JP6155636B2 - Wireless communication apparatus, signal adjustment circuit, and signal adjustment method - Google Patents

Description

  The present invention relates to a wireless communication device, a signal adjustment circuit, and a signal adjustment method.

  The mixer that plays the role of the signal frequency conversion function in the wireless communication device converts the signal from a low frequency (intermediate frequency, IF) to a high frequency (radio frequency, RF) when the wireless communication device has a transmission function (transmission mixer). On the other hand, when the wireless communication apparatus has a reception function (reception mixer), the signal is converted from a high frequency (RF) to a low frequency (IF). In either case, a local oscillation (LO) signal is used for frequency conversion.

  A conversion gain is used as an index of the frequency conversion efficiency of the signal by the mixer. The conversion gain is the output signal power of the mixer (RF signal power for the transmission mixer, IF signal power for the reception mixer) and the input signal power of the mixer (IF signal power for the transmission mixer, RF signal power for the reception mixer). The difference represents the difference, and the higher the conversion gain, the higher the output signal power with respect to the same input signal power, so that the conversion efficiency of the mixer is increased and a desirable operation is achieved. The conversion gain of the mixer is generally unimodal with respect to the LO signal power and has a maximum value. It is desirable in terms of the conversion efficiency of the mixer to operate the mixer with the LO signal power at which the maximum value is obtained.

  Patent Document 1 discloses a method for adjusting LO signal power input to a mixer. In Patent Document 1, when the wireless communication apparatus has a reception function, the influence of the mixer operation on the disturbing wave is suppressed by adjusting the LO signal power according to the power of the disturbing wave appearing in the output of the mixer. Yes.

  Since the LO signal power required for mixer operation is difficult to achieve with a local oscillator that generates the LO signal, a mixer driver amplifier is inserted between the local oscillator and the mixer, and the LO signal power generated by the local oscillator is It is common to amplify with a mixer driver amplifier. For example, Patent Documents 2 and 3 disclose examples in which a mixer driver amplifier for the LO signal is connected to the previous stage of the mixer. In Patent Document 2, the LO signal power input to the mixer is adjusted by adjusting the size of the mixer driver amplifier to control the conversion gain of the mixer. In Patent Document 3, the amplification gain of the mixer driver amplifier is controlled based on the comparison result between the LO signal amplified by the mixer driver amplifier and the reference DC signal supplied from the outside.

  The input / output characteristics of signal power to the mixer driver amplifier depend on environmental conditions such as temperature. FIG. 7 is a diagram showing the temperature dependence of the amplification gain (Linear Gain) and the saturation output power (Psat) in the linear region of the mixer driver amplifier, which is disclosed in Non-Patent Document 1. FIG. 7 shows that the gain and saturation output power in the linear region of the mixer driver amplifier decrease as the temperature increases from −25 degrees to 75 degrees. It is also shown that the saturation output power is smaller than the gain in the linear region with respect to temperature dependence.

  Further, not only the mixer drive amplifier but also the conversion characteristics of the mixer change depending on environmental conditions such as temperature. In particular, if the LO signal power dependency of the conversion gain of the mixer changes due to a change in environmental conditions such as temperature, even if the output of the mixer drive amplifier is constant, the conversion gain of the mixer may deteriorate.

  Summarizing the above, it can be seen that the techniques described in the above-mentioned prior art documents still have some problems as described below.

  When the input / output characteristics of the mixer driver amplifier change due to changes in environmental conditions such as temperature, the output signal power of the mixer driver amplifier (LO signal input power to the mixer) changes, and the conversion gain of the mixer deteriorates. In addition to the mixer drive amplifier, if the conversion characteristics of the mixer change due to changes in environmental conditions such as temperature, the conversion gain of the mixer may also deteriorate.

  In particular, when the LO signal frequency is a high frequency such as millimeter waves (30 GHz to 300 GHz), the conversion gain of the mixer tends to be more convex with respect to the LO signal power. This is because the input impedance of the mixer to the LO signal is likely to change with respect to the LO signal power as the frequency of the LO signal increases. Therefore, in a mixer that handles high-frequency signals, the necessity for adjusting the LO signal power input to the mixer in accordance with changes in environmental conditions such as temperature is further increased.

  According to Non-Patent Document 1, it is shown that the temperature dependence of the characteristics of the mixer driver amplifier is such that the saturated output power is smaller than the gain in the linear region. That is, it is desirable to operate the mixer driver amplifier in the saturation region rather than the linear region from the viewpoint of stabilizing the output signal power of the mixer driver amplifier.

