Portable or wearable electronic device

Abstract

To provide a portable or wearable electronic device, which converts a sound in a non-audible frequency band to a sound audible to humans and outputs the sound.SOLUTION: A portable or wearable electronic device, which converts an operation sound generated during operation of a target apparatus, comprises: a sound acquisition circuit 10 which acquires an operation sound including abnormal noise as a sound pressure time signal that is a signal indicating a change over time in sound pressure intensity; a signal conversion circuit 20 which converts a signal corresponding to the sound pressure time signal into frequency characteristics indicating the sound pressure intensity for each frequency including a human non-audible frequency band, obtains a sonified signal obtained by changing a frequency of an abnormal noise signal, which indicates the sound pressure intensity of abnormal noise in the non-audible frequency band in a signal corresponding to the frequency characteristics, into a human audible frequency band, and outputs the sonified signal as an audible sound signal that is a signal indicating a change over time in the sound pressure intensity; and a speaker 40 which generates a sound on the basis of the audible sound signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to portable or wearable electronic devices. [Background technology]

[0002] A diagnostic device for rotating equipment has been disclosed that detects acoustic signals in a frequency range inaudible to humans and determines whether or not there is an abnormality in the rotating equipment based on the detected acoustic signals (see, for example, Patent Document 1). This diagnostic device for rotating equipment performs signal processing such as filtering on the detected acoustic signals in the inaudible frequency range, and then performs a Fourier transform to determine whether or not there is an abnormality in the rotating equipment based on the peak value of the signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-173229 Summary of the Invention [Problem to be solved by the invention]

[0004] When a target device for inspection, such as a rotating machine, is in an abnormal state, a person may need to listen to any abnormal sounds emitted from the target device when repairing the abnormal device. However, the diagnostic device described in Patent Document 1 can determine whether the target device is in an abnormal state, but cannot allow a person to hear any abnormal sounds emitted from the target device.

[0005] An object of the present disclosure is to provide a portable or wearable electronic device that converts sounds in an inaudible frequency band into sounds audible to humans and outputs the converted sounds. [Means for solving the problem]

[0006] The invention described in claim 1 is A portable or wearable electronic device that converts the operating sound generated when a target device is operating, a sound acquisition circuit (10) that acquires operation sounds, including abnormal sounds, as a sound pressure time signal that indicates a change in sound pressure intensity over time; a signal conversion circuit (20) that converts a signal corresponding to the sound pressure time signal into frequency characteristics that indicate the intensity of sound pressure for each frequency including a frequency band that is inaudible to humans, and obtains an audible signal by converting the frequency of an abnormal sound signal that indicates the intensity of sound pressure of an abnormal sound in the inaudible frequency band in the signal corresponding to the frequency characteristics into a frequency band that is audible to humans, and outputs the audible signal as an audible sound signal that indicates a change in the intensity of sound pressure over time; a speaker (40) that generates a sound based on an audible sound signal; When the frequency of the abnormal sound signal spans a frequency band having a predetermined bandwidth, the signal conversion circuit calculates the audible signal so that at least a portion of the frequency of the abnormal sound signal is included in a high sensitivity band, which is a frequency band in which human hearing is more sensitive than other frequencies in the human audible frequency band, and removes sound pressure signals in a band equal to or greater than a predetermined frequency in a frequency band higher than the high sensitivity band in the audible signal.

[0007] With this, even if the operating sound of the target device contains abnormal noises at frequencies inaudible to humans, the portable or wearable electronic device can convert the frequency of the abnormal noise into a frequency audible to humans and emit it so that it can be heard by humans.

[0008] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic configuration diagram of an electronic device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating an example of processing executed by a DSP unit according to the present embodiment. [Figure 3]10A and 10B are diagrams illustrating an example of frequency characteristics determined by a DSP unit according to the present embodiment. [Figure 4] FIG. 1 is a diagram showing equal loudness curves. [Figure 5] 10A and 10B are diagrams illustrating an example of frequency characteristics determined by a DSP unit according to the present embodiment. [Figure 6] 10 is a diagram showing an example in which the DSP unit according to the present embodiment removes a partial band of the frequency characteristics. FIG. [Figure 7] FIG. 10 is a spectrogram showing abnormal noise in the inaudible frequency band before the frequency is changed. [Figure 8] FIG. 10 is a spectrogram showing abnormal noise in the inaudible frequency band after changing the frequency. [Figure 9] 10A and 10B are diagrams illustrating an example of frequency characteristics determined by a DSP unit according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present disclosure will be described with reference to Figs. 1 to 8. A sound conversion device 1, which is a portable or wearable electronic device of this embodiment, is a device that converts the frequency of an abnormal sound when the operating sound of a target device P that is the subject of inspection contains the abnormal sound, and outputs the abnormal sound with the converted frequency. The target device P is, for example, production equipment installed in a factory. The abnormal sound is a sound that is generated when the target device P operates in an abnormal state that is not a normal state.

