JP2006121529A - Class d amplifier device, amplification control program and information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a class D amplifier device or the like with high sound quality by eliminating the influence of sound quality deterioration factors due to an LPF. <P>SOLUTION: The class D amplifier S provided with an amplifier section 9 and an LPF 10 is provided with a test signal generator 8 for generating a test signal St for flattening a sound pressure characteristic, and a test signal St for phase characteristic compensation, respectively; and a comparator 14 for using any one of a sound collection signal Smc obtained by collecting sounds corresponding to each of the test signals St, and an output signal Sst from the output stage of an LPF 10, in that case to correct the sound pressure characteristic as the class D amplifier S and compensate the phase characteristic; and a control unit 12. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present application belongs to the technical field of class D amplifiers, amplification control programs, and information recording media, and more specifically, modulates a sound signal that is either a digital signal or an analog signal by, for example, a PWM (Pulse Width Modulation) method. It belongs to the technical field of a class D amplification device that amplifies the modulation signal obtained in this way, an amplification control program that operates in the class D amplification device, and an information recording medium that records the amplification control program.

  2. Description of the Related Art Conventionally, amplifying devices for audio products (hereinafter referred to as amplifiers as appropriate) include types such as a class A amplifier, a class B amplifier, and a class C amplifier, depending on a method for setting a bias voltage in a transistor constituting the amplifying device. . In addition to these, development of an amplifier called a class D amplifier (in general, it may be called a “switching amplifier” or a “PWM amplifier”) focusing on its high efficiency. Has been actively conducted. At this time, as the efficiency, for example, it is known that the analog amplifier is about 40%, whereas the class D amplifier has an efficiency of about 90%.

  Here, the class D amplifier modulates the sound signal, which is either a digital signal or an analog signal, by the PWM method, amplifies the modulation signal obtained by the modulation process as a rectangular wave, and then LPF This is an amplifier that outputs to a speaker via (Low Pass Filter).

  At this time, the LPF is a class D amplifying device that removes the carrier frequency component and its harmonic components that are inevitably generated due to the execution of the modulation process using the PWM method to improve the sound quality. Is an indispensable requirement. Specifically, it is realized as an LC filter using a coil and a capacitor.

  However, as described above, the LPF contributes to the improvement of the sound quality by removing the carrier frequency component and the like, but there are the following two problems that conversely deteriorate the sound quality due to the presence of the LPF. It has been pointed out from the past.

  That is, as a first problem, the LPF is configured as an LC filter as described above, and therefore, as shown in FIG. 1A, its cutoff frequency (in the case shown in FIG. 1A). The phase of the frequency component in the passing signal starts to rotate from about one-tenth of the frequency of 20 kilohertz), and rotates to about 180 degrees near the cutoff frequency. When this phase rotation occurs, for example, the sound of a high-pitched musical instrument played at the same time reaches the listener's position later than the sound of a low-pitched musical instrument, and the sound localization and sense of presence are impaired. Will be.

  Further, as a second problem, since the LPF is similarly configured as an LC filter, the flatness of the frequency characteristic is impaired due to the fluctuation of the load impedance of the speaker connected to the output end of the LPF. It is. That is, when designing the class D amplifier, the load impedance of the speaker to be connected is assumed to be a certain value, and the inductance of the coil and the capacitance of the capacitor are determined by optimizing the load impedance. However, in general, there are a plurality of types of load impedances. Therefore, when a speaker having a load impedance other than the load impedance assumed at the time of design is connected, as shown in FIG. Does not become flat. More specifically, a higher load impedance (8 ohms in the case of FIG. 1B) than the assumed load impedance (4 ohms in the case of FIG. 1B) as shown in FIG. When a speaker having the same frequency is connected, a peak occurs in the frequency characteristic around the cutoff frequency, while a speaker having a load impedance lower than the assumed load impedance (in the case of FIG. 1B, 2 ohms). When connected, the sound pressure level begins to attenuate at a frequency lower than the cutoff frequency. When this peak or level attenuation occurs, there arises a sound quality problem that harmonics of the sound to be reproduced are emphasized or lost.

