JP7758619B2 - wireless transmission device - Google Patents

Description

The present invention relates to a wireless transmission device for performing wireless transmission at high frequencies.

In sixth-generation mobile communications, in order to achieve wireless communications speeds exceeding 100 Gb/s, consideration is being given to using frequency bands above 100 GHz as wireless carrier frequencies, which have the potential to secure wide bandwidths, in addition to conventional submillimeter waves.

Figure 1 shows the configuration of a conventional wireless transmission device for performing amplitude/phase modulation or quadrature modulation. In the wireless transmission device 900, a BB signal generator 910 generates a baseband signal including an I-channel signal Data (I) and a Q-channel signal Data (Q), and inputs the signal to an IF signal generator 920. The IF signal generator 920 converts the baseband signal into an IF signal (intermediate frequency signal). Specifically, the IF signal generator 920 includes a local oscillator 921 with a frequency LO1, IF mixers 922 and 924, a phase converter 923, and an IF amplifier 925. The IF signal generator 920 includes the local oscillator 921, IF mixers 922 and 924, and phase converter 923 to form a quadrature mixer 926 (a mixer driven by local oscillation signals that are 90° out of phase with each other). An IF signal having a center frequency of LO1 is generated by a quadrature mixer 926. The IF signal is amplified by an IF amplifier 925 and then input to an RF signal generation unit 930. The RF signal generation unit 930 includes a local oscillator 931 having a frequency of LO2, an RF mixer 932, and an RF amplifier 933. The IF signal is multiplied by a local oscillation signal having a frequency of LO2 by the RF mixer 932 and frequency-converted to an RF signal. Finally, the RF signal is amplified by an RF amplifier 933 (often a power amplifier) to a power level required for wireless communication and is then emitted into space via an antenna 940. Here, for LO1, the center frequency of the IF signal, a low frequency band (typically several GHz to 10-odd GHz) is selected in which the local oscillator 921, IF mixers 922 and 924, and phase converter 923 constituting the IF signal generation unit 920 have good performance. Furthermore, if the conversion gain of the quadrature mixer is sufficiently large, the IF amplifier 925 between the IF signal generator 920 and the RF mixer 932 may be omitted. Because the frequency band of the RF signal is above 100 GHz, the frequency LO2 of the local oscillation signal that drives the RF mixer 932 is selected to be the sum or difference of the RF frequency of 100 GHz or higher and the IF frequency (usually close to 100 GHz).

S. A. Maas, “How to model intermodulation distortion,” IEEE MTT-S International Microwave Symposium (IMS), 1991. J. Zanen et al, “A Predistortion-Less Digital Transmitter With -50-dB ACLR Exploitating Output Conductance Linearization,” IEEE Solid-State Circuits Letters (SSC-L), Vol. 4, 2001.

However, when implementing wireless systems above 100 GHz, there is a problem of degraded communication quality due to imperfections in amplifiers and other hardware that make up wireless transmission equipment. This is due to the imperfections of amplifiers, particularly their greater nonlinearity, in frequency bands above 100 GHz. The nonlinear characteristics of amplifiers cause intermodulation distortion (IMD), which reduces the signal-to-noise ratio (SNR) of RF signals and generates adjacent channel leakage power (ACP), which can cause interference with other wireless systems. Therefore, it is important to reduce IMD as much as possible, especially in frequency bands above 100 GHz.

To explain this in more detail, amplifier imperfections, particularly nonlinearity, become significant in frequency bands above 100 GHz. This is due to the deterioration of the characteristics (gain, linearity, etc.) of electronic devices such as transistors contained in the amplifier as the frequency increases. The amplifier's nonlinear characteristics generate intermodulation distortion (IMD) (Non-Patent Document 1). Figure 2 shows an overview of the spectrum of an RF signal containing unwanted waves (the spectrum at P0 in Figure 1). As shown in Figure 2, unwanted waves 200 that overlap the signal bandwidth of the desired wave 300 reduce the signal-to-noise ratio (SNR) of the RF signal, and unwanted waves 200 that occur outside the signal bandwidth of the desired wave 300 generate adjacent channel leakage power (ACP) (Non-Patent Document 2), which can cause interference with other wireless systems. Therefore, in frequency bands above 100 GHz, it is important to reduce unwanted waves 200 as much as possible.

The present invention was made in consideration of these problems and aims to reduce unwanted waves.

