close

Вход

Забыли?

вход по аккаунту

?

JP2009171315

код для вставкиСкачать
Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2009171315
The present invention provides a voice signal transmitting / receiving apparatus in which a
speaker and a called party can easily hear a speaker's transmission voice by removing
background noise even when the speaker is in a noise environment. The voice signal transmitting
/ receiving apparatus 100 receives a received voice signal as well as a differential microphone
110 for converting a transmission voice into a transmission voice signal, an amplification unit
120 for amplifying a transmission voice signal from the differential microphone 110, and a
transmission voice. Transmission / reception unit 170 for transmitting signals, addition unit 130
for adding the reception voice signal from transmission / reception unit 170 and the
transmission voice signal from amplification unit 120 to generate an addition signal, and
receiving voice based on the addition signal And a speaker 140. [Selected figure] Figure 8
Audio signal transmitter and receiver
[0001]
The present invention relates to a voice signal transmitting / receiving apparatus, and more
particularly, to a voice signal transmitting / receiving apparatus which receives a transmission
voice from a speaker and transmits a transmission voice signal to the outside and receives a
reception voice signal from the outside to emit a receiving voice It relates to the device.
[0002]
2. Description of the Related Art A voice signal transmitting / receiving apparatus has been
known which receives a transmission voice from a speaker and transmits a transmission voice
04-05-2019
1
signal to the outside, and receives a reception voice signal from the outside to emit a reception
voice to the speaker.
Further, there have been proposed techniques for making it easy for the speaker to hear the
transmitted voice of the person even in a noisy environment, and for making it easier for the
other party to hear the received voice even in a noisy environment.
[0003]
For example, Japanese Patent Laid-Open No. 9-37380 (Patent Document 1) includes a noise
detector installed on the outer wall of a headset, first and second adaptive filters for inputting an
output signal of the noise detector, and A transmitting microphone provided near the mouth of
the speaker, a control speaker provided on the inner wall of the headset, and an error detector
provided on the inner wall of the headset; Subtract the output signal of 1 adaptive filter, update
the coefficient of the first adaptive filter so that this subtraction signal becomes smaller, and
update the coefficient of the second adaptive filter so that the output signal of the error detector
becomes smaller Discloses a configuration in which the output signal of the second adaptive
filter, the subtraction signal, and the reception signal from the communication device are added
and input to the control speaker, and the subtraction signal is used as the transmission output
signal to the communication device It is done.
[0004]
In Japanese Patent Laid-Open No. 7-240782 (Patent Document 2), a transmitting voice signal
obtained from a transmitting microphone via an A / D converter is used as a side sound via a
variable gain amplifier on the receiving side. A technique is disclosed for sending to an adder and
adding with received speech.
In addition, the background noise level detector detects the background noise level in the
transmission voice signal, and controls the gain of the variable gain amplifier according to the
detected background noise level to control the side tone level. It is disclosed.
[0005]
Further, in Japanese Patent Laid-Open No. 2000-101683 (Patent Document 3), a noise / voice
04-05-2019
2
separation unit separates a transmission voice signal from a voice input unit into noise and
transmission voice, and a signal addition unit decodes the signal by a voice decoding unit. A
technique is disclosed which adds the transmission voice signal from the noise / voice separation
unit according to the noise power calculated by the noise power calculation unit to the decoded
voice signal. Further, the level control unit controls the level of the decoded voice signal from the
signal addition unit according to the ratio of the noise power calculated by the noise power
calculation unit and the decoded voice power calculated by the decoded voice power calculation
unit A technology is disclosed in which the unit D / A converts the decoded voice signal from the
level control unit and outputs it via a speaker.
[0006]
In addition, Japanese Patent Application Laid-Open No. 5-30177 (Patent Document 4) discloses a
level calculator for detecting a background noise level when there is no utterance of a
transmitter, and voice / noise determination for detecting a noise section of a transmission signal.
And a handset side tone control circuit comprising an attenuation controller that outputs a
control signal that increases the attenuation of the variable attenuator when the noise level in the
noise zone is large.
[0007]
Further, in Japanese Patent Application Laid-Open No. 8-18630 (Patent Document 5), in a
handset provided with a transmitter and a receiver, the receiver face is provided for detecting a
sound between the receiver and the ear. A noise suppression handset is disclosed which
comprises a real-ear microphone and a noise microphone provided on the outer surface of the
handset for detecting noise.
The output of the noise microphone is superimposed on the receiver input by the receiver
amplifier circuit so that noise leaking between the ear and the receiver surface is minimized.
Also, the output of the noise microphone is superimposed on the transmission output by the
transmission amplification circuit so that the noise contained in the transmission signal is
minimized.
[0008]
In addition, Japanese Patent Laid-Open No. 3-147000 (Patent Document 6) includes two
04-05-2019
3
microphone units, means for converting the electric output of each microphone unit into an
envelope signal as electric power, and means for obtaining a difference signal between them. And
an audio input device having means for using the difference signal output as a signal for
detecting an audio section of the audio input device. JP-A-9-37380 JP-A-7-240782 JP-A-2000101683 JP-A-5-30177 JP-A-8-18630 JP-A-3-147000
[0009]
However, for example, in the case of the techniques described in JP-A-9-37380 (Patent
Document 1) and JP-A-8-18630 (Patent Document 5), noise is removed using an adaptive filter
or a noise canceller. For this reason, although the accuracy of removing steady noise is high, the
accuracy of removing unsteady noise is low. In the case of the techniques described in JP-A-7240782 (Patent Document 2), JP-A-2000-101683 (Patent Document 3), and JP-A-5-30177
(Patent Document 4), Since the gain of the transmission voice is controlled as well as the gain of
the noise, there is a problem that it is difficult for the speaker to hear the transmission voice.
[0010]
The present invention has been made to solve the above-mentioned problems, and the main
object of the present invention is to eliminate the background noise and eliminate the
background noise even when the speaker is in a noisy environment. It is an object of the present
invention to provide an audio signal transmitting / receiving apparatus in which the other party
can easily hear the speaker's transmitted voice.
[0011]
In order to solve the above problems, according to an aspect of the present invention, a voice
signal transmitting / receiving device receives transmitted voice at two points and converts it
into a transmission voice signal by taking an acoustic or electrical difference. Differential
microphone, a transmitting / receiving unit that receives a reception voice signal and transmits a
transmission voice signal, an addition unit that adds the reception voice signal from the
transmission / reception unit and the transmission voice signal to generate an addition signal,
and addition And a speaker for outputting a reception voice based on the signal.
[0012]
Preferably, the differential microphone of the audio signal transmitting / receiving device
04-05-2019
4
receives a transmitting voice at a first position and converts the voice into a first electric signal,
and transmits the transmitting voice at a second position. And a signal generator configured to
generate a transmission voice signal from the difference between the first electrical signal and
the second electrical signal.
Furthermore, preferably, the signal generation unit of the audio signal transmission / reception
device includes a first subtraction unit that calculates a difference signal between the first
electric signal and the second electric signal, and an amplification unit that amplifies the
difference signal. .
[0013]
Preferably, the audio signal transmitting / receiving device is input to the adding unit based on
the determination and a first determining unit that determines whether the amplitude or power
of the first electrical signal is larger than a predetermined threshold. And a first switching unit
for switching a signal.
The first switching unit inputs the transmission voice signal to the adding unit when the
amplitude or power of the first electrical signal is equal to or greater than a predetermined
threshold, and the amplitude or power of the first electrical signal is previously determined. If it
is less than the threshold, the first electric signal or the second electric signal is input to the
adding unit.
