JP5714039B2 - Measuring apparatus and measuring method - Google Patents

Description

  Embodiments described herein relate generally to a measuring apparatus and a measuring method for measuring an impulse response of a target system including an output apparatus and a receiving apparatus.

  As a measurement signal for measuring an impulse response or a frequency characteristic, a sine wave sweep signal whose frequency continuously changes with time is often used. A TSP (Time Stretched Pulse) signal is representative of a sine wave sweep signal, and has a characteristic that can be measured using a time signal having a maximum amplitude over the entire frequency. As a result, the measurement signal is suitable for a target system (speaker, etc.) having a substantially flat frequency characteristic, but in the case of a target system (such as directly measuring an earphone with a microphone) whose frequency characteristic is not flat, The low band was easily buried in noise, and the accuracy of the measurement results was low. Also, if you try to measure with loud sound, such as increasing the output power of the measurement signal or increasing the amplification factor of the receiver, the signal will be distorted because the high gain band exceeds the maximum reception level. May not be measured correctly.

Japanese Patent No. 45552016

  In the case of a target system that includes an output device (sealed earphone) and a reception device (microphone) and the frequency characteristics of the received signal are not flat, a TSP signal having a time signal having the maximum amplitude over the entire frequency is used. When measuring the impulse response, the accuracy of the measurement result may be low.

  An object of the present invention is to provide a measuring device and a measuring method capable of improving the accuracy of the measurement result of the impulse response of the target system including the output device and the receiving device.

According to an embodiment, the measuring device, an output device for outputting a first output signal corresponding to the first measurement signal to sweep the frequency by receiving the first output signal, first The impulse response is measured using a target system including a receiving device that outputs the received signal. Measuring device comprises an output means, a receiving means and a first arithmetic means. The output means outputs, as the first measurement signal, a first signal corresponding to a signal obtained by weighting a frequency component of a TSP (Time Stretched Pulse) signal to a value that decreases as the frequency increases. Supply. Receiving means when said first signal as the first measuring signal is supplied to said output device from said output means, receiving said first reception signal output from the receiving device. First arithmetic means, by performing a convolution operation on a signal for the reverse measurement having an inverse characteristic of the first reception signal and the first signal, computing the impulse response.

The perspective view which shows an example of the external appearance of the measuring apparatus (reproduction | regeneration apparatus) of embodiment. The block diagram which shows an example of the system configuration | structure of the measuring apparatus (reproducing apparatus) of embodiment. FIG. 3 is a block diagram illustrating an example of a configuration for measuring an impulse response and frequency characteristics of the media player according to the embodiment. The figure which shows the frequency characteristic of the sound output from the earphone and acquired with the microphone. The schematic diagram which shows the waveform which carried out the Fourier inverse transform of the general TSP signal. The figure which shows the amplitude spectrum of the sound output from an earphone when the TSP signal shown in FIG. 5 is input into an earphone. The figure which shows the frequency amplitude spectrum obtained by carrying out the Fourier transform of the waveform shown in FIG. The figure which shows the spectrum of the received signal at the time of measuring the output sound from an earphone close to a microphone. The figure which shows the frequency amplitude spectrum of the impulse response obtained from the spectrum shown in FIG. The figure which shows the spectrum of the received signal at the time of raising the volume of a reproduction signal or raising the gain of a microphone amplifier. The figure which shows the spectrum of the signal for a measurement which weighted with respect to the TSP signal. The figure which shows the weighting coefficient W (k) used when producing the TSP signal shown in FIG. 11, and 1 / W (k) used when producing the inverse TSP signal. The figure which shows the spectrum of the received signal at the time of measuring the output sound from an earphone close to a microphone using the TSP signal shown in FIG. The figure which shows the spectrum of a received signal at the time of raising a reproduction | regeneration volume or a receiving volume, and measuring the output sound from an earphone close to a microphone using the TSP signal shown in FIG. The figure which shows the frequency amplitude spectrum of the impulse response obtained from the spectrum shown in FIG. The block diagram which shows an example of a structure of the correction function of a media player. The figure which shows an example of the frequency characteristic which target characteristic data shows. The figure which shows an example of the frequency characteristic which the designed correction filter shows. The figure which shows the frequency characteristic of the sound output from the earphone. The flowchart which shows an example of the procedure which measures the frequency characteristic of the sound output from the earphone, and correct | amends the sound output from an earphone based on the measured frequency characteristic. The figure which shows the modification of the TSP signal shown in FIG. The figure which shows 1 / W (k) used when the weighting coefficient W (k) used when producing the TSP signal shown in FIG. 21, and its reverse TSP signal are produced.