Patent No. 4105549 Special table 2011-502429 JP2003-32048

Y. Hamada, M. Tanomura, M. Ito, K. Maruhashi, "A High Gain 77GHz Power Amplifier Operating at 0.7V Based on 90nm CMOS Technology," IEEE Microwave and Wireless Component Letters, vol.19, no.5, pp .329-331, May 2009.

  As described above, there is a problem that the conversion gain of the mixer changes due to the change in the input / output characteristics of the mixer driver amplifier depending on the environmental conditions such as temperature.

  Accordingly, an object of the present invention is to provide a wireless communication apparatus, a signal adjustment circuit, and a signal adjustment method in which the conversion gain of a mixer is stable against environmental changes such as temperature in order to solve the above-described problems. .

  A wireless communication apparatus according to an aspect of the present invention includes a mixer driver amplifier that amplifies a local oscillation signal, mixer driver amplifier power adjustment means that adjusts power of an output signal of the mixer driver amplifier, and an output signal of the mixer driver amplifier A mixer that generates the input signal after frequency conversion as an output signal by performing frequency conversion of the input signal based on the amplified local oscillation signal, and a mixer that detects the power of the output signal generated by the mixer The mixer driver amplifier power adjustment means based on the power of the output signal detected by the mixer power detection means so as to operate the mixer driver amplifier in a saturation region. The power of the output signal is adjusted.

  The signal adjustment circuit according to another aspect of the present invention includes a mixer driver amplifier that amplifies a local oscillation signal, a mixer driver amplifier power adjustment unit that adjusts power of an output signal of the mixer driver amplifier, and the mixer driver amplifier. By performing frequency conversion of the input signal based on the amplified local oscillation signal that becomes the output signal of the output signal, the mixer that generates the input signal after frequency conversion as an output signal, and the power of the output signal generated by the mixer Mixer power detection means for detecting, the mixer driver amplifier power adjustment means based on the power of the output signal detected by the mixer power detection means so as to operate the mixer driver amplifier in a saturation region. The power of the output signal of the driver amplifier is adjusted.

  According to another aspect of the present invention, there is provided a signal adjustment method comprising: amplifying a local oscillation signal to generate an output signal; and performing frequency conversion of the input signal based on the amplified output signal of the local oscillation signal Thus, the step of generating the input signal after frequency conversion as an output signal, the step of detecting the power of the output signal after frequency conversion of the input signal, and the amplification of the local oscillation signal are performed in a saturation region. And adjusting the power of the output signal after amplification of the local oscillation signal based on the detected power of the output signal.

  According to each embodiment of the present invention described above, the conversion gain of the mixer is stabilized against changes in environmental conditions such as temperature.

It is a block diagram which shows the structure of the radio | wireless communication apparatus concerning 1st Embodiment. It is the figure which showed the example of the drain voltage dependence of the input-output characteristic in a mixer driver amplifier. It is the figure which showed the example of the gate device voltage dependence of the input-output characteristic in a mixer driver amplifier. It is a figure shown about the method of adjusting the output signal electric power of a mixer driver amplifier. It is a block diagram which shows the structure of the radio | wireless communication apparatus concerning 2nd Embodiment. It is a block diagram which shows the structure of the radio | wireless communication apparatus concerning 3rd Embodiment. It is the figure which showed the example of the RF signal which appears in the output terminal of a subharmonic mixer, and the LO signal power dependence of 2LO leak. It is a figure which shows the temperature dependence of the gain and saturation output power in the linear area | region of a mixer driver amplifier.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Specific numerical values and the like shown in the following embodiments are merely examples for facilitating understanding of the invention, and are not limited thereto unless otherwise specified. In the following description and drawings, matters obvious to those skilled in the art are omitted or simplified as appropriate for the sake of clarity. In the embodiment described below, a case where the wireless communication apparatus is a wireless transmission apparatus will be described as an example. However, the present invention also holds the same argument for a wireless reception apparatus. That is, the present invention can be applied not only to a mixer that generates an RF signal by frequency-converting an IF signal as described below, but also to a mixer that generates an IF signal by frequency-converting an RF signal. Is possible.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a wireless communication apparatus 1 according to the first embodiment of the present invention.

  The wireless communication apparatus 1 according to the first embodiment includes a mixer 2, a mixer driver amplifier 3, a power detection unit 4, and a power adjustment unit 5.