[0014]
Preferably, the audio signal transmitting and receiving apparatus extracts the miscellaneous
audio signal based on the first electrical signal and the second electrical signal, and the amplitude
or power of the miscellaneous audio signal is larger than a predetermined threshold. And a
second switching unit that switches a signal input to the adding unit based on the determination.
The second switching unit inputs the transmission voice signal to the adding unit when the
amplitude or power of the miscellaneous speech signal is equal to or greater than a
predetermined threshold, and the amplitude or power of the miscellaneous speech signal is less
than the predetermined threshold And the first electric signal or the second electric signal is
input to the adding unit.
04-05-2019
5
[0015]
Preferably, the audio signal transmitting / receiving device switches the transmission audio
signal and the first electrical signal or the second electrical signal to the adding unit according to
the receiving unit that receives the switching instruction from the outside, and the switching
instruction according to the switching instruction. And a third switching unit for inputting.
[0016]
Preferably, the audio signal transmitting / receiving device is arranged between a signal
generation unit and an addition unit, a first determination unit which determines whether the
amplitude or power of the first electrical signal is larger than a predetermined threshold value.
And a fourth switching unit connected thereto.
The fourth switching unit inputs the transmission voice signal to the adding unit when the
amplitude or power of the first electrical signal is equal to or greater than a predetermined
threshold, and the amplitude or power of the first electrical signal is previously determined. If it
is less than the threshold, the transmission voice signal is not input to the addition unit.
[0017]
Preferably, the audio signal transmitting and receiving apparatus extracts the miscellaneous
audio signal based on the first electrical signal and the second electrical signal, and the amplitude
or power of the miscellaneous audio signal is larger than a predetermined threshold. And a fifth
switching unit connected between the signal generating unit and the adding unit. The fifth
switching unit inputs the transmission voice signal to the addition unit when the amplitude or
power of the electric signal from the first microphone is equal to or greater than a predetermined
threshold value, and the electric signal from the first microphone is When the amplitude or
power is less than a predetermined threshold, the transmission voice signal is not input to the
addition unit.
[0018]
Preferably, the audio signal transmitting / receiving apparatus further includes a sixth switching
04-05-2019
6
unit connected between the signal generating unit and the adding unit, and a receiving unit for
receiving a switching instruction from the outside. The sixth switching unit changes the state of
input / non-input of the transmission voice signal to the adding unit in response to the switching
command.
[0019]
Preferably, the noise detection unit has a cardioid characteristic. Preferably, the noise detection
unit is a delay unit that delays one of the first electric signal and the second electric signal for a
predetermined time, one signal delayed for a predetermined time by the delay unit, and the other
signal. And a delay unit for delaying any one of the first electric signal and the second electric
signal for a predetermined time and inputting the delayed signal to the second subtraction unit;
And a second determination unit that determines whether the amplitude or power of the signal is
greater than a predetermined threshold.
[0020]
Preferably, the speaker is an earphone or a sealed headphone.
[0021]
As described above, according to the present invention, even when the speaker is in a noisy
environment, the speaker and the other party can transmit and receive a voice signal that makes
it easy for the speaker and the other party to hear the transmitted voice of the speaker by
removing the background noise. An apparatus can be provided.
[0022]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
In the following description, the same components are denoted by the same reference numerals.
Their names and functions are also the same. Therefore, detailed description about them will not
be repeated.
04-05-2019
7
[0023]
First Embodiment <Entire Configuration of Audio Signal Transmitting / Receiving Device 100>
FIG. 1 is a schematic diagram showing an overall configuration of an audio signal transmitting /
receiving device 100 according to the present embodiment. The overall configuration of the
audio signal transmitting and receiving apparatus 100 according to the present invention will be
described with reference to FIG. The voice signal transmitting / receiving apparatus 100 is
typically realized by a mobile phone capable of wireless communication, a personal computer
capable of IP (Internet Protocol) phone, or the like.
[0024]
The audio signal transmitting / receiving apparatus 100 includes a differential microphone 110,
a gain adjustment unit 121, an adder 131, a closed speaker (for example, an earphone or a
closed headphone) 141, and a wireless communication device 171. In voice signal transmitting /
receiving apparatus 100 according to the present embodiment, voiced speech Pm of the speaker
of voice signal transmitting / receiving apparatus 100 and environmental noise (background
noise) Pn are received by differential microphone 110. At this time, the speaker's ear receives the
speech voice Pm of the speaker, the environmental noise (background noise) Pn, and the
reception voice Ps from the earplug speaker 141.
[0025]
<Functional Configuration of Audio Signal Transmitting / Receiving Device 100> FIG. 2 is a block
diagram showing a functional configuration of the audio signal transmitting / receiving device
100 according to the present embodiment. As shown in FIG. 2, the audio signal transmitting /
receiving apparatus 100 according to the present embodiment includes a differential microphone
110, an amplifying unit 120, an adding unit 130, an enclosed speaker 140, and a transmitting /
receiving unit 170. In the audio signal transmitting / receiving apparatus 100 according to the
present embodiment, each of the functional blocks described below is dedicated hardware such
as the differential microphone 110, the gain adjusting unit 121, the adder 131, and the wireless
communication apparatus 171. It is realized by a wear circuit or the like. The gain adjustment
unit 121 is intended to adjust the mixing level in the adder 131 and is not necessarily required.
04-05-2019
8
[0026]
However, the audio signal transmission / reception device 100 is a mobile phone or personal
computer having a CPU (Central Processing Unit) and a storage device, and the functional blocks
described below are realized as part of the functions of the CPU. It may be. That is, a control
program for realizing the following functions may be stored in the storage device, and the CPU
may read out and execute the control program from the storage device to realize the following
functional blocks.
[0027]
Each function will be described below. FIGS. 3A and 3B are side sectional views showing the
configurations of two types of differential microphones 110. FIG. FIG. 3 (a) shows one composed
of a plurality of microphones, and FIG. 3 (b) shows one composed of a single microphone. When
configured by a plurality of microphones, as shown in FIGS. 2 and 3A, the differential
microphone 110 includes a receiver 111 and a first subtraction unit 117. The receiver 111
includes a first microphone 111A, a second microphone 111B, and a substrate 119 separated by
a predetermined distance d.
[0028]
The first microphone 111A includes a vibrating membrane 113A. The vibrating film 113A
vibrates by the sound pressure reaching the first microphone 111A, and generates a first electric
signal according to the vibration. That is, the first microphone 111A receives the transmission
voice at the first position, converts it into the first electric signal, and outputs the first electric
signal to the first subtraction unit 117. .
[0029]
The second microphone 111B includes a vibrating membrane 113B. The vibrating membrane
113B vibrates due to the sound pressure reaching the second microphone 111B, and generates a
second electric signal according to the vibration. That is, the second microphone 111 B receives
the transmission voice at the second position, converts it into the second electric signal, and
04-05-2019
9
outputs the second electric signal to the first subtraction unit 117. .
[0030]
The first microphone 111A and the second microphone 111B are connected to the first
subtraction unit 117. The first subtraction unit 117 generates a first transmission voice signal
based on the first electric signal input from the first microphone 111A and the second electric
signal input from the second microphone 111B. And generating a differential signal between the
second electrical signal and the second electrical signal.
[0031]
<Principle of Noise Removal of Differential Microphone 110> Here, the nature of the sound wave
will be described. FIG. 4 is a graph showing the relationship between the sound pressure P and
the distance R from the sound source. As shown in FIG. 4, the sound wave attenuates as it travels
through a medium such as air, and the sound pressure (the strength and amplitude of the sound
wave) is reduced. The sound pressure P is inversely proportional to the distance from the sound
source, so the sound pressure P can be expressed as P = k / R (1) in relation to the distance R
from the sound source. In equation (1), k is a proportional constant.
