JPH07177595

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 JPH07177595
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to
acoustic input devices in the field of acoustic signal processing.
[0002]
2. Description of the Related Art A conventional sound input apparatus will be described with
reference to the drawings. The basic configuration of a conventional sound input device is shown
in FIG. A microphone 100 converts an acoustic signal transmitted in the air into an electrical
signal, an amplifier 101 amplifies the electrical signal output from the microphone, and an
earphone 102 converts the electrical signal output from the amplifier 101 into an acoustic
signal.
[0003]
In the conventional acoustic input device configured as described above, the sound wave that has
reached the microphone 100 is converted into an electrical signal according to the
characteristics of the microphone 100.
[0004]
03-05-2019
1
However, in the above configuration, there is only one microphone 100 to which the sound wave
reaches.
When the microphone 100 is nondirectional, unnecessary sound other than voice is
simultaneously converted into an electrical signal and amplified by the amplifier 101 and output
from the earphone 102 as unpleasant sound with poor clarity. Also, when the microphone 100 is
a directional microphone, only the sound in a limited direction is amplified and heard because
the sensitivity to the sound coming in from a certain direction is the best. For this reason, when
the position of the speaker changes, the directivity of the microphone 100 deviates from the
optimum directivity direction, and there is a problem that a sound different from the desired
voice is most amplified.
[0005]
In view of the foregoing, it is an object of the present invention to provide a sound input device
in which desired sounds and sounds can be heard well.
[0006]
A plurality of directional microphones, a selection means for selecting and outputting only one of
a plurality of input signals, an address generation means for generating an address assigned to
each microphone, and a search start A stop signal generating means for outputting a reset signal
in response to the switch; a stop signal generating means for outputting a stop signal in response
to the switch; and a timer for measuring time. .
[0007]
According to the above configuration, the directivity of the microphone can be freely changed,
and a desired acoustic signal can be obtained by selecting the directivity desired by the user.
[0008]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a block diagram of a
sound input apparatus according to a first embodiment of the present invention.
In FIG. 1, 1 is a microphone group in which a plurality of directional microphones are arranged
in an annular shape, 2 is an amplifier for amplifying an electric signal output from the selector
03-05-2019
2
10, and 3 is an electric signal output from the amplifier 2 converted into an acoustic signal.
Earphones 10, a selector for selecting one of a plurality of electric signals output from the
microphone group 1 based on the address output from the address generator 11, and
transmitting it to the amplifier 2, 11 is an address generator , Generate an address assigned to
each microphone and transmit it to the selector 10.
A timer 12 outputs a pulse at fixed time intervals to update the address.
A reset signal generator 20 outputs a reset signal to reset the address generator 11 and the timer
12 when the switch 30 is pressed. A stop signal generation unit 21 outputs a stop signal when
the switch 30 is released, stops the timer 12, and causes the address generation unit 11 to hold
the current address. Reference numeral 30 denotes a switch for outputting a start / stop signal of
the microphone search, and reference numeral 31 denotes a pull-up resistor.
[0009]
The operation of the sound input apparatus of the present embodiment configured as described
above will be described below. FIG. 2 is a timing chart of each signal generator. When the switch
30 is pressed, the reset signal generation unit 20 generates a reset signal which is a search start
signal of the microphone and resets the address generation unit 11 and the timer 12. The timer
12 starts its operation when it is reset, and generates a pulse at regular intervals. The address
generation unit 11 is initialized immediately after reset and outputs a predetermined address, but
is updated to the next address each time a pulse is input from the timer 12. The movement of the
address is shown in FIG. These addresses are assigned to the microphones M1, M2,..., Mn of the
microphone group 1, and the address following the last address has a ring type address which is
returned to the top address, and the cycle counter is used And can be easily configured. Next, the
selector 10 selects the microphone assigned to the address output from the address generation
unit 11 from the microphone group 1, and outputs the microphone signal to the amplifier 2. The
amplifier 2 amplifies this signal and transmits it to the earphone 3. The earphone 3 outputs the
electrical signal output from the amplifier 2 as an acoustic signal. Finally, when the switch 30 is
released, the stop signal generation unit 21 generates a stop signal which is a stop signal of the
search for the microphone and stops the timer 12. The address generation unit 11 holds and
outputs the current address because there is no pulse input from the timer 12.
