close

Вход

Забыли?

вход по аккаунту

?

DESCRIPTION JP2007208923

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 JP2007208923
An object of the present invention is to reliably prevent one-sided collapse and transmission
blocking and reception blocking. SOLUTION: A transmission signal speech section detection
means 9 for detecting a speech section of a transmission signal is provided, and the biased mode
control means 8 is configured to estimate magnitudes of estimated values PFn, PNn of noise
powers on the far end side and the near end side. Based on the relationship, the detection result
SDF2 of the reception signal / voice section detection unit 38 and the magnitude of the far-end
side background noise power estimated value PFn, either the transmission biased mode or the
neutral mode is set. Therefore, for example, if the background noise on the near end side is very
low, the far end background noise on the far end side is not set to the off-set biased mode,
thereby reliably preventing unsteady and transmission blocking and reception blocking. can do.
[Selected figure] Figure 1
Voice switching device
[0001]
TECHNICAL FIELD The present invention relates to a voice switching device used in a
loudspeaker communication terminal used in an intercom system or the like in a housing
complex.
[0002]
Conventionally, it is not necessary to have a handset at the time of a call, and an audio signal
transmitted from the other party's call terminal is transmitted to the caller from the other party
15-04-2019
1
by a speaker to the caller away from the call terminal. A voice communication system is provided
which enables half-duplex communication by collecting sound and transmitting it to the other
party's call terminal.
In such a speech communication system, a two-wire to four-wire conversion hybrid circuit is
required when the acoustic coupling between the speaker and the microphone, which is the
component, and the transmission path of the voice signal are formed in a two-wire form. A closed
loop is formed on the call path by the wraparound from the transmit signal path to the receive
signal path caused by the impedance mismatch at the end of the loop and by the acoustic
coupling between the speaker and the microphone at the other party's call terminal. Howling
occurs when the ratio is more than doubled, and if the howling occurs, the call can not be
continued, so a means for suppressing this is needed.
[0003]
Therefore, conventionally, by monitoring the transmission signal and the reception signal, it is
determined whether the communication state is the reception state or the transmission state, and
the transmission signal path or the reception signal path is determined according to the
determined communication state. A voice switching device (so-called voice switch) has been
widely used as a speech communication terminal, which reduces the closed loop gain by
inserting a loss in at least one side to prevent howling. The basic operation of the voice switching
device is to estimate the powers of the transmission signal and the reception signal, compare
their magnitude relationship, and insert a predetermined amount of loss on the side of smaller
instantaneous power.
[0004]
FIG. 4 is a block diagram showing a conventional voice switching device disclosed in Patent
Document 1. As shown in FIG. In this conventional example, a transmitter loss insertion means 1
for inserting a loss into a transmitter signal path L1 for transmitting a transmitter signal
collected by a microphone (not shown) of a speech communication terminal to a channel, and a
channel Receiver loss insertion means 2 for inserting a loss into the reception side signal path L2
for transmitting a reception signal received from a speaker to the speaker (not shown) of the
speech communication terminal, and the transmission side loss insertion means 1 A transmission
deviation mode setting amplifier 6 for extracting and amplifying a transmission signal, a
reception deviation mode setting amplifier 7 for extracting and amplifying a reception signal
15-04-2019
2
input to the reception side loss insertion means 2, and a transmission deviation mode setting The
speech mode is estimated based on the transmission signal and the reception signal amplified by
the amplifier 6 and the reception / bias mode setting amplifier 7, and according to the estimation
result, the transmission loss insertion means 1 and the reception loss insertion means 2 Insertion
loss control means 3 for controlling the amount of loss inserted in the paths L1 and L2 and
switching the speech mode to the transmission mode, reception mode and neutral mode, and the
noise power on the near end side included in the transmission signal The near-end background
noise power estimation means 4 and the far-end side background noise power estimation means
5 for estimating the far-end side noise power contained in the received signal, the far-end side
background noise power and the near-end background noise power There are provided a
transmission mode polarization mode setting amplifier 6 and a polarization mode control means
8 'for adjusting respective gains of the reception polarization mode setting amplifier 7 in
accordance with the estimated values PFn and PNn.
[0005]
The far-end side background noise power estimating means 5 and the near-end side background
noise power estimating means 4 are both realized by an integrator circuit or digital filter or the
like having characteristics of a slow rise and a steep fall. The background noise power estimation
means 5 estimates background noise (background noise) power constantly present in the
reception signal, and the near end side background noise power estimation means 4 noise power
constantly present in the transmission signal. presume.
[0006]
If the estimated value PFn of the far-end side background noise power is sufficiently larger than
the estimated value PNn of the near-end side background noise power (PFn >> PNn), the biased