The wireless transmission device of the present invention includes a BB signal generator that generates a baseband signal, an IF signal generator that converts the baseband signal to an IF signal, and an RF signal generator that converts the IF signal to an RF signal, and outputs the RF signal to an antenna. The wireless transmission device of the present invention also includes a BB adjuster that adjusts the amplitude of the baseband signal, an RF adjuster that adjusts the amplitude of the RF signal, and a control unit. The control unit extracts a portion of the RF signal to the antenna, determines an evaluation value that evaluates the relationship between the desired wave and the unwanted wave, and controls the BB adjuster and RF adjuster based on the evaluation value.

The wireless transmission device of the present invention adjusts the amplitude of the baseband signal and the amplitude of the RF signal based on an evaluation value that evaluates the relationship between the desired wave and the unwanted wave, thereby reducing the unwanted wave.

FIG. 1 is a diagram showing the configuration of a conventional wireless transmission device for performing amplitude/phase modulation or quadrature modulation. FIG. 2 is a diagram showing an outline of the spectrum (spectrum at P0 in FIG. 1) of an RF signal including IMD (unwanted waves). FIG. 1 is a diagram showing an example of the functional configuration of a wireless transmission device according to the present invention. 4 is a diagram showing an overview of the signals at the positions shown in FIG. 3; FIG. 10 is a diagram showing a modified example of the functional configuration of the wireless transmission device of the present invention. FIG. 4 is a diagram showing parameters (gain, OIP3, NF) of components used in the SNDR calculation in the configuration of FIG. 3 . 10 is a diagram showing the calculation results of SNDR when the gain of RF adjuster 137 (hereinafter referred to as "RF control gain") is set to 0 dB and the gain of BB adjusters 117 and 118 (hereinafter referred to as "BB control gain") is changed from -80 dB to 0 dB. FIG. 8 is a diagram showing calculation results of SNDR when the RF control gain is changed while the BB control gain is fixed at −41 dB, which is the value at which the maximum SNDR is obtained in FIG. 7 . FIG. 10 is a diagram showing the calculation results of SNDR when the RF control gain is set to 0 dB, −10 dB, −20 dB, and −30 dB and the BB control gain is changed from −60 to 0 dB in each case. FIG. 10 is a diagram showing the calculation results of the BB control gain that maximizes the SNDR when the RF control gain is changed. FIG. 10 is a diagram showing calculation results when the IF control gain is also controlled.

Embodiments of the present invention will be described in detail below. Components with the same functions will be assigned the same numbers, and duplicate explanations will be omitted.

Figure 3 shows an example of the functional configuration of a wireless transmission device of the present invention. Figure 4 is a diagram showing an overview of the signal at the position shown in Figure 3. The horizontal axis of Figure 4 represents frequency, and the vertical axis represents intensity. The wireless transmission device 100 includes a BB signal generation unit 110 that generates a baseband signal, an IF signal generation unit 120 that converts the baseband signal to an IF signal, an RF signal generation unit 130 that converts the IF signal to an RF signal, and a control unit 190, and outputs the RF signal to the antenna 940.

The BB signal generation unit 110 includes a BB adjuster 119 that adjusts at least the amplitude of the baseband signal. The BB adjuster 119 may also adjust the phase of the baseband signal. The BB signal generation unit 110 generates a baseband signal including an I-channel signal Data (I) and a Q-channel signal Data (Q). The BB adjuster 119 includes a BBI adjuster 117 that adjusts the amplitude and phase of the I-channel signal, and a BBQ adjuster 118 that adjusts the amplitude and phase of the Q-channel signal. The control unit 190 controls the BBI adjuster 117 and the BBQ adjuster 118.

The IF signal generation unit 120 includes a local oscillator 921 with a frequency of LO1, IF mixers 922 and 924, a phase converter 923, an IF amplifier 925, and an IF adjuster 127. The IF signal generation unit 120 includes the local oscillator 921, IF mixer 922, IF mixer 924, and phase converter 923, which together form a quadrature mixer 926 (a mixer driven by local oscillation signals that are 90° out of phase with each other). The quadrature mixer 926 generates an IF signal with a center frequency of LO1. The IF signal is amplified by the IF amplifier 925 and then input to the RF signal generation unit 930. The IF adjuster 127 adjusts the amplitude and phase of the IF signal. In the present invention, the IF adjuster 127 may not be provided, or may only adjust the amplitude. The reason for this will be explained later.