[0010]
03-05-2019
3
As described above, according to the present embodiment, one microphone is selected from the
plurality of microphones based on the microphone group 1 in which the plurality of directional
microphones are arranged in an annular shape and the address output from the address
generation unit 11 A selector 10 for outputting to the amplifier 2, an address generation unit 11
for outputting an address assigned to each microphone, a reset signal generating unit 20 for
outputting a search start signal of the microphone by the switch 30, a search By providing the
stop signal generation unit 21 that outputs the stop signal, the user can press the switch to start
searching for the microphone when it is difficult to hear the sound, and release the switch when
the user's desired sound is heard best Can stop the search of the microphone. For this reason, it
is possible to configure an audible input device with high intelligibility in which the user's desired
sound can be freely selected at any time.
[0011]
FIG. 4 is a block diagram of an acoustic input device according to a second embodiment of the
present invention. In FIG. 4, 1 is a microphone group in which n directional microphones are
arranged in an annular shape, 2 is an amplifier for amplifying the electric signal output from the
selector 5, and 3 is an electric signal output from the amplifier 2 as an acoustic signal. Earphone
to convert, 5 is a selector for selecting an input microphone based on the address value
transmitted from the maximum level detector 41 and transmitting it to the amplifier 2, 10 is
output from the microphone group 1 based on the address output from the address generation
unit 11 A selector 11 selects one of the plurality of electrical signals to be transmitted and
transmits the same to the A / D converter 40. An address generation unit 11 generates an
address assigned to each microphone and transmits the address to the selector 10. Reference
numeral 13 denotes a clock, which outputs a pulse at a constant time interval to start updating of
the address of the address generation unit 11 and A / D conversion of the A / D converter 40. An
A / D converter 40 A / D converts the electric signal output from the selector 10 and transfers it
to the memory 50. A memory 50 temporarily stores data output from the A / D converter 40. A
maximum level detector 41 obtains an average level of each microphone from data stored in the
memory, and transfers the address value of the microphone which is the maximum value to the
selector 5.
[0012]
The operation of the sound input apparatus of the present embodiment configured as described
above will be described below. In FIG. 4, when the power of the acoustic input device is turned
03-05-2019
4
on, the clock 13 starts its operation and outputs pulses at regular intervals. The address
generation unit 11 is initialized when the power is turned on, and outputs a predetermined
address. However, each time a pulse is input from the clock 13, the address generation unit 11 is
updated to the next address. The movement of the address is shown in FIG. These addresses are
assigned to the microphones M1, M2, ..., Mn of each of the microphone group 1 consisting of n
microphones, and the address following the last address has a ring-type address which is
returned to the start address. It can be easily configured using a cycle counter. Next, the selector
10 selects the microphone assigned to the address output from the address generation unit 11
from the microphone group 1, and outputs the microphone signal to the A / D converter 40. The
amplifier 2 amplifies the signal output from the selector 5 and transmits it to the earphone 3.
The earphone 3 outputs the electrical signal output from the amplifier 2 as an acoustic signal.
The A / D converter 40 A / D converts the signal output from the selector 10 and transfers the
signal to the memory 50. The memory 50 stores data sent from the A / D converter 40. Here, a
description will be given using the flow chart of the selector output signal of FIG. 5 and the data
address in the memory of FIG. In FIG. 4, when one clock pulse is generated, the address of the
address generation unit 11 is updated by one and the microphone selected by the selector 10
changes by one. For this reason, the microphone selected for each clock pulse changes and the
data flow as shown in FIG. The signal selected by the selector 10 is digitized by the A / D
converter 40 and sequentially stored in the memory as shown in FIG. Therefore, in the case of n
microphones, the same microphone data is stored in the memory every n−1, and the sampling
frequency for the same microphone is 1 / n of the clock frequency. The maximum level detector
41 obtains the average level of each microphone from the data stored in the memory 50, and
transmits to the selector 5 the address value of the microphone which is the maximum value
among them.
