JP2012023584A - Amplifying apparatus and gain control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an amplifying apparatus and a gain control method capable of controlling a gain constantly even if a gain variation amount caused by temperature is changed with time.SOLUTION: An amplification section 1 has cascade-connected amplifiers 1a to 1d. A measuring part 2 measures a floor noise (thermal noise) outputted from the amplification section 1 while preventing a signal from being inputted into the amplification section 1. A control section 3 is capable of controlling a gain of the amplification section 1 constantly by controlling biases of amplifiers 1b to 1d so that the floor noise measured by the measuring part 2 becomes constant.

Description

  The present invention relates to an amplifying apparatus that controls gain and a gain control method thereof.

  The amplifier may be required to have a constant gain. For example, in a sensing device such as a radar, the gain of the amplifier is required to be constant in order to keep the minimum reception sensitivity constant.

  On the other hand, the gain of the amplifier changes due to factors such as a temperature change, a time-dependent change of the amplifying element, or a bias change. In particular, in the case of a multistage amplifier, even if the gain fluctuation amount per stage is small, the fluctuation amount in the multistage becomes large.

  Therefore, there is an amplifying apparatus that controls the gain of the amplifier to be constant. For example, an amplifier that controls the bias so that the relationship between the temperature and the gain fluctuation amount of the amplifier is measured in advance and stored in a memory, and the gain fluctuation due to the temperature change is suppressed from the temperature detected by a thermistor or the like. is there.

  Conventionally, there has been proposed a radio signal transmission device that appropriately controls characteristic deterioration caused by a temperature change of a power amplifier when a radio signal to be transmitted is a burst signal (see, for example, Patent Document 1).

  In addition, an automatic gain control device has been proposed that suppresses the occurrence of errors in code identification determination due to reduction of the code arrangement of various multi-level modulations due to the addition of noise (see, for example, Patent Document 2). reference).

JP 2007-33599A Japanese Patent Laid-Open No. 10-210098

However, the conventional amplifying apparatus has a problem that the gain cannot be controlled to be constant when the amount of gain variation due to temperature changes with time.
The present invention has been made in view of such points, and an object thereof is to provide an amplifying apparatus and a gain control method capable of controlling the gain to be constant without being affected by the change in the amount of gain fluctuation due to temperature. To do.

  In order to solve the above problems, an amplifying apparatus for amplifying a signal is provided. The amplifying apparatus includes an amplifying unit having amplifiers connected in multiple stages, a measuring unit for measuring floor noise output from the amplifying unit, and the amplifying unit so that the floor noise measured by the measuring unit is constant. And a control unit for controlling the gain of the.

  According to the disclosed apparatus and method, the gain can be controlled to be constant without being affected by the change in the gain fluctuation amount due to the temperature.

It is the figure which showed the amplifier which concerns on 1st Embodiment. It is a hardware diagram of the amplifying device which concerns on 2nd Embodiment. It is a block diagram of CPU. It is a figure explaining the relationship between a gain and floor noise. It is a figure explaining the influence of the output noise power density of an amplifier when a gain and a noise figure change with temperature changes. It is the flowchart which showed operation | movement of CPU. It is a block diagram of CPU concerning a 3rd embodiment. It is the flowchart which showed operation | movement of CPU. It is a hardware diagram of the amplifier concerning a 4th embodiment.

Hereinafter, the present embodiment will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating an amplifying apparatus according to the first embodiment. As illustrated in FIG. 1, the amplification device includes an amplification unit 1, a measurement unit 2, and a control unit 3.

The amplifying unit 1 includes amplifiers 1a to 1d connected in multiple stages.
The measurement unit 2 measures the floor noise (thermal noise) output from the amplification unit 1. The floor noise output from the amplifying unit 1 can be measured by the signal output from the amplifying unit 1 while no signal is input to the amplifying unit 1.

  The control unit 3 controls the gain of the amplification unit 1 so that the floor noise measured by the measurement unit 2 is constant. For example, the control unit 3 controls the gain of the amplifier 1 by controlling the bias of the amplifiers 1b to 1d so that the floor noise output from the amplifier 1 is constant.