  The wireless communication apparatus 1 according to the first embodiment has a transmission function of converting an IF signal into an RF signal using an LO signal (local oscillation signal), and is provided with a mixer 2 for that purpose. A mixer driver amplifier 3 is connected to the front stage of the LO signal end of the mixer 2 for amplification of the LO signal. Further, the power detection means 4 is connected to the output terminal of the mixer 2, and the power of the RF signal output from the mixer 2 is detected by the power detection means 4. Further, the power adjusting means 5 is connected to the mixer driver amplifier 3, and the power adjusting means 5 adjusts the output signal power of the mixer driver amplifier 3.

  The mixer 2 frequency-converts the IF signal (“Rif” in the figure) based on the LO signal (“Plo” in the figure) output from the mixer driver amplifier 3, thereby converting the RF signal (“Prf” in the figure). Generate and output. The mixer driver amplifier 3 amplifies the input LO signal (“Pin” in the figure), and outputs the amplified LO signal (“Plo” in the figure) to the mixer 2. The mixer driver amplifier 3 is composed of a circuit (IC (Integrated Circuit)) on which a MOS transistor is mounted, and the drain voltage and gate bias voltage of the MOS transistor can be controlled from the outside. The power detection unit 4 detects the RF signal power (RF signal power) output from the mixer 2, generates an RF signal power notification signal indicating the detected RF signal power, and outputs the RF signal power notification signal to the power adjustment unit 5. The power adjustment means 5 controls the drain voltage (“Vd” in the figure) and the gate bias voltage (“Vg” in the figure) based on the RF signal power indicated by the RF power notification signal output from the power detection means 4. As a result, the output signal power of the mixer driver amplifier 3 is adjusted. The power detection unit 4 and the power adjustment unit 5 are also configured by, for example, a circuit (IC).

  FIG. 2A is a diagram showing an example of drain voltage dependency of input / output characteristics in the mixer driver amplifier 3. FIG. 2B is a diagram showing an example of the gate bias voltage dependency of the input / output characteristics in the mixer driver amplifier 3. FIG. 2A and FIG. 2B show patterns for four different magnitudes of voltages as input / output characteristics according to the drain voltage or the gate device voltage, for example. As shown in FIG. 2A, when the drain voltage is increased, both the amplification gain in the linear region and the saturated output power in the saturation region are increased. On the other hand, as shown in FIG. 2B, when the gate bias voltage is changed, only the amplification gain in the linear region changes, and the saturated output power is constant. When the gate bias voltage is increased, the amplification gain in the linear region increases, so that the range of input signal power at which the mixer driver amplifier 3 operates in the saturation region increases.

  FIG. 3 is a diagram illustrating a method for adjusting the output signal power of the mixer driver amplifier 3. Based on FIG. 3, a method for stabilizing and maximizing the conversion gain of the mixer 2 in the present embodiment will be described below.

  As a first step, the power adjustment means 5 controls the drain voltage of the mixer driver amplifier 3 and sets the drain voltage so that the RF signal power detected by the power detection means 4 is maximized. Thereby, the LO signal power dependency of the conversion gain of the mixer 2 can be acquired, and the LO signal power can be set to maximize the conversion gain of the mixer 2. In this step, it is desirable to set the gate bias voltage to a high voltage in advance so that the mixer driver amplifier 3 is in the saturation region. As the gate device voltage, an arbitrary voltage that is considered to be sufficient for the mixer driver amplifier 3 to be in the saturation region in the usage environment of the wireless communication apparatus 2 may be set in advance.

  Also, the drain voltage that maximizes the RF signal power in the power adjusting means 5 may be specified by any method. For example, as shown in FIG. 3, the drain voltage supplied to the mixer driver amplifier 3 is changed stepwise, and the drain voltage at which the RF signal power is maximized among the respective drain voltages is the maximum RF signal power. The drain voltage may be determined to be set to be supplied to the mixer driver amplifier 3.

  As a second step, the power adjustment unit 5 controls the gate bias voltage of the mixer driver amplifier 3 and sets the gate bias voltage within a range where the RF signal power detected by the power detection unit 4 is constant. When the dependence of the RF signal power on the gate bias is within a certain range, the mixer driver amplifier 3 operates in the saturation region, so the gate bias voltage is set within this range.

  The identification of the gate bias voltage at which the RF signal power in the power adjusting means 5 is constant may be performed by any method. For example, the gate bias voltage supplied to the mixer driver amplifier 3 is changed stepwise, and the RF signal power becomes constant among the gate bias voltages (for example, there is no change in the RF signal power or less than a predetermined value). ) Any gate bias voltage included in the range may be determined to be a gate bias voltage within a range in which the RF signal power is constant, and may be set to be supplied to the mixer driver amplifier 3.

