Technical Field
[0001] The invention relates to a sound processing apparatus.
Background Art
[0002] Some conventional vehicles are provided with a sound processing apparatus that allows
an occupant of a vehicle to talk with an operator of an emergency notification center
when an accident or other emergency arises in the vehicle. Such a sound processing
apparatus is disclosed in Japanese Unexamined Patent Application Publication
2016-107972.
[0003] US 2016/192084 A1 discloses a MEMS microphone sensitive to audible sounds and ultrasounds. The system
also provides signal processing including a sigma-delta conversion in order to filter
signals received by the microphone. The acoustic signal may be processed by another
apparatus. A threshold is provided to detect activity for voice or ultrasound. A detected
ultrasound event is used to send control signals to an external device.
[0004] US 2017/251302 A1 describes a sound processing apparatus for a microphone, providing a band splitter
for splitting a digital audio signal provided by the microphone to audible (SP1) and
ultrasonic or near ultrasonic frequency range signal (SP2), a threshold detection
on the inaudible signal (SP2) is performed.
[0005] The sound processing apparatus includes a loudspeaker, a signal output unit, a microphone,
a failure diagnosis part, a signal processor, and a wireless communication part. Using
a diagnostic signal of frequencies outside the voice band, the signal output unit
modulates diagnostic data and allows the modulated signal to be outputted from the
loudspeaker. The output modulated signal is acquired by the microphone and converted
into an electric signal. The failure diagnosis part demodulates the electric signal
inputted from the microphone to generate data and determines whether the generated
data includes any data that matches the diagnostic data. When determined that the
demodulated data includes data that matches the diagnostic data, the failure diagnosis
part determines that the loudspeaker is not in failure. When determined that the demodulated
data does not include data that matches the diagnostic data, the failure diagnosis
part determines that the loudspeaker is in failure. The modulated signal, which is
of frequencies outside the voice band, is difficult to be heard by the occupant of
the vehicle. When the failure diagnosis part determines that the loudspeaker is not
in failure, the signal processor subsequently generates sound data based on the voice
of the occupant acquired by the microphone and transmits the sound data through the
wireless communication part, while processing the sound data received from the operator
through the wireless communication part to output the processed sound data to the
loudspeaker. This allows the occupant to talk to the operator.
Summary of Invention
Technical Problem
[0006] In the above conventional sound processing apparatus, the occupant cannot talk with
the operator until the failure diagnosis part completes the failure diagnosis for
the loudspeaker.
[0007] The invention provides a sound processing apparatus capable of performing failure
diagnosis while performing sound processing.
Solution to Problem
[0008] In order to solve the above problem, a first aspect of the invention provides a sound
processing apparatus as defined in claim 1. In one embodiment, the sound processing
apparatus includes a microphone, a first band-pass filter, an audio signal processor,
a Fourier transformer, and a signal level determiner. The microphone is configured
to simultaneously acquire an audible sound having a frequency in an audible range
and an inaudible sound having a frequency in an inaudible range, to convert an acquired
audible and inaudible sound into electric signals, and to output the electric signals.
The first band-pass filter is configured to receive the electrical signals outputted
from the microphone and remove components of the electrical signals that are outside
the audible range. The audio signal processor is configured to apply predetermined
signal processing to the electric signals that have passed through the first band-pass
filter. The Fourier transformer is configured to receive the electrical signals outputted
from the microphone and perform a frequency analysis on the received electric signals
so as to obtain frequency components of the electric signals. The obtained frequency
components include frequency components in the inaudible range. The signal level determiner
is configured to perform a first determination as to whether the frequency components
in the inaudible range have a signal level being equal to or greater than a threshold
value. In the sound processing apparatus of this aspect, the signal level determiner
can perform the first determination while the audio signal processor is performing
the signal processing. If it is determined in the first determination that the signal
level of the frequency components in the inaudible ranges is not equal to or greater
than the threshold value, the sound processing apparatus is able to detect failure
of the loudspeaker.
[0009] The signal level determiner may be further configured to perform a second determination
when it is determined in the first determination that the frequency components in
the inaudible range is equal to or greater than the threshold value. The second determination
may be made such that it is determined whether the frequency components in the inaudible
range have a signal level within a predetermined range, the predetermined range being
equal to or greater than the threshold value. In the sound processing apparatus of
this aspect, the signal level determiner can perform the first and second determinations
while the audio signal processor is performing the signal processing. If it is determined
in the first and second determinations that the signal level of the frequency components
in the inaudible ranges is equal to or greater than the threshold value and is not
within the predetermined range equal to or greater than the threshold value, the sound
processing apparatus is able to detect deterioration of the loudspeaker.
[0010] In the present invention, a plurality of the microphones is provided. Also, in one
embodiment, a plurality of the Fourier transformers is provided, and each of the Fourier
transformers being configured to perform a frequency analysis on the electric signals
outputted from a corresponding one of the microphones so as to obtain frequency components
of the electric signals. The obtained frequency components include frequency components
in the inaudible range. A plurality of the signal level determiners is provided, and
each of the signal level determiners is configured to perform the first determination.
In the sound processing apparatus of this aspect, if all the signal level determiners
each determine in the first determination that the signal level of the frequency components
in the inaudible ranges is not equal to or greater than the threshold value, the sound
processing apparatus is able to detect failure of all the microphones or a speaker
connected to or installed in the sound processing apparatus. Also, if at least one
of the signal level determiners each determine in the first determination that the
signal level of the frequency components in the inaudible ranges is not equal to or
less than the threshold value, the sound processing apparatus is able to detect failure
of the at least one of the microphones or a speaker.
[0011] The signal level determiners may be configured such that, when at least one of the
signal level determiners determines in the first determination that the signal level
of the frequency components in the inaudible range is equal to or greater than the
threshold value, the at least one of the signal level determiners further performs
the second determination. In the sound processing apparatus of this aspect, if all
the signal level determiners each determine in the first and second determinations
that the signal level of the frequency components in the inaudible range is equal
to or greater than the threshold value but not within a predetermined range equal
to or greater than the threshold value, the sound processing apparatus is able to
detect deterioration of a loudspeaker. Also, if at least one of the signal level determiners
each determine in the first and second determinations that the signal level of the
frequency components in the inaudible range is equal to or greater than the threshold
value but not within the predetermined range equal to or greater than the threshold
value, the sound processing apparatus is able to detect deterioration of the at least
one of the microphones or a speaker.