[0013]
As described above, according to the present embodiment, one microphone is selected from the
plurality of microphones based on the microphone group 1 in which the plurality of directional
microphones are arranged in an annular shape and the address output from the address
generation unit 11 The average level of each microphone is determined, the selector 10
outputting to the amplifier 2, the address generation unit 11 outputting the address assigned to
each microphone, the A / D converter 40, the memory 50 storing data, Among them, by
providing the maximum level detector 41 for transmitting the address value of the microphone
which is the maximum value to the address generation unit 11, the microphone which is always
the best directivity direction is selected. Therefore, since the sound with the highest level is
always the target signal and the directivity of the microphone is selected, the user can obtain a
good sound with a good signal-to-noise ratio.
03-05-2019
5
[0014]
FIG. 7 is a block diagram of an acoustic input device according to a third embodiment of the
present invention. In FIG. 7, 1 is a microphone group in which n directional microphones are
arranged in an annular shape, 2 is an amplifier for amplifying the electric signal output from the
selector 10, and 3 is an electric signal output from the amplifier 2 as an acoustic signal. The
earphone to convert, 10 is a selector for selecting one of a plurality of electric signals output
from the microphone group 1 based on the address output from the address generation unit 11
and transmitting it to the amplifier 2, 11 is an address generation unit And generates an address
assigned to each microphone and transmits it to the selector 10. Reference numeral 13 denotes a
clock, which outputs a pulse at a constant time interval to start updating of the address of the
address generation unit 11 and A / D conversion of the A / D converter 40. An A / D converter
40 A / D converts the electric signal output from the selector 10 and transfers it to the memory
50. A memory 50 temporarily stores data output from the A / D converter 40. Reference numeral
60 denotes a power extraction unit for obtaining an average power from each data in the
memory, and 61 denotes a pitch extraction unit for obtaining a pitch frequency of voice from
each data in the memory. Reference numeral 70 denotes a determination unit, which transmits to
the selector 5 the address of the microphone for which the pitch frequency is present and the
average power is maximum.
[0015]
The operation of the sound input apparatus of the present embodiment configured as described
above will be described below. In FIG. 7, when the power of the acoustic input device is turned
on, the clock 13 starts its operation and outputs pulses at regular intervals. The address
generation unit 11 is initialized when the power is turned on, and outputs a predetermined
address. However, each time a pulse is input from the clock 13, the address generation unit 11 is
updated to the next address. The movement of the address is shown in FIG. These addresses are
assigned to the microphones M1, M2, ..., Mn of each of the microphone group 1 consisting of n
microphones, and the address following the last address has a ring-type address which is
returned to the start address. It can be easily configured using a cycle counter. Next, the selector
10 selects the microphone assigned to the address output from the address generation unit 11
from the microphone group 1, and outputs the microphone signal to the A / D converter 40. The
amplifier 2 amplifies the signal output from the selector 5 and transmits it to the earphone 3.
The earphone 3 outputs the electrical signal output from the amplifier 2 as an acoustic signal.
The A / D converter 40 A / D converts the signal output from the selector 10 and transfers the
signal to the memory 50. The memory 50 stores data sent from the A / D converter 40. Here, a
03-05-2019
6
description will be given using the flow chart of the selector output signal of FIG. 5 and the data
address in the memory of FIG. In FIG. 4, when one clock pulse is generated, the address of the
address generation unit 11 is updated by one and the microphone selected by the selector 10
changes by one. For this reason, the microphone selected for each clock pulse changes and the
data flow as shown in FIG. The signal selected by the selector 10 is digitized by the A / D
converter 40 and sequentially stored in the memory as shown in FIG. Therefore, in the case of n
microphones, the same microphone data is stored in the memory every n−1, and the sampling
frequency for the same microphone is 1 / n of the clock frequency. The power extraction unit 60
obtains an average power of a preset period from each data stored in the memory 50 and
transmits the average power to the determination unit 70. The pitch extraction unit 61 obtains
the pitch frequency of the sound from each data stored in the memory 50 and transmits it to the
determination unit 70. The determination unit 70 transmits the address of the microphone
having a pitch frequency and the maximum average power to the selector 5 based on the average
power transmitted from the power extraction unit 60 and the pitch frequency transmitted from
the pitch extraction unit 61.