[0032]
And, as is clear from FIG. 4 and the equation 1, the sound pressure (amplitude of the sound
wave) is sharply attenuated at a position close to the sound source (left side of the graph) and is
gently attenuated as it gets away from the sound source. That is, the sound pressure transmitted
to two positions (d0 and d1, d2 and d3) at which the distance from the sound source differs by
Δd is largely attenuated from d0 to d1 where the distance from the sound source is small (P0P1) There is not much attenuation from d2 to d3 where the distance from the sound source is
large (P2-P3).
[0033]
When the differential microphone 110 according to the present embodiment is applied to the
04-05-2019
10
audio signal transmitting / receiving device 100 represented by a mobile phone, the speech from
the speaker is generated from the vicinity of the differential microphone 110. Therefore, the
voice of the speaker is greatly attenuated between the first microphone 111A and the second
microphone 111B, and the voice of the speaker's speech received by the first microphone 111A
and the second microphone 111B. A big difference appears in sound pressure.
[0034]
On the other hand, in the background noise, the sound source is located at a position far from the
differential microphone 110 as compared to the speech of the speaker. Therefore, the sound
pressure of the background noise hardly attenuates between the first microphone 111A and the
second microphone 111B, and the speech of the speaker received by the first microphone 111A
and the second microphone 111B. There is almost no difference in the sound pressure of the
voice.
[0035]
Next, the noise removal principle in the differential microphone 110 according to the present
embodiment will be described. As described above, since the difference in sound pressure
between the background noises received by the first microphone 111A and the second
microphone 111B is very small, they are generated by the first microphone 111A and the second
microphone 111B. The first subtraction unit 117 substantially cancels the noise signal for the
background noise. On the other hand, since the difference in sound pressure of the speech of the
speaker received by the first microphone 111A and the second microphone 111B is large, it is
generated by the first microphone 111A and the second microphone 111B. The first subtraction
unit 117 does not cancel out the signal for the uttered speech. That is, the first subtraction unit
117 mainly outputs, as the transmission voice signal, a speech voice signal for the speech voice
generated by the first microphone 111A and the second microphone 111B.
[0036]
Thus, it can be regarded that the differential microphone 110 mainly outputs a speech signal
corresponding to the speech of the speaker. That is, the electrical signal (transmission voice
signal) output from the differential microphone 110 can be regarded as a signal representing the
speech voice of the speaker from which noise has been removed. That is, according to the
04-05-2019
11
differential microphone 110 according to the present embodiment, it is possible to provide an
audio signal transmitting / receiving device capable of acquiring an electric signal indicating a
speech of a speaker with noise removed by a simple configuration. Can. Then, the differential
microphone 110 according to the present embodiment can efficiently remove voice from a sound
source located far away compared to the speaker's mouth even with non-stationary noise.
[0037]
<Modification of Differential Microphone> Next, a modification of the differential microphone
110 will be described. As shown in FIG. 3 (b), the differential microphone 110 includes a third
microphone 111 C and a substrate 119. The third microphone 111C includes a vibrating
membrane 113C. The vibrating membrane 113C vibrates by the sound pressures Pf and Pb from
the two directions reaching the third microphone 111C, and generates a third electric signal
according to the vibration. That is, the third microphone 111C receives the transmission voice
transmitted from the two directions and converts it into a third electric signal.
[0038]
In the differential microphone 110 according to the present modification, the vibrating
membrane 113C receives the sound pressure Pf and Pb from both upper and lower sides, and
the vibrating membrane 113C vibrates according to the sound pressure difference of (Pf−Pb).
Therefore, when sound pressure of the same magnitude is simultaneously applied to both sides
of the vibrating membrane 113C, the two sound pressures are canceled by the vibrating
membrane 113C, and the vibrating membrane 113 does not vibrate. Conversely, when there is a
difference in sound pressure received on both sides, the vibrating membrane 113C vibrates due
to the sound pressure difference.
[0039]
The acoustic wave transmitted to the upper surface of the diaphragm 113C and the acoustic
wave transmitted to the lower surface of the diaphragm 113C around the substrate 119 are
different in the transmission distance. Then, as described above, the sound pressure (amplitude
of the sound wave) is sharply attenuated at a position close to the sound source (the left side of
the graph in FIG. 4) and is gentle to a position away from the sound source (the right side in the
graph Attenuate. Therefore, the sound pressure Pf transmitted to the upper surface of the
04-05-2019
12
vibrating membrane 113C and the sound pressure Pb transmitted to the lower surface of the
vibrating membrane 113C around the substrate 119 are largely different from each other for the
sound wave corresponding to the speech of the speaker. On the other hand, the difference
between the sound pressure Pf transmitted to the upper surface of the vibrating film 113C and
the sound pressure Pb transmitted to the lower surface of the vibrating film 113C around the
substrate 119 is very small. Become.
[0040]
Since the difference between the sound pressure Pf and Pb of the background noise received by
the vibrating membrane 113 C is very small, the sound pressure to the background noise is
substantially canceled by the vibrating membrane 113. On the other hand, since the difference
between the sound pressures Pf and Pb of the speech of the speaker received by the diaphragm
113C is large, the sound pressure for the speech is not canceled by the diaphragm 113C. Thus,
the third microphone 111C (differential microphone 110) outputs the third signal obtained by
the vibration of the diaphragm 113C as a transmission voice signal.
[0041]
Thus, the differential microphone 110 can be regarded as mainly outputting a signal
corresponding to the speech of the speaker. That is, the electrical signal output from the
differential microphone 110 can be regarded as a signal representing only the speech of the
speaker from which noise has been removed. That is, according to the differential microphone
110 according to the present modification, it is possible to provide the audio signal transmitting
/ receiving apparatus 100 capable of acquiring an electric signal indicating a speech of a speaker
with noise removed by a simple configuration. Can. Then, the differential microphone 110
according to the present modification can remove even non-stationary noise as long as it is voice
from a sound source located far from the speaker's mouth.
[0042]
<Functional Configuration of Audio Signal Transmitting / Receiving Device 100> In FIG. 2, the
amplifying unit 120 is realized by an amplifier circuit or the like using an operational amplifier
or the like, and is used for the differential microphone 110, the adding unit 130 and the
transmitting / receiving unit 170. It is connected. The amplification unit 120 amplifies the
04-05-2019
13
transmission voice signal input from the differential microphone 110 and outputs the amplified
signal to the transmission / reception unit 170 and the addition unit 130.
[0043]
The transmission / reception unit 170 is realized by a wireless communication device 171 such
as an antenna (not shown), and is connected to the amplification unit 120 and the addition unit
130. The transmission / reception unit 170 receives a reception voice signal and transmits a
transmission voice signal. More specifically, transmission / reception unit 170 transmits the
transmission voice signal input from amplification unit 120 to the outside, receives a reception
voice signal from the outside, and outputs the reception voice signal to addition unit 130.
[0044]
The addition unit 130 is connected to the transmission / reception unit 170, the amplification
unit 120, and the closed speaker 140. The addition unit 130 adds the reception voice signal
input from the transmission / reception unit 170 and the transmission voice signal input from
the amplification unit 120 to generate an addition signal, and outputs the addition signal to the
closed speaker 140.
[0045]
The closed speaker 140 is realized by an earphone, closed headphones, or the like, and converts
the addition signal input from the addition unit 130 into a received voice and outputs the
received voice. By sealing the speaker's ear with the closed speaker 140, it is made difficult for
background noise (environment noise Pn) to directly enter the speaker's ear. More specifically,
by wearing the earphones or the closed type headphones, the speaker can reduce the speech
sound Pm and the background noise (environment noise Pn) that directly enter the ear by about
20 dB.