  As a setting condition of the gate bias voltage in the second step, in addition to the condition that the mixer driver amplifier 3 is in a saturation region, a spurious component (LO leak, image component, etc.) of the RF signal appearing at the output terminal of the mixer 2 Various conditions may be added such as a condition for minimizing the power consumption and a condition for minimizing the power consumption of the mixer driver amplifier 3.

  Specifically, when the condition for minimizing the spurious component of the RF signal is added, the power detection means 4 further detects the power of the spurious component output together with the RF signal when detecting the power of the RF signal. (Spurious component power) is detected, and a spurious component power notification signal indicating the detected spurious component power is generated and output to the power adjusting means 5. Based on the spurious component power indicated by the spurious component power notification signal output from the power detection means 4 in addition to the RF signal power notification signal, the power adjustment means 5 is within the range in which the RF signal power is constant. A gate bias voltage that minimizes the component power is set to be supplied to the mixer driver amplifier 3.

  When a condition for minimizing the power consumption of the mixer driver amplifier 3 is added, the power adjustment means 5 supplies the mixer driver amplifier 3 with a gate bias voltage that is minimum within a range where the RF signal power is constant. Set to

  In the present embodiment, the mixer driver amplifier 3 is composed of a circuit IC equipped with a MOS transistor. However, a circuit utilizing a bipolar transistor, a structure equipped with a HEMT (high electron mobility transistor), etc. Various configurations are possible. For example, in the case of a configuration using a bipolar transistor, the collector current is controlled instead of the drain voltage, and the base current is controlled instead of the gate bias voltage.

  As described above, in the present embodiment, based on the power of the RF signal detected by the power detection unit 4, the output signal of the mixer driver amplifier 3 (the mixer driver amplifier 3 is operated in the saturation region). The power of the amplified LO signal) is adjusted. According to this, since the mixer driver amplifier 3 can be operated in a saturation region having low dependency on environmental conditions such as temperature, the LO signal amplified by the mixer driver amplifier 3 is supplied to the mixer 2 in a stable state. Can do. Therefore, the conversion gain of the mixer 2 that operates based on the LO signal can also be stabilized.

  In the present embodiment, the power of the RF signal output from the mixer 2 is detected by the power detection means 4, and the mixer driver amplifier 3 is controlled to operate in the saturation region based on the detected power of the RF signal. doing. According to this, since the LO signal can be adjusted while observing the fluctuation of the output signal (RF signal) of the mixer 2 that is the final output, the change in the conversion characteristics of the mixer 2 due to environmental conditions such as temperature is also taken into consideration. An optimum mixer driver amplifier 3 can be set.

(Second Embodiment)
FIG. 4 is a block diagram showing the configuration of the wireless communication apparatus 11 according to the second embodiment of the present invention.

  The wireless communication apparatus 11 according to the second embodiment includes a mixer 12, a mixer driver amplifier 13, a power detection unit 14, and a power adjustment unit 15. In principle, the operations of the mixer 12, the mixer driver amplifier 13, the power detection means 14, and the power adjustment means 15 are different from those of the first embodiment except for the contents described later, according to the first embodiment. Since the operations are the same as those of the mixer 2, the mixer driver amplifier 3, the power detection unit 4, and the power adjustment unit 5, detailed description thereof will be omitted as appropriate.

  In the second embodiment, unlike the first embodiment, the bias that can control the mixer driver amplifier 13 by the power adjusting means 15 is only the gate bias voltage, and the drain voltage of the mixer driver amplifier 13 is constant. is there.

  In the second embodiment, the power adjustment means 15 controls the gate bias voltage of the mixer driver amplifier 13 and is detected by the power detection means 4 in the same manner as in the second step of the first embodiment. The gate bias voltage is set within a range where the RF output power is constant. In the present embodiment, various conditions may be added as conditions for setting the gate bias voltage, as in the first embodiment. Thereby, even in the case of controlling only the gate bias voltage, the conversion gain of the mixer can be stabilized and maximized.

  Also according to the present embodiment, the mixer driver amplifier 3 can be operated in a saturation region where the dependence on environmental conditions such as temperature is low, so that the LO signal amplified by the mixer driver amplifier 3 is supplied to the mixer 2 in a stable state. The conversion gain of the mixer 2 can be stabilized.