Hereinafter, embodiments will be described with reference to the drawings.
First, with reference to FIG. 1 and FIG. The measuring apparatus (reproducing apparatus) of the present embodiment is realized by, for example, a notebook portable personal computer 10.

  FIG. 1 is a perspective view of the computer 10 with the display unit opened. The computer 10 includes a computer main body 11 and a display unit 12. A display panel 17 having a liquid crystal panel is incorporated in the display unit 12. A microphone is provided in the display unit 12. The display unit 12 is provided with a microphone hole 19 so that the microphone can efficiently collect sound.

  The display unit 12 is attached to the computer main body 11 so as to be rotatable between an open position where the upper surface of the computer main body 11 is exposed and a closed position covering the upper surface of the computer main body 11. The computer main body 11 has a thin box-shaped housing. On the top surface thereof, there are a keyboard 13, a power button 14 for powering on / off the computer 10, a touch pad 16, and speakers 18A and 18B. Has been placed.

Next, the system configuration of the computer 10 will be described with reference to FIG.
As shown in FIG. 2, the computer 10 includes a CPU 101, a north bridge 102, a main memory 103, a south bridge 104, a graphics processing unit (GPU) 105, a video memory (VRAM) 105A, a sound controller 106, a BIOS- A ROM 109, a LAN controller 110, a hard disk drive (HDD) 111, a DVD drive 112, an embedded controller / keyboard controller IC (EC / KBC) 116, and the like are provided.

  The CPU 101 is a processor that controls the operation of the computer 10 and executes various application programs such as an operating system (OS) 121 and a media player 122 that are loaded from the hard disk drive (HDD) 111 to the main memory 103. The media player 122 is application software for reproducing moving image (video) and audio files. The CPU 101 also executes a BIOS (Basic Input Output System) stored in the BIOS-ROM 109. The BIOS is a program for hardware control.

  The north bridge 102 is a bridge device that connects the local bus of the CPU 101 and the south bridge 104. The north bridge 102 also includes a memory controller that controls access to the main memory 103. The north bridge 102 also has a function of executing communication with the GPU 105 via a PCI EXPRESS standard serial bus or the like.

  The GPU 105 is a display controller that controls a liquid crystal panel 171 used as a display monitor of the computer 10. The GPU 105 uses the VRAM 105A as a work memory. A video signal generated by the GPU 105 is sent to the liquid crystal panel 171.

  The south bridge 104 controls each device on an LPC (Low Pin Count) bus and each device on a PCI (Peripheral Component Interconnect) bus. The south bridge 104 includes an IDE (Integrated Drive Electronics) controller for controlling the hard disk drive (HDD) 111 and the DVD drive 112. Further, the south bridge 104 has a function of executing communication with the sound controller 106. The sound controller 106 is a sound source device. In order to output audio data to be reproduced to the speakers 18A and 18B, a circuit such as a D / A converter that converts a digital signal into an electric signal and an amplifier that amplifies the electric signal is provided. Have. The sound controller 106 includes circuits such as a microphone amplifier that amplifies the electric signal input from the microphone 113 and an A / D converter that converts the amplified electric signal into a digital signal.

  The embedded controller / keyboard controller IC (EC / KBC) 116 is a one-chip microcomputer in which an embedded controller for power management and a keyboard controller for controlling the keyboard (KB) 13 and the touch pad 16 are integrated. . The embedded controller / keyboard controller IC (EC / KBC) 116 has a function of powering on / off the computer 10 in accordance with the operation of the power button 14 by the user.