[0046]
FIG. 5 (a) is an image diagram showing the sound pressure of the voice heard by the other party
and the speaker when the preceding voice signal transmitting / receiving apparatus 100 is used,
and FIG. 5 (b) is a differential microphone 110 and an earplug type. FIG. 5C is an image diagram
04-05-2019
14
showing the sound pressure of the voice heard by the other party and the speaker when the
speaker (earphone) or the closed type headphone is adopted, and FIG. 5C uses the voice signal
transmitting / receiving apparatus 100 according to the present embodiment It is the image
figure which showed the sound pressure of the other party and the voice which a speaker hears
in the case of having made.
[0047]
For example, it is assumed that the speech sound and background noise input to the microphone
of the speech signal transmitting and receiving device have the same sound pressure (94 dB).
At this time, as shown in FIG. 5 (a), when the preceding voice signal transmitting / receiving
apparatus is used, the voice heard by the other party is the background voice of the speaker
amplified by the amplification unit (94 dB) and the background. The noise (94 dB) is combined.
Then, the sound pressure of the voice heard by the speaker is a combination of the speech voice
(80 dB) arriving from the speaker's mouth and the background noise (94 dB). Here, 80 dB of
speech delivered from the speaker's mouth is the distance from the speaker's mouth to the
speaker's ear compared to the distance from the speaker's mouth to the microphone of the voice
signal transmitting / receiving device. This is because the sound pressure attenuation rate of the
speech voice whose distance from the sound source is short is larger than the sound pressure
attenuation rate of the background noise whose distance from the sound source is long. In this
case, the speaker speaks a louder voice because his / her speech is difficult to hear. As a result,
the other party may hear a loud voice from the speaker and may feel uncomfortable.
[0048]
Since the audio signal transmitting / receiving apparatus 100 according to the present
embodiment includes the differential microphone 110, background noise can be reduced. For
this reason, as shown in FIG. 5B, the voice heard by the other party is a combination of the
speech voice (94 dB) of the speaker amplified by the amplification unit 120 and the background
noise (80 dB). Further, by providing the closed type speaker 140 such as an earphone or a closed
type headphone, it is possible to reduce speech sound and background noise which a speaker
hears. The closed loudspeaker 140 reduces the sound pressure of the voice heard by the speaker
by about 20 dB, and the voice heard by the speaker becomes a speech voice (60 dB) and
background noise (74 dB).
04-05-2019
15
[0049]
Then, audio signal transmitting / receiving apparatus 100 according to the present embodiment
amplifies an electrical signal corresponding to speech (94 dB) and background noise (80 dB),
which are transmission audio signals output from differential microphone 110. , This is added to
the received voice signal. Then, the addition signal is output as a received voice from the closedtype speaker 140. Here, if the amplification factor is set so that the speech voice heard by the
speaker is 94 dB, the speech heard by the speaker will be speech voice (94 dB) and background
noise (83.5 dB).
[0050]
As described above, according to voice signal transmitting / receiving apparatus 100 according
to the present embodiment, the background noise level is lower than the voiced speech level for
both the communication partner and the speaker under an environment where the voiced speech
and the background noise are at the same level Can be suppressed to a level lower than 10 dB, so
that the transmitted voice on the speaker side can be heard clearly.
[0051]
Second Embodiment FIG. 6 is a graph showing the relationship between the distance R from the
sound source converted to logarithms and the sound pressure P output from the microphone
converted to logarithms (dB: decibel) .
The dotted line shows the characteristics of a normal microphone, and the solid line shows the
characteristics of a differential microphone.
[0052]
As shown in FIG. 6, the sound pressure level (dB) detected and output by the differential
microphone 110 shows a characteristic that decreases greatly as the distance from the sound
source becomes larger than that of a normal microphone. Since the pressure difference is taken
out as an output signal, the output level is lowered by x at a normally assumed distance r
between the speaker and the microphone as compared to a normal microphone.
04-05-2019
16
[0053]
Therefore, in order to obtain a transmission voice signal of the same level as the normal
microphone, the gain of the amplification unit 120 needs to be higher than that of the normal
microphone.
The amount by which the gain is increased depends on the microphone spacing. For example,
when the microphone spacing is set to about 5 mm, it is necessary to increase the gain by about
15 dB.
[0054]
On the other hand, assuming that the noise level of the first-stage preamplifier used in the
microphone is the same between the normal microphone and the differential microphone, the
SNR (Signal to Noise Ratio) of the differential microphone is disadvantageous compared to the
normal microphone. become. For example, when the microphone spacing is set to about 5 mm,
there is a disadvantage of about 15 dB. That is, the amount by which the gain is increased is
disadvantageous in order to obtain the transmission voice signal of the same level as the normal
microphone.
[0055]
Therefore, in a quiet environment (in an environment where background noise is small), the
noise of the first-stage preamplifier of the microphone can not be ignored relative to the signal
level of background noise output from the differential microphone 110, and this amplifier noise
There is a possibility that the other party or the speaker may hear (it is easy to be recognized).
That is, by using the differential microphone 110, the SNR of the voice signal transmitting /
receiving apparatus 100 may be reduced, and amplifier noise may be heard by the other party or
the speaker.
[0056]
The audio signal transmitting / receiving apparatus 100 according to the present embodiment
04-05-2019
17
and the following third to seventh embodiments has a configuration for solving such a problem.
Specifically, when placed in a state where background noise is small, audio signal transmitting /
receiving apparatus 100 according to the present embodiment is not an audio signal from
differential microphone 110, but an audio signal from one microphone 111A. To generate a
received voice signal.
[0057]
About the whole structure of the audio | voice signal transmitter / receiver 100 according to this
Embodiment, since it is the same as that of the above-mentioned Embodiment 1, detailed
description is not repeated. Further, the configuration of the differential microphone 110
constituting the audio signal transmitting / receiving device 100 and the noise removal principle
by the differential microphone 110 are also similar to those of the above-described first
embodiment, and therefore the detailed description will not be repeated. However, in the audio
signal transmitting / receiving apparatus 100 according to the first embodiment, the differential
microphone 110 may be configured to detect an electrical difference as shown in FIG. The
configuration may be such that the acoustic difference as shown in b) is detected, but the
differential microphone 110 of the audio signal transmitting / receiving apparatus 100 according
to the second to seventh embodiments described below is as shown in FIG. It is assumed that the
electric difference is detected.
[0058]
<Functional Configuration of Audio Signal Transmitting / Receiving Device 100> FIG. 7 is a block
diagram showing a functional configuration of the audio signal transmitting / receiving device
100 according to the present embodiment. As shown in FIG. 7, the audio signal transmitting /
receiving apparatus 100 according to the present embodiment includes a differential microphone
110, an amplifying unit 120, an adding unit 130, an enclosed speaker 140, and a first
determination unit 151. A first switching unit 161 and a transmitting / receiving unit 170 are
included. Also in the audio signal transmitting / receiving apparatus 100 according to the
present embodiment, each of the functional blocks described below is realized by a dedicated
hardware circuit or the like.
[0059]
04-05-2019
18
However, the audio signal transmission / reception device 100 is a mobile phone or personal
computer having a CPU (Central Processing Unit) and a storage device, and the functional blocks
described below are realized as part of the functions of the CPU. It may be. That is, a control
program for realizing the following functions may be stored in the storage device, and the CPU
may read out and execute the control program from the storage device to realize the following
functional blocks.