(Third embodiment)
FIG. 5 is a block diagram showing a configuration of the wireless communication device 21 according to the first embodiment of the present invention.

  The wireless communication apparatus 11 according to the second embodiment includes a sub-harmonic mixer 22, a mixer driver amplifier 23, a power detection unit 24, and a power adjustment unit 25. The operation of each of the mixer driver amplifier 23, the power detection means 24, and the power adjustment means 25 is basically the mixer driver amplifier according to the first embodiment, except for the contents that will be described later as different points from the first embodiment. 3, the operation of each of the power detection unit 4 and the power adjustment unit 5 is the same as that of the power adjustment unit 5, and thus detailed description will be omitted as appropriate.

  The wireless communication device 21 is equipped with a sub-harmonic mixer 22 that uses a second harmonic of the LO signal input to the mixer for frequency conversion as a mixer. The subharmonic mixer 22 generates and outputs an RF signal by frequency-converting the IF signal based on the LO signal output from the mixer driver amplifier 23.

  In addition to the RF signal, a signal that is a second harmonic of the LO signal (2LO leak) appears at the output end of the subharmonic mixer 22. The 2LO leak occurs at the same time as the frequency conversion of the subharmonic mixer 22, and if the 2LO leak power becomes high, the RF signal is disturbed. Therefore, the 2LO leak power is preferably low.

  In the third embodiment, unlike the first embodiment, when the power detection unit 24 detects the power of the RF signal, the power of the 2LO leak (2LO leak power) further output together with the RF signal is detected. ) Is generated, and a 2LO leak power notification signal indicating the detected 2LO leak power is generated and output to the power adjustment means 25. The power adjustment unit 25 then biases the drain (drain voltage) to reduce the 2LO leakage power based on the 2LO leakage power indicated by the 2LO leakage power notification signal output from the power detection unit 24 in addition to the RF signal power notification signal. And the gate bias voltage) are set to be supplied to the mixer driver amplifier 23.

  FIG. 6 is a diagram illustrating an example of dependency of the RF signal appearing at the output terminal of the subharmonic mixer 22 and the LO signal power of the 2LO leak in the wireless communication device 21 according to the third embodiment of the present invention. In the present embodiment, the power adjustment unit 25 sets a point where the difference between the RF output power and the power of 2LO leakage is a certain level (constant power difference) as the LO signal power set point. As this constant level, a power difference at which the RF signal power does not become too low and the 2LO leakage power becomes low may be arbitrarily set in advance according to the dependency shown in FIG. In accordance with the LO signal power, the power adjusting means 25 controls the bias of the mixer driver amplifier 23 so that the mixer driver amplifier 23 operates in the saturation region. Thus, it is possible to minimize the power of 2LO leakage while maximizing the RF output power appearing at the output terminal of the subharmonic mixer 22.

  Specifically, in the first step, the bias control of the mixer driver amplifier 23 is performed in place of the operation of setting the drain voltage so that the RF signal power detected by the power detection means 4 is maximized. The operation of setting the drain voltage may be performed so that the power difference between the RF signal power detected by the means 4 and the 2LO leakage power becomes the above-described constant power difference.

  Further, the drain voltage at which the power difference between the RF signal power and the 2LO leakage power in the power adjusting means 25 becomes a constant power difference may be specified by any method. For example, the drain voltage supplied to the mixer driver amplifier 3 is changed stepwise, and the drain voltage of the respective drain voltages that is closest to the constant power difference between the RF signal power and the 2LO leakage power is defined as the RF signal power. It may be determined that the power difference of the 2LO leakage power is a drain voltage that is a constant power difference and is set to be supplied to the mixer driver amplifier 3.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

1, 11, 21 Wireless communication device 2, 12, 22 Mixer 3, 13, 23 Mixer driver amplifier 4, 14, 24 Power detection means 5, 15, 25 Power adjustment means Pif IF signal Prf RF signal Pin LO signal (before amplification) )
Plo LO signal (after amplification)
Vd Drain voltage Vg Gate device voltage

Claims (9)