[0011] 1, the sound conversion device 1 includes an A / D conversion unit 10, a DSP unit 20, a D / A conversion unit 30, and a speaker 40. The sound conversion device 1 acquires information about the operation sound of the target device P from a microphone MC provided outside the sound conversion device 1.

[0012] The microphone MC is a sound detection unit that detects the operating sound of the target device P that is the inspection target, and outputs a signal corresponding to the detected operating sound to the outside as a sound pressure signal. The microphone MC is installed inside the target device P, and transmits the sound pressure signal corresponding to the operating sound of the target device P as an analog signal to the A / D conversion unit 10, for example, at predetermined intervals. Note that the microphone MC may be installed outside the target device P as long as it can collect the operating sound of the target device P.

[0013] The A / D conversion unit 10 is a sound acquisition unit that receives a sound pressure signal corresponding to the operation sound transmitted from the microphone MC. The A / D conversion unit 10 is composed of a microcomputer including a CPU, a memory such as a ROM, and a RAM, an input circuit, an output circuit, and their peripheral circuits. The A / D conversion unit 10 samples the analog signal transmitted from the microphone MC at a predetermined sampling interval and converts the analog signal into a digital signal. The A / D conversion unit 10 then acquires the operation sound generated when the target device P operates as a sound pressure time signal, which is a time signal indicating the change in sound pressure intensity over time. The sound pressure time signal contains information on the change in sound pressure intensity over time. The A / D conversion unit 10 outputs the acquired sound pressure time signal to the DSP unit 20. In this embodiment, the A / D conversion unit 10 functions as a sound acquisition circuit.

[0014] The DSP unit 20 is composed of a microcomputer including a CPU, a memory such as a ROM or RAM, an input circuit, an output circuit, and peripheral circuits. The memory includes a RAM, a ROM, a writable non-volatile memory medium, etc.

[0015] The storage unit also stores in advance a program for the DSP unit 20 to execute signal processing, which will be described later, and information, which will be described later, relating to abnormal noise from the target device P. When the sound pressure time signal converted into a digital signal from the A / D conversion unit 10 is transmitted to the input circuit, the DSP unit 20 executes signal processing in accordance with the program stored in the storage unit, and transmits a digital signal relating to the processed sound pressure signal from the output circuit to the D / A conversion unit 30. When executing a program recorded in the ROM of the storage unit or a writable non-volatile storage medium, the DSP unit 20 uses the RAM of the storage unit as a working area.

[0016] The D / A conversion unit 30 is a signal output unit that converts the digital signal input from the DSP unit 20 into an analog signal and outputs it. The D / A conversion unit 30 is composed of a microcomputer including a CPU, a ROM, a RAM, and other storage units, an input circuit, an output circuit, and their peripheral circuits. The D / A conversion unit 30 outputs a signal corresponding to the sound pressure signal converted into an analog signal to the speaker 40. The RAM, ROM, and writable non-volatile storage media in the A / D conversion unit 10, the DSP unit 20, and the D / A conversion unit 30 are all non-transient tangible storage media.

[0017] The speaker 40 is a sound generating unit that outputs a sound related to an abnormal sound from the target device P based on a signal input from the D / A conversion unit 30. The speaker 40 is installed, for example, near the target device P, and generates a sound related to an abnormal sound from the target device P to alert an operator who is near the target device P.

[0018] 2 to 5, the operation of the sound conversion device 1 configured as above will be described below. When the A / D conversion unit 10 receives a signal corresponding to the operating sound of the target device P from the microphone MC, the A / D conversion unit 10 acquires the operating sound generated when the target device P operates as a sound pressure time signal, and outputs the sound pressure time signal to the DSP unit 20.

[0019] When the DSP unit 20 receives the sound pressure time signal from the A / D conversion unit 10, it reads and executes a predetermined program from the storage unit, thereby performing the processing shown in FIG.

[0020] Specifically, when the DSP unit 20 receives the sound pressure time signal from the A / D conversion unit 10, first in step S10, the DSP unit 20 performs a Fourier transform on the received sound pressure time signal to convert the sound pressure time signal into a signal indicating the intensity of sound pressure for each frequency. For example, the DSP unit 20 extracts only a predetermined length of time from the input sound pressure time signal and performs a short-time Fourier transform on it to convert it into a signal indicating the intensity of sound pressure for each frequency. Hereinafter, the signal obtained by performing a short-time Fourier transform on the sound pressure time signal received from the A / D conversion unit 10 is also referred to as a post-Fourier transform signal.

[0021] The DSP unit 20 of this embodiment obtains a Fourier-transformed signal by converting the sound pressure time signal received from the A / D conversion unit 10 into sound pressure intensity for each frequency in a frequency band including a frequency band audible to ordinary people and a frequency band inaudible to ordinary people. For example, the frequency band audible to ordinary people is set to 20 Hz to 15,000 Hz, and the frequency band above 15,000 Hz is set to an inaudible frequency band.