  As will be described in detail below, the change in the floor noise output from the amplifying unit 1 is dominated by the change in the gain. Therefore, by controlling the floor noise output from the amplification unit 1 to be constant, the gain of the amplification unit 1 can be controlled to be constant.

  As described above, the amplification device measures the floor noise output from the amplification unit 1 and controls the gain of the amplification unit 1 so that the floor noise output from the amplification unit 1 is constant. Thus, the amplifying apparatus can control the gain to be constant without being affected by the change in the gain fluctuation amount due to the temperature.

[Second Embodiment]
Next, a second embodiment will be described in detail with reference to the drawings.
FIG. 2 is a hardware diagram of the amplifying apparatus according to the second embodiment. As shown in FIG. 2, the amplifying apparatus includes an amplifying unit 11, an A / D (Analog to Digital) converter (A / D in the figure, hereinafter referred to as A / D) 12, a CPU (Central Processing Unit) 13, a D / D An A (Digital to Analog) converter (D / A in the figure, hereinafter referred to as D / A) 14 and a storage unit 15 are included. The amplifying apparatus shown in FIG. 2 is used in, for example, a sensing apparatus such as a radar, and amplifies a high-frequency received signal that is irradiated and reflected from a target.

  The amplifying unit 11 includes a plurality of amplifiers 11a to 11d connected in four stages. The amplifying unit 11 can change the gain by controlling the bias of the second to fourth stage amplifiers 11b to 11d excluding the first stage amplifier 11a.

  The amplifiers 11a to 11d are, for example, grounded source amplifier circuits of field effect transistors. The amplifiers 11b to 11d can change the gain by controlling the gate voltage of the field effect transistor.

The A / D 12 performs analog-digital conversion on the signal output from the amplification unit 11. The analog-digital converted signal is input to the CPU 13.
The CPU 13 measures the floor noise output from the amplifying unit 11 based on the signal output from the A / D 12. The CPU 13 outputs the bias of the amplifying unit 11 so that the measured floor noise is constant. The CPU 13 outputs a bias to the D / A 14.

  FIG. 3 is a block diagram of the CPU. As illustrated in FIG. 3, the CPU 13 includes a measurement unit 21, a comparison unit 22, and a bias control unit 23. The functions of these units can be realized, for example, by executing a program stored in the flash memory.

The measurement unit 21 measures a signal output from the A / D 12 when no signal is input to the amplification unit 11 as floor noise.
For example, it is assumed that the amplification device in FIG. 2 is applied to a sensing device such as a radar. In this case, the measurement unit 21 measures, as floor noise, a signal output from the A / D 12 when the transmission signal is not irradiated on the target, that is, when the reflected signal is not received by the antenna. The measurement unit 21 measures floor noise in a state where the input of the amplification unit 11 is terminated, for example, in a state where the input of the amplification unit 11 is connected to the antenna.

  The comparison unit 22 compares the floor noise measured by the measurement unit 21 with the target value stored in the storage unit 15. As will be described in detail below, the gain change of the amplifiers 11a to 11d appears as a change in floor noise. Therefore, the CPU 13 can control the gain of the amplifier 11 to be constant by controlling the bias of the amplifiers 11b to 11d so that the floor noise output from the amplifier 11 becomes the target value.

  Based on the comparison result of the comparison unit 22, the bias control unit 23 changes the bias output to the amplification unit 11 via the D / A 14 by a predetermined value. For example, when the comparison unit 22 determines that the floor noise measured by the measurement unit 21 is larger than the target value stored in the storage unit 15, the bias control unit 23 decreases the bias by a predetermined value. As a result, the gain of the amplifying unit 11 is smaller than the current gain by a predetermined value. The bias control unit 23 increases the bias by a predetermined value when the comparison unit 22 determines that the floor noise measured by the measurement unit 21 is smaller than the target value stored in the storage unit 15. As a result, the gain of the amplifying unit 11 is larger than the current gain by a predetermined value. The bias control unit 23 repeats the above control to control the gain of the amplification unit 11 to be constant.