  Next, functions of the media player 122 will be described. The media player 122 has a function of measuring the impulse response and frequency characteristics of the sound output from the sealed earphone. A configuration for measuring frequency characteristics will be described with reference to FIG.

  The media player 122 includes a measurement signal output unit 231, an impulse response calculation unit 233, a frequency characteristic calculation unit 234, and the like.

  The measurement signal output unit 231 outputs, for example, TSP signal data stored in the HDD 111 to the D / A converter 221.

  The sound controller 106 includes a D / A converter (digital-analog conversion circuit) 221, an amplifier 222, a microphone amplifier 223, an A / D converter (analog-digital conversion circuit) 224, and the like.

  The measurement signal output unit 231 outputs the digital data TSP signal data 241 to the D / A converter 221. The D / A converter 221 converts the TSP signal 241 into an analog measurement signal. The converted analog measurement signal is amplified by the amplifier 222, and the amplified analog measurement signal is supplied to the sealed earphone 200. The earphone 200 outputs a sound corresponding to the supplied measurement signal. The sound output from the earphone 200 is received by the microphone 113. The microphone 113 converts the received sound into an electrical measurement signal (reception signal) and supplies the measurement signal to the microphone amplifier 223. The microphone amplifier 223 amplifies the supplied measurement signal and supplies the amplified measurement signal to the A / D converter 224. The A / D converter 224 converts the measurement signal into digital data, and outputs the converted measurement signal to the impulse response calculation unit 233. The impulse response calculation unit 233 calculates an impulse response by convolving the inverse TSP signal data 235 with the measurement signal (convolution operation is performed on the measurement signal and the inverse TSP signal data 235). It is well known that the calculation amount of the impulse response may be reduced by calculating the convolution operation as a product of the measurement signal and the Fourier transform of the inverse TSP signal data 235. The inverse TSP signal data 235 is stored in the HDD 111, for example.

  The impulse response calculation unit 233 supplies the calculated impulse response to the frequency measurement calculation unit 234. The frequency measurement calculation unit 234 calculates a frequency amplitude spectrum by performing Fourier transform on the impulse response. FIG. 4 shows frequency characteristics of sound output from the earphone 200 and acquired by the microphone 113.

  Note that the reproduction-side amplifier 222 is adjusted so that the volume is appropriate for the earphone 200, and the reception-side microphone amplifier 223 is adjusted so that the dynamic range of the measurement signal can be used as wide as possible. Necessary for high measurements.

The TSP signal is a signal whose frequency continuously changes with time in order to sweep the frequency, and is often used when measuring characteristics of an acoustic device. There are various improved types of TSP signals. For example, standard TSP signals and log-TSP signals with logarithm sweeping so that the frequency sweep becomes slower as the frequency is lower are defined as follows in the frequency domain. Is done.

  Here, N is a signal length of TSP or Log-TSP, m is a parameter for determining a pulse width, k is a parameter for determining a frequency, and superscript * indicates a complex conjugate.

The inverse TSP signal is defined as a complex conjugate of the TSP signal in the frequency domain. For use in measurement, H _TSP (k) is inversely Fourier transformed to convert it into a signal having time as a parameter, and the converted signal is reproduced and used.

FIG. 5 shows a schematic diagram of a waveform obtained by inverse Fourier transform of H _TSP (k). Thus, the TSP signal is constituted by a sine wave having a constant amplitude and a continuously changing frequency. FIG. 5 shows an example in which the amplitude value is 100% for the sake of simplicity, but in practice it is safer to set it slightly lower due to the calculation error and the like. The measurement signal is input to a measurement target (earphone) and the output is observed to obtain a reception signal.

  FIG. 6 shows an example of the received signal. In the example shown in FIG. 6, the amplitude of the waveform near the center is small, but in the other regions, the same 100% amplitude as the reproduction signal is obtained. An impulse response can be obtained by convolving the inverse TSP signal with this received signal. Further, a frequency amplitude spectrum as shown in FIG. 7 can be obtained by Fourier transforming the impulse response.