[0060]
Hereinafter, each function will be described, but the differential microphone 110 according to
the present embodiment, the amplification unit 120, the addition unit 130, the closed-type
speaker 140, and the transmission / reception unit 170 according to the first embodiment. And
the detailed description will not be repeated here.
[0061]
As shown in FIG. 7, the first determination unit 151 is connected to the first microphone 111 </
b> A and the first switching unit 161.
First determination unit 151 determines whether the amplitude of the first electric signal from
first microphone 111A is larger than a predetermined threshold value, and outputs the
determination result to first switching unit 161. . Here, the predetermined threshold may be
stored in the first determination unit 151. Alternatively, the first determination unit 151 may be
configured to read the threshold stored in another storage device or the like and compare the
read threshold with the amplitude of the first electrical signal.
[0062]
The first switching unit 161 is connected to the first microphone 111 </ b> A or the second
microphone 111 </ b> B, the amplification unit 120, the first determination unit 151, and the
addition unit 130. The first switching unit 161 adds the transmission voice signal from the
amplification unit 120 when the amplitude of the first electric signal is equal to or greater than a
predetermined threshold value based on the determination result of the first determination unit
151. The signal is input to the unit 130, and the first electric signal or the second electric signal
is input to the adding unit 130 when the amplitude of the first electric signal is less than a
predetermined threshold.
04-05-2019
19
[0063]
That is, according to the magnitude of the sound pressure of the sound obtained from the first
microphone 111A, the first switching unit 161 obtains the differential sound obtained by the
differential microphone 110 and the single microphone 111A (111B). The selected single signal
is switched and output to the addition unit 130.
[0064]
Similarly, based on the determination result of the first determination unit 151, the first
switching unit 161 transmits the transmission voice from the amplification unit 120 when the
amplitude of the first electrical signal is equal to or greater than a predetermined threshold. A
signal is output to the transmitting and receiving unit 170, and when the amplitude of the first
electrical signal is less than a predetermined threshold, the first electrical signal or the second
electrical signal is output to the transmitting and receiving unit 170.
[0065]
As described above, the audio signal transmitting / receiving apparatus 100 according to the
present embodiment generates the received audio signal and the transmitted audio signal using
one microphone 111A (111B) under an environment where the background noise is small. Is
configured to not drop.
As a result, even if the background noise is small, noise generated in the amplifier circuit can not
be heard by the speaker or the other party.
[0066]
In the present embodiment, the first determination unit 151 determines based on the amplitude
of the first electrical signal from the first microphone 111A, but is limited to the amplitude of the
first electrical signal. Other parameters may be used as long as they change according to the
signal level, such as the power of the first electrical signal.
[0067]
04-05-2019
20
Furthermore, the amplification unit 120 may be configured in the differential microphone 110.
In addition, the amplification unit 120 is not necessarily required, and may be configured as a
part of the first subtraction unit 117.
[0068]
Third Embodiment Also in the case of voice signal transmitting / receiving apparatus 100
according to the present embodiment, when placed in a state where background noise is small, it
is not a voice signal from differential microphone 110 but one microphone 111A (111B). The
voice signal of is used to generate a received voice signal.
[0069]
About the whole structure of the audio | voice signal transmitter / receiver 100 according to this
Embodiment, since it is the same as that of the above-mentioned Embodiment 1, detailed
description is not repeated.
Further, the configuration of the differential microphone 110 constituting the audio signal
transmitting / receiving device 100 and the noise removal principle by the differential
microphone 110 are also similar to those of the above-described first embodiment, and therefore
the detailed description will not be repeated.
[0070]
<Functional Configuration of Audio Signal Transmitting / Receiving Device 100> FIG. 8 is a block
diagram showing a functional configuration of the audio signal transmitting / receiving device
100 according to the present embodiment.
As shown in FIG. 8, the audio signal transmitting / receiving apparatus 100 according to the
present embodiment includes a differential microphone 110, an amplifying unit 120, an adding
unit 130, an enclosed speaker 140, a noise detecting unit 153, and a second And a transmission
/ reception unit 170. Also in the audio signal transmitting / receiving apparatus 100 according to
the present embodiment, each of the functional blocks described below is realized by a dedicated
04-05-2019
21
hardware circuit or the like.
[0071]
However, the audio signal transmission / reception device 100 is a mobile phone or personal
computer having a CPU (Central Processing Unit) and a storage device, and the functional blocks
described below are realized as part of the functions of the CPU. It may be. That is, a control
program for realizing the following functions may be stored in the storage device, and the CPU
may read out and execute the control program from the storage device to realize the following
functional blocks.
[0072]
Hereinafter, each function will be described, but the differential microphone 110 according to
the present embodiment, the amplification unit 120, the addition unit 130, the closed-type
speaker 140, and the transmission / reception unit 170 according to the first embodiment. And
the detailed description will not be repeated here.
[0073]
As shown in FIG. 8, the noise detection unit 153 is connected to the first microphone 111 </ b>
A, the second microphone 111 </ b> B, and the first switching unit 161.
The noise detection unit 153 extracts a noise signal based on the first electric signal from the
first microphone 111A and the second electric signal from the second microphone 111B, and the
amplitude of the noise signal is predetermined. It is determined whether the threshold value is
larger than the threshold value, and the determination result is output to the second switching
unit 162.
[0074]
FIG. 9 is a functional block diagram showing a functional configuration of the noise detection
unit 153. As shown in FIG. As shown in FIG. 9, the noise detection unit 153 includes a delay unit
154, a second subtraction unit 155, and a second determination unit 152. Although a normal
04-05-2019
22
differential microphone shows bi-directional characteristics, here, by giving an appropriate delay
amount to the second microphone 111B in the delay unit 154, the directional characteristics are
made to be of the cardioid type.
[0075]
FIG. 10 shows the directivity characteristic of the microphone when the delay amount of the
delay unit 154 is changed. When the delay amount of the delay unit 154 is 0, as shown in FIG.
10A, the directional characteristics are obtained, and sensitivity is given to one direction and the
opposite side with respect to the receiving unit 111.
[0076]
By changing the delay amount of the delay unit 154, the directivity characteristic of the
microphone also changes, and the direction of the null changes. When the delay amount is a
predetermined time τ (formula 1), as shown in FIG. 10B, the directivity characteristic of the
microphone becomes a cardioid type.
[0077]
In order to realize the cardioid characteristics as shown in FIG. 10B, the predetermined time τ
according to the present embodiment is set to: τ = d / c (Equation 1). Here, d is the distance
between the first microphone 111A and the second microphone 111B, and c is the propagation
velocity of the sound wave.
[0078]
The delay unit 154 delays the output of the second microphone 111B, which is the microphone
on the side closer to the speaker (transmission voice incoming side), by a predetermined time τ,
and outputs the delayed signal to the second subtraction unit 155.
[0079]
04-05-2019
23
The second subtraction unit 155 is connected to the first microphone 111 </ b> A, the delay unit
154, and the second determination unit 152.
The second subtraction unit 155 generates a difference signal between the first electric signal
and the output of the delay unit 154, and outputs the difference signal as a noise signal to the
second determination unit 152.
[0080]
As shown in FIG. 10, the noise detection unit 153 has a cardioid characteristic that has
directional null in the 0 ° direction (on the second microphone 111B side on the straight line
connecting the first microphone 111A and the second microphone 111B). By arranging the
receiver 111 so that the speaker's mouth (for example, a microphone such as a mobile phone) is
positioned in this direction, the voice in the direction of the speaker is cut and emitted from the
direction other than the speaker direction. Can be selectively extracted.
[0081]
The second determination unit 152 is connected to the second subtraction unit 155 and the
second switching unit 162.