Returning to the description of FIG. The D / A 14 converts the digital bias value output from the CPU 13 into an analog bias voltage and outputs the analog bias voltage to the amplifiers 11b to 11d.
The storage unit 15 stores a target value for the CPU 13 to control the floor noise uniformly. The storage of the target value in the storage unit 15 is performed, for example, when the amplifying device is shipped from the factory.

  For example, it is assumed that the amplification device in FIG. 2 is applied to a sensing device such as a radar. In this case, when the sensing device is shipped from the factory, the CPU 13 measures the floor noise output from the amplifying unit 11. As described above, the floor noise is measured in a state where the input of the amplifying unit 11 is terminated and no reflected signal is input. The CPU 13 stores the measured floor noise as a target value in the storage unit 15. Alternatively, the floor noise output from the amplifying unit 11 at the time of design may be calculated and stored as a target value in the storage unit 15 at the time of factory shipment.

Next, the relationship between gain and floor noise will be described.
FIG. 4 is a diagram illustrating the relationship between gain and floor noise. FIG. 4 shows the amplifying unit 31. The amplifying unit 31 includes amplifiers 31a to 31d that are connected in four stages.

As shown in FIG. 4, the input noise power density input to the amplifying unit 31 (the noise power density of the input of the amplifying unit 31 when the input of the amplifying unit 31 is terminated and no signal is input to the amplifying unit 31). Is N ₀ . Further, each of the noise figure of the amplifier 31a~31d and F ₁ to F _4, the gain and G ₁ ~G _4.

  In this case, the overall output noise power density N of the amplification unit 31 is expressed by the following equation (1).

Note that G in Expression (1) represents the overall gain of the amplifying unit 31 and is represented by G = G ₁ × G ₂ × G ₃ × G ₄ . Further, F in equation (1) represents the overall noise figure of the amplifying unit 31, and is represented by the following equation (2).

  When Expression (2) is substituted into Expression (1), N in Expression (1) is represented by the following Expression (3).

In the equation (3), the second and subsequent terms of the equation (2) are α.
The gains G _{1 to} G ₄ are generally sufficiently large with respect to the noise figures F _{1 to} F ₄ . Therefore, α in equation (3) is sufficiently small and can be ignored. Then, from Equation (3), the overall output noise power density N of the amplification unit 31 depends on the input noise power density N ₀ , the overall gain G of the amplification unit 31, and the noise figure F ₁ of the first stage amplifier 31 a. To do.

Here, consider a case where the input noise power density N ₀ , the gains G _{1 to} G _{4 of} the amplifiers 31 a to 31 d, and the noise figures F _{1 to} F _{4 of the} amplifiers 31 a to 31 d change. When the gains G _{1 to} G ₄ change, the product of the change appears as a change in the output noise power density N from G and G = G ₁ × G ₂ × G ₃ × G ₄ in Equation (3).

On the other hand, even if the noise figures F _{1 to} F _{4 of} the amplifiers 31a to 31d change, the change in the output noise power density N is only the change of the noise figure F ₁ from the equation (3). As described above, when the gains G _{1 to} G ₄ change, the change in the product affects the output noise power density N, and the noise figure F ₁ and the input noise power density N ₀ change greatly. However, the effect on the output noise power density N is smaller than when the gains G _{1 to} G ₄ are changed.

  That is, the change in the output noise power density N of the amplification unit 31 is dominated by the change in the gain G of the amplification unit 31. That is, if the output noise power density N is controlled to be constant, the gain G of the amplifying unit 31 can be controlled to be constant.

  The output noise power density N in the case of an n-stage amplifier is as follows. First, the noise figure F of the entire n stages is expressed by the following equation (4).

Here, F _i represents the noise figure in the i-th amplifier. G _j represents the gain of the j-th amplifier.
When Expression (4) is substituted into Expression (1), the output noise power density N of the entire n stages shown in the following Expression (5) is obtained.

  Note that G in the equation (5) is represented by the following equation (6).

G _i represents the gain of the i-th amplifier.
FIG. 5 is a diagram for explaining the influence of the output noise power density of the amplifying device when the gain and noise figure change due to temperature change. N ₀ shown in FIG. 5 indicates the input noise power density. G _i represents the gain of the amplifier in one stage. F _i represents the noise figure of the amplifier in one stage. Hereinafter, a case of an amplifying apparatus having six stages of amplifiers connected in multiple stages will be described.