  In FIG. 7, the frequency observed at the same level as the input is shown as 0 dB. In the received signal shown in FIG. 7, the amplitude of the spectrum of the frequency corresponding to the depression near the center of the received signal in FIG. 6 is observed to be lower than 0 dB.

  For example, when measuring the frequency characteristics of an earphone, the measurement signal shown in FIG. 5 is reproduced by an audio player, the sound output from the earphone is acquired by a microphone, and the impulse response of the earphone is convoluted with the inverted TSP signal. And frequency characteristics can be obtained.

  By the way, when the microphone 113 is brought close to the sealed earphone 200 and the output sound of the earphone 200 is measured, the sound is observed to be smaller as the frequency becomes lower. This is because the sealed earphone 200 is designed in consideration of resonance in a sealed state by putting it on the ear, so that it is difficult to hear low sounds when measured in an open state. Here, such a system is called a high-pass system.

A received signal obtained by receiving the sound output from the high-pass system by the microphone 113 has a waveform shown in FIG. As shown in FIG. 8, the amplitude in the low frequency range is observed to be extremely small compared to the amplitude in the high frequency range. The impulse response is generated by convolving the inverse TSP signal with the frequency amplitude spectrum shown in FIG. FIG. 9 shows the frequency amplitude spectrum of the generated impulse response. In the high frequency range, a volume around 0 dB, which is the same level as the measurement signal, is obtained. As the frequency decreases, the amplitude also decreases. If the amplitude is too small, it will be buried in noise and correct measurements will not be obtained. When the volume of the reproduction signal is increased by the amplifier 222 or the amplification factor of the microphone amplifier 223 is increased by increasing the level of the reception signal, the reception signal has a waveform as shown in FIG. In the high frequency range, there arises a problem that the distortion exceeds the upper limit value of the amplitude. In order to solve these problems, in this embodiment, a signal weighted to the frequency component of the TSP signal is used as a measurement signal. Specifically, the measurement signal M (k) obtained by multiplying the frequency weight W (k) by H (k) in the expression (1) or (2) as in the expression (3) is used.

The inverse TSP signal (M _inv (k)) is defined by the following equation (4).

  The weight can be similarly applied to TSP signals other than the aforementioned TSP signal and Log-TSP signal.

  It is practical to determine the weights experimentally. The amplitude pattern of the received signal is observed with respect to several measurement objects, and a weight of W (k) <1 is set for a frequency component having a large amplitude. Ideally, by setting the inverse characteristic of the average frequency amplitude spectrum of the target system as W (k), the received signal can be made a signal with almost no amplitude deviation.

  The measurement signal shown in FIG. 11 is an amplitude weighted TSP signal created by designing W (k) for the high-pass system. The amplitude of the measurement signal is suppressed by using a smaller value of W (k) as the gain of the target system is higher.

  FIG. 12 is a diagram showing the weighting factor W (k) used when creating the TSP signal shown in FIG. 11 and 1 / W (k) used when creating the inverse TSP signal. When it is known that the target system is a system that rises in the high frequency range, as shown in FIG. 12, a high frequency fall weight having an inverse characteristic is applied to the TSP to reduce the low frequency. It is possible to measure accurately from the high frequency range. The weight 1 / W (k) applied to the inverse TSP is designed to be symmetric with respect to the weight W (k) with respect to 0 dB.

  By outputting this TSP signal from the high-pass system, a received signal with no bias in amplitude as shown in FIG. 13 is obtained. However, the playback volume level and the reception volume level are the same as in the conventional method. Since the weight W (k) of the measurement signal is close to 1 in the low frequency range, a waveform with a small amplitude similar to the conventional one is observed. Since the amplitude of the measurement signal is suppressed by W (k) in the high frequency range, a small waveform is observed as it is. If it remains as it is, the entire band is buried in noise and it makes no sense, but by increasing the playback volume or reception volume, the observed waveform becomes as shown in FIG. 14, and measurement can be performed with a high gain regardless of the low frequency range and the high frequency range. . When the frequency amplitude spectrum is obtained after performing the inverse TSP process, the frequency amplitude spectrum becomes a waveform shown in FIG. The signal in the low frequency range has a value in the vicinity of 0 dB because the volume is increased to compensate for the lowering of the gain in the target system because the volume is increased. Since the amplitude of the signal in the high frequency range is reduced in advance, even if the gain in the high frequency range of the target system is high, the maximum amplitude of the received signal is not exceeded. Further, since the received signal is observed larger than the reproduced signal, a frequency amplitude characteristic higher than 0 dB can be obtained. In this way, by processing the amplitude value of the TSP signal in advance according to the properties of the target system, the dynamic range of the received signal can be used effectively, and the band where the reception level is low and buried in the noise conventionally. Can be measured at a sufficient volume.