The RF signal generation unit 130 includes a local oscillator 931 with a frequency LO2, an RF mixer 932, an RF amplifier 933, and an RF adjuster 137. The IF signal is multiplied by the local oscillator signal with a frequency LO2 by the RF mixer 932 and frequency-converted to an RF signal. The RF adjuster 137 adjusts at least the amplitude of the RF signal. The RF adjuster 137 may also adjust the phase of the RF signal. The adjusted RF signal is amplified by the RF amplifier 933 (often a power amplifier) to the power value required to achieve wireless communication.

The control unit 190 extracts a portion of the RF signal to the antenna 940, obtains an evaluation value for evaluating the relationship between the desired wave and the unwanted wave, and controls at least the BB adjuster 119 and the RF adjuster 137 based on the evaluation value. The evaluation value for evaluating the relationship between the desired wave and the unwanted wave is as follows:
SNR = power of desired signal / noise power (Equation 1)
SNDR = power of desired signal / (noise power + third-order cross distortion) (Equation 2)
However, it is not limited to these. Other evaluation values may be used. For example, (power of desired wave/power of unwanted wave in ACP portion) may be used as the evaluation value.

The control unit 190 will now be described in detail. The control unit 190 has a coupler 195, a desired wave power detection unit 191, an IF band unwanted signal extraction unit 192, a low-frequency unwanted signal extraction unit 193, an unwanted power detection unit 172, and a calculation unit 180. The desired wave power detection unit 191 detects the power of the desired wave 300 in the RF signal. The IF band unwanted signal extraction unit 192 extracts the unwanted wave 200 in the RF signal as an IF band unwanted signal 220, which is a signal in the frequency band of the IF signal, using a local oscillator 931 in the RF signal generation unit 130. The low-frequency unwanted signal extraction unit 193 lowers the frequency of the IF band unwanted signal 220 using a local oscillator 921 in the IF signal generation unit 120, and extracts the low-frequency unwanted signal 230. The unwanted power detection unit 172 detects the power of the low-frequency unwanted signal 230 (the power of the ACP unwanted wave 200). The calculation unit 180 calculates an evaluation value that evaluates the relationship between the desired wave 300 and the unwanted wave 200, and controls the BBI adjuster 117, BBQ adjuster 118, IF adjuster 127, and RF adjuster 137 based on the evaluation value.

The coupler 195 extracts a portion of the RF signal (typically about 1/10 to 1/100). The signal shown in Figure 4A is the signal at point P1, and its center frequency is frequency _fRF in the RF signal band. The signal shown in Figure 4A has a high ratio of unwanted waves 200 to desired waves 300.

The extracted RF signal is distributed to the desired wave power detector 191 and the IF band unwanted signal extractor 192. The desired wave power detector 191 is composed of a bandpass filter 150 that passes the signal bandwidth of the desired wave, and a power meter 170. The output from the power meter 170 is the power of the desired wave. Generally, the minimum received power of a power meter in frequency bands above 100 GHz is approximately -30 dBm. Since the output power of a typical wireless transmission device is approximately 0 dBm, if the coupling degree of the coupler 195 is 1/100 (approximately -20 dB), the power input to the power meter will be -20 dBm, making it possible to measure the power value.

Meanwhile, it is difficult to measure the unwanted wave 200 in the same way as the desired wave 300. Typically, the level of the unwanted wave 200 is at least 20 dB lower than the desired wave 300. Therefore, even if the power of the desired wave 300 is 0 dBm, the power value of the unwanted wave 200 will be -40 dBm or less when taking into account the coupling factor of 1/100 of the coupler 195, making it impossible to detect with a power meter. If the power value of the unwanted wave 200 can be converted to near DC (low frequency), it is possible to measure power values as low as -70 dBm using a high-resolution analog-to-digital converter (ADC). Therefore, in this invention, the power of the ACP portion of the unwanted wave 200 is measured using the following configuration.

The IF band unwanted signal extraction unit 192 is composed of filter 151, RF mixer 161, and filter 152. Filter 151 transmits the ACP portion. Figure 4(B) shows the transmission characteristic F151 of filter 151 and signal 210 (signal at point P2) of the transmitted ACP portion (thick line portion). RF mixer 161 multiplies signal 210 by a local oscillation signal of frequency LO2 output by local oscillator 931 of the RF signal generation unit 130. Figure 4(C) shows the output signal of RF mixer 161 (signal at point P3). The output signal of RF mixer 161 includes signal 221 having the sum of the ACP frequency and LO2, and signal 220 having the difference frequency. Signal 220 having the difference frequency corresponds to the IF band. Filter 152 has transmission characteristic F152 and outputs signal 220. Therefore, only the signal 220 shown by the bold line in Figure 4(D) (the signal at point P4) is obtained.