  As shown in FIG. 5, the input noise power density at the temperature T1 is set to -174.00 dBm / Hz. Further, the gain of the one-stage amplifier is 6.00 dB, and the noise figure of the one-stage amplifier is 7.00 dB.

  In this case, the gain G of the entire six-stage amplifier is 36.00 dB as shown in FIG. 5, and the noise figure F of the entire six-stage amplifier is 8.03 dB as shown in FIG. Further, the output noise power density N of the entire six-stage amplifier is −129.97 dBm / Hz as shown in FIG.

  Here, it is assumed that the temperature has changed from T1 to T2 (T1 <T2). As shown in FIG. 5, the input noise power density at the temperature T2 is set to -174.00 dBm / Hz. Further, it is assumed that the gain of the amplifier in the first stage changes from 6.00 dB to 5.00 dB, and the noise figure in the amplifier of one stage changes from 7.00 dB to 7.50 dB.

  In this case, the gain G of the entire six-stage amplifier is 30.00 dB as shown in FIG. 5, and the noise figure F of the entire six-stage amplifier is 8.90 dB as shown in FIG. Further, the output noise power density N of the entire six-stage amplifier is −135.10 dBm / Hz as shown in FIG.

  Therefore, the gain change ΔG due to the change from the temperature T1 to the temperature T2 is −6.00 dB as shown in FIG. 5, and the noise figure change ΔF is 0.86 dB as shown in FIG. Further, the change ΔN in the output noise power density is −5.14 dB as shown in FIG.

  As shown in FIG. 5, the change in the output noise power density N is dominated by the change in the gain G of the entire amplifier. For example, as shown by ΔG and ΔF in FIG. 5, ΔG is larger than ΔF and greatly contributes to ΔN.

  Next, consider a case where the output noise power density N at the temperature T2 is returned to the value at the temperature T1. For example, it is assumed that the output noise power density N of the entire six-stage amplifier is controlled to be −135.10 dBm / Hz to −129.97 dBm / Hz by controlling the bias of the six-stage amplifier.

  In this case, the gain G of the entire six-stage amplifier is 35.45 dB, and the difference from the original gain is −0.55 dB. That is, by controlling the output noise power density N to be constant, the gain can be controlled to be constant with considerable accuracy. Note that the gain shift of -0.55 dB is the same as the noise figure shift in the example of FIG.

FIG. 6 is a flowchart showing the operation of the CPU. CPU13 repeats the process of the following steps. It is assumed that the target value is stored in the storage unit 15 in advance.
[Step S1] The measurement unit 21 measures the signal output from the A / D 12 as floor noise. The measurement unit 21 terminates the input of the amplification unit 11 and measures floor noise in a state where no signal is input.

[Step S <b> 2] The comparison unit 22 compares the target value stored in the storage unit 15 with the floor noise measured by the measurement unit 21.
[Step S3] The comparison unit 22 determines whether the difference between the target value and the floor noise measured by the measurement unit 21 is greater than or equal to a threshold value. When the difference between the target value and the floor noise is greater than or equal to the threshold value, the comparison unit 22 proceeds to step S4. The comparison unit 22 ends the process when the difference between the target value and the floor noise is smaller than the threshold value.

  That is, the comparison unit 22 prevents the bias control of the amplifiers 11b to 11d of the amplification unit 11 from being frequently performed by the processing of the next steps S4 to S6. In FIG. 3, the description of the processing function of step S3 of the comparison unit 22 is omitted. The comparison unit 22 may not have the processing function of step S3.

  [Step S <b> 4] The comparison unit 22 determines whether the floor noise measured by the measurement unit 21 is larger than the target value stored in the storage unit 15. When the floor noise is larger than the target value, the comparison unit 22 proceeds to step S5. When the floor noise is smaller than the target value, the comparison unit 22 proceeds to step S6.