[0022] In this case, the DSP unit 20 converts the sound pressure time signal received from the A / D conversion unit 10 into sound pressure intensity for each frequency in a frequency band from 20 Hz to a predetermined maximum frequency, which includes both audible and inaudible frequency bands. The maximum frequency that can be converted by the DSP unit 20 is set to, for example, 50,000 Hz, which is an inaudible frequency. Note that the maximum frequency that can be converted by the DSP unit 20 is not limited to 50,000 Hz, and may be set to a frequency greater than 50,000 Hz (e.g., 100,000 Hz) or a frequency less than 50,000 Hz (e.g., 30,000 Hz).

[0023] Next, in step S20, the DSP unit 20 obtains frequency characteristics that emphasize the sound pressure intensity of frequencies related to abnormal noise from the target device P in the inaudible frequency band from the Fourier transformed signal including the audible frequency band and the inaudible frequency band.

[0024] Here, the storage unit of the DSP unit 20 pre-stores information about the frequencies of abnormal sounds when the abnormal sounds are included in the operation sounds of the target device P, as information about the abnormal sounds included in the operation sounds of the target device P. Specifically, the storage unit of the DSP unit 20 stores information that the frequencies of the actual abnormal sounds of the target device P span a frequency band having a predetermined bandwidth. Furthermore, the storage unit of the DSP unit 20 pre-stores information about frequency bands within the inaudible frequency band that are included in the abnormal sounds and information about frequency bands that are not included in the abnormal sounds, for the operation sounds that include the actual abnormal sounds of the target device P.

[0025] Incidentally, abnormal noises of the target device P occur when the target device P is operating in an abnormal state, not a normal state. The abnormal noises generated when the target device P is operating in an abnormal state are likely to contain relatively the same frequency bands each time the target device P changes from a normal state to an abnormal state. For this reason, information on the frequency bands contained in the actual abnormal noises of the target device P and information on the frequency bands not contained in the abnormal noises can be obtained from experimental results, etc., in which actual operating sounds containing abnormal noises when the target device P is operated in an abnormal state are collected and analyzed.

[0026] In an experiment to obtain information on frequency bands included in actual abnormal noise from the target device P and information on frequency bands not included in abnormal noise, it may be determined whether or not a frequency band is included in an abnormal noise based on predetermined reference information. The reference information may be, for example, a predetermined threshold value for determining whether or not an abnormal noise is included when obtaining the sound pressure intensity obtained by performing Fourier analysis on the operating sound signal of the target device P. In this case, it is possible to perform Fourier analysis on the operating sound signal that includes actual abnormal noise when the target device P is operated in an abnormal state, and adopt the frequency band having a sound pressure intensity equal to or greater than the predetermined threshold as the frequency band of the abnormal noise.

[0027] Then, based on the information on the frequency band contained in the abnormal sound, the DSP unit 20 enhances the sound pressure intensity of the frequency band contained in the abnormal sound from the target device P in the inaudible frequency band from the Fourier transformed signal converted in step S10.

[0028] 3, an example of a method in which the DSP unit 20 enhances the intensity of the sound pressure in the frequency band contained in the abnormal noise of the target device P when the abnormal noise of the target device P is sound in the frequency band from 17,500 Hz to 19,500 Hz in the inaudible frequency band will be described. In this case, information on the frequency band from 17,500 Hz to 19,500 Hz is stored in the storage unit of the DSP unit 20 as information on the frequency band contained in the abnormal noise. In other words, the storage unit of the DSP unit 20 stores information that the frequency of the abnormal noise is from 17,500 Hz to 19,500 Hz.

[0029] The storage section of the DSP section 20 also stores information on frequency bands below 17,500 Hz and above 19,500 Hz as information on frequency bands that are not included in abnormal sounds. That is, the storage section of the DSP section 20 stores information that abnormal sounds are not included in sounds in the audible frequency band. The storage section of the DSP section 20 also stores information that abnormal sounds are not included in sounds in the inaudible frequency band below 17,500 Hz and above 19,500 Hz.

[0030] The DSP unit 20, which has information about the frequency band of such abnormal noise, performs an increase adjustment on the Fourier-transformed signal converted in step S10, increasing the signal intensity in the frequency band from 17,500 Hz to 19,500 Hz by a predetermined increment. Furthermore, the DSP unit 20 performs a decrease adjustment, decreasing the sound pressure intensity in the frequency band below 17,500 Hz and the frequency band above 19,500 Hz by a predetermined decrement.

[0031] This allows the DSP unit 20 to obtain the frequency characteristic Fs1 shown in Fig. 3, in which the intensity of the abnormal sound signal, which is the sound pressure signal of the abnormal sound from the target device P, is emphasized for the Fourier-transformed signal converted in step S10. The frequency characteristic Fs1 shown in Fig. 3 shows an example of a sound pressure signal in which the intensity of the abnormal sound signal has been emphasized. The frequency characteristic Fs1 in which the intensity of the abnormal sound signal has been emphasized in this way is the sound pressure signal corresponding to the Fourier-transformed signal converted in step S10.