[0012] The microphones are disposed at different distances from a loudspeaker capable of
emitting inaudible sounds. The respective threshold values for the signal level determiners
differ from one another according to the respective distances from the corresponding
microphones to the loudspeaker. In the sound processing apparatus of the present invention,
each threshold value is set according to the distance from the corresponding microphone
to the loudspeaker, improving the accuracy of determination by the plurality of signal
level determiners.
[0013] The respective threshold values and the predetermined ranges for the signal level
determiners may differ from one another according to the respective distances from
the corresponding microphones to the loudspeaker. In the sound processing apparatus
of this aspect, each threshold value and each predetermined range is set according
to the distance from the corresponding microphone to the loudspeaker, improving the
accuracy of determination by the plurality of signal level determiners.
[0014] The sound processing apparatus according to any of the above aspects may further
include a loudspeaker. The loudspeaker may be configured to emit an inaudible sound,
or alternatively configured to simultaneously emit audible and inaudible sounds.
[0015] A second aspect of the invention provides a sound processing apparatus according
to claim 8. The sound processing apparatus of this aspect includes a second band-pass
filter in place of the or each Fourier transformer. The second band-pass filter may
be configured to receive the electrical signals outputted from the at least one microphone
and remove frequency components of the electrical signals that are other than frequency
components in the inaudible range. The signal level determiner may be configured to
perform a first determination as to whether the frequency components in the inaudible
range, which have passed through the second band-pass filter, have a signal level
being equal to or greater than a threshold value. Also in the sound processing apparatus
of this aspect, the signal level determiner can perform the first determination while
the audio signal processor is performing the signal processing. If it is determined
in the first determination that the signal level of the frequency components in the
inaudible range is not equal to or greater than the threshold value, the sound processing
apparatus is able to detect failure of the loudspeaker. It should be noted that the
sound processing apparatus of the second aspect may have a similar configuration as
that of various aspects of the signal processing apparatus of the first aspect described
above.
Brief Description of Drawings
[0016]
Fig. 1 is a block diagram of a sound processing apparatus according to a first embodiment
of the invention.
Fig. 2 is a graph showing results of a simulation performed with the sound processing
apparatus.
Description of Embodiments
[0017] The following discussion is directed to various embodiments of the invention.
First embodiment
[0018] The following is a description of a sound processing apparatus D according to a plurality
of embodiments including the first embodiment of the invention, with reference to
Fig. 1. Fig. 1 shows the sound processing apparatus D according to the first embodiment.
The sound processing apparatus D can be installed in an electronic equipment that
requires sound processing. For example, the sound processing apparatus D may be installed
in an emergency notification device, a telephone conference device, a television receiver
or other acoustic devices, an automatic teller machine, a ticket vending machine,
a personal computer, or a smartphone or a tablet computer or other portable mobile
terminals.
[0019] The sound processing apparatus D includes at least one loudspeaker 100, at least
one microphone 200, at least one first band-pass filter 300, at least one audio signal
processor 400, at least one Fourier transformer (FFT) 500, at least one signal level
determiner 600, at least one analog-to-digital converter (A/D converter) 700, and
at least one second band-pass filter 800. Each of these elements of the sound processing
apparatus D will be described in detail below.
[0020] The loudspeaker 100 is configured to emit an inaudible sound, or alternatively configured
to emit an audible sound and an inaudible sound simultaneously and individually. The
inaudible sound is any sound of frequencies in an inaudible range and cannot be heard
by humans. For example, the inaudible sound may be of frequencies in the range from
20 kHz to 24 kHz. The audible sound is any sound of frequencies in an audible range
and can be heard by humans. For example, the audible sound may be of frequencies in
the range from 300 Hz to 3 kHz.
[0021] The at least one microphone 200 is able to acquire an audible sound and an inaudible
sound simultaneously and individually. The at least one microphone 200 is configured
to acquire ambient sounds, convert the acquired sounds into electric signals, and
output the electric signals. Ambient sounds include at least one of an audible sound
and an inaudible sound. The audible sound acquired includes an audible sound emitted
from the loudspeaker 100, a voice of a user of the sound processing apparatus D, and/or
an ambient noise. The inaudible sound acquired includes an inaudible sound emitted
from the loudspeaker 100 and/or an ambient noise. Specifically, when the at least
one microphone 200 simultaneously acquires audible and inaudible sounds, the electric
signals include signals corresponding to the audible sound (hereinafter referred to
as "audible signals") and signals corresponding to an inaudible sound (hereinafter
referred to as "inaudible signals"). When the at least one microphone 200 acquires
audible sounds only, the electric signals are audible signals. When the at least one
microphone 200 acquires inaudible sounds only, the electric signals are inaudible
signals.
[0022] The electric signals (audible signals and/or inaudible signals) outputted from the
at least one microphone 200 are converted into digital signals by the at least one
A/D converter 700, and the converted digital electric signals are inputted into the
at least one first band-pass filter 300 and the at least one Fourier transformer 500.
The output of the first band pass filter 300 is fed to the audio signal processor
400, and the output of the Fourier transformer 500 is inputted to the second bandpass
filter 800. Accordingly, the processing by the at least one first band-pass filter
300 and the at least one audio signal processor 400 and the processing by the at least
one Fourier transformer 500 and the signal level determiner 600 are performed as parallel
processing to be described and as shown in Fig. 1.
[0023] The at least one first band-pass filter 300, the at least one audio signal processor
400, the at least one Fourier transformer (FFT) 500, the at least one signal level
determiner 600, and the at least one A/D converter 700 may be constituted by respective
logic circuits in an integrated circuit, or alternatively constituted by respective
pieces of software to be processed by a processor, or alternatively constituted by
discrete logic circuits.
[0024] The or each first band-pass filter 300 is configured to filter electric signals (audible
signals and/or inaudible signals) inputted thereinto and output the filtered electric
signals to the associated audio signal processor 400. Specifically, the at least one
first band-pass filter 300 is configured to filter components of electric signals
so as to pass components within the audible range (i.e. audible signals within the
voice band, such as the range from 125 Hz to 8 kHz) only and remove components outside
the audible range.
[0025] The at least one audio signal processor 400 is configured to generate a test signal
according to predetermined information input and allow the test signal to be outputted
from the loudspeaker 100. The loudspeaker 100 emits an inaudible sound on the basis
of the inputted test signal. Some non-limiting examples of the predetermined information
input are predetermined operation information input inputted to the at least one audio
signal processor 400 through an input part of the electronic equipment, information
inputted to the at least one audio signal processor 400 from a timer circuit in the
electronic equipment or the sound processing apparatus D when a preset time expires,
and an output signal form an impact sensor or other sensor in the electronic equipment.
