Amplification control device, test signal generation module, test device, amplification control method, program, and recording medium

1. An amplification control device for controlling an amplifier, an amplification factor of which is controlled based on an analog control signal, and which amplifies an analog input signal and outputs an analog output signal, comprising:

a component acquirer that transforms, by the discrete Fourier transform, a digital output signal converted from the analog output signal into digital form, thereby acquiring a desired frequency component of the digital output signal;

a differentiator that acquires a difference between the electric power of the frequency component acquired by the component acquirer and a target value of the electric power of the frequency component; and

a digital control signal outputter that outputs, based on the difference acquired by the differentiator, a digital control signal for controlling the amplification factor of the amplifier,

wherein the analog control signal is obtained by converting the digital control signal into analog form,

wherein the digital control signal outputter comprises a control signal recorder that records the digital control signal,

wherein the control signal recorder records, before a desired analog output signal is obtained, an appropriate control signal which is the digital control signal causing the desired analog output signal to be obtained when a predetermined analog input signal is fed to the amplifier, and

wherein the appropriate control signal is calculated based on the predetermined analog input signal and the desired analog output signal.

2. The amplification control device according to claim 1 , comprising a sample number setter that sets the number of samples used in the discrete Fourier transform carried out by the component acquirer,

wherein the sample number setter sets the number of the samples, such that the number of samples in (P+1) th discrete Fourier transform carried out by the component acquirer can be larger than the number of samples in P th discrete Fourier transform, where P is a positive integer.

3. The amplification control device according to claim 2 , wherein the sample number setter increases the number of samples when the number of times of the discrete Fourier transform carried out by the component acquirer exceeds a predetermined number of times.

4. The amplification control device according to claim 1 , wherein the digital output signal is obtained by lowering the frequency of the analog output signal, and converting the resulting signal into digital form.

5. A test signal generation module comprising:

the amplification control device according to claim 1 ;

the amplifier;

an A/D converter that converts the analog output signal into digital form;

a D/A converter that converts the digital control signal into analog form; and

a test signal generator that generates a test signal for testing a device under test to which the analog output signal is fed,

wherein the test signal is the analog input signal.

6. A test device comprising:

the test signal generation module according to claim 5 ;

a response analysis module that analyzes a response of the device under test when the analog output signal is fed; and

a controller that controls the test signal generator based on an operation of the response analysis module.

7. An amplification control method for controlling an amplifier, an amplification factor of which is controlled based on an analog control signal, and which amplifies an analog input signal and outputs an analog output signal, comprising:

component acquiring that transforms, by the discrete Fourier transform, a digital output signal converted from the analog output signal into digital form, thereby acquiring a desired frequency component of the digital output signal;

differentiating that acquires a difference between the electric power of the frequency component acquired by the component acquiring and a target value of the electric power of the frequency component; and

digital control signal outputting that outputs, based on the difference acquired by the differentiating, a digital control signal for controlling the amplification factor of the amplifier,

wherein the analog control signal is obtained by converting the digital control signal into analog form,

wherein the digital control outputting comprises recording the digital control signal in a control signal recorder,

wherein the control signal recorder records, before a desired analog output signal is obtained, an appropriate control signal which is the digital control signal causing the desired analog output signal to be obtained when a predetermined analog input signal is fed to the amplifier, and

wherein the appropriate control signal is calculated based on the predetermined analog input signal and the desired analog output signal.

8. A computer-readable medium having a program of instructions for execution by a computer to perform an amplification control process for controlling an amplifier, an amplification factor of which is controlled based on an analog control signal, and which amplifies an analog input signal and outputs an analog output signal, said amplification control process comprising:

component acquiring that transforms, by the discrete Fourier transform, a digital output signal converted from the analog output signal into digital form, thereby acquiring a desired frequency component of the digital output signal;

differentiating that acquires a difference between the electric power of the frequency component acquired by the component acquiring and a target value of the electric power of the frequency component; and

digital control signal outputting that outputs, based on the difference acquired by the differentiating, a digital control signal for controlling the amplification factor of the amplifier,

wherein the analog control signal is obtained by converting the digital control signal into analog form,

wherein the digital control outputting comprises recording the digital control signal in a control signal recorder,

wherein the control signal recorder records, before a desired analog output signal is obtained, an appropriate control signal which is the digital control signal causing the desired analog output signal to be obtained when a predetermined analog input signal is fed to the amplifier, and

wherein the appropriate control signal is calculated based on the predetermined analog input signal and the desired analog output signal.

