired wave of the TX1 signal and the desired wave of the TX2 signal to cancel out incompletely. Therefore, the amplitude A of the desired wave remaining in the composite wave due to this incomplete cancellation is measured. 1,M and phase θ 1d,M and measure.

[0115] In the desired wave suppression process, the amplitude A of the desired wave in the composite wave measured in the desired wave measurement process is 1,M and phase θ 1d,M Based on this, the current correction value H for suppressing the desired wave for the TX1 signal is calculated. 1(M-1) is corrected to obtain the correction value H for suppressing the desired wave when measuring spurious signals in the Mth sub-processing. 1(M) Then, the correction value H 1(M) The output TX1 signal is updated by generating the I1 signal and Q1 signal based on the above. This correction of the desired wave suppression correction value is performed so that the amplitude and phase of the desired wave of the TX1 signal match the amplitude and phase of the desired wave of the TX2 signal. This results in a state where the desired wave of the TX1 signal and the desired wave of the TX2 signal in the composite wave completely cancel each other out. In this example, the desired wave measurement process and the desired wave suppression process correspond to the desired wave correction process.

[0116] In the spurious measurement process, the amplitude γ of the image component of the TX1 signal in the composite wave in which the desired waves of the TX1 signal and the TX2 signal are completely canceled out by the desired wave suppression process is 1,0,M and phase angle η 1,0,M , the amplitude of the local leak a 1,0,M and phase angle λ 1,0,M In this example, the spurious measurement process is the spurious measurement step.

[0117] In spurious correction processing, the correction value H for suppressing the desired wave is calculated based on the measurement results of spurious measurement processing. 1(M) Then, the corrected correction value H for suppressing the desired wave is 1(M) is set in the calibration signal generator 24, and the set correction value H for suppressing the desired wave is 1(M) The output TX1 signal is updated again by generating the I1 signal and the Q1 signal based on the above. As a result, the desired wave of the TX1 signal and the desired wave of the TX2 signal in the composite wave completely cancel each other out, and the image component and local leak of the TX1 signal are suppressed. In this example, the spurious correction process corresponds to the correction value calculation step.

[0118] Desired wave suppression correction value H 1(M) is the image correction value H, which is the correction value for correcting the I1 signal and Q1 signal. 1(M) and the offset value OF 1(M) The I1 signal and Q1 signal output from the calibration signal generator 24 are 01 , Q 01 In the following explanation, the desired wave suppression correction value H 1(M) When distinguishing between the two, the uncorrected one is called the desired wave suppression correction value H 1(M),0 , the corrected value is called the desired wave suppression correction value H 1(M),0 The image correction value H 1(M) and the offset value OF 1(M) For the uncorrected image, the image correction value H 1(M),0 , offset value OF 1(M),0 , and the uncorrected one is the image correction value H 1(M),1 , offset value OF 1(M),1 The correction value H for suppressing the desired wave for the TX2 signal is 2(M)、 Image Correction H 2(M) , offset value OF 2(M) The same is true for

[0119]

number

[0120] The sub-processing is repeated as described above. In the first sub-processing, the desired wave suppression correction value H 1(M),0 Image correction value H 1(1),0 , offset value OF 1(1),0 is expressed as in equation (16).

[0121]

number

[0122] In addition, in the first sub-processing, the correction value H for suppressing the desired wave corrected based on the measurement results of the spurious measurement process is 1(M),1 Image correction value H 1(1),1 , offset value OF 1(1),1 is expressed as in equation (17).

[0123]

number

[0124] In the second and subsequent M sub-processings, the correction value H for suppressing the desired wave before spurious correction is 1(M),0 The image correction value H is calculated as 1(M),0 , offset value OF 1(M),0 is the image correction value H obtained by correcting spurious signals in the previous (M-1) sub-processing. 1(M-1),1 and offset value OF 1,M-1 Using this, it is expressed as equation (18).

[0125]

number

[0126] In addition, in the second and subsequent M sub-processes, the correction value H for suppressing the desired wave after correcting the spurious 1(M),1 The image correction value H is calculated as 1(M),1, offset value OF 1(M),1 is expressed as in equation (19).

[0127]

number

[0128] In each sub-process, the correction value H for suppressing the desired wave for the TX2 signal is 2(M) The image correction value H 2(M) , offset value OF 2(M) is expressed as in equation (20). In this example, the amplitude of the IQ data on the TX2 signal side, i.e., the channel carrier signals I02 and Q02, is set to "M / 100" times that in normal mode. Therefore, the image correction value H 2(M) This is a setting that does not change.