  Therefore, the present application has been made in view of the above-mentioned problems, and an example of the purpose is to eliminate the influence of a sound quality lowering factor caused by LPF essential as a class D amplification device, and to achieve high sound quality class D amplification. An apparatus, an amplification control program that operates in the class D amplification device, and an information recording medium that records the amplification control program

  In order to solve the above problem, the invention according to claim 1 amplifies a sound signal by an amplifying unit such as an amplifying unit and outputs the amplified signal to a speaker via a low-pass filter unit such as an LPF for removing high-frequency noise. In the class D amplifying device, a sound pressure test signal generating means such as a test signal generating section for generating a sound pressure test signal having a preset continuous waveform having a constant amplitude and outputting it to the amplifying means; and the low-pass filter means Phase test signal generating means such as a test signal generating section that generates a phase test signal that has a preset frequency corresponding to the cut-off frequency and is a signal for only one or a plurality of wavelengths, and outputs the phase test signal to the amplifying means And collecting the sound emitted from the speaker by outputting the sound pressure test signal and the phase test signal to the speaker via the amplification means and the low-pass filter means, respectively. A sound collecting means such as a microphone for generating a sound collecting signal, and the sound pressure test signal and the phase test signal are output to the low-pass filter means via the amplifying means, so that the low-pass filter means sends the sound to the speaker. Using the switching means such as a switch for switching between a filter output signal to be output and the sound collection signal, and using either one of the filter output signal or the sound collection signal output from the switching means, the class D And a correction unit such as a comparison unit that corrects at least the sound pressure characteristics as an amplification device.

  In order to solve the above problems, the invention according to claim 6 amplifies the sound signal by an amplifying means such as an amplifying unit and outputs the amplified signal to a speaker via a low-pass filter means such as an LPF for removing high frequency noise A computer included in the class D amplification device generates a sound pressure test signal having a preset continuous waveform with a constant amplitude and outputs the sound pressure test signal to the amplification means, and a cutoff frequency of the low-pass filter means A phase test signal generating means for generating a phase test signal having a frequency set in advance and corresponding to only one or a plurality of wavelengths and outputting the phase test signal to the amplifying means, the sound pressure test signal, and the phase A sound collection signal obtained by collecting a sound emitted from the speaker by outputting a test signal to the speaker through the amplification unit and the low-pass filter unit, respectively, Switching means for switching the filter output signal output from the low-pass filter means to the speaker by outputting the sound pressure test signal and the phase test signal to the low-pass filter means via the amplification means, and Using either one of the filter output signal or the collected sound signal output from the switching unit, it functions as a correcting unit that at least corrects the phase characteristic of the class D amplifier.

  In order to solve the above-mentioned problem, in the invention described in claim 7, the amplification control program described in claim 6 is recorded so as to be readable by the computer.

  Next, the best mode for carrying out the present application will be described with reference to FIGS.

  In each of the embodiments described below, a class D amplifier (a preamplifier that adjusts the volume and tone of the sound signal itself, etc.) that amplifies the sound signal, which is either a digital signal or an analog signal, is modulated by the PWM method. This is an embodiment when the present application is applied to (including).

  FIG. 2 is a block diagram showing a schematic configuration of the class D amplifier according to the embodiment, and FIG. 3 is a diagram showing the operation thereof.

(I) Embodiment As shown in FIG. 2, a class D amplifier S according to an embodiment includes a preamplifier 2, a modulator 3, an equalizer 4, a DTC (Dead Time Controller) 5 connected to an input terminal 1, From an FIR (Finite Impulse Response) type filter 6, a half bridge unit 7, a test signal generation unit 8 as a sound pressure test signal generation unit and a phase test signal generation unit, an amplification unit 9, a coil 10A and a capacitor 10B An LPF 10 as a low-pass filter means that functions as an LC filter, a control section 12, an operation section 13 as an input means, a comparison section 14 as a correction means, a sound pressure flattening means, and a phase correction means, and an A / D (Analog / Digital) converter 15, switch 16, switch 18 as switching means, and microphone 17 as sound collection means. Ri, the output signal Ssp from the LPF10 is configured to be outputted to the speaker 11.