  By the way, if it is allowed to increase the reproduction volume by the amplifier 222, it is possible to adjust so that the reception signal does not overflow by lowering the reception side level without using this method. Then, the noise superimposed on the target system can be reduced, so that the S / N ratio is likely to be increased even if the low-frequency received signal is weak. However, in reality, sufficient performance cannot be obtained due to problems such as circuit noise mounted after reception and quantization distortion. Therefore, it is effective to secure a sufficient amplitude at the received signal stage using this method. In addition, in a device that is not a measurement device such as a personal computer or a smartphone, there are many cases where the microphone level cannot be changed freely. In such a case, it is necessary to make adjustments based on the level of the reproduction signal, and this method is also effective in this case.

  Next, the playback function of the media player using the frequency characteristics of the sound output from the earphone 200 will be described. The playback function of the media player has a correction function that causes the sound output from the earphone 200 to have a target frequency characteristic based on the measured frequency characteristic of the earphone 200. Next, the configuration of the correction function of the media player will be described with reference to FIG.

  As shown in FIG. 16, the media player includes a measurement characteristic acquisition unit 401, a target characteristic acquisition unit 402, a correction filter design unit 404, a decoding unit 406, a correction unit 407, and the like.

  The measurement characteristic acquisition unit 401 acquires the frequency characteristic data 234 generated by the frequency characteristic calculation unit 234. The target characteristic acquisition unit 402 acquires target characteristic data indicating the target frequency characteristic of the sound that is output from the earphone 200 and reaches the eardrum (hereinafter referred to as target characteristic) from the target characteristic storage unit 403. The target characteristic storage unit 403 stores, for example, a plurality of target characteristic data. One of the plurality of target characteristic data indicates, for example, an ideal frequency characteristic. Another plurality of target characteristic data corresponds to a plurality of music genres. FIG. 17 shows an example of the frequency characteristic indicated by the target characteristic data. The target characteristic acquisition unit 402 acquires one target characteristic data selected by the user from among a plurality of target characteristic data stored in the target characteristic storage unit 403.

  The correction filter design unit 404 designs a correction filter (correction data) 405 for bringing the sound that is output from the earphone 200 and reaches the eardrum close to the target characteristic, based on the target characteristic data and the frequency characteristic data. The frequency characteristics indicated by the correction filter 405 are shown in FIG. The correction filter 405 has parameters used in, for example, a general parametric equalizer. Parameters used in the parametric equalizer are the center frequency, the width of the band to be adjusted, and the volume.

  The decoding unit 406 generates audio data by decoding data encoded in a compression format such as MP3. The correction unit 407 corrects the audio data based on the correction filter created by the correction filter design unit 404. The corrected audio data is input to the D / A converter. The D / A converter converts the audio data into an electric signal and outputs the converted electric signal to the amplifier. The amplifier amplifies the electric signal and outputs the amplified electric signal to the earphone 200. FIG. 19 shows the frequency characteristics (correction characteristics) of the sound output from the earphone 200. As shown in FIG. 19, it can be seen that the correction characteristics substantially match the target characteristics.

  Next, a procedure for measuring the frequency characteristic of the sound output from the earphone 200 and correcting the sound output from the earphone 200 based on the measured frequency characteristic will be described with reference to the flowchart of FIG.