A mixer driver amplifier that amplifies the local oscillation signal;
Mixer driver amplifier power adjusting means for adjusting the power of the output signal of the mixer driver amplifier;
A mixer that generates the input signal after frequency conversion as an output signal by performing frequency conversion of the input signal based on the amplified local oscillation signal that becomes the output signal of the mixer driver amplifier;
Mixer power detection means for detecting the power of the output signal generated by the mixer,
The mixer driver amplifier power adjustment means adjusts the power of the output signal within a range in which the power of the output signal detected by the mixer power detection means is constant when the power of the output signal of the mixer driver amplifier is changed. A wireless communication apparatus that operates the mixer driver amplifier in a saturation region by using power of an output signal of the mixer driver amplifier. A mixer driver amplifier that amplifies the local oscillation signal;
Mixer driver amplifier power adjusting means for adjusting the power of the output signal of the mixer driver amplifier;
A mixer that generates the input signal after frequency conversion as an output signal by performing frequency conversion of the input signal based on the amplified local oscillation signal that becomes the output signal of the mixer driver amplifier;
Mixer power detection means for detecting the power of the output signal generated by the mixer,
The mixer driver amplifier power adjustment means adjusts the power of the output signal of the mixer driver amplifier based on the power of the output signal detected by the mixer power detection means so that the mixer driver amplifier operates in a saturation region. Adjusting the power of the output signal of the mixer driver amplifier so that the power of the output signal detected by the mixer power detection means is maximized , and
The mixer driver amplifier power adjustment means adjusts the power of the output signal within a range in which the power of the output signal detected by the mixer power detection means is constant when the power of the output signal of the mixer driver amplifier is changed. The mixer driver amplifier is operated in a saturation region by using the power of the output signal of the mixer driver amplifier .
Wireless communication device. The mixer power detection means further detects the power of a spurious component included in the output signal,
The mixer driver amplifier power adjustment unit is configured to be an output signal power that minimizes a spurious component power detected by the mixer power detection unit among powers of an output signal that causes the mixer driver amplifier to operate in a saturation region. The power of the output signal of the mixer driver amplifier is adjusted,
The wireless communication apparatus according to claim 1 or 2 . The mixer driver amplifier power adjustment means includes:
Adjusting the power of the output signal of the mixer driver amplifier so that the power of the output signal for operating the mixer driver amplifier in a saturation region is the power of the output signal that minimizes the power consumption of the mixer driver amplifier. Characterized by the
The wireless communication apparatus according to claim 1 or 2 . The mixer is a sub-harmonic mixer;
The mixer power detection means further detects the power of 2LO leakage generated together with the output signal by the mixer,
The mixer driver amplifier power adjustment unit adjusts the power of the output signal of the mixer driver amplifier so that the power difference between the output signal detected by the mixer power detection unit and the power of 2LO leakage becomes a predetermined constant power difference. It is characterized by
The wireless communication apparatus according to claim 1 or 2. The mixer driver amplifier power adjustment means includes:
The power of the output signal of the mixer driver amplifier is adjusted by controlling the bias of the mixer driver amplifier,
The wireless communication apparatus according to any one of claims 1 to 5 . The mixer driver amplifier power adjustment means includes:
By controlling the drain voltage of the mixer driver amplifier, the power of the output signal of the mixer driver amplifier is adjusted so that the power of the output signal is maximized,
By controlling the gate bias voltage of the mixer driver amplifier, the power of the output signal of the mixer driver amplifier is adjusted so that the mixer driver amplifier operates in a saturation region,
The wireless communication apparatus according to claim 2. A mixer driver amplifier that amplifies the local oscillation signal;
Mixer driver amplifier power adjusting means for adjusting the power of the output signal of the mixer driver amplifier;
A mixer that generates the input signal after frequency conversion as an output signal by performing frequency conversion of the input signal based on the amplified local oscillation signal that becomes the output signal of the mixer driver amplifier;
Mixer power detection means for detecting the power of the output signal generated by the mixer,
The mixer driver amplifier power adjustment means adjusts the power of the output signal within a range in which the power of the output signal detected by the mixer power detection means is constant when the power of the output signal of the mixer driver amplifier is changed. A signal adjustment circuit for operating the mixer driver amplifier in a saturation region by using power of an output signal of the mixer driver amplifier. Amplifying the local oscillation signal to generate an output signal;
Generating an input signal after frequency conversion as an output signal by performing frequency conversion of the input signal based on the output signal after amplification of the local oscillation signal;
Detecting the power of the output signal after frequency conversion of the input signal;
Adjusting the power of the output signal after amplification of the local oscillation signal based on the power of the detected output signal so that amplification of the local oscillation signal is performed in a saturation region;
With
The adjusting step includes
When the power of the output signal after amplification of the local oscillation signal is changed, the power of the output signal within a range in which the power of the output signal detected in the detecting step is constant is amplified. Amplification of the local oscillation signal is performed in the saturation region by using the power of the later output signal,
Signal adjustment method.

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