[0032] The predetermined increase amount and the predetermined decrease amount for emphasizing the intensity of the abnormal sound signal are values ​​that can emphasize the intensity of the abnormal sound signal in the Fourier transformed signal and are set in advance in the storage unit of the DSP unit 20. The absolute values ​​of the predetermined increase amount and the predetermined decrease amount may be set to the same value or different values.

[0033] As shown in Fig. 3, in the frequency characteristic Fs1, the sound pressure signal in the frequency band below 17,500 Hz and above 19,500 Hz has significantly lower sound pressure intensity than the sound pressure signal in the frequency band from 17,500 Hz to 19,500 Hz. In the frequency characteristic Fs1, the sound pressure signal hardly changes even when the frequency changes in the frequency band below 17,500 Hz and above 19,500 Hz.

[0034] In contrast, in the frequency band from 17,500 Hz to 19,500 Hz, the rate of change in the sound pressure signal relative to a change in frequency is relatively large. Furthermore, in the frequency band from 17,500 Hz to 19,500 Hz, the shape of the change in the sound pressure signal is mountain-shaped. Specifically, from the frequency value of 17,500 Hz toward the frequency where the magnitude of the sound pressure signal is maximum, the sound pressure signal increases as the frequency increases. Furthermore, from the frequency where the magnitude of the sound pressure signal is maximum to the frequency value of 19,500 Hz, the sound pressure signal decreases as the frequency increases.

[0035] As described above, in the frequency characteristic Fs1 shown in Fig. 3, the shape indicating the abnormal noise signal is mountain-shaped, but in general, the shape of the sound pressure signal obtained by Fourier transforming abnormal noise generated in production equipment, etc. tends to be mountain-shaped. Among abnormal noise signals indicated by such a mountain shape, the frequency at which the sound pressure signal magnitude is maximum is the center frequency of the frequency band included in the abnormal noise or a frequency around that center frequency. Note that in the frequency characteristic Fs1 shown in Fig. 3, the sound pressure signal is maximum at a frequency of 19,200 Hz, which is higher than the center frequency of 18,500 Hz, within the frequency band from 17,500 Hz to 19,500 Hz.

[0036] Next, in step S30, the DSP unit 20 shifts the frequency of the frequency characteristic Fs1, which has emphasized the intensity of the abnormal sound signal, so that at least a part of the frequency of the abnormal sound signal is included in the audible frequency band. Specifically, the DSP unit 20 changes the frequency of the frequency characteristic Fs1 so that at least a part of the frequency of the sound pressure signal, which has been emphasized in step S20, is included in the audible frequency band. As a result, at least a part of the abnormal sound signal in the inaudible frequency band is included in the audible frequency band.

[0037] Incidentally, within the human audible frequency band, there are frequency bands to which the human hearing sensitivity is higher than other frequency bands. Here, high human hearing sensitivity means that humans can hear a louder sound even if the sound pressure intensity is constant. In other words, the perceived loudness of a sound that humans can hear changes depending on the frequency. The fact that the perceived loudness of a sound that humans can hear changes depending on the frequency will be explained with reference to the equal loudness curves in Figure 4.

[0038] Equal loudness curves are based on a sound with a predetermined loudness value at 1000 Hz in the audible frequency band, and represent the magnitude of a sound pressure signal that can be heard as loud as a sound with this loudness value, for each frequency. Regarding equal loudness curves, we will explain the change in frequency and the change in the magnitude of a sound pressure signal when a person tries to listen to a sound with a certain loudness value, using the loudness value of 20 phon as an example.

[0039] When a person hears a 20-phon sound, the smaller the frequency, the more the sound pressure signal needs to be increased by 20 dB in frequency bands below 1000 Hz, as shown in Figure 4. Also, when a person hears a 20-phon sound, the more the sound pressure signal needs to be increased by 20 dB in frequency bands above 1000 Hz, even in the frequency band from 1000 Hz to approximately 2000 Hz.

[0040] However, in the frequency band from about 2000 Hz to about 5000 Hz, humans can hear a 20-phon sound even if the sound pressure signal is less than 20 dB. Specifically, in the frequency band from about 2000 Hz to about 5000 Hz, the closer you get to 3500 Hz, the center frequency of this frequency band, the smaller the sound pressure signal required for humans to hear a 20-phon sound becomes.

[0041] However, when a person hears a sound of 20 phon, the sound pressure signal must be made larger than 20 dB in a frequency band larger than approximately 5000 Hz.

[0042] Thus, in the frequency band from about 2000 Hz to about 5000 Hz, humans can perceive a 20-phon sound even if the sound pressure signal is smaller than 20 dB, which is the magnitude of the reference sound sound pressure signal. Furthermore, in the frequency band from about 3000 Hz to about 4000 Hz, the sound pressure signal required for humans to hear a 20-phon sound can be made smaller. In other words, when the sound frequency is 3000 Hz to 4000 Hz, humans perceive it as a louder sound than when the sound frequency is different from the 3000 Hz to 4000 Hz band, even if the sound pressure signal is constant.