[0026] The at least one audio signal processor 400 is also configured to receive audible
signals that have passed through the at least one first band-pass filter 300, performs
predetermined signal processing, generates sound data adapted for wireless or wired
transmission, and causes a wireless or wired communication part of the electronic
equipment to output the sound data. It should be appreciated that the above signal
processing may be echo removal, equalization, noise removal, or other processing for
making audible signals easier to hear when outputted from another loudspeaker than
the loudspeaker 100. The signal processing may be hereinafter referred to as first
audio signal processing.
[0027] The at least one audio signal processor 400 is further configured to processes data
received through the communication part of the electronic equipment to convert the
data into audio signals (this processing may be hereinafter referred to as second
audio signal processing), and transmit the audio signals to the loudspeaker 100. Based
on such audio signal input, the loudspeaker 100 emits audible sounds. The at least
one audio signal processor 400 may also be configured to mix the test signal and the
audio signals and transmit the mixed signals to the loudspeaker 100, so that the loudspeaker
100 can emit inaudible sounds and audible sounds simultaneously.
[0028] The or each Fourier transformer 500 is configured to perform fast Fourier transform
(FFT) processing on electric signal inputs (audible signals and/or inaudible signals)
from the corresponding A/D converter 700, thereby performing frequency analysis (spectrum
analysis) of the electric signals to obtain the frequency components of the electric
signals, which include frequency components within the audible range, i.e. frequency
components of the audible signals, and/or frequency components in the inaudible range,
i.e. the frequency components of the inaudible signals. The or each Fourier transformer
500 is further configured to output the obtained frequency components of the electric
signals to the corresponding second band-pass filter 800.
[0029] The or each second band-pass filter 800 is configured to filter frequency components
of electric signals inputted thereinto and output the filtered frequency components
to the corresponding signal level determiner 600. Specifically, the or each second
band-pass filter 800 is configured to filter frequency components of inputted electric
signals so as to pass frequency components in the inaudible ranges (i.e. frequency
components of the inaudible signals) and remove other frequency components.
[0030] The at least one signal level determiner 600 has configuration A) or B) described
below, for example.
Configuration A): The or each signal level determiner 600 is configured to perform
first determination processing and outputs the result to the electronic equipment.
In the first determination processing, it is determined whether the inputted frequency
components of the inaudible ranges have a signal level equal to or greater than a
threshold value prestored in a memory in the corresponding logic circuit or processor.
The threshold value is set to a signal level of the frequency components corresponding
to the inaudible sound emitted by a loudspeaker 100 functioning normally.
Where the or each signal level determiner 600 has configuration A) described above,
the result of the first determination processing is either A-1) or A-2) below.
Result A-1): When the or each signal level determiner 600 determines that the signal
level of the frequency components in the inaudible ranges is equal to or greater than
the threshold value, it is detected that the loudspeaker 100 is not in failure.
Result A-2): When the or each signal level determiner 600 determines that the signal
level of the frequency components in the inaudible ranges is not equal to or greater
than the threshold value (i.e. is less than the threshold value), it is detected that
that the loudspeaker 100 is in failure.
Configuration B): The or each signal level determiner 600 may be configured to additionally
perform second determination processing when it is determined in the first determination
processing that the signal level of the frequency components in the inaudible ranges
is equal to or greater than the threshold value. In the second determination processing,
it is determined whether the signal level is within a predetermined range prestored
in a memory in the corresponding logic circuit or processor. This predetermined range
is set as a range equal to or greater than the threshold value of frequency components
corresponding to inaudible sounds emitted by a loudspeaker 100 functioning normally.
When the or each signal level determiner 600 of configuration B) described above performs
the first and second determination processing, it is determined as one of B-1), B-2),
or B-3) below.
Determination B-1): When the or each signal level determiner 600 determines that the
signal level of the frequency components in the inaudible ranges is equal to or greater
than the threshold value and within the predetermined range, it is detected that the
loudspeaker 100 is not in failure.
Determination B-2): When the or each signal level determiner 600 determines that the
signal level of the frequency components in the inaudible ranges is not equal to or
greater than the threshold value (i.e. is less than the threshold value), it is detected
that that the loudspeaker 100 is in failure.
Determination B-3): When the or each signal level determiner 600 determines that the
signal level of the frequency components in the inaudible ranges is equal to or greater
than the threshold value but not within the predetermined range, it is detected that
that the loudspeaker 100 is deteriorated.
[0031] For reference purposes, the following is a result of a simulation performed. In this
simulation, an inaudible sound of 20.5 kHz was emitted from a loudspeaker, the inaudible
sound and ambient noises were acquired by a microphone, and the electric signals from
the microphone were subjected to frequency analysis by the Fourier transformer 500
in a manner as described above. The simulation result is shown in Fig. 2. In this
simulation, the signal level determiner 600 performs the first determination processing
as to whether the signal level of the frequency components in an inaudible range from
20.0 kHz to 24.0 kHz is equal to or greater than a threshold value, namely -45 dB.
Also, when the signal level determiner 600 determines in the first determination processing
that the signal level is equal to or greater than the threshold value, the signal
level determiner 600 performs the second determination processing as to whether the
signal level of the frequency components in the inaudible range is within a predetermined
range, namely -40 dB to -10 dB, that is greater than the threshold value. If the signal
level of the frequency components in the inaudible range is within the range from
-40 dB to -10 dB, the loudspeaker is functioning normally (see Fig. 2); and if the
signal level is less than -45 dB, the loudspeaker is in failure; and if the signal
level is greater than or equal to -45 dB or less than -40 dB, the loudspeaker is deteriorated.
In Fig. 2, frequency components of 2 kHz or lower are shown as frequency components
of noises.
[0032] It should be noted that the or each signal level determiner 600 is only required
to be configured to perform at least the first determination processing but not the
second determination processing.
[0033] In the present invention, a plurality of the microphones 200 is provided. The plurality
of microphones 200 include at least two, namely first and second, microphones 200,
but may be any number of microphones 200. In the embodiment of Fig. 1, the plurality
of microphones 200 include first, second, and third microphones 200. The plurality
of microphones 200 may be disposed in one of the following arrangements 1) to 3).
- 1) All of the microphones 200 are disposed at the same distance from the loudspeaker
100.