  The amplifying unit 9 is composed of, for example, MOS (Metal Oxide Silicon) type n-type FETs (Field Effect Transistors) 20 and 21, and DC power sources V1 and V2.

  At this time, in the amplifying unit 9, the source terminal of the FET 20 is connected to the positive electrode of the DC power source V1, the negative electrode of the DC power source V1 is connected to the positive electrode of the DC power source V2, and the negative electrode of the DC power source V2 is the FET 21. The drain terminal is connected, and the source terminal of the FET 21 is connected to the drain terminal of the FET 20. A connection point to the LPF 10 is provided between the FET 20 and the FET 21, and the DC power sources V1 and V2 are grounded.

  Here, the DTC 5 always causes the FET 21 included in the corresponding amplifying unit 9 to transition from on to off after the FET 20 has transitioned from off to on, and the FET 21 always finishes from on to off. To transit the FET 20 from OFF to ON. The function of the DTC 5 prevents the generation of a large current due to the FET 20 and the FET 21 being simultaneously turned on.

  The half-bridge circuit 7 is a switching circuit for using n-type FETs for both the FETs 20 and 21 included in the amplifying unit 9.

  Next, the operation will be described.

(A) Calculation operation of correction value and phase characteristic correction value for flattening sound pressure characteristic First, the sound pressure characteristic as the class D amplifier S in a state where the speaker 11 is connected is flattened and further the phase characteristic is corrected. An initial setting operation for performing the setting will be described. The initial setting operation is performed before the sound is actually reproduced / output using the class D amplifier S.

  When the initial setting operation is performed, the switch 16 is connected to the comparison unit 14 and the test signal generation unit 8 based on the control signal Scsw1 from the control unit 12, while the switch 18 is connected to the control unit 12 Is connected to the microphone 17 side based on the control signal Scsw2.

  In this state, when the sound pressure characteristic of the class D amplifier S is flattened, the test signal generator 8 generates a test signal St that is a continuous sine wave having a preset amplitude, and switches the switch via the switch 16. The signal Ssw is output to the equalizer 4.

  Here, the frequency of the test signal St monotonously increases or decreases monotonically in the frequency band in order to execute the flattening process for all frequencies included in the frequency band whose sound pressure characteristics should be flattened. In this way, the test signal generator 8 is controlled.

  Then, the equalizer 4 in the initial setting state outputs the switch signal Ssw (that is, the test signal St itself) as it is to the filter 6 as the equalizer signal Sv.

  Next, the filter 6 in the initial setting state outputs the equalizer signal Sv (similarly, the test signal St itself) as it is to the DTC 5 as the filter signal Sfr.

  Further, the DTC 5 controls the filter signal Sfr so as to realize the operations of the FETs 20 and 21 described above, and then outputs the filter signal Sfr to the half bridge circuit 7 as a control filter signal Sd.

  Then, the half-bridge circuit 7 performs processing set in advance as the half-bridge circuit 7 on the output control filter signal Sd, and applies the drive signals Sdd1 and Sdd2 to the gate terminal of the FET 20 and the gate terminal of the FET 21. Output each separately.

  Thereafter, the class D amplification operation using the DC power sources V1 and V2 is executed by the on / off operation of the FETs 20 and 21 similar to the actual sound reproduction, and the resulting amplified signal So is output to the LPF 10. The

  Then, the LPF 10 performs a high-frequency cutoff process on the amplified signal So, and outputs the output signal Ssp to the speaker 11 to the speaker 11 to perform a corresponding sound emission.

  Next, the emitted sound is collected by the microphone 17, and a corresponding sound collection signal Smc is output from the microphone 17 to the switch 18. Then, the signal is output to the A / D converter 15 as a switch signal Sck (that is, the sound collection signal Smc itself) via the switch 18, converted from an analog signal to a digital signal, and then to the comparison unit 14 as a digital sound collection signal Sdmc. Is output.

  As a result, the comparison unit 14 detects the sound pressure of the digital sound collection signal Sdmc that is output as the frequency of the test signal St changes within the necessary frequency band, and controls the change with respect to the frequency as a control signal. It outputs to the control part 12 as Scm.