9. An amplification control device for controlling an amplifier, an amplification factor of which is controlled based on an analog control signal, and which amplifies an analog input signal and outputs an analog output signal, comprising:

a component acquirer that transforms, by the discrete Fourier transform, a digital output signal converted from the analog output signal into digital form, thereby acquiring a desired frequency component of the digital output signal;

a differentiator that acquires a difference between the electric power of the frequency component acquired by the component acquirer and a target value of the electric power of the frequency component; and

a digital control signal outputter that outputs, based on the difference acquired by the differentiator, a digital control signal for controlling the amplification factor of the amplifier,

wherein the analog control signal is obtained by converting the digital control signal into analog form,

wherein the digital control signal outputter comprises a control signal recorder that records the digital control signal,

wherein the control signal recorder records, before a desired analog output signal is obtained, an appropriate control signal which is the digital control signal causing the desired analog output signal to be obtained when a predetermined analog input signal is fed to the amplifier,

wherein the appropriate control signal is recorded in the control signal recorder in a state in which the predetermined analog input signal is fed to the amplifier, and the desired analog output signal is obtained, and

wherein the control signal recorder records the appropriate control signal before the desired analog output signal is obtained again after the state.

10. The amplification control device according to claim 9 , comprising a sample number setter that sets the number of samples used in the discrete Fourier transform carried out by the component acquirer,

wherein the sample number setter sets the number of the samples, such that the number of samples in (P+1) th discrete Fourier transform carried out by the component acquirer can be larger than the number of samples in P th discrete Fourier transform, where P is a positive integer.

11. The amplification control device according to claim 10 , wherein the sample number setter increases the number of samples when the number of times of the discrete Fourier transform carried out by the component acquirer exceeds a predetermined number of times.

12. The amplification control device according to claim 9 , wherein the digital output signal is obtained by lowering the frequency of the analog output signal, and converting the resulting signal into digital form.

13. A test signal generation module comprising:

the amplification control device according to claim 9 ;

the amplifier;

an A/D converter that converts the analog output signal into digital form;

a D/A converter that converts the digital control signal into analog form; and

a test signal generator that generates a test signal for testing a device under test to which the analog output signal is fed,

wherein the test signal is the analog input signal.

14. A test device comprising:

the test signal generation module according to claim 13 ;

a response analysis module that analyzes a response of the device under test when the analog output signal is fed; and

a controller that controls the test signal generator based on an operation of the response analysis module.

15. An amplification control method for controlling an amplifier, an amplification factor of which is controlled based on an analog control signal, and which amplifies an analog input signal and outputs an analog output signal, comprising:

component acquiring that transforms, by the discrete Fourier transform, a digital output signal converted from the analog output signal into digital form, thereby acquiring a desired frequency component of the digital output signal;

differentiating that acquires a difference between the electric power of the frequency component acquired by the component acquiring and a target value of the electric power of the frequency component; and

digital control signal outputting that outputs, based on the difference acquired by the differentiating, a digital control signal for controlling the amplification factor of the amplifier,

wherein the analog control signal is obtained by converting the digital control signal into analog form,

wherein the digital control outputting comprises recording the digital control signal in a control signal recorder,

wherein the control signal recorder records, before a desired analog output signal is obtained, an appropriate control signal which is the digital control signal causing the desired analog output signal to be obtained when a predetermined analog input signal is fed to the amplifier,

wherein the appropriate control signal is recorded in the control signal recorder in a state in which the predetermined analog input signal is fed to the amplifier, and the desired analog output signal is obtained, and

wherein the control signal recorder records the appropriate control signal before the desired analog output signal is obtained again after the state.

16. A computer-readable medium having a program of instructions for execution by a computer to perform an amplification control process for controlling an amplifier, an amplification factor of which is controlled based on an analog control signal, and which amplifies an analog input signal and outputs an analog output signal, said amplification control process comprising:

component acquiring that transforms, by the discrete Fourier transform, a digital output signal converted from the analog output signal into digital form, thereby acquiring a desired frequency component of the digital output signal;

differentiating that acquires a difference between the electric power of the frequency component acquired by the component acquiring and a target value of the electric power of the frequency component; and

digital control signal outputting that outputs, based on the difference acquired by the differentiating, a digital control signal for controlling the amplification factor of the amplifier,

wherein the analog control signal is obtained by converting the digital control signal into analog form,

wherein the digital control outputting comprises recording the digital control signal in a control signal recorder,

wherein the control signal recorder records, before a desired analog output signal is obtained, an appropriate control signal which is the digital control signal causing the desired analog output signal to be obtained when a predetermined analog input signal is fed to the amplifier,

wherein the appropriate control signal is recorded in the control signal recorder in a state in which the predetermined analog input signal is fed to the amplifier, and the desired analog output signal is obtained, and

wherein the control signal recorder records the appropriate control signal before the desired analog output signal is obtained again after the state.