[0043] The above explanation was given using an example where the loudness value is 20 phon regarding the change in frequency and the change in the magnitude of the sound pressure signal when a person tries to listen to a sound of a certain volume. However, even if the loudness value is other values, the correspondence relationship between the change in frequency and the change in the magnitude of the sound pressure signal is the same.

[0044] For this reason, in this embodiment, the band from 3000 Hz to 4000 Hz, which is a frequency band within the human audible frequency band to which human hearing is more sensitive than other frequency bands, is defined as the high sensitivity band.The DSP unit 20 in the sound converter 1 of this embodiment then changes the frequency of the frequency characteristic Fs1 calculated in step S20 so that at least a part of the frequency band of the abnormal sound from the target device P is included in the high sensitivity band.

[0045] Specifically, the DSP unit 20 first removes sound pressure signal information in the frequency band of 15,000 Hz or less, including the audible frequency band, from the frequency characteristic Fs1 calculated in step S20. Then, the DSP unit 20 changes the frequency of the frequency characteristic Fs1 so that 18,500 Hz, which is the center frequency of the frequency band from 17,500 Hz to 19,500 Hz that is the frequency band of abnormal noise, is included in the high sensitivity band.

[0046] For example, the DSP unit 20 of this embodiment subtracts 15,000 Hz from the frequency value of the frequency characteristic Fs1 so that the sound pressure signal from 17,500 Hz to 19,500 Hz, which is the frequency band of the abnormal noise, overlaps with the entire high sensitivity band.

[0047] As a result, the frequency band values ​​included in the abnormal sound signal after the frequency has been shifted are frequencies included in the audible frequency band, from 2500 Hz to 4500 Hz. The frequency of the abnormal sound signal after the frequency has been changed includes the entire high sensitivity band from 3000 Hz to 4000 Hz, as shown in Figure 5, and the sound pressure signal at 18500 Hz, which is the center frequency of the frequency band of the abnormal sound, is included in this high sensitivity band. Among the frequencies of the abnormal sound signal after the frequency has been changed, the frequency at which the sound pressure signal has a maximum magnitude is 4200 Hz. Among the frequencies of the abnormal sound signal after the frequency has been changed, the frequency at which the sound pressure signal has a maximum magnitude is not included in the high sensitivity band.

[0048] Hereinafter, the signal obtained by the DSP unit 20 shifting the frequency of the frequency characteristic Fs1 will also be referred to as the audible signal. The frequency characteristic Fs2 shown in Fig. 5 is an example of the audible signal.

[0049] The lower limit of the sensitive band may be set to a frequency lower than 3000 Hz (e.g., 2500 Hz) if the frequency band is one in which human hearing is more sensitive than other frequency bands, and the upper limit of the sensitive band may be set to a frequency higher than 4000 Hz (e.g., 4500 Hz) if the frequency band is one in which human hearing is more sensitive than other frequency bands.

[0050] In this case, the DSP section 20 can appropriately change the subtraction value for obtaining the audible signal in accordance with the set lower limit value and upper limit value of the high sensitivity band.

[0051] Next, in step S40, the DSP unit 20 performs low-pass filtering on the audible signal obtained in step S30. Specifically, the DSP unit 20 removes sound pressure signals in a band equal to or greater than a predetermined frequency in a frequency band higher than the high sensitivity band. As shown in Fig. 6, the DSP unit 20 of this embodiment removes sound pressure signals in a frequency band equal to or greater than 6000 Hz, which is a frequency band higher than 4000 Hz, the upper limit of the high sensitivity band, and higher than 4500 Hz, the upper limit of the frequency of abnormal sound signals in the audible signal.

[0052] The lower limit of the frequency band removed by the DSP unit 20 may be a frequency lower than 6000 Hz (for example, 5000 Hz) as long as it is higher than the upper limit of the frequency of the abnormal sound signal in the audible signal. The lower limit of the frequency band removed by the DSP unit 20 may be a frequency higher than 6000 Hz (for example, 7000 Hz) as long as it is higher than the upper limit of the frequency of the abnormal sound signal in the audible signal.

[0053] Next, in step S50, the DSP unit 20 performs an inverse Fourier transform on the audible signal after the low-pass filter processing, converting the audible signal into a signal indicating a change in the intensity of sound pressure over time. Specifically, the DSP unit 20 extracts only a predetermined period of time, the same as that used in the short-time Fourier transform of the audible signal, and performs an inverse short-time Fourier transform on the extracted period, thereby converting the audible signal into an audible signal, which is a time signal indicating a change in the intensity of sound pressure over time. The DSP unit 20 outputs the converted audible signal to the D / A conversion unit 30.