[0016]
As described above, according to this embodiment, the microphone group 1 in which a plurality
of directional microphones are arranged in a ring shape, and the selector 5 that selects and
outputs one microphone from the plurality of microphones based on the input address, 10, an
address generation unit 11 for outputting an address assigned to each microphone, an A / D
converter 40, a memory 50 for storing data, and a power for obtaining an average power from
the data stored in the memory 50 An extracting unit 60, a pitch extracting unit 61 for obtaining a
voice pitch from data stored in the memory 50, and a determining unit 70 for outputting to the
selector 5 an address value of a microphone which has a pitch and maximum average power. By
providing the microphone, the microphone is always directed in the direction of the speaker. As a
result, the voice of the speaker is the easiest to hear, and the sound coming from a direction
different from that of the speaker is suppressed, so that the user can obtain a good sound that
the voice of the speaker is easy to hear.
[0017]
FIG. 8 is a block diagram of an acoustic input device according to a fourth embodiment of the
present invention. In FIG. 8, 4 is a microphone group consisting of n nondirectional microphones,
6 is a delay unit for delaying and outputting the electric signal outputted from each microphone
by a time determined by the delay control unit 80, and 82 is a delay An adder that adds n
03-05-2019
7
outputs from the unit 6 into one output, 2 is an amplifier that amplifies the electric signal output
from the adder 82, 3 converts the electric signal output from the amplifier 2 into an acoustic
signal The earphone 12 is a timer, and when a predetermined time has elapsed, the CPU 90 is
interrupted to notify that the time has elapsed. Reference numeral 30 denotes a switch for
outputting a signal of directional control start / stop of the microphone group 4, and reference
numeral 31 denotes a pull-up resistor. A delay control unit 80 controls the delay time of each of
the delay units 6 based on the data transferred from the coefficient storage unit 81. Reference
numeral 81 denotes a coefficient storage unit for storing a coefficient representing an amount of
delay corresponding to n microphones, and reference numeral 90 denotes a CPU which detects
on / off of the switch 30, timer interrupt control, and stored in the coefficient storage unit 81.
Control is performed to transfer existing data to the delay control unit 80.
[0018]
The operation of the sound input apparatus of the present embodiment configured as described
above will be described below. In FIG. 8, when the switch 30 is pressed, the CPU 90 starts
directivity control of the microphone group 4 and simultaneously resets the timer 12. The timer
12 starts counting immediately after reset, and interrupts the CPU 90 to notify it after a
predetermined time has elapsed. The coefficient storage unit 81 stores in advance the amount of
delay time of each microphone for determining several directivity patterns of the microphone
group 4 as a coefficient. When the CPU 90 starts directivity control of the microphone group 4,
one set is selected from the coefficients representing several directivity patterns stored in the
coefficient storage unit 81, and is transferred to the delay control unit 80 as coefficient data. Ru.
The delay control unit 80 controls each delay time amount in the delay unit 6 based on the
coefficient data transferred from the coefficient storage unit 81, and realizes the directivity
pattern of the microphone group 4 stored in the coefficient storage unit 81. Do. Here, the sound
coming from the directivity direction of the microphone group 4 is converted into an electric
signal by the microphone group 4 and delayed by a time determined by the delay unit 6
respectively. This signal is added by the adder 82 and then amplified by the amplifier 2 and
output as an acoustic signal by the earphone 3. Next, every time a predetermined time elapses, a
timer interrupt by the timer 12 is generated. When a timer interrupt occurs, the CPU 90 selects a
directivity pattern next to the previous directivity pattern from among several directivity patterns
stored in the coefficient storage unit 81 and transfers it to the delay control unit 80. The delay
control unit 80 controls the amount of delay time in the delay unit 6 based on the new coefficient
data transferred from the coefficient storage unit 81, and the directivity pattern of the
microphone 4 group stored in the coefficient storage unit 81. To achieve. Finally, when the
switch 30 is released, the CPU stops directivity control of the microphone group 4. The delay
control unit 80 holds the current state, and the directivity of the microphone group 4 is fixed.