- 2) All of the plurality of microphones 200 are disposed at different distances from
the loudspeaker 100. For example, where the microphones 200 include first and second
microphones 200, the first microphone 200 is positioned at a smaller distance from
the loudspeaker 100 than the second microphone 200 is. Where the microphones 200 include
first to third microphones 200, the first microphone 200 is positioned at a shorter
distance from the loudspeaker 100 than the second and third microphones 200 are, the
second microphone 200 is positioned at a larger distance from the loudspeaker 100
than the first microphone 200 is, and the third microphone 200 is positioned at a
larger distance from the loudspeaker 100 than the first and second microphones 200
are.
- 3) At least two of the plurality of microphones 200 are disposed at the same distance
from the loudspeaker 100, whereas at least one other microphone 200 is disposed at
a distance from the loudspeaker 100, the distance being different from that of the
at least two of the microphones 200 from the loudspeaker 100. For example, where the
microphones 200 include first to third microphones 200, the second and third microphones
200 are positioned at the same distance from the loudspeaker 100, whereas the first
microphone 200 is disposed at a smaller or larger distance from the loudspeaker 100
than the second and third microphones 200 are.
[0034] It is preferable that the plurality of microphones 200 be fixed in position with
respect to the loudspeaker 100 in accordance with one of the above aspects. This arrangement
establishes the distance between each microphone 200 and the loudspeaker 100, thereby
establishing acoustic characteristics (signal level) of the microphones 200 in response
to inaudible sounds emitted from the loudspeaker 100. The loudspeaker 100 may emit
inaudible sounds at a constant volume level or at varying volume levels in response
to the volume adjustment to the loudspeaker 100.
[0035] Where the volume level of inaudible sounds is always constant, it is preferable that
the at least one audio signal processor 400 output a test signal including information
on the (always constant) volume level of the inaudible sounds, and cause the loudspeaker
100 to emit inaudible sounds at an always constant volume on the basis of the test
signal including such information. Also, such information may preferably be included
in test signal also in a case where the at least one audio signal processor 400 is
configured to mix the test signal and the audio signals. In this case, the audio signals
may contain information on the volume level of the audible sounds, and the at least
one audio signal processor 400 may causes the loudspeaker 100 to emit audible sounds
at a volume level different from that of the inaudible sounds. If the information
on the volume levels of the test signal and the audio signals are such that both the
volume levels are the same, it is possible to emit the inaudible sounds and the audible
sounds at the same volume level.
[0036] Where the volume level of inaudible sounds varies, the at least one signal level
determiner 600 may preferably be further configured to raise or lower the threshold
value on the memory according to the volume level of the loudspeaker 100. Alternatively,
the at least one signal level determiner 600 may be configured to correct the signal
level of the frequency components in the inaudible range according to the volume level
of the loudspeaker 100, and perform the first determination processing, or the first
and second determination processing.
[0037] Where a plurality of the microphones 200 is provided, in accordance with the number
of the microphones 200, there may be provided a plurality of the A/D converters 700,
the first band-pass filters 300, the audio signal processors 400, the Fourier transformers
500, the second band-pass filters 800, and the signal level determiners 600 (see Fig.
1). In this case, each of the A/D converter 700, each of the band-pass filters 300,
each of the audio signal processors 400, each of the Fourier transformers 500, each
of the band-pass filters 800, and each of the signal level determiners 600 operate
corresponding to each of the microphones 200 and perform processing in one of the
manners described above.
[0038] Where some (at least two) of the microphones 200 are disposed at different distances
from the loudspeaker 100, the corresponding ones (at least two) of the signal level
determiners 600 may refer to different threshold values, according to the distances
between such microphones 200 and the loudspeaker 100. For example, where the distance
between the first microphone 200 and the loudspeaker 100 is (i) smaller or (ii) larger
than the distance between the second microphone 200 and the loudspeaker 100, the signal
level determiner 600 corresponding to the first microphone 200 may refer to a (i)
smaller or (ii) larger, respectively, threshold value than the threshold value that
the signal level determiner 600 corresponding to the second microphone 200 refers
to. The plurality of signal level determiners 600 may refer to one and the same threshold
value.
[0039] Where some (at least two) of the microphones 200 are disposed at different distances
from the loudspeaker 100, the corresponding ones (at least two) of the signal level
determiners 600 may refer to different predetermined ranges equal to or greater than
the threshold values, according to the distances between such microphones 200 and
the loudspeaker 100. For example, where the distance between the first microphone
200 and the loudspeaker 100 is (i) smaller or (ii) larger than the distance between
the second microphone 200 and the loudspeaker 100, the signal level determiner 600
corresponding to the first microphone 200 may refer to a (i) smaller or (ii) larger,
respectively, predetermined range equal to or greater than threshold value than the
predetermined range that the signal level determiner 600 corresponding to the second
microphone 200 refers to. The plurality of signal level determiners 600 may refer
to one and the same predetermined range equal to or greater than threshold value (s).
[0040] Where a plurality of signal level determiners 600 is provided each having configuration
A) described above, the result of the first determination processing is one of A-1-1)
to A-1-3) below.
Result A-1-1): When all the signal level determiners 600 determine that the signal
level of the frequency components in the inaudible range is equal to or greater than
the threshold value, it is detected that that the loudspeaker 100 is not in failure.
Result A-1-2): When all the signal level determiners 600 determine that the signal
level of the frequency components in the inaudible range is not equal to or greater
than the threshold value (less than the threshold value), it is detected that that
the loudspeaker 100 is in failure.
Result A-1-3): When at least one of the signal level determiners 600 determines that
the signal level of the frequency components in the inaudible range is equal to or
greater than the threshold value, and the remaining one or ones of the signal level
determiners 600 determines that is not equal to or greater than the threshold value
(less than the threshold value), it is detected that that the loudspeaker or loudspeakers
100 corresponding to such remaining one or ones of the signal level determiners 600
is in failure.
[0041] Where a plurality of signal level determiners 600 is provided each having configurations
A) and B) described above, the result of the first and second determination processing
is one of B-1-1) to B-1-6) below.
Result B-1-1): When all the signal level determiners 600 determine that the signal
level of the frequency components in the inaudible range is equal to or greater than
the threshold value and within the predetermined range, it is detected that the loudspeaker
100 is not in failure.
Result B-1-2): When all the signal level determiners 600 determine that the signal
level of the frequency components in the inaudible range is not equal to or greater
than the threshold value (less than the threshold value), it is detected that the
loudspeaker 100 or all the microphones 200 are in failure.