[0054] 2 functions as a signal conversion circuit by executing the program stored in the storage unit. The DSP unit 20 may include a plurality of circuit modules each having a one-to-one correspondence with the processes of steps S10 to S50.

[0055] The D / A conversion unit 30 converts the audible sound signal input from the DSP unit 20 into an analog signal and outputs it. That is, the D / A conversion unit 30 outputs to the speaker 40 a signal corresponding to the sound pressure signal in a state in which the frequency of the abnormal sound included in the operating sound of the target device P has been changed from the inaudible frequency band to the audible frequency band.

[0056] The speaker 40 then outputs the abnormal sound of the target device P that has been converted from the inaudible frequency band to the audible frequency band based on the signal input from the D / A conversion unit 30. In this embodiment, the speaker 40 is installed in the vicinity of the target device P. Therefore, the sound conversion device 1 can make the abnormal sound audible to people present in the vicinity of the target device P. Therefore, for example, when a person is performing repair work on equipment that has broken down and is generating an abnormal sound, the person can perform the repair work on the equipment while listening to the abnormal sound, and can quickly determine whether the repair work on the equipment has been completed.

[0057] 7 and 8 show the results of simulating a spectrogram when the operating sound of the target device P is changed from the inaudible frequency band to the audible frequency band using the sound converter 1 of this embodiment. Note that the operating sound of the target device P includes not only the operating sound when it operates in a normal state but also the abnormal sound when it operates in an abnormal state.

[0058] Fig. 7 shows the simulation results of the abnormal noise in the inaudible frequency band before the frequency change, shown in a spectrogram including time components, frequency components, and sound pressure signal components. Fig. 8 shows the simulation results of the abnormal noise in the audible frequency band after the frequency change, shown in a spectrogram including frequency components, time components, and sound pressure signal components. In the spectrograms shown in Figs. 7 and 8, the horizontal axis represents the time component, the vertical axis represents the frequency component, and the density of the hatching indicates the magnitude of the sound pressure signal. The darker the hatching, the greater the sound pressure signal.

[0059] As shown in Fig. 7, the operating sounds of the target device P before the frequency change mainly include sounds with the largest sound pressure signal magnitude in the band below 8000 Hz as the operating sounds of the target device P when it operates in a normal state. Furthermore, sounds with smaller sound pressure signals than the sounds in the band below 8000 Hz are included in the band from 8000 Hz to 10000 Hz, and sounds with the smallest sound pressure signal magnitude are included in the band above 10000 Hz. These three sounds, each with a different sound pressure signal magnitude, are sounds generated by the target device P when it operates in a normal state, and include audible and inaudible frequency bands.

[0060] The sound in the band above 10,000 Hz when the target device P is operating in a normal state includes a sound of 17,000 Hz in the inaudible frequency band, which is an abnormal sound when the target device P is operating in an abnormal state. In the simulation to obtain the spectrogram shown in Fig. 7, a 17,000 Hz sound having a sound pressure signal of a predetermined magnitude was generated intermittently as an abnormal sound when the target device P is operating in an abnormal state.

[0061] Furthermore, as shown in Fig. 8, the operating sound of the target device P after the frequency change includes three sounds with different sound pressure signal amplitudes, similar to the spectrogram shown in Fig. 7, as operating sounds when the target device P operates in a normal state. Furthermore, a 2000 Hz sound is included as an abnormal sound whose frequency has been changed from the inaudible frequency range to the audible frequency range. In this way, by outputting a sound whose frequency has been changed from the inaudible frequency range to the audible frequency range, a person can hear the abnormal sound whose frequency has been changed to the audible frequency range.

[0062] As described above, the DSP unit 20 of the sound conversion device 1 converts the sound pressure time signal into frequency characteristics, converts the frequency of the abnormal sound signal in the inaudible frequency band to a frequency in the audible frequency band to obtain an audible signal, and outputs the obtained audible signal as an audible sound signal to the D / A conversion unit 30. Then, based on the signal input from the D / A conversion unit 30, the speaker 40 outputs the abnormal sound of the target device P that has been converted from the inaudible frequency band to the audible frequency band.

[0063] According to this, even if the operating sound of the target device P includes an abnormal sound with a frequency in the inaudible frequency range for humans, the frequency of the abnormal sound can be converted into a frequency range audible to humans and then generated so that the sound can be heard by humans.

[0064] Furthermore, according to the above embodiment, the following effects can be obtained.

[0065] (1) In the above embodiment, the DSP unit 20 obtains the audible signal so that at least a part of the abnormal sound signal falls within a high sensitivity band in which the sensitivity of human hearing is higher than other frequency bands in the human audible frequency band.

[0066] The reason for obtaining the audible signal in this manner is that, as described above, even if the magnitude of the sound pressure signal of the sound is constant, the sensitivity of human hearing varies depending on the frequency of the sound. Therefore, according to this embodiment, the frequency band of the abnormal sound is changed to be included in a high sensitivity band in which the sensitivity of human hearing is higher than other frequency bands in the human audible frequency band, making it easier for people to hear the abnormal sound.