03-05-2019
8
[0019]
As described above, according to this embodiment, the microphone group 4 including a plurality
of nondirectional microphones and the delay unit 6 delaying and outputting the electric signal
output from each microphone by the time determined by the delay control unit 80 , An adder 82
that adds n outputs from the delay unit 6 into one output, an amplifier that amplifies the electric
signal output from the adder 82, and an acoustic signal output from the amplifier 2 Earphones 3
for converting into, timer 12 for interrupting CPU 90 to notify that time has elapsed when a
predetermined time has elapsed, switch 30 for outputting signals of directional control start /
stop of microphone group 4; Delay control unit 80 for controlling the delay time of each of delay
units 6 based on the data transferred from coefficient storage unit 81; and each of the n
microphones. The coefficient storage unit 81 stores a coefficient representing the amount of
delay time, and the CPU 90 performs detection of on / off of the switch 30, timer interrupt
control, and transfer of data stored in the coefficient storage unit 81 to the delay control unit 80.
By setting the button, the user presses the switch to start directivity control of the microphone
group when it is difficult to hear the sound, and fixes the directivity of the microphone group by
releasing the switch when the desired sound can be heard best. be able to. For this reason, the
user's desired sound can be freely selected at any time, and an audible input device with high
clarity can be configured.
[0020]
FIG. 9 is a block diagram of the sound input apparatus in the fifth embodiment of the present
invention. In FIG. 9, 4 is a microphone group consisting of n nondirectional microphones, and 6
and 6a are delay units for delaying the electric signals output from the microphones by the time
determined by the delay control units 80 and 80a, respectively, and outputting them. , 82, 82a is
an adder that adds n outputs from the delay unit 6 to form one output, 2 is an amplifier for
amplifying the electric signal output from the adder 82, 3 is the electric output from the
amplifier 2 The earphone converts the signal into an acoustic signal, 40 is an A / D converter for
A / D converting the electric signal output from the adder 82, 50 is a memory for storing A / D
converted data, 41 is a maximum level It is a detector and obtains an average level from each
data stored in the memory, and transmits information representing the directivity pattern at the
maximum time to the CPU 90. A delay unit 7 delays an A / D conversion start signal output from
the CPU 90 and transmits it to the A / D converter 40. A timer 12 interrupts the CPU 90 after a
predetermined time has elapsed and the time has elapsed Inform Reference numerals 80 and 80a
denote delay control units, which control the delay times of the delay units 6 and 6a based on the
data transferred from the coefficient storage units 81 and 81a. Reference numerals 81 and 81a
03-05-2019
9
denote coefficient storage units that store coefficients representing the amounts of delay
corresponding to n microphones. A CPU 90 performs timer interrupt control, control for
transferring data stored in the coefficient storage unit 81, 81a to the delay control unit 80, 80a,
and output of an A / D conversion start signal.
[0021]
The operation of the sound input apparatus of the present embodiment configured as described
above will be described below. In FIG. 9, when the sound input device is powered on, the CPU 90
starts operation and starts directivity control of the microphone group 4 and simultaneously
resets the timer 12. The timer 12 starts counting immediately after reset, and interrupts the CPU
90 to notify it after a predetermined time has elapsed. In the coefficient storage units 81 and
81a, the amount of delay time of each microphone for determining several directivity patterns of
the microphone group 4 is stored in advance as a coefficient. When the CPU 90 starts directivity
control of the microphone group 4, one set is selected from the coefficients representing several
directivity patterns stored in the coefficient storage unit 81, 81a, and the delay control unit 80 is
selected as coefficient data. It is transferred to 80a. The delay control unit 80, 80a controls the
amount of delay time in each of the delay units 6, 6a based on the coefficient data transferred
from the coefficient storage unit 81, 81a, and the microphones stored in the coefficient storage
unit 81, 81a Implement group 4 directivity patterns. Here, the sound coming from the directivity
direction of the microphone group 4 is converted into an electric signal by the microphone group
4 and delayed by a time determined by the delay units 6 and 6a. The signals output from the
delay units 6, 6a are added by the adders 82, 82a, respectively. The signal output from the adder
82 a is amplified by the amplifier 2 and output as an acoustic signal by the earphone 3. The
signal output from the adder 82 is input to the A / D converter 40. When the A / D conversion
start signal is input from the delay unit 7, the A / D converter 40 starts A / D conversion, and
stores data in the memory 50. The maximum level detector 41 obtains an average level from the
data of each directivity pattern stored in the memory 50, and transmits information representing
the directivity pattern which is the largest among them to the CPU 90. When the directivity
pattern at the maximum level is transmitted from the maximum level detector 41, the CPU 90
transmits a coefficient for realizing the directivity pattern from the coefficient storage unit 81a to
the delay control unit 80a. The delay control unit 80a controls the delay time of each of the delay
units 6a to realize the directivity pattern at the maximum level. Next, every time a predetermined
time elapses, a timer interrupt by the timer 12 is generated. When a timer interrupt occurs, the
CPU 90 selects a directivity pattern next to the previous directivity pattern from among several
directivity patterns stored in the coefficient storage unit 81 and transfers it to the delay control
unit 80.