Result B-1-3): When all the signal level determiners 600 determine that the signal
level of the frequency components in the inaudible range is equal to or greater than
the threshold value but not within the predetermined range, it is detected that the
loudspeaker 100 or all the microphones 200 are deteriorated.
Result B-1-4): When all the signal level determiners 600 determine that the signal
level of the frequency components in the inaudible range is equal to or greater than
the threshold value, and the at least one of the signal level determiners 600 determines
that the signal level of the frequency components in the inaudible range equal to
or greater than the threshold value is within the predetermined range, and the remaining
one or ones of the signal level determiners 600 determine that the signal level of
the frequency components in the inaudible range equal to or greater than the threshold
value is not within the predetermined range, it is detected that the microphone or
microphones 200 corresponding to such remaining one or ones of the signal level determiners
600 are deteriorated.
Result B-1-5): When at least one of the signal level determiners 600 determines that
the signal level of the frequency components in the inaudible range is equal to or
greater than the threshold value and within the predetermined range, and when the
remaining one or ones of the signal level determiners 600 determine that the signal
level of the frequency components in the inaudible range is not equal to or greater
the threshold value (less than the threshold value), it is detected that the microphone
or microphones 200 corresponding to such remaining one or ones of the signal level
determiners 600 are in failure.
Result B-1-6): When at least one of the signal level determiners 600 determines that
the signal level of the frequency components in the inaudible range is equal to or
greater than the threshold value but not within the predetermined range, and when
the remaining one or ones of the signal level determiners 600 determine that the signal
level of the frequency components in the inaudible range is not equal to or greater
than the threshold value (less than the threshold value value), it is detected that
the microphone or microphones 200 corresponding to the at least one of the signal
level determiners 600 are deteriorated, and that the microphone or microphones 200
corresponding to such remaining one or ones of the signal level determiners 600 are
in failure.
[0042] It is possible to unitize all of, or some of, the at least one loudspeaker 100, the
at least one microphone 200, the at least one first band-pass filter 300, the at least
one audio signal processor 400, the at least one Fourier transformer (FFT) 500, the
at least one second band-pass filter 800, the at least one signal level determiner
600, and the at least one A/D converter 700 may be unitized. If a plurality of microphones
200 is provided, it is also possible to unitize only the at least one loudspeaker
100 and the microphones 200.
[0043] In accordance with the determinations A-1) to A-2), B-1) to B-3), A-1-1) to A-1-3),
and B-1-1) to B-1-6), it is possible to notify or transmit the determination result,
particularly, the failure or deterioration of the loudspeaker 100, or the failure
or deterioration of the at least one microphone 200. Such notification or transmission
may be provided in one of the following manners (1) to (4). (1) The electronic equipment
may include a display part or the like configured to display the notification. (2)
The electronic equipment may be configured to transmit the determination result via
its communication part. (3) The sound processing apparatus D may include a display
part or the like configured to display the notification. (4) The sound processing
apparatus D may include a notification part configured to operate the electronic equipment
to display the notification via a display part or the like of the electronic equipment.
(5) The sound processing apparatus D may include a notification part configured to
operate the electronic equipment to transmit the determination result via a communication
part of the electronic equipment. The notification part can also be implemented by
a logic circuit, or by software to processed by a processor.
[0044] The sound processing apparatus D configured as described above provide at least the
following technical features and effects.
Technical features and effects 1): The sound processing apparatus D can detect a failure
of the loudspeaker 100 as described for determinations A-1) to A-2) by carrying out
the first determination processing at the at least one signal level determiner 600
while performing the first and/or second audio signal processing at the at least one
audio signal processor 400 (i.e. while allowing a user to carry out audio communication).
This is because the processing by the at least one audio signal processor 400 and
the first determination processing by the at least one signal level determiner 600
can be performed in parallel.
Technical features and effects 2): the sound processing apparatus D can detect a failure
and a deterioration of the loudspeaker 100 as described for determinations B-1) to
B-3 by carrying out the first and second determination processing at the at least
one signal level determiner 600 while performing the first and/or second audio signal
processing at the at least one audio signal processor 400 (i.e. while allowing a user
to carry out audio communication). This is because the processing by the at least
one audio signal processor 400 and the first and second determination processing by
the at least one signal level determiner 600 can be performed in parallel.
Technical features and effects 3): Where the sound processing apparatus D includes
a plurality of the microphones 200, the Fourier transformers 500, the second band-pass
filters 800, the signal level determiners 600, and the A/D converters 700, when each
of the signal level determiners 600 performs the first determination processing, it
is possible to detect not only a failure of the loudspeaker 100 but also a failure
of the corresponding microphones 200 as described for determination A-1-1) to A-1-3).
Technical features and effects 4): Where the sound processing apparatus D includes
a plurality of the microphones 200, the Fourier transformers 500, the second band-pass
filters 800, the signal level determiners 600, and the A/D converters 700, when each
of the signal level determiners 600 performs the first determination processing, and
performs the second determination processing on the signal level of frequency components
in the inaudible range which is equal to or greater than the threshold value, it is
possible to detect not only a failure but also deterioration of the corresponding
loudspeaker 100 and the microphone 200 as described for determinations B-1-1) to B-1-6).
Technical features and effects 5): The sound processing apparatus D provides improved
accuracy of the detection of inaudible sounds of the at least two signal level determiners
600, in a case where the sound processing apparatus D includes a plurality of the
microphones 200, the Fourier transformers 500, the second band-pass filters 800, the
signal level determiners 600, and the A/D converters 700, and where the distances
of at least two of the microphones 200 from the loudspeaker 100 differ from each other
and threshold values of at least two signal level determiners 600, or threshold values
and predetermined ranges of at least two signal level determiners 600 are individually
set according to the distances of the corresponding microphone 200 from the loudspeaker
100.
[0045] It should be noted that the sound processing apparatus of the invention is not limited
to the above embodiments and may be modified in any manner within the scope of the
claims. Some modification examples will be described below.
[0046] The loudspeaker can be omitted in the invention. In this case, it is preferable to
utilize a loudspeaker of the electronic equipment connected to the sound processing
apparatus. Also, the loudspeaker of the invention may be configured to emit only inaudible
sounds, but not audible sounds. In this case, as a substitute for a loudspeaker for
audible sounds, it is possible to utilize a loudspeaker of the electronic equipment
connected to the sound processing apparatus D. A plurality of loudspeakers may be
provided in the invention. In this case, all of the loudspeakers may be configured
to emit audible and inaudible sounds, or at least one of the of loudspeakers is configured
to emit an audible sound, and at least one different loudspeaker may be configured
to emit an inaudible sound.