[0067] (2) In the above embodiment, the DSP unit 20 obtains the audible signal so that the center frequency of the frequency band of the abnormal sound signal is included in the high sensitivity band.

[0068] The reason for obtaining the audible signal in this manner is that, as described above, the frequency band included in the abnormal sound tends to have a large sound pressure signal at and around the center of the frequency band. Therefore, according to this embodiment, the frequency band in which the sound pressure signal in the abnormal sound signal tends to be large can be included in the high sensitivity band, making it even easier for people to hear the abnormal sound.

[0069] (3) In the above embodiment, the DSP unit 20 removes sound pressure signals in a band of 6000 Hz or higher, which is a predetermined frequency in a frequency band higher than the high sensitivity band.

[0070] This emphasizes the sound pressure signal of abnormal noise contained in a frequency band below 6000 Hz, making it easier for people to hear the abnormal noise.

[0071] (4) In the above embodiment, the DSP unit 20 obtains frequency characteristics that emphasize the intensity of the abnormal sound signal, and obtains the audible signal based on the frequency characteristics in which the intensity of the abnormal sound signal has been emphasized.

[0072] According to this, the audible signal is generated based on frequency characteristics in which the sound pressure signal of the abnormal noise is emphasized, making it even easier for people to hear the abnormal noise.

[0073] (5) In the above embodiment, the DSP unit 20 performs an increase adjustment to increase the intensity of the sound pressure of the frequency included in the abnormal sound signal and a decrease adjustment to decrease the intensity of the sound pressure of the frequency different from the frequency included in the abnormal sound signal, thereby emphasizing the intensity of the abnormal sound signal.

[0074] This makes it easier for people to hear abnormal sounds because the abnormal sound signal is more emphasized in the frequency characteristics than when high-pass filtering is performed, which passes only sounds above a specified frequency.

[0075] (Other embodiments) Representative embodiments of the present disclosure have been described above, but the present disclosure is not limited to the above-described embodiments and can be modified in various ways, for example, as follows.

[0076] In the above embodiment, an example has been described in which the DSP unit 20 performs Fourier transform processing on the sound pressure time signal, and the frequency characteristics are obtained by emphasizing the intensity of the sound pressure in the frequency band related to the abnormal sound for the Fourier transformed signal, but the present invention is not limited to this.

[0077] For example, the DSP unit 20 may use well-known signal processing software to perform Fourier transform processing on a signal in which the sound pressure intensity in a frequency band related to an abnormal sound in the sound pressure time signal is emphasized, thereby obtaining the frequency characteristics. That is, the DSP unit 20 may perform processing equivalent to step S10 after performing processing equivalent to step S20 in the processing shown in Fig. 2. In this case, the signal obtained by performing processing equivalent to step S20 in the processing shown in Fig. 2 is a sound pressure signal corresponding to the sound pressure time signal.

[0078] In the above embodiment, an example has been described in which the DSP unit 20 calculates the audible signal by changing the frequency band of the abnormal sound signal to a frequency band smaller than before the change, but this is not limiting. For example, if the frequency of the abnormal sound is smaller than the audible frequency band, the DSP unit 20 may calculate the audible signal by changing the frequency band of the abnormal sound signal to a frequency larger than before the change.

[0079] In the above embodiment, an example has been described in which the speaker 40, which is a sound generating unit, is installed near the target device P, but the present invention is not limited to this. For example, the speaker 40 may be installed away from the target device P. Specifically, the speaker 40 may be mounted on a portable or wearable electronic device carried by the worker, and may be provided in, for example, a mobile phone, a tablet terminal, a smartwatch, or the like.

[0080] According to this, the sound converter 1 can make the abnormal sound heard by people who are not in the vicinity of the target device P. Therefore, people can hear the abnormal sound even when they are located far away from the equipment.

[0081] In the above embodiment, an example has been described in which the DSP unit 20 determines the audible signal so that at least a portion of the frequencies of the abnormal sound signal in the frequency characteristics is included in the high sensitivity band, but this is not limiting. For example, the DSP unit 20 may determine the audible signal so that all of the frequencies of the abnormal sound signal in the frequency characteristics are included in a frequency band other than the high sensitivity band in the audible frequency band.

[0082] In the above embodiment, an example has been described in which the DSP unit 20 determines the audible signal so that the center frequency in the frequency band of the abnormal sound signal is included in the high sensitivity band, but this is not limiting. For example, as shown in Fig. 9, the DSP unit 20 may determine the audible signal so that the frequency at which the sound pressure signal is greatest in the frequency band of the abnormal sound signal is included in the high sensitivity band.

[0083] According to this, the frequency at which the sound pressure signal in the frequency band of the abnormal sound is greatest is included in the high sensitivity band, so that the abnormal sound can be made more audible to people.