03-05-2019
10
The delay control unit 80 controls the amount of delay time in the delay unit 6 based on the new
coefficient data transferred from the coefficient storage unit 81, and the directivity pattern of the
microphone 4 group stored in the coefficient storage unit 81. To achieve. FIG. 10 is a diagram
showing an example of the arrangement of microphones and a directivity pattern. In this case,
the distance between the microphones at both ends is α cm, and the directivity patterns are
seven of a, b, c, ..., f, g. Therefore, assuming that the velocity of sound traveling through the air is
β cm / sec, the maximum delay time is α / β sec and the delay time of the delay unit 6 needs
to be set to α / β sec or more. Further, since the time interval of the timer 12 is the time
interval of the A / D conversion start signal output by the CPU 90, the time setting of the timer
12 must also be set to a time of α / β sec or more. FIG. 11 is an explanatory diagram of a signal
flow of an adder output, and FIG. 12 is an explanatory diagram of a data address stored in a
memory. Each time a timer interrupt is generated by the timer 12, the directivity pattern changes
and the flow of data a, b, c, ..., f, g, a, b, c, ..., f, g, a, as shown in FIG. Repeat the seven directivity
patterns in the order b. Therefore, as shown in FIG. 12, the data of the same directivity pattern is
stored in order every seven data stored in the memory 50. Therefore, the sampling frequency for
the same directivity pattern is β / 7α Hz or less. The sampling frequency for the same
directivity pattern in the case of n directivity patterns is β / nα Hz or less. The sampling
frequency β / nα is preferably 2000 Hz or more because the first formant component of the
vowel is approximately 1000 Hz or less.
[0022]
As described above, according to the present embodiment, the microphone group 4 including a
plurality of nondirectional microphones and the electric signals output from the microphones are
delayed and output by the time determined by the delay control units 80 and 80a, respectively. A
/ D conversion for A / D converting the electric signals output from the adders 82 and 82a,
which add one output from the delay units 6 and 6a and the n outputs from the delay unit 6 as
one output The average level is determined from the data stored in the memory 40, the memory
50 for storing the A / D converted data, and each data stored in the memory, and the information
representing the directivity pattern at the maximum time among The maximum level detector 41
to transmit to the delay unit 7, the A / D conversion start signal output from the CPU 90 is
delayed, and the delay unit 7 to transmit to the A / D converter 40; And delay control units 80
and 80a that control the delay time of each of the delay units 6 and 6a based on the data
transferred from the coefficient storage units 81 and 81a, and n. The coefficient storage unit 81,
81a that stores the coefficient representing the delay amount corresponding to each microphone,
timer interrupt control, and the data stored in the coefficient storage unit 81, 81a are transferred
to the delay control unit 80, 80a By providing the CPU 90 that outputs the control and the A / D
conversion start signal, a directivity pattern with a high level is always selected. Therefore, since
the sound with the largest level is always used as the target signal and the directivity of the
03-05-2019
11
microphone group 4 is selected, the user can obtain a good sound with a good signal-to-noise
ratio.