[0047] The plurality of microphones of the invention may be disposed at the same distance,
although this alternative is not covered by the appended claims, or at different distances
(as covered by the appended claims), from the respective loudspeakers. In either case,
as described above, the plurality of signal level determiners may refer to different
threshold values, and/or different predetermined ranges equal to or greater than the
threshold values, according to the distances between the corresponding microphones
200 and the respective loudspeakers 100.
[0048] The at least one A/D converter of the invention may be omitted in a case where the
at least one microphone is configured for digital outputting. It is also possible
to provide one or more D/A converters at a rear stage of the at least one audio signal
processor of the invention.
[0049] The at least one Fourier transformer may be omitted in the invention. In this case,
the at least one second band-pass filter 800 may preferably be configured to pass
only the frequency components in the inaudible range (and remove frequency components
of electric signals other than the frequency components in the inaudible range), and
the at least one signal level determiner may preferably be at least configured to
receive the frequency components in the inaudible range from the at least one second
band-pass filter 800 and perform a first determination as to whether the signal level
of the frequency components in the inaudible range is equal to or greater than a threshold
value.
[0050] It should be appreciated that the above embodiments and variants of the sound processing
apparatus are described above by way of examples only. The materials, shapes, dimensions,
numbers, arrangements, and other configurations of the constituents of the sound processing
apparatus may be modified in any manner if they can perform similar functions. The
configurations of the embodiments and the variants described above may be combined
in any possible manner, as far as they fall under the scope of the appended claims.
Reference Signs List
[0051]
- D:
- sound processing apparatus
100: loudspeaker
200: microphone
300: band-pass filter
400: audio signal processor
500: Fourier transformer
600: signal level determiner
700: A/D converter
1. A sound processing apparatus (D) comprising:
a plurality of microphones (200) configured to simultaneously acquire an audible sound
having a frequency in an audible range and an inaudible sound having a frequency in
an inaudible range, to convert an acquired sound into electric signals, and to output
the electric signals;
a plurality of first band-pass filters (300) each configured to receive the electrical
signals outputted from a respective microphone (200) and remove components of the
electrical signals that are outside the audible range;
an audio signal processor (400) to apply predetermined signal processing to the electric
signals that have passed through the respective first band-pass filters (300);
a plurality of Fourier transformers (500) each configured to receive the electrical
signals outputted from a respective microphone (200) and perform a frequency analysis
on the received electric signals so as to obtain frequency components of the electric
signals, the obtained frequency components including frequency components in the inaudible
range; and
a plurality of signal level determiners (600) to perform a first determination as
to whether the respective frequency components in the inaudible range have a signal
level being equal to or greater than a threshold value,
characterised in that
the microphones (200) are disposed at different distances from a loudspeaker (100)
capable of emitting inaudible sounds, and
the respective threshold values for the signal level determiners (600) differ from
one another according to the respective distances from the corresponding microphones
(200) to the loudspeaker (100).
2. The sound processing apparatus (D) according to claim 1, wherein
the signal level determiners (600) are configured such that, when at least one of
the signal level determiners (600) determines in the first determination that the
signal level of the frequency components in the inaudible range is equal to or greater
than the threshold value, the at least one of the signal level determiners (600) further
performs a second determination, and
the second determination is made such that it is determined whether the frequency
components in the inaudible range have a signal level within a predetermined range,
the predetermined range being equal to or greater than the threshold value.
3. The sound processing apparatus (D) according to claim 2, wherein
the respective threshold values and the predetermined ranges for the signal level
determiners (600) differ from one another according to the respective distances from
the corresponding microphones (200) to the loudspeaker (100).
4. The sound processing apparatus (D) according to any one of the preceding claims further
comprising a loudspeaker (100) capable of emitting an inaudible sound.
5. The sound processing apparatus (D) according to any one of claims 1 to 3 further comprising
a loudspeaker (100) capable of simultaneously emitting audible and inaudible sounds.
6. The sound processing apparatus (D) according to any one of the preceding claims further
comprising a plurality of second band-pass filters (800) to filter the frequency components
of respective electric signals obtained by the frequency analysis so as to remove
frequency components other than the frequency components in the inaudible range and
to output the filtered frequency components to respective signal level determiners
(600).
7. The sound processing apparatus (D) according to any one of claims 1 to 3 further comprising
a loudspeaker (100), the loudspeaker (100) being configured to emit at least an inaudible
sound,
wherein the plurality of microphones (200) is fixed in position with respect to the
loudspeaker (100), and the microphones (200) and the loudspeaker (100) are unitized.
8. A sound processing apparatus (D) comprising:
a plurality of microphones (200) configured to simultaneously acquire audible sound
having a frequency in an audible range and an inaudible sound having a frequency in
an inaudible range, to convert the acquired audible and inaudible sounds into electric
signals, and to output the electric signals;
a plurality of first band-pass filters (300) to receive the electrical signals outputted
from respective microphones (200) and remove frequency components of the electrical
signals that are outside the audible range;
an audio signal processor (400) to apply predetermined signal processing to the respective
electric signals that have passed through the first band-pass filters (300);
a plurality of second band-pass filters (800) to receive the electrical signals outputted
from respective microphones (200) and remove components of the electrical signals
that are other than frequency components in the inaudible range; and
a plurality of signal level determiners (600) to perform a first determination as
to whether respective frequency components in the inaudible range, which have passed
through the respective second band-pass filters (800), have a signal level being equal
to or greater than a threshold value,
characterised in that
the microphones (200) are disposed at different distances from a loudspeaker (100)
capable of emitting inaudible sounds, and
the respective threshold values for the signal level determiners (600) differ from
one another according to the respective distances from the corresponding microphones
(200) to the loudspeaker (100).
9. An electronic equipment comprising the sound processing apparatus (D) according to
any one of the preceding claims.