[0084] In the above embodiment, an example has been described in which the DSP unit 20 shifts the frequency of the frequency characteristic Fs1 so that the center frequency of the frequency band of the abnormal sound signal falls within the high sensitivity band, but the present invention is not limited to this. For example, the DSP unit 20 may shift only the sound pressure signal of the center frequency of the frequency band of the abnormal sound signal into the high sensitivity band so that the center frequency of the frequency band of the abnormal sound signal falls within the high sensitivity band.

[0085] In the above embodiment, an example has been described in which the DSP unit 20 removes sound pressure signals in a band equal to or greater than 6000 Hz, which is a predetermined frequency in a frequency band higher than the high sensitivity band. However, the present invention is not limited to this. For example, the DSP unit 20 may be configured not to remove sound pressure signals in a band equal to or greater than a predetermined frequency in a frequency band higher than the high sensitivity band. In other words, the DSP unit 20 may execute a process shown in FIG. 2 in which the process of step S40 is omitted.

[0086] In the above embodiment, an example has been described in which the DSP unit 20 obtains frequency characteristics that emphasize the intensity of the abnormal sound signal, and obtains a sonified signal based on the frequency characteristics in which the intensity of the abnormal sound signal has been emphasized, but the present invention is not limited to this.

[0087] For example, the DSP unit 20 may obtain the audible signal based on frequency characteristics in which the intensity of the allophone signal is not emphasized. That is, the DSP unit 20 may execute a process in which the process of step S20 is omitted from the process shown in FIG.

[0088] In the above embodiment, an example has been described in which the DSP unit 20 emphasizes the intensity of the abnormal sound signal by performing an increase adjustment to increase the intensity of the sound pressure of frequencies included in the abnormal sound signal and a decrease adjustment to decrease the intensity of the sound pressure of frequencies different from the frequencies included in the abnormal sound signal. However, the processing of the DSP unit 20 is not limited to this.

[0089] For example, the DSP section 20 may emphasize the intensity of the abnormal noise signal by performing only one of the increase adjustment and the decrease adjustment.

[0090] In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential unless they are specifically stated as essential or are clearly considered essential in principle.

[0091] In the above-described embodiments, when numerical values ​​such as the number, values, amounts, ranges, etc. of components of the embodiments are mentioned, they are not limited to the specific numbers unless they are expressly stated as being essential or are clearly limited to a specific number in principle.

[0092] In the above-described embodiments, when referring to the shapes, positional relationships, etc. of components, etc., the shapes, positional relationships, etc. are not limited to those unless otherwise specified or when they are limited in principle to specific shapes, positional relationships, etc. [Explanation of symbols]

[0093] 10 Sound acquisition section 40 Sound generating unit S10 Characteristic acquisition section S30 Frequency change unit S50 signal inverse converter

Claims

1. A portable or wearable electronic device that converts the operating sound of a target device, a sound acquisition circuit (10) that acquires the operation sound, including the abnormal sound, as a sound pressure time signal that indicates a change in the intensity of the sound pressure over time; a signal conversion circuit (20) that converts a signal corresponding to the sound pressure time signal into frequency characteristics that indicate the intensity of sound pressure for each frequency including a frequency band that is inaudible to humans, obtains an audible signal by changing the frequency of an abnormal sound signal that indicates the intensity of sound pressure of the abnormal sound in the inaudible frequency band in the signal corresponding to the frequency characteristics to a frequency band that is audible to humans, and outputs the audible signal as an audible sound signal that indicates a change in the intensity of sound pressure over time; a speaker (40) that generates a sound based on the audible sound signal; When the frequency of the abnormal sound signal spans a frequency band having a predetermined bandwidth, the signal conversion circuit calculates the audible signal so that at least a portion of the frequency of the abnormal sound signal falls within a high sensitivity band, which is a frequency band in which human hearing is more sensitive than other frequencies in the human audible frequency band, and removes sound pressure signals in a band equal to or greater than a predetermined frequency in a frequency band higher than the high sensitivity band in the audible signal.

2. The portable or wearable electronic device according to claim 1 , wherein the signal conversion circuit determines the audible signal so that a center frequency of the frequency band of the abnormal sound signal is included in the high sensitivity band.

3. 3. The portable or wearable electronic device according to claim 1, wherein the signal conversion circuit determines the audible signal so that the frequency at which the sound pressure signal is greatest in the frequency band of the abnormal sound signal is included in the high sensitivity band.

4. 4. The portable or wearable electronic device according to claim 1, wherein the signal conversion circuit determines the frequency characteristics in which the intensity of the abnormal sound signal is emphasized, and determines the audible signal based on the frequency characteristics in which the intensity of the abnormal sound signal is emphasized.

5. 5. The portable or wearable electronic device according to claim 4, wherein the signal conversion circuit emphasizes the intensity of the abnormal sound signal by performing at least one of an increase adjustment that increases the intensity of sound pressure at a frequency included in the abnormal sound signal and a decrease adjustment that decreases the intensity of sound pressure at a frequency different from the frequency included in the abnormal sound signal.

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