[0023]
FIG. 13 is a block diagram of the sound input apparatus in the sixth embodiment of the present
invention. In FIG. 13, reference numeral 4 denotes a microphone group including n
nondirectional microphones. 6, 6a are delay units for delaying the electric signals output from
the respective microphones by a time determined by the delay control units 80, 80a,
respectively, and 82, 82a are for adding n outputs from the delay unit 6 Two output adders, 2 is
an amplifier for amplifying the electric signal output from the adder 82, 3 is an earphone for
converting the electric signal output from the amplifier 2 into an acoustic signal, 40 is output
from the adder 82 An A / D converter for A / D converting an electrical signal, 50 a memory for
storing A / D converted data, 60 a power extracting unit for obtaining an average power from
each data in the memory and transmitting it to the CPU 90, 61 Is a pitch extraction unit for
obtaining a pitch frequency of voice from data in the memory and transmitting it to the CPU 90.
A delay unit 7 delays an A / D conversion start signal output from the CPU 90 and transmits it to
the A / D converter 40. A timer 12 interrupts the CPU 90 after a predetermined time has elapsed
and the time has elapsed Inform Reference numerals 80 and 80a denote delay control units,
which control the delay times of the delay units 6 and 6a based on the data transferred from the
coefficient storage units 81 and 81a. Reference numerals 81 and 81a denote coefficient storage
units that store coefficients representing the amounts of delay corresponding to n microphones.
Reference numeral 90 denotes a CPU, which is a timer interrupt control, a control for
transferring data stored in the coefficient storage unit 81 to the delay control unit 80, and a
coefficient of a directivity pattern having a pitch frequency and a maximum average power.
Control from the coefficient storage unit 81a to the delay control unit 80a, and output of an A /
D conversion start signal.
[0024]
The operation of the sound input apparatus of the present embodiment configured as described
above will be described below. In FIG. 13, when the sound input device is powered on, the CPU
90 starts operation and starts directivity control of the microphone group 4 and simultaneously
resets the timer 12. The timer 12 starts counting immediately after reset, and interrupts the CPU
90 to notify it after a predetermined time has elapsed. In the coefficient storage units 81 and
81a, the amount of delay time of each microphone for determining several directivity patterns of
the microphone group 4 is stored in advance as a coefficient. When the CPU 90 starts directivity
03-05-2019
12
control of the microphone group 4, one set is selected from the coefficients representing several
directivity patterns stored in the coefficient storage unit 81, 81a, and the delay control unit 80 is
selected as coefficient data. It is transferred to 80a. The delay control unit 80, 80a controls the
amount of delay time in each of the delay units 6, 6a based on the coefficient data transferred
from the coefficient storage unit 81, 81a, and the microphones stored in the coefficient storage
unit 81, 81a Implement group 4 directivity patterns. Here, the sound coming from the directivity
direction of the microphone group 4 is converted into an electric signal by the microphone group
4 and delayed by a time determined by the delay units 6 and 6a. The signals output from the
delay units 6, 6a are added by the adders 82, 82a, respectively. The signal output from the adder
82 a is amplified by the amplifier 2 and output as an acoustic signal by the earphone 3. The
signal output from the adder 82 is input to the A / D converter 40. When the A / D conversion
start signal is input from the delay unit 7, the A / D converter 40 starts A / D conversion, and
stores data in the memory 50. The power extraction unit 60 obtains the average power of a
preset period from each data stored in the memory 50, and transmits the average power to the
CPU 90. The pitch extraction unit 61 obtains the pitch frequency of the sound from the data
stored in the memory 50 and transmits it to the CPU 90. The CPU 90 uses the average power
transmitted from the power extraction unit 60 and the pitch frequency transmitted from the
pitch extraction unit 61 to control the delay of the coefficient of the directivity pattern having the
maximum power from the coefficient storage unit 81a. Transmit to the unit 80a. The delay
control unit 80a controls the delay time of each of the delay units 6a to realize a directivity
pattern at the maximum power with a pitch present. Next, every time a predetermined time
elapses, a timer interrupt by the timer 12 is generated.