  The measurement signal output unit 231 outputs the measurement sound from the earphone 200 by outputting the measurement signal to the sound controller 106 (step 501). The sound output from the earphone 200 is received by the microphone 113 (step 502). The acquired reception signal is supplied to the impulse response calculation unit 233. The impulse response calculation unit 233 calculates an impulse response by convolving the inverse TSP signal data 235 with the measurement signal (step B503). The impulse response calculation unit 233 supplies the calculated impulse response to the frequency measurement calculation unit 234. The frequency measurement calculation unit 234 calculates a frequency amplitude spectrum by performing Fourier transform on the impulse response (step B504).

  The target characteristic acquisition unit 402 acquires target characteristic data from the target characteristic storage unit 403 (step 505). The correction filter design unit 404 designs the correction filter 405 based on the frequency characteristic data 234 and the target characteristic data (step 506).

  The decoding unit 406 decodes the music data that has been compression-encoded (step 507). The correction unit 407 corrects the music data decoded based on the correction filter 405 (step 508). The correction unit 407 outputs the corrected music data to the sound controller 106. The sound controller 106 converts the music data into a music signal, amplifies the converted music signal, and outputs the amplified music signal to the earphone 200 (step 509).

  It is also possible to perform steps 501 to 506, store the parameters of the designed correction filter, read the parameters during music reproduction, and perform processing from step 506. Since the characteristics of the earphones do not fluctuate greatly, once the first half step is performed once and the parameters of the correction filter are obtained, the subsequent measurement can be saved by using those parameters.

  According to the present embodiment, when listening with the earphone 200, it sounds like a sound close to the ideal earphone 200. For example, when reproducing music, it is possible to enjoy high-quality music. In addition, even with an earphone 200 with low price and poor characteristics, the user can easily correct the characteristics of the earphone 200 by himself.

  Note that the coefficient of the correction filter is designed by comparing the frequency characteristics of the measured earphone with the characteristics of the ideal earphone. This means that a filter that fills the difference between the characteristics of the two earphones is designed. Therefore, when the same variation is added to the two characteristics, the variation does not appear in the difference.

(Modification)
FIG. 21 is obtained by flattening the amplitude control of the TSP signal shown in FIG. 10 in a predetermined range of the low frequency region and the high frequency region. If the level in the low frequency region is too large, there is a problem that the distortion of the reproduction signal becomes large, and it is effective to flatten to a certain level. If the signal on the high frequency side is too small, there is a problem that the quantization distortion increases and the accuracy of the reproduced signal is lowered, and it is effective to set a lower limit of the amplitude of the measurement signal. Only one of the methods is effective.

  FIG. 22 shows the weighting factor W (k) used when creating the TSP signal of FIG. 21 and 1 / W (k) used when creating the inverse TSP signal. Compared to the case of FIG. 11, the amplitude of the low range and the high range is limited so that the measurement signal does not become too large or too small.

  The weight W (k) indicates a first value C1 in a frequency range (˜Log (k1)) lower than the first frequency, and a first frequency and a second frequency higher than the first frequency. In the frequency range between (Log (k1) to Log (k2)), values from the first value C1 to the second value C2 lower than the first value C1 are shown, and the second frequency (Log (k2) In the higher frequency range, the second value C2 is indicated.

  The weight 1 / W (k) applied to the inverse TSP is designed to be symmetric with respect to the weight W (k) with respect to 0 dB.

  Since the procedure of impulse response calculation, frequency characteristic calculation, and playback function processing of this embodiment can be realized by a program, the software is installed in a normal computer through a computer-readable storage medium storing the program. By executing this, it is possible to easily realize the same effect as in the present embodiment.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  231 ... Measurement signal output unit, 233 ... frequency characteristic data generation unit, 234 ... frequency characteristic data, 312 ... sound absorbing material, 401 ... measurement characteristic acquisition unit, 402 ... target characteristic acquisition unit, 403 ... target characteristic storage unit, 404 ... Correction filter design unit, 405... Correction filter, 406... Decode unit, 407... Correction unit, 410.