[0129]

number

[0130] In the sub-processing before the 100th time (M<100), the correction value H 1(M) is corrected to cancel out the desired waves of the TX1 and TX2 signals, while measuring the image components and local leak, and based on the measurement results, the correction value H 1(M) Then, in the spurious correction process in the 100th sub-process, the correction value H for suppressing the desired wave obtained by that process is used to output the TX1 signal with the image component and local leak suppressed. 1(100) That is, the image correction value H 1(100),1 , offset value OF 1(100),1 is set as the first correction value to be used in the normal mode performed following the first adjustment mode. In this way, the first correction value for the TX1 signal is determined.

[0131] As described above, the amplitudes of the TX1 and TX2 signals are changed in stages toward the amplitudes in the normal mode, and the first correction value is determined. 1(M) , offset value OF 1(M) However, there is a possibility that the amplitude may deviate from the target amplitude. Therefore, it is preferable to take the above-mentioned procedure of gradually increasing the amplitude, assuming nonlinear distortion. The image correction value H 1(M) , offset value OF 1(M) is calculated gradually as the amplitude increases, so that the first correction value can be calculated without being affected by the nonlinear distortion of the first quadrature modulator 34.

[0132] 6 and 7 show the distribution of frequency components of the TX1 signal before and after adjustment when the image component and local leak of the TX1 signal are suppressed using the procedure shown in FIG. 5. FIG. 6 shows a measurement of the TX1 signal output from the first quadrature modulator 34 before adjustment, and FIG. 7 shows that after adjustment. FIG. 8 shows the distribution of frequency components of the composite wave of the TX1 signal and the TX2 signal output from the combiner 51 during adjustment. Note that during this measurement, adjustment was also made to minimize the third-order nonlinear component from the mixer. The frequency component distribution shown in FIG. 8 was measured via the amplifier 52 (470 Ω resistor).

[0133] As shown in Figure 6, before adjustment, the image component and local leak of the TX1 signal have an intensity of -50 dB or more relative to the desired wave, but after adjustment, it is found to be smaller than -70 dB as shown in Figure 7. Also, as shown in Figure 8, it can be seen that the desired waves of the TX1 signal and TX2 signal in the composite wave are canceled out during adjustment.

[0134] While the above describes an example in which the quadrature modulation device is provided in a quantum computer, the present invention is not limited thereto. For example, the quadrature modulation device can be used in wireless devices, etc. For example, the quadrature modulation device can be used in devices with two or more transmission systems, such as MIMO (Multi-Input Multi-Output) systems that transmit signals using multiple antennas. Furthermore, a single modulated signal may be output to the outside. In this case, a second quadrature modulation unit may be provided as a calibration quadrature modulation unit that outputs a second modulated wave including a desired wave that cancels the desired wave of the first modulated wave from the first quadrature modulation unit during spurious measurement, in addition to the first quadrature modulation unit that outputs the modulated signal to the outside. Note that in the above example, one of the first quadrature modulation unit and the second quadrature modulation unit serves as a calibration modulation unit that cancels the other desired wave. Also, in the above example, the I signal and Q signal are corrected to cancel out the desired waves of the TX1 signal and the TX2 signal. However, instead of this, the desired waves may be corrected by adjusting the phase difference and amplitude difference of the carrier waves input to the quadrature modulator. Furthermore, although the above describes an example of suppressing image components and local leaks as spurious components, spurious components are not limited to these, and it is also possible to suppress nonlinear components resulting from harmonic components arising from the nonlinear characteristics of the quadrature modulator that generates the TX1 signal and the TX2 signal, such as the second-order nonlinear component "LO+2IF" and the third-order nonlinear component "LO-3IF." [Explanation of symbols]

[0135] 12 Quadrature Modulation Device 17 Modulation section 18 Measuring part 21 First quadrature modulation unit 22 Second quadrature modulation unit 23 Correction unit 32a, 32b 42a, 42b DA converter 33 First local oscillator 53 Down Converter 53a mixer 53b Third local oscillator 53b 54 AD converter 55 Signal Processing Unit