  Based on the sound pressure characteristic when the speaker 11 is connected, the control unit 12 sets the sound pressure for each frequency in order to flatten the sound pressure characteristic when the actual sound is output. The value of the control signal Sce for controlling the equalizer 4 to be controlled is set.

  At this time, more specifically, as the operation of the control unit 12, for example, although the class D amplifier S is designed on the assumption that the load impedance of the speaker 11 is 4 ohms, the load impedance is 8 When a sound pressure characteristic having a convex portion as indicated by a symbol “8Ω” in FIG. 1B is obtained as the digital sound collection signal Sdmc due to the connection of the ohmic speaker 11, the control unit 12. Controls the equalizer 4 so as to exhibit a sound pressure control characteristic that cancels the convex part (that is, a sound pressure control characteristic having a concave part that only cancels the convex part at a frequency at which the convex part appears). The control signal Sce for setting is set. Similarly, although the class D amplifier S is designed on the assumption that the load impedance of the speaker 11 is 4 ohms, the speaker 11 having a load impedance of 2 ohms is connected. When the sound pressure characteristic that decreases early as shown by the symbol “2Ω” in FIG. 1B is obtained as the digital sound collection signal Sdmc, the control unit 12 increases the sound pressure in the high frequency region. The control signal Sce for controlling the equalizer 4 is set so as to exhibit a proper sound pressure control characteristic.

  Through the above series of operations, the test operation for flattening the sound pressure characteristics of the class D amplifier S when the speaker 11 is actually connected is completed, and the control signal Sce obtained as a result is stored in the control unit 12. Are stored in a memory (not shown).

  Next, when correcting the phase characteristic of the class D amplifier S, the test signal generation unit 8 has a preset amplitude (for example, a frequency that has a preset amplitude and does not cause phase rotation in the phase characteristic (for example, The test signal St (see symbol St in FIG. 3 (a)) having a cutoff frequency of the LPF 10 having a cutoff frequency of 20 kilohertz and a signal corresponding to only one wavelength has the same amplitude and the phase. A test signal St (FIG. 3 (b) having a frequency set in advance as a frequency at which rotation occurs (for example, 10 kHz when the cutoff frequency is 20 kHz) and a signal corresponding to only one wavelength. ) (See symbol St)), respectively, are generated separately with a time difference, and output to the comparison unit 14, and is also equalized as a switch signal Ssw via the switch 16. And outputs it to The 4. In this case, the test signal St is not limited to a signal for only one wavelength, and may be a signal for a plurality of wavelengths as long as the start timing as each test signal St can be distinguished. .

  Then, the equalizer 4 and the filter 6 that are in the initial setting state, the DTC 5, the half bridge circuit, the amplifying unit 9, and the LPF 10 function in the same manner as in the case of correcting the above-described sound pressure characteristics. Sound emission corresponding to the output signal Ssp (the output signal Ssp resulting from the amplification of the two types of test signals St) is executed.

  Next, the emitted sound is collected by the microphone 17, and the corresponding sound collection signal Smc is output from the microphone 17 via the switch 18 to the A / D converter 15 as the switch signal Sck, and is output from the analog signal. After being converted into a digital signal, it is output to the comparison unit 14 as a digital sound collection signal Sdmc.

  Thus, the comparison unit 14 compares the phase of the original test signal St and the corresponding digital sound collection signal Sdmc for each of the two types of test signals St, and extracts the phase difference. More specifically, as the phase difference extraction processing, as shown in FIG. 3A, first, a test signal St having a frequency at which phase rotation does not occur and a digital sound collection signal Sdmc corresponding thereto are phase-converted. By comparing, a phase delay Δt (see FIG. 3A) due to the distance between the speaker 11 and the microphone 17 is detected, and then a test signal St having a frequency at which phase rotation occurs and corresponding to this. The phase delay Δt ′ caused by the phase rotation to be corrected with respect to the phase delay Δt caused by the distance between the speaker 11 and the microphone 17 by comparing the phase of the digital sound collection signal Sdmc to be performed (FIG. 3B). ))) Is added to detect the phase delay (Δt + Δt ′). Then, the phase difference caused by the phase rotation to be corrected is calculated by calculating the difference between the respective phase delays in the comparison unit 14 (more specifically, by subtracting the phase delay Δt from the phase delay (Δt + Δt ′)). Δt ′ is detected. Then, the value of the control signal Scf for controlling the characteristics of the filter 6 is set so as to correct the phase rotation detected as the phase delay Δt ′.