The second determination unit 152 determines whether the amplitude of the noise signal from
the second subtraction unit 155 is larger than a predetermined threshold value, and outputs the
determination result to the switching unit 162. Here, the predetermined threshold may be stored
in the second determination unit 152. In addition, the second determination unit 152 may be
configured to read the threshold stored in another storage device or the like and compare the
read threshold with the amplitude of the noise signal.
[0082]
In FIG. 8, the second switching unit 162 is connected to the first microphone 111A or the second
microphone 111B, the amplification unit 120, the noise detection unit 153 (second
determination unit 152), and the addition unit 130. ing. The second switching unit 162 transmits
the transmission voice signal from the amplification unit 120 when the amplitude of the noise
signal is equal to or greater than a predetermined threshold based on the determination of the
04-05-2019
24
noise detection unit 153 (second determination unit 152). Is input to the adding unit 130, and
the first electrical signal or the second electrical signal is input to the adding unit 130 when the
amplitude of the noise signal is less than a predetermined threshold.
[0083]
That is, according to the magnitude of the sound pressure of the background noise, the second
switching unit 162 selects the differential audio signal (DIF) acquired by the differential
microphone 110 and the single acquired by one microphone 111A (111B). The signal (SGL) is
switched to be output to the addition unit 130.
[0084]
Similarly, on the basis of the determination result of the noise detection unit 153 (second
determination unit 152), the second switching unit 162 transmits the signal from the
amplification unit 120 when the amplitude of the noise signal is equal to or greater than a
predetermined threshold. The transmission voice signal is output to the transmission / reception
unit 170, and the first electric signal or the second electric signal is output to the transmission /
reception unit 170 when the amplitude of the noise signal is less than a predetermined threshold.
[0085]
Thus, in an environment where the background noise is small, the audio signal transmitting /
receiving apparatus 100 according to the present embodiment generates SNR by generating a
received audio signal or a transmitted audio signal using one microphone 111A (111B). It is
configured not to decline.
As a result, even in an environment where background noise is small, noise of the amplifier
circuit and the like are difficult to hear by the speaker or the other party.
[0086]
In the present embodiment, the gain of amplification section 120 is the level of the speaker voice
signal (DIF) obtained by differential microphone 110 and the speaker voice signal (the signal
obtained by one microphone 111A (111B). It is preferable to set the gain so that the levels of
04-05-2019
25
SGL) become almost equal.
Thereby, it is possible to suppress the fluctuation of the speaker voice signal level when the
signal is switched by the second switching unit 162, and it is possible to perform transmission
without a sense of incongruity.
[0087]
In addition, although the second determination unit 152 determines based on the amplitude of
the noise signal, it is not limited to only the amplitude of the noise signal, and changes according
to the noise signal level such as the power of the noise signal. If it is a thing, it may be another
parameter.
[0088]
Furthermore, the amplification unit 120 may be configured in the differential microphone 110.
In addition, the amplification unit 120 is not necessarily required, and may be configured as a
part of the first subtraction unit 117.
[0089]
Fourth Embodiment In the above second and third embodiments, when the background noise is
small, the voice signal from one microphone 111A (111B) is not the voice signal from the
differential microphone 110. The voice signal transmitting / receiving apparatus 100 according
to the present embodiment receives the switching command from the speaker and generates the
voice signal from the differential microphone 110. Instead, the voice signal from one microphone
111A is used to generate a reception voice signal and a transmission voice signal.
[0090]
About the whole structure of the audio | voice signal transmitter / receiver 100 according to this
Embodiment, since it is the same as that of the above-mentioned Embodiment 1, detailed
description is not repeated.
04-05-2019
26
Further, the configuration of the differential microphone 110 constituting the audio signal
transmitting / receiving device 100 and the noise removal principle by the differential
microphone 110 are also similar to those of the above-described first embodiment, and therefore
the detailed description will not be repeated.
[0091]
<Functional Configuration of Audio Signal Transmitting and Receiving Device 100> FIG. 11 is a
block diagram showing a functional configuration of the audio signal transmitting and receiving
device 100 according to the present embodiment. As shown in FIG. 11, the audio signal
transmitting / receiving apparatus 100 according to the present embodiment includes a
differential microphone 110, an amplifying unit 120, an adding unit 130, an enclosed speaker
140, an operation unit 158, and a receiving unit 159. And a third switching unit 163 and a
transmitting / receiving unit 170. Also in the audio signal transmitting / receiving apparatus 100
according to the present embodiment, each of the functional blocks described below is realized
by a dedicated hardware circuit or the like.
[0092]
However, the audio signal transmission / reception device 100 is a mobile phone or personal
computer having a CPU (Central Processing Unit) and a storage device, and the functional blocks
described below are realized as part of the functions of the CPU. It may be. That is, a control
program for realizing the following functions may be stored in the storage device, and the CPU
may read out and execute the control program from the storage device to realize the following
functional blocks.
[0093]
Hereinafter, each function will be described, but the differential microphone 110 according to
the present embodiment, the amplification unit 120, the addition unit 130, the closed-type
speaker 140, and the transmission / reception unit 170 according to the first embodiment. And
the detailed description will not be repeated here. As shown in FIG. 11, the operation unit 158 is
realized by, for example, an operation button in a mobile phone, a keyboard or a mouse in a
personal computer, and the like, and receives a switching instruction from a speaker.
04-05-2019
27
[0094]
The reception unit 159 is connected to the operation unit 158 and the third switching unit 163.
Reception unit 159 receives an external switching instruction via operation unit 158, and
outputs the switching instruction to third switching unit 163.
[0095]
The third switching unit 163 is connected to the first microphone 111A or the second
microphone 111B, the amplification unit 120, the reception unit 159, and the addition unit 130.
In response to the switching command, the third switching unit 163 transmits the transmission
voice signal from the amplification unit 120 and the first electric signal from the first
microphone 111A or the second electric signal from the second microphone 111B. , And output
to the adding unit 130. That is, the third switching unit 163 switches between the differential
voice acquired by the differential microphone 110 and the single signal acquired by one
microphone 111A (111B) according to the operation of the speaker, and adds the unit. It outputs
to 130.
[0096]
Similarly, in response to the switching command, the third switching unit 163 transmits the
transmission voice signal from the amplification unit 120 and the first electric signal from the
first microphone 111A or the second electric signal from the second microphone 111B. The
electric signal is switched to be output to the transmitting and receiving unit 170.
[0097]
As described above, in the voice signal transmitting / receiving apparatus 100 according to the
present embodiment, under circumstances where the background noise is small, that is, when the
noise of the amplifier circuit or the like is heard by the speaker or the other party, etc. By
generating the reception voice signal and the transmission voice signal using the microphone
111A (111B), the SNR is not reduced.
04-05-2019
28
As a result, it is possible to make the noise of the amplifier circuit and the like inaudible to the
speaker or the other party even in an environment where the background noise is small.
[0098]
In the present embodiment, the gain of amplification section 120 is the level of the speaker voice
signal (DIF) obtained by differential microphone 110 and the speaker voice signal (the signal
obtained by one microphone 111A (111B). It is preferable to set the gain so that the levels of
SGL) become almost equal. Thereby, it is possible to suppress the fluctuation of the speaker voice
signal level when the signal is switched by the second switching unit 162, and it is possible to
perform transmission without a sense of incongruity.
[0099]
Furthermore, the amplification unit 120 may be configured in the differential microphone 110.
In addition, the amplification unit 120 is not necessarily required, and may be configured as a
part of the first subtraction unit 117.
[0100]
Fifth Embodiment The voice signal transmitting / receiving apparatus 100 according to the
present embodiment does not add the voice signal from the differential microphone 110 to the
received voice signal when placed in a state where the background noise is small, and the
received voice signal Are input to the closed speaker 140.