1. Eine Tonverarbeitungsvorrichtung (D), die Folgendes umfasst:
eine Vielzahl von Mikrofonen (200), die konfiguriert sind, um einen hörbaren Ton,
der eine Frequenz in einem hörbaren Bereich aufweist, und einen unhörbaren Ton, der
eine Frequenz in einem unhörbaren Bereich aufweist, gleichzeitig zu erfassen, um einen
erfassten Ton in elektrische Signale umzuwandeln und um die elektrischen Signale auszugeben;
eine Vielzahl von ersten Bandpassfiltern (300), die jeweils konfiguriert sind, um
die von einem jeweiligen Mikrofon (200) ausgegebenen elektrischen Signale zu empfangen
und Komponenten der elektrischen Signale, die außerhalb des hörbaren Bereichs liegen,
zu entfernen;
einen Audiosignalprozessor (400), um eine vorher festgelegte Signalverarbeitung auf
die elektrischen Signale, die die jeweiligen ersten Bandpassfilter (300) durchlaufen
haben, anzuwenden;
eine Vielzahl von Fourier-Transformatoren (500), die jeweils konfiguriert sind, die
von einem jeweiligen Mikrofon (200) ausgegebenen elektrischen Signale zu empfangen
und eine Frequenzanalyse an den empfangenen elektrischen Signalen durchzuführen, um
Frequenzkomponenten der elektrischen Signale zu erhalten, wobei die erhaltenen Frequenzkomponenten
Frequenzkomponenten im unhörbaren Bereich beinhalten; und
eine Vielzahl von Signalpegelbestimmern (600), um eine erste Bestimmung durchzuführen,
ob die jeweiligen Frequenzkomponenten im unhörbaren Bereich einen Signalpegel aufweisen,
der gleich einem oder größer als ein Schwellenwert ist,
dadurch gekennzeichnet, dass
die Mikrofone (200) in unterschiedlichen Abständen von einem Lautsprecher (100) angeordnet
sind, der fähig ist, unhörbare Töne zu emittieren, und
sich die jeweiligen Schwellenwerte für die Signalpegelbestimmer (600) gemäß den jeweiligen
Abständen von den entsprechenden Mikrofonen (200) zu dem Lautsprecher (100) voneinander
unterscheiden.
2. Tonverarbeitungsvorrichtung (D) gemäß Anspruch 1, wobei
die Signalpegelbestimmer (600) so konfiguriert sind, dass, wenn mindestens einer der
Signalpegelbestimmer (600) bei der ersten Bestimmung bestimmt, dass der Signalpegel
der Frequenzkomponenten im unhörbaren Bereich gleich dem oder größer als der Schwellenwert
ist, der mindestens eine der Signalpegelbestimmer (600) eine zweite Bestimmung durchführt,
und
die zweite Bestimmung so vorgenommen wird, dass bestimmt wird, ob die Frequenzkomponenten
im unhörbaren Bereich einen Signalpegel innerhalb eines vorher festgelegten Bereichs
aufweisen, wobei der vorher festgelegte Bereich gleich dem oder größer als der Schwellenwert
ist.
3. Tonverarbeitungsvorrichtung (D) gemäß Anspruch 2, wobei
sich die jeweiligen Schwellenwerte und die vorher festgelegten Bereiche für die Signalpegelbestimmer
(600) gemäß den jeweiligen Abständen von den entsprechenden Mikrofonen (200) zu dem
Lautsprecher (100) voneinander unterscheiden.
4. Tonverarbeitungsvorrichtung (D) gemäß einem der vorhergehenden Ansprüche, die ferner
einen Lautsprecher (100) umfasst, der fähig ist, einen unhörbaren Ton zu emittieren.
5. Tonverarbeitungsvorrichtung (D) gemäß einem der vorhergehenden Ansprüche 1 bis 3,
die ferner einen Lautsprecher (100) umfasst, der fähig ist, hörbare und unhörbare
Töne gleichzeitig zu emittieren.
6. Tonverarbeitungsvorrichtung (D) gemäß einem der vorhergehenden Ansprüche, die ferner
eine Vielzahl von zweiten Bandpassfiltern (800) umfasst, um die Frequenzkomponenten
von jeweiligen elektrischen Signalen, die durch die Frequenzanalyse erhalten werden,
zu filtern, um Frequenzkomponenten, die von den Frequenzkomponenten im unhörbaren
Bereich abweichen, zu entfernen, und um die gefilterten Frequenzkomponenten an jeweilige
Signalpegelbestimmer (600) auszugeben.
7. Tonverarbeitungsvorrichtung (D) gemäß einem der vorhergehenden Ansprüche 1 bis 3,
die ferner einen Lautsprecher (100) umfasst, wobei der Lautsprecher (100) konfiguriert
ist, um mindestens einen unhörbaren Ton zu emittieren,
wobei die Vielzahl von Mikrofonen (200) in Position in Bezug auf den Lautsprecher
(100) fixiert ist und die Mikrofone (200) und der Lautsprecher (100) vereinheitlicht
sind.
8. Eine Tonverarbeitungsvorrichtung (D), die Folgendes umfasst:
eine Vielzahl von Mikrofonen (200), die konfiguriert sind, um einen hörbaren Ton,
der eine Frequenz in einem hörbaren Bereich aufweist, und einen unhörbaren Ton, der
eine Frequenz in einem unhörbaren Bereich aufweist, gleichzeitig zu erfassen, um den
erfassten hörbaren und unhörbaren Ton in elektrische Signale umzuwandeln und um die
elektrischen Signale auszugeben;
eine Vielzahl von ersten Bandpassfiltern (300), um die von jeweiligen Mikrofonen (200)
ausgegebenen elektrischen Signale zu empfangen und Frequenzkomponenten der elektrischen
Signale, die außerhalb des hörbaren Bereichs liegen, zu entfernen; einen Audiosignalprozessor
(400), um eine vorher festgelegte Signalverarbeitung auf die jeweiligen elektrischen
Signale, die die ersten Bandpassfilter (300) durchlaufen haben, anzuwenden;
eine Vielzahl von zweiten Bandpassfiltern (800), um die von jeweiligen Mikrofonen
(200) ausgegebenen elektrischen Signale zu empfangen und Frequenzkomponenten der elektrischen
Signale, die von den Frequenzkomponenten im unhörbaren Bereich abweichen, zu entfernen;
und
eine Vielzahl von Signalpegelbestimmern (600), um eine erste Bestimmung durchzuführen,
ob jeweilige Frequenzkomponenten im unhörbaren Bereich, die die jeweiligen zweiten
Bandpassfilter (800) durchlaufen haben, einen Signalpegel aufweisen, der gleich einem
oder größer als ein Schwellenwert ist,
dadurch gekennzeichnet, dass
die Mikrofone (200) in unterschiedlichen Abständen von einem Lautsprecher (100) angeordnet
sind, der fähig ist, unhörbare Töne zu emittieren, und
sich die jeweiligen Schwellenwerte für die Signalpegelbestimmer (600) gemäß den jeweiligen
Abständen von den entsprechenden Mikrofonen (200) zu dem Lautsprecher (100) voneinander
unterscheiden.