  Through the series of operations described above, the test operation for correcting the phase characteristics (phase rotation) of the class D amplifier S when the speaker 11 is connected is completed, and the control signal Scf obtained as a result is stored in the control unit 12. Are stored in a memory (not shown).

(B) Sound Pressure Characteristic and Phase Characteristic Correction Operation During Reproduction Next, each correction operation during sound reproduction performed using the values of the control signals Sce and Scf obtained as described above will be described.

  At the time of actual sound reproduction, first, when an operation for setting or changing the operation of the entire class D amplifier S is performed by the user in the operation unit 13, an operation signal Sop corresponding to the operation is generated. To the control unit 12.

  Thereby, the operation unit 12 controls the control signal Scsw1 so as to switch the switch 16 to the modulator 3 side, and outputs the control signal Scsw1 to the switch 16. At this time, the switch 18 may be switched to any terminal side.

  In parallel with this, the control unit 12 reads out the sound pressure characteristic flattening control signal Sce acquired by the above-described sound pressure characteristic flattening operation from the memory and outputs it to the equalizer 4 to flatten the sound pressure characteristic. The equalizer 4 is set so as to have such a frequency characteristic, and the control signal Scf for phase characteristic correction acquired by the above-described phase characteristic correction operation is read from the memory and output to the filter 6, and the filter 6 is output to the phase characteristic. It is set so as to have a filter characteristic for correction.

  In this state, the preamplifier 2 performs processing such as waveform deformation and volume adjustment based on the user's operation on the sound signal Sin, and outputs the processed signal Sp to the modulator 13.

  Next, the modulator 13 performs modulation processing of a preset PWM system on the processing signal Sp to generate a modulation signal Spw, and outputs the modulation signal Spw to the equalizer 4 through the switch 16.

  Then, the equalizer 4 set for the sound pressure characteristic flattening performs the sound pressure characteristic flattening process indicated by the control signal Sce on the switch signal Ssw, and outputs it to the filter 6 as the equalizer signal Sv.

  Next, the filter 6 set for phase characteristic correction performs a filter process for phase characteristic correction on the equalizer signal Sv and outputs it to the DTC 5 as a filter signal Sfr.

  Further, the DTC 5 controls the filter signal Sfr so as to realize the operations of the FETs 20 and 21 described above, and then outputs the filter signal Sfr to the half bridge circuit 7 as a control filter signal Sd.

  Then, the half-bridge circuit 7 performs processing set in advance as the half-bridge circuit 7 on the output control filter signal Sd, and applies the drive signals Sdd1 and Sdd2 to the gate terminal of the FET 20 and the gate terminal of the FET 21. Output each separately.

  Thereafter, the class D amplification operation using the DC power sources V1 and V2 is executed by the on / off operation of the FETs 20 and 21 similar to the actual sound reproduction, and the resulting amplified signal So is output to the LPF 10. The

  Then, the LPF 10 performs a high-frequency cutoff process on the amplified signal So, and outputs the output signal Ssp to the speaker 11 to the speaker 11 to perform a corresponding sound emission.

  As described above, actual sound reproduction accompanied by the class D amplification operation is executed in a state where the sound pressure flattening process and the phase characteristic correction process are performed.

  As described above, according to the sound pressure characteristic flattening process and the phase characteristic correction process according to the first embodiment, the sound pressure as the class D amplifier S using the digital sound collection signal Sdmc corresponding to each test signal St. Since the characteristics are flattened, the sound pressure characteristics can be flattened according to the actual sound environment including the load impedance of the speaker 11, and the class D amplifier S having good sound quality can be realized.