[0101]
About the whole structure of the audio | voice signal transmitter / receiver 100 according to this
Embodiment, since it is the same as that of the above-mentioned Embodiment 1, detailed
description is not repeated.
Further, the configuration of the differential microphone 110 constituting the audio signal
transmitting / receiving device 100 and the noise removal principle by the differential
microphone 110 are also similar to those of the above-described first embodiment, and therefore
04-05-2019
29
the detailed description will not be repeated.
[0102]
<Functional Configuration of Audio Signal Transmitting and Receiving Device 100> FIG. 12 is a
block diagram showing a functional configuration of the audio signal transmitting and receiving
device 100 according to the present embodiment. As shown in FIG. 12, the audio signal
transmitting / receiving apparatus 100 according to the present embodiment includes a
differential microphone 110, an amplifying unit 120, an adding unit 130, an enclosed speaker
140, and a first determination unit 151. A fourth switching unit 161 and a transmitting /
receiving unit 170 are included. Also in the audio signal transmitting / receiving apparatus 100
according to the present embodiment, each of the functional blocks described below is realized
by a dedicated hardware circuit or the like.
[0103]
However, the audio signal transmission / reception device 100 is a mobile phone or personal
computer having a CPU (Central Processing Unit) and a storage device, and the functional blocks
described below are realized as part of the functions of the CPU. It may be. That is, a control
program for realizing the following functions may be stored in the storage device, and the CPU
may read out and execute the control program from the storage device to realize the following
functional blocks.
[0104]
Hereinafter, each function will be described, but the differential microphone 110 according to
the present embodiment, the amplification unit 120, the addition unit 130, the closed type
speaker 140, the first determination unit 151, and the transmission / reception unit 170 Since
the second embodiment is the same as those according to the first embodiment, the detailed
description will not be repeated here.
[0105]
As shown in FIG. 12, the fourth switching unit 164 is connected to the amplification unit 120, the
first determination unit 151, and the addition unit 130.
04-05-2019
30
The fourth switching unit 164 connects the amplifying unit 120 and the adding unit 130 when
the amplitude of the first electric signal is equal to or greater than a predetermined threshold
based on the determination result of the first determining unit 151. That is, the transmission
voice signal from the amplification unit 120 is input to the addition unit 130, and the
amplification unit 120 and the addition unit 130 are not connected when the amplitude of the
first electric signal is less than a predetermined threshold. That is, the transmission voice signal
from the amplification unit 120 is not input to the addition unit 130.
[0106]
As described above, the audio signal transmitting / receiving apparatus 100 according to the
present embodiment is configured such that the SNR is not reduced by generating the received
audio signal without using the differential microphone 110 under an environment where the
background noise is small. ing. As a result, even if the background noise is small, noise generated
in the amplifier circuit can not be heard by the speaker.
[0107]
Although the amplification unit 120 and the transmission / reception unit 170 are connected in
the present embodiment, the fourth switching unit 164 and the transmission / reception unit
170 may be connected. Then, as in the second embodiment, when the fourth switching unit 164
determines that the amplitude of the first electrical signal is equal to or greater than a
predetermined threshold value based on the determination result of the first determination unit
151, The transmission voice signal from the amplification unit 120 is output to the transmission
and reception unit 170, and the first electric signal or the second electric signal is transmitted
and received when the amplitude of the first electric signal is less than a predetermined
threshold. It may be configured to output to
[0108]
By this, the audio signal transmitting / receiving apparatus 100 according to the present
embodiment is configured such that the SNR is not lowered by generating the transmission audio
signal using one microphone 111A (111B) under the environment where the background noise is
04-05-2019
31
small. It is done. As a result, even if the background noise is small, noise generated in the
amplifier circuit can not be heard by the other party.
[0109]
In the present embodiment, the amplification unit 120 is not necessarily required. The
amplification unit 120 may be configured in the differential microphone 110 or may be
configured as a part of the first subtraction unit 117.
[0110]
Sixth Embodiment The voice signal transmitting / receiving apparatus 100 according to the
present embodiment also does not add the voice signal from the differential microphone 110 to
the received voice signal when it is placed in a situation where the background noise is small. A
signal is input to the closed speaker 140.
[0111]
About the whole structure of the audio | voice signal transmitter / receiver 100 according to this
Embodiment, since it is the same as that of the above-mentioned Embodiment 1, detailed
description is not repeated.
Further, the configuration of the differential microphone 110 constituting the audio signal
transmitting / receiving device 100 and the noise removal principle by the differential
microphone 110 are also similar to those of the above-described first embodiment, and therefore
the detailed description will not be repeated.
[0112]
<Functional Configuration of Audio Signal Transmitting / Receiving Device 100> FIG. 13 is a
block diagram showing a functional configuration of the audio signal transmitting / receiving
device 100 according to the present embodiment. As shown in FIG. 13, the audio signal
transmitting / receiving apparatus 100 according to the present embodiment includes a
differential microphone 110, an amplifying unit 120, an adding unit 130, an enclosed speaker
04-05-2019
32
140, a noise detecting unit 153, and a fifth And a transmission / reception unit 170. Also in the
audio signal transmitting / receiving apparatus 100 according to the present embodiment, each
of the functional blocks described below is realized by a dedicated hardware circuit or the like.
[0113]
However, the audio signal transmission / reception device 100 is a mobile phone or personal
computer having a CPU (Central Processing Unit) and a storage device, and the functional blocks
described below are realized as part of the functions of the CPU. It may be. That is, a control
program for realizing the following functions may be stored in the storage device, and the CPU
may read out and execute the control program from the storage device to realize the following
functional blocks.
[0114]
Hereinafter, each function will be described, but the differential microphone 110 according to
the present embodiment, the amplification unit 120, the addition unit 130, the closed-type
speaker 140, the noise detection unit 153, and the transmission / reception unit 170 are
implemented. The detailed description is not repeated here as it is similar to those according to
the third aspect.
[0115]
The fifth switching unit 165 is connected to the amplification unit 120, the noise detection unit
153, and the addition unit 130.
The fifth switching unit 165 performs the amplification unit 120 and the addition unit 130 when
the amplitude of the noise signal is equal to or greater than a predetermined threshold value
based on the determination result of the noise detection unit 153 (second determination unit
152). And the transmission voice signal from the amplification unit 120 is input to the addition
unit 130, and when the amplitude of the noise signal is less than a predetermined threshold, the
amplification unit 120 and the addition unit 130 are not connected. That is, the transmission
voice signal from the amplification unit 120 is not input to the addition unit 130.
[0116]
04-05-2019
33
As described above, the audio signal transmitting / receiving apparatus 100 according to the
present embodiment is configured such that the SNR is not reduced by generating the received
audio signal without using the differential microphone 110 under an environment where the
background noise is small. ing. As a result, even if the background noise is small, noise generated
in the amplifier circuit can not be heard by the speaker.
[0117]
Although the amplification unit 120 and the transmission and reception unit 170 are connected
in the present embodiment, the fifth switching unit 165 and the transmission and reception unit
170 may be connected. Then, as in the third embodiment, the fifth switching unit 165
determines that the amplitude of the noise signal is equal to or greater than a predetermined
threshold value based on the determination result of the noise detection unit 153 (second
determination unit 152). In this case, the transmission voice signal from the amplification unit
120 is output to the transmission / reception unit 170, and the first electric signal or the second
electric signal is transmitted / received when the amplitude of the noise signal is less than a
predetermined threshold. It may be configured to output to
[0118]
By this, the audio signal transmitting / receiving apparatus 100 according to the present
embodiment is configured such that the SNR is not lowered by generating the transmission audio
signal using one microphone 111A (111B) under the environment where the background noise is
small. It is done. As a result, even if the background noise is small, noise generated in the
amplifier circuit can not be heard by the other party.