The low-frequency unwanted signal extraction unit 193 consists of an IF mixer 162 and an amplifier 171. The RF mixer 162 outputs a low-frequency unwanted signal obtained by multiplying the local oscillation signal of frequency LO1 output by the local oscillator 921 of the IF signal generation unit 120 by signal 220. Figure 4 (E) shows the low-frequency unwanted signal 230 (signal at point P5), which is the output signal of the RF mixer 161. The low-frequency unwanted signal 230 is a signal near direct current (DC).

The unwanted power detection unit 172 detects the power of the low-frequency unwanted signal 230. A detector may be used for the unwanted power detection unit 172. The detector may be a diode-based square-law detector or the like. However, considering the losses in the RF mixer 161, IF mixer 162, filter 151, and filter 152, it is expected that the power of the low-frequency unwanted signal 230 at point P5 will be low. In that case, the signal may be amplified by amplifier 171 to a power value sufficient for square-law detection, as necessary. Unlike the 100 GHz band, amplifiers with sufficient gain and linearity are available in the low-frequency band, making this low-frequency amplification easy.

Fig. 4(F) shows the waveform at point P1 when the unwanted waves have been reduced by the control of the control unit 190. The unwanted waves 250 have been reduced more than the unwanted waves 200 in Fig. 4(A). According to the wireless transmission device 100, the amplitude of at least the baseband signal and the amplitude of the RF signal are adjusted based on an evaluation value that evaluates the relationship between the desired wave and the unwanted waves, thereby reducing the unwanted waves.
[Modification 1]

Figure 5 shows a modified example of the functional configuration of the wireless transmission device of the present invention. If a 100 GHz band amplifier 173 with known gain and sufficient linearity is available, the measurement of the power of unwanted waves in the ACP portion can be performed with a simpler configuration, such as the control unit 199 of the wireless transmission device 101 shown in Figure 5. The amplifier 173 amplifies the signal 210, which is the signal obtained by filtering the ACP portion with the filter 151, to a level that can be measured by the detection unit 174 (typically a minimum received power of approximately -30 dBm). In this case, the following conditions must be met: the gain has little drift over time, the gain is known, and the IMD generated by the amplifier 173 is relatively small. However, if such an amplifier 173 were available, the configuration shown in Figure 3 could be simplified.

<Simulation and control method 1>
The control unit 190 calculates an evaluation value for evaluating the relationship between the desired wave and the unwanted wave, and controls the amplitude and phase in the BBI adjuster 117, the BBQ adjuster 118, the IF adjuster 127, and the RF adjuster 137 based on the evaluation value. In other words, eight variables can be controlled, but the amount of calculation required to find the optimal control value increases. Therefore, first,
(1) The phase is not controlled (the amount of phase shift is fixed).
(2) The amplitude of the IF adjuster 127 is not controlled (the gain is fixed).
(3) The amplitudes of the BBI adjuster 117 and the BBQ adjuster 118 are controlled under the condition that they are the same. In other words, only the amplitudes of the BB adjuster 119 and the RF adjuster 137 are controlled. In this simulation, the following evaluation value is used to evaluate the relationship between the desired wave and the unwanted wave:
SNDR = power of desired signal / (noise power + third-order cross distortion) (Equation 2)
is used.

SNDR, which can be considered an SNR that takes distortion into account, is often used in wireless communication circuit design. To calculate the denominator noise power, information on the noise figure (NF) of each component in Figure 3 is required. To calculate third-order intermodulation distortion (IM3), information on the third-order intermodulation distortion/desired signal output intercept point (OIP3), a quantity related to the value of third-order intermodulation distortion, is required. Figure 6 shows the parameters (gain, OIP3, NF) of the components used in this SNDR calculation in the configuration shown in Figure 3. The parameters of the IF mixer 922, IF amplifier 925, RF mixer 932, and RF amplifier 933 were typical and realized in the respective frequency bands. The gain of the control elements has a negative value, and the phase shift is fixed as described above. In this case, the control elements function as variable attenuators. Variable attenuators are components implemented using variable resistors, etc., and because they have no gain, their linearity can generally be made high. Therefore, for convenience, the OIP3 of these control elements is assumed to be infinite. Furthermore, the input power of the baseband I-channel signal and Q-channel signal is -3 dBm each, meaning that the total input power of the baseband signal for the I-channel signal and Q-channel signal is 0 dBm. The desired signal bandwidth and environmental temperature are set to 1 GHz and 290 K, respectively, and only thermal noise is considered in the noise floor calculation.