9. Eine elektronische Ausrüstung, die die Tonverarbeitungsvorrichtung (D) gemäß einem
der vorhergehenden Ansprüche umfasst.
1. Appareil de traitement de sons (D) comportant :
une pluralité de microphones (200) configurés pour acquérir de manière simultanée
un son audible ayant une fréquence dans une gamme des fréquences audibles et un son
inaudible ayant une fréquence dans une gamme des fréquences inaudibles, pour convertir
un son acquis en signaux électriques, et pour émettre en sortie les signaux électriques
;
une pluralité de premiers filtres à bande passante (300) configurés chacun pour recevoir
les signaux électriques émis en sortie en provenance d'un microphone respectif (200)
et pour retirer des composantes des signaux électriques qui se trouvent hors de la
gamme des fréquences audibles ;
un processeur de signaux audio (400) servant à appliquer un traitement de signal prédéterminé
au niveau des signaux électriques qui sont passés au travers des premiers filtres
à bande passante respectifs (300) ;
une pluralité de transformateurs de Fourier (500) configurés chacun pour recevoir
les signaux électriques émis en sortie en provenance d'un microphone respectif (200)
et pour effectuer une analyse de fréquence sur les signaux électriques reçus de manière
à obtenir des composantes de fréquence des signaux électriques, les composantes de
fréquence obtenues comprenant des composantes de fréquence dans la gamme des fréquences
inaudibles ; et
une pluralité de dispositifs de détermination de niveau de signal (600) servant à
effectuer une première détermination pour savoir si les composantes de fréquence respectives
dans la gamme des fréquences inaudibles ont un niveau de signal qui est égal ou supérieur
à une valeur de seuil,
caractérisé en ce que
les microphones (200) sont disposés à différentes distances par rapport à un haut-parleur
(100) en mesure d'émettre des sons inaudibles, et
les valeurs de seuil respectives pour les dispositifs de détermination de niveau de
signal (600) diffèrent les unes des autres en fonction des distances respectives entre
les microphones correspondants (200) et le haut-parleur (100).
2. Appareil de traitement de sons (D) selon la revendication 1, dans lequel
les dispositifs de détermination de niveau de signal (600) sont configurés de telle
sorte que, quand au moins l'un des dispositifs de détermination de niveau de signal
(600) détermine dans la première détermination que le niveau de signal des composantes
de fréquence dans la gamme des fréquences inaudibles est égale ou supérieure à la
valeur de seuil, ledit au moins l'un des dispositifs de détermination de niveau de
signal (600) effectue par ailleurs une deuxième détermination, et
la deuxième détermination est effectuée de telle sorte qu'il est déterminé si les
composantes de fréquence de la gamme des fréquences inaudibles ont un niveau de signal
se trouvant dans les limites d'une gamme prédéterminée, la gamme prédéterminée étant
égale ou supérieure à la valeur de seuil.
3. Appareil de traitement de sons (D) selon la revendication 2, dans lequel
les valeurs de seuil respectives et les gammes prédéterminées pour les dispositifs
de détermination de niveau de signal (600) diffèrent les unes des autres en fonction
des distances respectives entre les microphones correspondants (200) et le haut-parleur
(100).
4. Appareil de traitement de sons (D) selon l'une quelconque des revendications précédentes,
comportant par ailleurs un haut-parleur (100) en mesure d'émettre un son inaudible.
5. Appareil de traitement de sons (D) selon l'une quelconque des revendications 1 à 3,
comportant par ailleurs un haut-parleur (100) en mesure d'émettre de manière simultanée
des sons audibles et inaudibles.
6. Appareil de traitement de sons (D) selon l'une quelconque des revendications précédentes,
comportant par ailleurs une pluralité de deuxièmes filtres à bande passante (800)
servant à filtrer les composantes de fréquence des signaux électriques respectifs
obtenus par l'analyse de fréquence de manière retirer des composantes de fréquence
autres que les composantes de fréquence dans la gamme des fréquences inaudibles et
pour émettre en sortie les composantes de fréquence filtrées à destination de dispositifs
de détermination de niveau de signal respectifs (600).
7. Appareil de traitement de sons (D) selon l'une quelconque des revendications 1 à 3,
comportant par ailleurs un haut-parleur (100), le haut-parleur (100) étant configuré
pour émettre au moins un son inaudible,
dans lequel la pluralité de microphones (200) est fixée en position par rapport au
haut-parleur (100), et les microphones (200) et le haut-parleur (100) sont modularisés.
8. Appareil de traitement de sons (D) comportant :
une pluralité de microphones (200) configurés pour acquérir de manière simultanée
un son audible ayant une fréquence dans une gamme des fréquences audibles et un son
inaudible ayant une fréquence dans une gamme des fréquences inaudibles, pour convertir
les sons audibles et inaudibles acquis en signaux électriques, et pour émettre en
sortie les signaux électriques ;
une pluralité de premiers filtres à bande passante (300) servant à recevoir les signaux
électriques émis en sortie en provenance de microphones respectifs (200) et pour retirer
des composantes de fréquence des signaux électriques qui se trouvent hors de la gamme
des fréquences audibles ;
un processeur de signaux audio (400) servant à appliquer un traitement de signal prédéterminé
au niveau des signaux électriques respectifs qui sont passés au travers des premiers
filtres à bande passante (300) ;
une pluralité de deuxièmes filtres à bande passante (800) servant à recevoir les signaux
électriques émis en sortie en provenance des microphones respectifs (200) et à retirer
des composantes des signaux électriques qui sont autres que des composantes de fréquence
dans la gamme des fréquences inaudibles; et
une pluralité de dispositifs de détermination de niveau de signal (600) servant à
effectuer une première détermination pour savoir si les composantes de fréquence respectives
dans la gamme des fréquences inaudibles, qui sont passées au travers des deuxièmes
filtres à bande passante respectifs (800) ont un niveau de signal qui est égal ou
supérieur à une valeur de seuil,
caractérisé en ce que
les microphones (200) sont disposés à différentes distances par rapport à un haut-parleur
(100) en mesure d'émettre des sons inaudibles, et
les valeurs de seuil respectives pour les dispositifs de détermination de niveau de
signal (600) diffèrent les unes des autres en fonction des distances respectives entre
les microphones correspondants (200) et le haut-parleur (100).
9. Équipement électronique comportant l'appareil de traitement de sons (D) selon l'une
quelconque des revendications précédentes.