[0119]
In the present embodiment, the amplification unit 120 is not necessarily required. The
amplification unit 120 may be configured in the differential microphone 110 or may be
configured as a part of the first subtraction unit 117.
04-05-2019
34
[0120]
Seventh Embodiment In the above fifth and sixth embodiments, when the background noise is
small, the voice signal from differential microphone 110 is not added to the received voice signal,
and the received voice signal is closed. The voice signal transmitting / receiving apparatus 100
according to the present embodiment receives the switching command from the speaker and
adds the voice signal from the differential microphone 110 to the received voice signal. Instead,
the received audio signal is input to the closed speaker 140.
[0121]
About the whole structure of the audio | voice signal transmitter / receiver 100 according to this
Embodiment, since it is the same as that of the above-mentioned Embodiment 1, detailed
description is not repeated.
Further, the configuration of the differential microphone 110 constituting the audio signal
transmitting / receiving device 100 and the noise removal principle by the differential
microphone 110 are also similar to those of the above-described first embodiment, and therefore
the detailed description will not be repeated.
[0122]
<Functional Configuration of Audio Signal Transmitting / Receiving Device 100> FIG. 14 is a
block diagram showing a functional configuration of the audio signal transmitting / receiving
device 100 according to the present embodiment. As shown in FIG. 14, the audio signal
transmitting / receiving apparatus 100 according to the present embodiment includes a
differential microphone 110, an amplifying unit 120, an adding unit 130, an enclosed speaker
140, an operation unit 158, and a receiving unit 159. And a sixth switching unit 166 and a
transmitting / receiving unit 170. Also in the audio signal transmitting / receiving apparatus 100
according to the present embodiment, each of the functional blocks described below is realized
by a dedicated hardware circuit or the like.
[0123]
However, the audio signal transmitting / receiving device 100 is a mobile phone or personal
04-05-2019
35
computer having a CPU (Central Processing Unit) and a storage device, and the functional blocks
described below are realized as part of the functions of the CPU. May be That is, a control
program for realizing the following functions may be stored in the storage device, and the CPU
may read out and execute the control program from the storage device to realize the following
functional blocks.
[0124]
Hereinafter, each function will be described, but the differential microphone 110 according to
the present embodiment, the amplification unit 120, the addition unit 130, the closed type
speaker 140, the operation unit 158, the reception unit 159, and the transmission / reception
unit 170 Is the same as those according to the fourth embodiment, the detailed description will
not be repeated here.
[0125]
As shown in FIG. 14, the sixth switching unit 166 is connected to the amplification unit 120, the
reception unit 159, and the addition unit 130.
The sixth switching unit 163 changes the connection between the amplification unit 120 and the
addition unit 130 in response to the switching instruction. That is, the sixth switching unit 163
connects or cancels the connection between the amplifying unit 120 and the adding unit 130
according to the switching instruction.
[0126]
As described above, the voice signal transmitting / receiving apparatus 100 according to the
present embodiment receives a speaker's command in an environment where the background
noise is small, that is, when noise of the amplifier circuit is heard by the speaker or the other
party. Accordingly, the SNR is not reduced by generating the reception voice signal without using
the differential microphone 110. As a result, even if the background noise is small, noise
generated in the amplifier circuit can not be heard by the speaker.
[0127]
04-05-2019
36
In the present embodiment, the output of the amplification unit 120 and the transmission /
reception unit 170 are connected, but the output of the sixth switching unit 166 may be
connected to the transmission / reception unit 170. Then, in the same manner as in the fourth
embodiment, the sixth switching unit 166 outputs the transmission voice signal from the
amplification unit 120 to the transmission / reception unit 170 in response to the switching
command from the reception unit 159, or the first electricity The configuration may be such that
the signal or the second electrical signal is output to the transmission / reception unit 170.
[0128]
Further, in the present embodiment, the amplification unit 120 is not necessarily required. The
amplification unit 120 may be configured in the differential microphone 110 or may be
configured as a part of the first subtraction unit 117.
[0129]
In the first to seventh embodiments described above, the embodiments have been described in
which the type of the audio signal input to the adding unit 130 is switched or the transmission
voice signal itself is not input to the adding unit 130. The function may be nullified, that is, the
differential microphone 110 may be changed to one having the same function as a normal
microphone. That is, the path (hole) of the sound wave for the sound pressure P1 or the sound
pressure P2 shown in FIG. 3A is closed, or the sound pressure Pf shown in FIG. 3B or the sound
pressure Pb shown in FIG. The function as the differential microphone 110 may be invalidated by
closing the passage (hole) of the sound wave with respect to the sound pressure.
[0130]
It should be understood that the embodiments disclosed herein are illustrative and nonrestrictive in every respect. The scope of the present invention is indicated not by the above
description but by the claims, and is intended to include all modifications within the meaning and
scope equivalent to the claims.
[0131]
04-05-2019
37
FIG. 1 is a schematic view showing an entire configuration of an audio signal transmitting and
receiving apparatus according to an embodiment of the present invention. FIG. 1 is a block
diagram showing a functional configuration of an audio signal transmitting / receiving apparatus
according to Embodiment 1. FIG. 2 is a side cross-sectional view showing the configuration of
two types of differential microphones. It is a graph which shows the relationship between sound
pressure P and distance R from a sound source. It is an image figure showing the sound pressure
of the voice which a calling party and a speaker hear. It is the graph which showed the
relationship between what converted distance R from a sound source into logarithm, and what
converted sound pressure P which a microphone outputs into logarithm. FIG. 7 is a block
diagram showing a functional configuration of an audio signal transmitting and receiving device
according to a second embodiment. FIG. 16 is a block diagram showing a functional
configuration of an audio signal transmitting and receiving device according to a third
embodiment. It is a functional block diagram which shows the function structure of a noise
detection part. It is an image figure which shows the directional characteristic of a microphone.
FIG. 16 is a block diagram showing a functional configuration of an audio signal transmitting and
receiving device according to a fourth embodiment. FIG. 18 is a block diagram showing a
functional configuration of an audio signal transmitting and receiving device according to a fifth
embodiment. FIG. 21 is a block diagram showing a functional configuration of an audio signal
transmitting and receiving device according to a sixth embodiment. FIG. 21 is a block diagram
showing a functional configuration of an audio signal transmitting and receiving device
according to a seventh embodiment.
Explanation of sign
[0132]
DESCRIPTION OF SYMBOLS 100 audio signal transmission / reception apparatus, 110
differential microphone, 111 receiver, 111A, 111B, 111C microphone, 113A, 113B, 113C
diaphragm, 117 1st subtraction part, 119 board | substrates, 120 amplifier, 130 addition part,
131 addition , 140 sealed speakers, 141 earplug speakers (earphones), 151 first determination
unit, 152 second determination unit, 153 noise detection unit, 154 delay unit, 155 second
subtraction unit, 158 operation unit, 159 reception unit, 161 first switching unit, 162 second
switching unit, 163 third switching unit, 164 fourth switching unit, 165 fifth switching unit, 166
sixth switching unit, 170 transceiver unit, 171 Wireless communication device, P sound pressure,
Pm voiced speech, Pn environment noise, Ps received speech.
04-05-2019
38
Документ
Категория
Без категории
Просмотров
0
Размер файла
56 Кб
Теги
jp2009171315
1/--страниц
Пожаловаться на содержимое документа