Figure 7 shows the calculation results for SNDR when the gain of RF regulator 137 (hereinafter referred to as "RF control gain") is set to 0 dB and the gain of BB regulators 117 and 118 (hereinafter referred to as "BB control gain") is changed from -80 dB to 0 dB. The horizontal axis is BB control gain, and the vertical axis is SNDR. It can be seen that by changing the BB control gain from 0 dB (no control) to -41 dB, the SNDR can be improved from -60 dB to 17.6 dB.

Furthermore, Figure 8 shows the calculation results for SNDR when the RF control gain is changed while the BB control gain is fixed at -41 dB, the value at which the maximum SNDR was obtained in Figure 7. By changing the RF control gain from 0 dB (no control) to -19 dB, the maximum SNDR value can be improved from 17.6 dB to 26.1 dB.

When the present invention is applied to an actual wireless transmission device, the important thing is a method (control method) for finding the values of the BB control gain and RF control gain described above to maximize the SNDR. This finding method will be explained below. If the BB control gain and RF control gain are changed as parameters independently to maximize the SNDR (or an evaluation value for evaluating the relationship between the desired wave and the unwanted wave, which is used instead of the SNDR: for example, the evaluation value of Equation 1), then if the number of cases for the BB control gain is M and the number of cases for the RF control gain is N, then:
Calculation amount = MN (Formula 3)
For example, when M=N=100, 10,000 calculations are required, which poses a problem of an extremely large amount of calculations.

In the present invention, it is not necessary to vary the parameters independently, making it possible to reduce the amount of calculation. The reason for this is explained below. Figure 9 shows the SNDR calculation results when the RF control gain is set to 0 dB, -10 dB, -20 dB, and -30 dB, and the BB control gain is varied from -60 to 0 dB in each case. There is a certain relationship between the BB control gain and RF control gain that yield the maximum value in the four graphs in Figure 9. When the RF control gain is large, the BB control gain that yields the maximum SNDR value becomes smaller. Furthermore, as can be seen from Figures 7 and 8, although SNDR has a maximum value for the BB control gain and RF control gain, the response to each gain is linear outside the maximum point (places other than the apex of the mountain-shaped curve). Therefore, it is expected that the relationship between the BB control gain and RF control gain that yields the maximum SNDR value will also be linear.

FIG. 10 shows the calculation results of the BB control gain that maximizes the SNDR when the RF control gain is changed. It can be seen from FIG. 10 that the relationship between the two can be linearly approximated. Since a straight line is uniquely determined once two points are determined, once the two points in FIG. 10 are found, the combination of RF control gain and BB control gain that gives the maximum SNDR can be found without MN iterative calculations. The largest of the maximum SNDR values determined by these combinations is the optimal control parameter value when controlling only the amplitude of the BB regulators 117 and 118 and the amplitude of the RF regulator 137. To find the equation for the straight line, it is necessary to find the maximum SNDR when the BB control gain is changed for two different RF control gains (the reverse is also possible). The amount of calculation required for this is:
Calculation amount = min (M, N) x 2 (Formula 4)
It can be seen that the amount of calculation can be made much smaller than the amount of calculation (Equation 3) when the two parameters are changed independently.

In other words, the control unit 190 can reduce the amount of calculation by determining the combination of the BB control gain, which is the adjustment amount for the BB adjuster 119, and the RF control gain, which is the adjustment amount for the RF adjuster 137, by taking advantage of the fact that combinations that yield good evaluation values are linear.

<Simulation and Control Method 2>
Control method 1 describes a case in which the IF control gain of IF adjuster 127, which is fixed, is changed. However, the phase shift amount of IF adjuster 127 is fixed. If the IF control gain, which is the control gain of IF adjuster 127, is also changed, the SNDR improvement amount can be greater than that of control method 1. FIG. 11 shows calculation results when the IF control gain is also controlled. By changing the IF control gain from 0 dB (no control) to −10 dB, the maximum SNDR can be improved to 27.5 dB, which is greater than the 26.1 dB obtained in FIG. 8. Control method 2 involves three variables. To find the variables for improving the SNDR, first, the IF control gain is fixed to a certain value, and the BB control gain and RF control gain are changed using control method 1 to find the maximum SNDR for a certain value of the IF control gain. Next, the IF control gain is fixed to another value, and the BB control gain and RF control gain are similarly changed to find the maximum SNDR. If the number of IF control gains is K, the amount of calculation required to find the variable that maximizes the SNDR improvement is as follows:
Amount of calculation = min (M, N) x 2 x K (Formula 5)
is given by