  Further, since the phase rotation is also corrected using the digital sound collection signal Sdmc corresponding to the test signal St, it is possible to improve the sound quality from both the sound pressure and the phase.

  Further, in the phase characteristic correction processing, the phase rotation is corrected using the phase difference between the digital sound collection signals Sdmc corresponding to the two kinds of test signals St shown in FIG. Can be corrected.

(II) Modified Embodiment Next, a modified embodiment according to the present application will be described.

  First, as a first variation, in the above-described embodiment, when obtaining the control signal Scf for phase characteristic correction, two types of test signals St shown in FIGS. 3A and 3B are used. As described above, the control signal Scf can be calculated using only the test signal St having a frequency at which phase rotation occurs as shown in FIG.

  In this case, it is necessary that the user measures the distance from the speaker 11 to the microphone 17 in advance and inputs the measured value using the operation unit 13. That is, if the measured value of this distance is used, the phase delay Δt shown in FIG. 3B can be calculated separately, and this is used as the test signal St having a frequency at which phase rotation occurs as described above. By subtracting the corresponding digital sound collection signal Sdmc from the phase delay (Δt + Δt ′) detected by phase comparison, the phase delay Δt ′ caused by the phase rotation to be corrected can be detected. Then, the value of the control signal Scf for controlling the characteristics of the filter 6 is set so as to correct the phase rotation detected as the phase delay Δt ′.

  As described above, according to the first modification, the phase of the digital sound collection signal Sdmc corresponding to the test signal St having a frequency predicted to cause phase rotation and the distance between the speaker 11 and the microphone 17 are set. Since the phase rotation is corrected based on this, effective phase characteristic improvement can be performed using a small number of test signals St.

  Next, as a second modification, in the above-described embodiment, the case where each correction operation is performed using the sound collection signal Smc output from the microphone 17 has been described. For example, the correction operation is performed by a user who has purchased a product in which the class D amplifier S is mounted, with the speaker 11 connected before starting actual use.

  On the other hand, for example, at the time of shipment as a product of the class D amplifier S, the switch 18 is connected to the LPF 10 side, and the sound pressure flattening process is performed using the signal obtained by digitizing the output signal Ssp by the A / D converter 15 as it is. It is also possible to determine the value of the control signal Sce for.

  In this case, a dummy load having a preset load impedance (for example, 8Ω) is connected to a terminal to which the speaker 11 is to be connected after sales, thereby reproducing the state in which the speaker 11 is connected in a pseudo manner. can do.

  In this state, the test signal St, which is a continuous sine wave for the sound pressure characteristic flattening process described above, that is, its frequency monotonously increases or decreases monotonically in the frequency band where the sound pressure characteristic should be flattened. The test signal St to be output is output to the equalizer 4 and the control signal Sce for flattening the sound pressure characteristic is generated using the output signal Ssp output from the LPF 10 correspondingly.

  In the second variation, the filter 6 is set so as to have a filter characteristic corresponding to a predetermined arbitrary phase delay time.

  As described above, according to the second modification, the sound pressure characteristic is flattened using the output signal Ssp output from the LPF 10 in response to the test signal St for flattening the sound pressure characteristic. Even in a state where the sound from 11 cannot be collected (for example, in a test stage at the time of product shipment), the sound quality can be improved by improving the sound pressure characteristics.

  Furthermore, as a third modification, a program corresponding to the correction control processing as the control unit 12 and the comparison unit 14 described above is recorded on an information recording medium such as a flexible disk or a hard disk, or acquired via the Internet or the like. It is also possible to use the computer as the control unit 12 and the comparison unit 14 according to the embodiment by reading out and executing these by a general-purpose computer.

It is a figure which shows the problem of a prior art, (a) is a figure which shows the problem as a phase characteristic, (b) is a figure which shows the problem as a sound pressure characteristic. It is a block diagram which shows the outline | summary structure of the class D amplifier of embodiment. It is a figure which shows operation | movement of the class D amplifier of embodiment, (a) is a figure (I) explaining phase characteristic correction operation, (b) is a figure (II) explaining phase characteristic correction operation.