Claims (13)

A first output unit for outputting an output signal corresponding to the first measurement signal to sweep the frequency by receiving the first output signal, the receiving device and for outputting a first received signal A measuring device for measuring an impulse response using a target system including:
Output means for supplying, to the output device, a first signal corresponding to a signal obtained by weighting a frequency component of a TSP (Time Stretched Pulse) signal as a first measurement signal with a weight that decreases as the frequency increases. When,
Receiving means for when said first signal as the first measuring signal is supplied to said output device from said output means, receiving said first reception signal output from the receiving device,
By performing convolution operation on the signal inverse measure having an inverse characteristic of the first reception signal and the first signal, measuring apparatus comprising a first arithmetic means you calculating the impulse response . The output device includes a sealed earphone,
The receiving device includes a microphone that approaches the sealed earphone and receives an output signal output from the output device,
The measuring apparatus according to claim 1 . The weight indicates a first value in a frequency range lower than the first frequency, and the first value in a frequency range between the first frequency and a second frequency higher than the first frequency. A value between the second value lower than the first value, and the second value in a frequency range higher than the second frequency;
Measurement apparatus according to any one of claims 1 and 2. Second calculation means for calculating a frequency characteristic of the first output signal output from the output device when the first signal is supplied from the output means to the output device based on the impulse response. The measuring apparatus according to any one of claims 1, 2, and 3 . Before SL first arithmetic means, said first received signal and the claim that calculates the product of the Fourier transform of the inverse measurement signal 1,2,3, measuring device according to any one of 4 . Precalculated claims 1, 2, 3, 4 comprising said storage unit further stores measurement signal data representing the first signal, measuring device according to any one of 5. Using a first output device for outputting an output signal corresponding to a first measurement signal, by receiving the first output signal, a target system including a receiving device and for outputting a first received signal Measuring the impulse response,
As the first measurement signal, a first signal corresponding to a signal obtained by weighting a frequency component of a TSP (Time Stretched Pulse) signal with a weight that decreases as the frequency increases is supplied to the output device,
In the case of supplying the first signal before SL output device, receiving the first reception signal output from the receiving device,
Calculating the impulse response by performing a convolution operation on the first received signal and an inverse measurement signal having an inverse characteristic of the first signal;
Measuring method. The output device includes a sealed earphone,
The receiving device includes a microphone that approaches the sealed earphone and receives an output signal output from the output device,
The measuring method according to claim 7. The weight indicates a first value in a frequency range lower than the first frequency, and the first value in a frequency range between the first frequency and a second frequency higher than the first frequency. A value between the second value lower than the first value, and the second value in a frequency range higher than the second frequency;
The measurement method according to any one of claims 7 and 8. 10. The method according to claim 7, further comprising calculating a frequency characteristic of the first output signal output from the output device when the first signal is supplied to the output device based on the impulse response. The measurement method according to any one of the above. The measurement method according to claim 7, wherein the calculation of the impulse response includes calculating a product of the first received signal and a Fourier transform of the inverse measurement signal. . The measurement method according to any one of claims 7, 8, 9, 10, and 11, wherein the first signal is obtained based on pre-calculated measurement signal data stored in a storage unit. And earphone for outputting a first output signal corresponding to the first measurement signal to sweep the frequency, close to the earphone, by receiving the first output signal, the first received signal A measuring device for measuring an impulse response using a target system including a microphone to output,
Output means for supplying, to the earphone, a first signal corresponding to a signal obtained by weighting a frequency component of a TSP (Time Stretched Pulse) signal as a first measurement signal with a weight that decreases as the frequency increases. ,
A receiving means for the case of supplying to the earphone of the first signal from said output means, receiving said first reception signal output from the microphone,
By performing convolution operation on the signal inverse measure having an inverse characteristic of the first reception signal and the first signal, a first arithmetic means for calculating the impulse response,
Second computing means for computing frequency characteristic data indicating a frequency characteristic of the first received signal based on the impulse response;
Correction data generating means for generating correction data for correcting the frequency characteristic based on the frequency characteristic data and target frequency characteristic data indicating the target frequency characteristic;
Correction means for correcting audio data based on the correction data;
An audio signal output means for outputting an audio signal based on the corrected audio data to the earphone.

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