  [Step S5] The bias controller 23 outputs a bias smaller than the bias currently output to the D / A 14 by a predetermined value. That is, the bias control unit 23 controls the gain of the amplifying unit 11 to decrease.

  [Step S <b> 6] The bias controller 23 outputs a bias larger than the bias currently output to the D / A 14 by a predetermined value. That is, the bias control unit 23 performs control so that the gain of the amplification unit 11 is increased.

  In this way, the amplifying apparatus does not control the gain by measuring the temperature, but measures the floor noise output from the amplifying unit 11 and controls the gain of the amplifying unit 11 so that the floor noise becomes constant. I did it. As a result, the amplifying apparatus can control the gain to be constant even if the gain fluctuation amount due to temperature changes.

  In addition, an amplifying apparatus that measures the relationship between temperature and gain fluctuation amount in advance and stores it in a memory or the like is expensive because it measures the gain at each temperature. On the other hand, in the amplifying apparatus of FIG. 2, the target value of the floor noise may be measured only once, and the cost can be reduced.

  In an amplifying apparatus that measures the relationship between temperature and gain fluctuation amount in advance and stores it in a memory or the like, the measurement may be performed on a representative sample and the result may be used for another amplifying apparatus. In this case, the amount to be corrected also varies due to device variations or the like. On the other hand, in the amplifying apparatus of FIG. 2, since the gain of the amplifying unit 11 is controlled so that the floor noise is constant, variations in the constant gain control can be suppressed.

In FIG. 2, the biases of the amplifiers 11b to 11d except for the first-stage amplifier 11a are controlled, but the bias of the amplifier 11a may also be controlled. However, when the bias of the amplifier 11a at the first stage is controlled, the noise figure F ₁ changes. The change in the noise figure F ₁ affects the output noise power density N as described with reference to FIG. Therefore, as shown in FIG. 2, it is desirable to control the biases of the amplifiers 11b to 11d in the second and subsequent stages excluding the first stage.

Further, the CPU 13 can be realized by an ASIC (Application Specific Integrated Circuit).
[Third Embodiment]
Next, a third embodiment will be described in detail with reference to the drawings. In the second embodiment, the bias of the amplifier is changed by a predetermined value so that the floor noise output from the amplifying unit is constant. In the third embodiment, when the floor noise deviates from the target value by a predetermined value, the bias is controlled so that the floor noise is changed to the target value by the amount of the deviation. The hardware diagram of the amplifying device in the third embodiment is the same as that in FIG.

FIG. 7 is a block diagram of a CPU according to the third embodiment. As illustrated in FIG. 7, the CPU 13 includes a measurement unit 41, a calculation unit 42, and a bias control unit 43.
The measurement unit 41 is the same as the measurement unit 21 described with reference to FIG.

The calculation unit 42 calculates the difference between the floor noise measured by the measurement unit 41 and the target value stored in the storage unit 15.
The bias control unit 43 outputs the bias changed according to the difference calculated by the calculation unit 42 to the D / A 14. For example, when the floor noise is greater than the target value by ndB, the bias control unit 43 changes the bias so that the floor noise is reduced by ndB. In addition, when the floor noise is n dB smaller than the target value, the bias control unit 43 changes the bias so that the floor noise becomes n dB larger.

  The amplifying apparatus, for example, is not shown in the hardware diagram of FIG. 2, but is a bias that stores information in which a difference between a target value and floor noise is associated with a bias for changing the floor noise of the difference. It has a storage unit. The bias control unit 43 refers to the bias storage unit based on the difference calculated by the calculation unit 42 and calculates the bias output to the D / A 14.

FIG. 8 is a flowchart showing the operation of the CPU. CPU13 repeats the process of the following steps. It is assumed that the target value is stored in the storage unit 15 in advance.
[Step S11] The measurement unit 41 measures the signal output from the A / D 12 as floor noise. The measurement unit 41 terminates the input of the amplification unit 11 and measures the floor noise in a state where no signal is input.