<Control Method 3>
Control method 3 is similar to control method 1 in that the gain and phase of both BBI adjuster 117 and BBQ adjuster 118 are changed. By changing the phases of the I channel and Q channel, it is possible to correct the phase imbalance of phase converter 923 and IF mixers 922 and 924 included in the quadrature mixer used to generate the IF signal. Furthermore, by changing the gains of the I channel and Q channel, it is possible to correct the amplitude imbalance of phase converter 923 included in the quadrature mixer and the error in the conversion gain of IF mixers 922 and 924.

<Control Method 4>
In control methods 1 to 3, the phase shift amounts of RF adjuster 137 and IF adjuster 127 are also adjusted. By controlling the phase as well, the SNDR can be further improved significantly.

100, 101, 900 Wireless transmission device 110, 910 BB signal generation unit 117 BBI adjuster 118 BBQ adjuster 119 BB adjuster 120, 920 IF signal generation unit 127 IF adjuster 130, 930 RF signal generation unit 137 RF adjuster 150 Bandpass filter 151, 152 Filter 161 RF mixer 162 IF mixer 170 Power meter 171 Amplifier 172 Unwanted power detection unit 173 Amplifier 174 Detection unit 180 Calculation unit 190, 199 Control unit 191 Desired wave power detection unit 192 IF band unwanted signal extraction unit 193 Low frequency unwanted signal extraction unit 195 Coupler 921, 931 Local oscillator 922, 924 IF mixer 923: phase converter 925: IF amplifier 926: quadrature mixer 932: RF mixer 933: amplifier 940: antenna

Claims (8)

A wireless transmission device comprising: a BB signal generation unit that generates a baseband signal; an IF signal generation unit that converts the baseband signal into an IF signal; and an RF signal generation unit that converts the IF signal into an RF signal, and outputs the RF signal to an antenna,
a BB adjuster that adjusts the amplitude of a baseband signal;
an RF adjuster for adjusting the amplitude of the RF signal;
a control unit that extracts a portion of an RF signal to an antenna, calculates an evaluation value that evaluates a relationship between a desired wave and an unwanted wave, and controls the BB adjuster and the RF adjuster based on the evaluation value;
A wireless transmission device comprising: 2. The wireless transmission device according to claim 1,
the control unit determines a combination of a BB control gain, which is an adjustment amount of the BB adjuster, and an RF control gain, which is an adjustment amount of the RF adjuster, by utilizing linearity between the BB control gain and the RF control gain, which results in a combination that obtains a good evaluation value. 3. The wireless transmission device according to claim 1,
The control unit
a desired wave power detection unit that detects the power of a desired wave in an RF signal;
an IF band unwanted signal extraction unit that extracts unwanted waves from the RF signal as an IF band unwanted signal, which is a signal in the frequency band of the IF signal, using a local oscillator in the RF signal generation unit;
a low-frequency unwanted signal extraction unit that extracts the IF band unwanted signal as a low-frequency unwanted signal by using a local oscillator in the IF signal generation unit;
and an unwanted power detection unit that detects the power of a low-frequency unwanted signal. The wireless transmission device according to any one of claims 1 to 3,
the baseband signal includes an I-channel signal and a Q-channel signal;
the BB adjuster comprises a BBI adjuster for adjusting the amplitude and phase of an I-channel signal, and a BBQ adjuster for adjusting the amplitude and phase of a Q-channel signal;
The wireless transmission device, wherein the control unit controls the BBI adjuster and the BBQ adjuster. 5. The wireless transmission device according to claim 4,
The radio transmission device, wherein the RF adjuster also adjusts the phase of the RF signal. The wireless transmission device according to any one of claims 1 to 3,
moreover,
It also includes an IF adjuster that adjusts the amplitude of the IF signal.
The wireless transmission device, wherein the control unit also controls the IF adjuster. 6. The wireless transmission device according to claim 4,
moreover,
It also has an IF adjuster that adjusts the amplitude and phase of the IF signal.
The wireless transmission device, wherein the control unit also controls the IF adjuster. 8. The wireless transmission device according to claim 6,
the control unit determines the BB control gain, the IF control gain, and the RF control gain by repeating a process of determining a combination of the BB control gain and the RF control gain while fixing the IF control gain, which is an adjustment amount of the IF adjuster, for only predetermined candidates of the IF control gain.