Claims

1. a modulation unit including a first quadrature modulation unit that outputs a first modulated wave obtained by quadrature-modulating a first carrier wave using a first I signal and a first Q signal, and a second quadrature modulation unit that quadrature-modulates a second carrier wave having a frequency different from that of the first carrier wave using a second I signal and a second Q signal, and outputs a second modulated wave in which the frequency of a desired wave coincides with the frequency of a desired wave of the first modulated wave and the frequency of an image component differs from the frequency of the image component of the first modulated wave; a measurement unit including a down converter that receives the first modulated wave, the second modulated wave, or a composite wave of the first modulated wave and the second modulated wave as a target wave and that reduces the frequency of the target wave, an AD converter that digitally converts a signal output from the down converter, and a signal processing unit that measures the target wave based on the output of the AD converter; Equipped with when the measurement unit measures the spurious of the first modulated wave from the composite wave, the modulation unit outputs the first modulated wave and the second modulated wave, each of which has the same amplitude and an opposite phase between the desired waves, and suppresses the desired waves of the first modulated wave and the second modulated wave in the composite wave; The downconverter includes a fractional N-type PLL circuit that outputs a local signal, and a mixer that mixes the local signal with the target wave. A quadrature modulation device characterized by:

2. when calculating a desired wave suppression correction value that makes the amplitudes of the desired waves of the first modulated wave and the second modulated wave equal and the desired waves in opposite phases, the modulation unit selectively outputs the first modulated wave with reduced amplitude obtained by inputting the first I signal and the first Q signal with reduced amplitude to the first quadrature modulation unit, and the second modulated wave with reduced amplitude obtained by inputting the second I signal and the second Q signal with reduced amplitude to the second quadrature modulation unit; The signal processing unit calculates the desired wave suppression correction value from a measurement value obtained by measuring the amplitude and phase of a desired wave of the first modulated wave while only the first modulated wave is being output from the modulation unit and a measurement value obtained by measuring the amplitude and phase of a desired wave of the second modulated wave while only the second modulated wave is being output, and when the measurement unit measures the spurious of the first modulated wave from the composite wave, relatively corrects the first I signal and the first Q signal and the second I signal and the second Q signal using the desired wave suppression correction value.

2. The quadrature modulation device according to claim 1.

3. a correction unit that corrects the first I signal and the first Q signal based on a first correction value when the first modulated wave is output to an external device; The signal processing unit obtains the first correction value for correcting the first I signal and the first Q signal so as to reduce the signal intensity of the image component and the local leak of the first modulated wave, based on measurement values ​​including amplitudes and phase angles of the image component and the local leak of the first modulated wave measured from the composite wave in which the desired wave of the first modulated wave and the second modulated wave is suppressed.

3. The quadrature modulation device according to claim 1, wherein the first and second inputs are connected to the first and second inputs.

4. the correction unit corrects the second I signal and the second Q signal based on a second correction value when outputting the second modulated wave to an external device; The signal processing unit further determines the second correction value for correcting the second I signal and the second Q signal so as to reduce the signal intensity of the image component and the local leak of the second modulated wave, based on measurement values ​​including amplitudes and phase angles of the image component and the local leak of the second modulated wave measured from the composite wave in which the desired wave of the first modulated wave and the second modulated wave is suppressed.

4. The quadrature modulation device according to claim 3.

5. a first modulated wave output step of outputting a first modulated wave obtained by quadrature-modulating a first carrier wave using the first I signal and the first Q signal; a second modulated wave output step of quadrature-modulating a second carrier wave using a second I signal and a second Q signal to output a second modulated wave in which a desired wave coincides with the frequency of the desired wave of the first modulated wave but is in opposite phase, and the frequency of an image component differs from the frequency of the image component of the first modulated wave; an amplitude increasing step of increasing the amplitude of the desired wave of the second modulated wave in a stepwise manner until the amplitude becomes a normal amplitude; a desired wave correcting step of correcting the first I signal and the first Q signal each time the amplitude of the desired wave of the second modulated wave increases so that the desired waves of the first modulated wave and the second modulated wave in a combined wave obtained by combining the first modulated wave and the second modulated wave cancel each other out; a spurious measurement step of measuring an image component and a local leak of the first modulated wave in a composite wave resulting from the cancellation of desired waves, every time the first I signal and the first Q signal are corrected in the desired wave correction step; a correction value calculation step of calculating correction values ​​for correcting the first I signal and the first Q signal so as to reduce the signal intensities of the image component and local leak of the first modulated wave, based on measurement results of the image component and local leak of the first modulated wave in the composite wave, every time the image component and local leak are measured in the spurious measurement step; and At least before the desired wave of the second modulated wave has a normal amplitude, each time the correction value is obtained, the first I signal and the first Q signal are corrected by the obtained correction value to output the first modulated wave, and the correction value obtained when the desired wave of the second modulated wave has a normal amplitude is set as a first correction value for correcting the first I signal and the first Q signal when the first modulated wave is output to the outside. A spurious correction method comprising:

6. a correction step of correcting the first I signal and the first Q signal when the first modulated wave is output to the outside, based on the first correction value obtained by the spurious correction method according to claim 5 ; A method for correcting quadrature modulation, comprising:

Images