[Step S12] The calculation unit 42 calculates the difference between the target value stored in the storage unit 15 and the floor noise measured by the measurement unit 41.
[Step S13] The calculation unit 42 determines whether the difference between the target value and the floor noise measured by the measurement unit 41 is equal to or greater than a threshold value. If the difference between the target value and the floor noise is greater than or equal to the threshold value, the calculation unit 42 proceeds to step S14. If the difference between the target value and the floor noise is smaller than the threshold value, the calculation unit 42 ends the process.

  That is, the calculation unit 42 prevents the bias control of the amplifiers 11b to 11d of the amplification unit 11 from being frequently performed by the processing in the next step S14. In FIG. 7, description of the processing function of step S13 of the calculation unit 42 is omitted. The calculation unit 42 may not have the processing function of step S13.

  [Step S14] The bias controller 43 changes the bias according to the difference calculated by the calculator 42 and outputs the bias to the D / A 14. For example, when the measured floor noise is n dB larger than the target value, the bias control unit 43 changes the bias so that the gain of the amplifying unit 11 decreases by n dB and outputs the bias to the D / A 14. In addition, when the measured floor noise is smaller than the target value by ndB, the bias control unit 43 changes the bias so that the gain of the amplifying unit 11 increases by ndB, and outputs it to the D / A 14. Thereby, the gain of the amplifying unit 11 is controlled to be constant.

  As described above, when the floor noise deviates from the target value by a predetermined value, the amplifying apparatus outputs a bias so that the floor noise is changed to the target value by the deviated amount. Also by this, the amplification device can control the gain of the amplification unit 11 to be constant.

[Fourth Embodiment]
Next, a fourth embodiment will be described in detail with reference to the drawings. In the second embodiment and the third embodiment, the gain of the amplifier is controlled by the bias of the amplifier of the amplifier. In the fourth embodiment, the amplifying unit includes an attenuator, and the gain of the amplifying unit is controlled by controlling the attenuation amount of the attenuator.

FIG. 9 is a hardware diagram of the amplifying apparatus according to the fourth embodiment. 9, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.
As illustrated in FIG. 9, the amplifying unit 11 includes an attenuator 51. The attenuator 51 is a variable attenuator that can vary the amount of signal attenuation. The amplifying unit 11 can change the overall gain according to the attenuation amount of the attenuator 51.

  The function of the CPU 13 is the same as that described in FIG. 3 or FIG. However, the CPU 13 is different in that it outputs not the bias of the amplifiers 11b to 11d but the attenuation signal for controlling the attenuation amount of the attenuator 51 to the D / A 14.

  For example, when the CPU 13 in FIG. 9 has the function described in FIG. 3, the measurement unit 21 and the comparison unit 22 are the same. The bias control unit 23 outputs an attenuation signal to the D / A 14 so that the attenuation amount of the attenuator 51 changes by a predetermined value based on the comparison result of the comparison unit 22.

  For example, if the bias control unit 23 determines that the floor noise measured by the measurement unit 21 is larger than the target value stored in the storage unit 15 by the comparison unit 22, the attenuation amount of the attenuator 51 increases by a predetermined value. Output an attenuation signal. As a result, the gain of the amplifying unit 11 is smaller than the current gain by a predetermined value. In addition, when the comparison unit 22 determines that the floor noise measured by the measurement unit 21 is smaller than the target value stored in the storage unit 15, the bias control unit 23 reduces the attenuation amount of the attenuator 51 by a predetermined value. Output an attenuation signal. As a result, the gain of the amplifying unit 11 is larger than the current gain by a predetermined value. The bias control unit 23 repeats the above control to control the gain of the amplification unit 11 to be constant.

  Further, for example, when the CPU 13 in FIG. 9 has the functions described in FIG. 7, the functions of the measurement unit 41 and the calculation unit 42 are the same. About the bias control part 43, the attenuation signal changed according to the difference calculated by the calculation part 42 is output to D / A14.

  For example, when the floor noise is n dB larger than the target value, the bias control unit 43 changes the attenuation signal so that the floor noise becomes n dB lower, and outputs the attenuated signal to the D / A 14. In addition, when the floor noise is n dB smaller than the target value, the bias control unit 43 changes the attenuation signal so that the floor noise becomes n dB larger, and outputs the attenuated signal to the D / A 14.