Explanation of symbols

1 Input Terminal 2 Preamplifier 3 Modulator 4 Equalizer 5 DTC
6 Filter 7 Half Bridge 8 Test Signal Generator 9 Amplifier 10 LPF
DESCRIPTION OF SYMBOLS 11 Speaker 12 Control part 13 Operation part 14 Comparison part 15 A / D converter 16, 18 Switch 17 Microphone 20, 21 FET
V1, V2 DC power supply

Claims (7)

In a class D amplifier that amplifies a sound signal by an amplifying unit and outputs the amplified signal to a speaker through a low-pass filter unit for high-frequency noise removal,
A sound pressure test signal generating means for generating a sound pressure test signal having a preset continuous waveform having a predetermined amplitude and outputting the same to the amplifying means;
A phase test signal generating means for generating a phase test signal which has a preset frequency corresponding to a cutoff frequency of the low pass filter means and is a signal for only one or a plurality of wavelengths and outputs the phase test signal to the amplifying means; ,
The sound pressure test signal and the phase test signal are output to the speaker via the amplifying unit and the low-pass filter unit, respectively, thereby collecting the sound emitted from the speaker and generating a sound collection signal. Sound collection means;
The sound pressure test signal and the phase test signal are output to the low-pass filter means via the amplification means, so that a filter output signal output from the low-pass filter means to the speaker, and the sound collection signal, Switching means for switching;
Correction means for correcting at least a sound pressure characteristic as the class D amplifying device using either one of the filter output signal or the collected sound signal output from the switching means;
A class-D amplifying apparatus comprising: In the class D amplification device according to claim 1,
The correction means includes
Sound pressure flattening means for flattening the sound pressure characteristics using the collected sound signal corresponding to the sound pressure test signal;
Phase correction means for correcting phase rotation in the phase characteristics of the class D amplification device using the collected sound signal corresponding to the phase test signal;
A class-D amplifying device comprising: The class D amplification device according to claim 2,
The phase test signal generating means includes a first phase test signal that is the phase test signal having a frequency at which the phase rotation is predicted to occur, and the phase test signal having a frequency at which the phase rotation is predicted not to occur. A second phase test signal that is separately generated and output to the amplification means,
The phase correction means corrects the phase rotation by using a phase difference between the collected sound signal corresponding to the first phase test signal and the collected sound signal corresponding to the second phase test signal. Class D amplifier. The class D amplification device according to claim 2,
An input unit used for inputting a distance between the speaker and the sound collecting unit;
The phase test signal generating means generates the phase test signal having a frequency at which the phase rotation is predicted to occur and outputs the phase test signal to the amplification means.
The class D amplification device, wherein the phase correction means corrects the phase rotation based on a phase of the sound collection signal corresponding to the phase test signal and the distance. In the class D amplification device according to claim 1,
The correction means includes
A class-D amplifying apparatus comprising: a sound pressure flattening means for flattening the sound pressure characteristics using the filter output signal corresponding to the sound pressure test signal. A computer included in a class D amplifier that amplifies a sound signal by an amplifying unit and outputs the amplified signal to a speaker through a low-pass filter unit for noise removal.
A sound pressure test signal generating means for generating a sound pressure test signal having a preset continuous waveform having a predetermined amplitude and outputting the sound pressure test signal to the amplifying means;
A phase test signal generating means for generating a phase test signal that has a preset frequency corresponding to a cutoff frequency of the low-pass filter means and that is a signal for only one or a plurality of wavelengths, and outputs the phase test signal to the amplifying means;
A sound collection signal obtained by collecting the sound emitted from the speaker by outputting the sound pressure test signal and the phase test signal to the speaker via the amplification unit and the low-pass filter unit, respectively. Switching means for switching the filter output signal output from the low-pass filter means to the speaker by outputting the sound pressure test signal and the phase test signal to the low-pass filter means via the amplification means; and ,
Correction means for correcting at least a phase characteristic as the class D amplification device by using either the filter output signal or the collected sound signal output from the switching means,
An amplification control program characterized by functioning as   7. An information recording medium in which the amplification control program according to claim 6 is recorded so as to be readable by the computer.

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