When a timer interrupt occurs, the CPU 90 selects a directivity pattern next to the previous
directivity pattern from among several directivity patterns stored in the coefficient storage unit
81 and transfers it to the delay control unit 80. The delay control unit 80 controls the amount of
delay time in the delay unit 6 based on the new coefficient data transferred from the coefficient
storage unit 81, and the directivity pattern of the microphone 4 group stored in the coefficient
storage unit 81. To achieve. FIG. 10 is a diagram showing an example of the arrangement of
microphones and a directivity pattern. In this case, the distance between the microphones at both
ends is α cm, and the directivity patterns are seven of a, b, c, ..., f, g. Therefore, assuming that the
velocity of sound traveling through the air is β cm / sec, the maximum delay time is α / β sec
and the delay time of the delay unit 6 needs to be set to α / β sec or more. Further, since the
time interval of the timer 12 is the time interval of the A / D conversion start signal output by the
CPU 90, the time setting of the timer 12 must also be set to a time of α / β sec or more. FIG. 11
is an explanatory diagram of a signal flow of an adder output, and FIG. 12 is an explanatory
diagram of a data address stored in a memory. Each time a timer interrupt is generated by the
timer 12, the directivity pattern changes and the flow of data a, b, c, ..., f, g, a, b, c, ..., f, g, a, as
shown in FIG. Repeat the seven directivity patterns in the order b. Therefore, as shown in FIG. 12,
the data of the same directivity pattern is stored in order every seven data stored in the memory
03-05-2019
13
50. Therefore, the sampling frequency for the same directivity pattern is β / 7α Hz or less. The
sampling frequency for the same directivity pattern in the case of n directivity patterns is β /
nα Hz or less. The sampling frequency β / nα is preferably 2000 Hz or more because the first
formant component of the vowel is approximately 1000 Hz or less.
[0025]
As described above, according to the present embodiment, the microphone group 4 including a
plurality of nondirectional microphones and the electric signals output from the microphones are
delayed and output by the time determined by the delay control units 80 and 80a, respectively. A
/ D conversion for A / D converting the electric signals output from the adders 82 and 82a,
which add one output from the delay units 6 and 6a and the n outputs from the delay unit 6 as
one output 40, a memory 50 for storing A / D converted data, a power extracting unit 60 for
obtaining an average power from each data in the memory and transmitting it to the CPU 90, and
a pitch frequency of voice from the data in the memory A pitch extraction unit 61 transmitted to
the CPU 90, a delay unit 7 delaying an A / D conversion start signal output from the CPU 90, and
transmitting it to the A / D converter 40, and a predetermined time elapses And a timer 12 for
interrupting the CPU 90 to notify that time has elapsed, and a delay control unit 80 for
controlling the delay time of each of the delay units 6 and 6a based on the data transferred from
the coefficient storage units 81 and 81a, 80a, coefficient storage units 81 and 81a for storing
coefficients representing delay amounts corresponding to n microphones, timer interrupt control,
and data stored in the coefficient storage unit 81 are transferred to the delay control unit 80
Control, control to transfer the coefficient of the directivity pattern having the pitch frequency
and the average power being maximum from the coefficient storage unit 81a to the delay control
unit 80a, and outputting the A / D conversion start signal , And the microphone group 4 always
has directivity in the direction of the speaker. As a result, the voice of the speaker is the easiest to
hear, and the sound coming from a direction different from that of the speaker is suppressed, so
that the user can obtain a good sound that the voice of the speaker is easy to hear.
[0026]
In the first, second and third embodiments, the microphone group 1 has a plurality of directional
microphones arranged in an annular shape, but may be arranged in a fan shape. Further, in the
second and fifth embodiments, the maximum level detector 41 obtains the maximum value of
each average level, but may obtain the maximum value of the average amplitude and the
maximum value of the average power. In the third and sixth embodiments, the power extraction
unit 60 obtains the average power of each data stored in the memory, but may obtain the
03-05-2019
14
average level and the average amplitude.
[0027]
According to the present invention, the user presses the switch to start the microphone search
when it is difficult to hear the sound, and releases the switch when the user's desired sound is
heard the best. -Can be stopped. For this reason, it is possible to configure an audible input
device with high intelligibility in which the user's desired sound can be freely selected at any
time. Further, according to the present invention, by providing the pitch extraction unit and the
power extraction unit, the microphone always has directivity in the direction of the speaker. For
this reason, the speaker's voice is the most audible and the sound coming from a direction
different from the speaker is suppressed, so that the user can obtain a good sound that the
speaker's voice can be easily heard.
03-05-2019
15