As described above, the amplifying apparatus can also control the gain of the amplifying unit 11 to be constant by controlling the attenuation amount of the attenuator 51.
The techniques disclosed in the above embodiments include the techniques shown in the following supplementary notes.

(Supplementary note 1) In an amplifying apparatus for amplifying a signal,
An amplifying unit having amplifiers connected in multiple stages;
A measurement unit for measuring floor noise output from the amplification unit;
A control unit for controlling the gain of the amplification unit so that the floor noise measured by the measurement unit is constant;
An amplifying device comprising:

(Additional remark 2) The said control part controls the bias of the amplifier after the 2nd stage of the said amplifying part, The amplification apparatus of Additional remark 1 characterized by the above-mentioned.
(Supplementary note 3)
A comparison unit for comparing the floor noise measured by the measurement unit with a target value;
A bias control unit that changes a bias to be output to the amplifier of the amplification unit by a predetermined value based on a comparison result of the comparison unit;
The amplifying apparatus according to appendix 1 or 2, characterized by comprising:

(Supplementary Note 4) The control unit
A calculation unit for calculating a difference between the floor noise measured by the measurement unit and a target value;
A bias control unit that changes a bias output to the amplifier of the amplification unit according to the difference calculated by the calculation unit;
The amplifying apparatus according to appendix 1 or 2, characterized by comprising:

(Supplementary Note 5) The amplification unit is
It has an attenuator that changes the amount of attenuation of the signal according to the attenuation signal,
The controller is
A comparison unit for comparing the floor noise measured by the measurement unit with a target value;
An attenuation control unit that changes the attenuation signal output to the attenuator of the amplification unit by a predetermined value based on the comparison result of the comparison unit;
The amplifying apparatus as set forth in appendix 1, wherein:

(Supplementary Note 6) The amplification unit is
It has an attenuator that changes the amount of attenuation of the signal according to the attenuation signal,
The controller is
A calculation unit for calculating a difference between the floor noise measured by the measurement unit and a target value;
An attenuation control unit that changes the attenuation signal output to the attenuator of the amplifying unit according to the difference calculated by the calculating unit;
The amplifying apparatus as set forth in appendix 1, wherein:

(Supplementary note 7) In a gain control method of an amplifying apparatus for amplifying a signal,
Measure the floor noise output from the amplifying unit having amplifiers connected in multiple stages,
Controlling the gain of the amplifier so that the measured floor noise is constant;
A gain control method.

DESCRIPTION OF SYMBOLS 1 Amplification part 1a-1d Amplifier 2 Measurement part 3 Control part

Claims (6)

In an amplification device for amplifying a signal,
An amplifying unit having amplifiers connected in multiple stages;
A measurement unit for measuring floor noise output from the amplification unit;
A control unit for controlling the gain of the amplification unit so that the floor noise measured by the measurement unit is constant;
An amplifying device comprising:   The amplifying apparatus according to claim 1, wherein the control unit controls a bias of amplifiers in the second and subsequent stages of the amplifying unit. The controller is
A comparison unit for comparing the floor noise measured by the measurement unit with a target value;
A bias control unit that changes a bias to be output to the amplifier of the amplification unit by a predetermined value based on a comparison result of the comparison unit;
The amplifying apparatus according to claim 1, wherein: The controller is
A calculation unit for calculating a difference between the floor noise measured by the measurement unit and a target value;
A bias control unit that changes a bias output to the amplifier of the amplification unit according to the difference calculated by the calculation unit;
The amplifying apparatus according to claim 1, wherein: The amplification unit is
It has an attenuator that changes the amount of attenuation of the signal according to the attenuation signal,
The controller is
A comparison unit for comparing the floor noise measured by the measurement unit with a target value;
An attenuation control unit that changes the attenuation signal output to the attenuator of the amplification unit by a predetermined value based on the comparison result of the comparison unit;
The amplifying apparatus according to claim 1, comprising: In a gain control method of an amplifying apparatus for amplifying a signal,
Measure the floor noise output from the amplifying unit having amplifiers connected in multiple stages,
Controlling the gain of the amplifier so that the measured floor noise is constant;
A gain control method.

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