mode control means 8 ' The talk mode is set to the transmission polarization mode by setting the
gain GT of the amplifier 6 to G (> 0) [dB] and the gain GR of the reception polarization mode
setting amplifier 7 to 0 [dB], and the near-end background noise If the power estimate PNn is
sufficiently larger than the far-end background noise power estimate PFn (PNn >> PFn), the gain
GR of the receiver deflection mode setting amplifier 7 is G [dB] and transmission bias By setting
the gain GT of the mode setting amplifier 6 to 0 [dB], the speech mode is set to the reception
biased mode, and the difference between the estimated value PFn of far-end background noise
power and the estimated value PNn of near-end background noise power Is not large enough In
each gain GR of the reception unbalance mode setting amplifier 7 and transmission unbalance
mode setting amplifier 6, the GT is set to the neutral mode as 0 [dB].
[0007]
That is, when the difference between the background noise level on the far end side and the
15-04-2019
3
background noise level on the near end side is large, the insertion loss amount control means 3
that monitors the transmission signal and the reception signal to estimate the call state, for
example, In the situation where the background noise level on the side is large, it is always
determined to be in the receiving state, and in the situation where the background noise level on
the near end side is large, it is always determined to be in the transmitting state. A phenomenon
(so-called one-sided collapse) may occur in which the call state is fixed to one of the transmission
states.
[0008]
On the other hand, in the above conventional example, as described above, the biased mode
control means 8 'compares the estimated value PFn of the far-end background noise power with
the estimated value PNn of the near-end background noise power, When the estimated value PFn
of the power is sufficiently large, the insertion loss amount control is performed by amplifying
the transmission signal monitored by the insertion loss amount control means 3 by the gain G
[dB] by the transmission / depolarization mode setting amplifier 6 When the means 3 is set to a
state that makes it easy to determine that it is a transmission state (transmission bias mode), and
the estimated value PNn of the near-end side background noise power is sufficiently large,
monitoring is performed by the insertion loss amount control means 3 The reception signal is
amplified by the gain G [dB] by the receiver deflection mode setting amplifier 7 so that the
insertion loss amount control means 3 is set to a state easy to determine that it is in the
reception state (reception bias mode). Good at suppressing Thereby making it possible to obtain
a Switching Characteristics.
[0009]
However, in the prior art described in the above-mentioned Patent Document 1, for example, in
the case of the transmission bias mode, so-called reception blocking is likely to occur because the
gain of the transmission bias mode setting amplifier 6 is increased or In the mode, so-called
transmission blocking tends to occur because the gain of the reception / biased mode setting
amplifier 7 is increased.
Here, reception blocking refers to an amplifier for setting a transmission bias polarization mode
of an acoustic echo signal generated by acoustic coupling between a speaker and a microphone
on the near end side when voice is input from the far end side when the near end side is silent.
The power level at the output point of 6 becomes higher than the power level at the output point
of the amplifier 7 for receiving / biased mode setting of the original signal (received signal), and
the voice switching device switches to the transmitting state. It refers to the phenomenon that
15-04-2019
4
voices input from the end can not be heard on the near end.
Also, with transmission blocking, when the voice is input from the near end while the far end is
silent, the reception bias mode setting of the line echo signal caused by the acoustic coupling at
the far end or the signal wraparound in the transmission processing means The power level at
the output point of the power amplifier is higher than the power level at the output point of the
transmission bias mode setting amplifier of the original signal (transmission signal), and the
voice switching device switches to the reception state. It refers to the phenomenon that voices
input from the near end can not be heard on the far end.
[0010]
On the other hand, not only the difference between the far-end background noise power
estimated value PFn and the near-end background noise power estimated value PNn but also the
acoustic side feedback gain and the line side feedback gain The difference between the estimated
value PFn of the far-end side background noise power and the estimated value PNn of the nearend side background noise power is sufficiently large by setting the transmitting biased mode,
the receiving biased mode, and the neutral mode in consideration of the estimated value Even if
the situation continues for a fixed time or more, when the estimated value of the acoustic side
feedback gain exceeds the predetermined value or the estimated value of the line side feedback
gain exceeds the predetermined value, transition to the transmission bias mode or the reception
bias mode is prevented. It has been proposed to prevent one-sided collapse without causing
transmission blocking and receiving blocking (see Patent Document 2).
JP 2002-359580 A (paragraphs 0081-0085, FIG. 21) JP 2003-324369 A
[0011]
However, even in the conventional example described in Patent Document 2 above, for example,
when background noise on the near end side is very small, slight background noise on the far
end side causes biased mode control means 8 'to be in the transmission biased mode. There is a
problem that reception blocking occurs as a result of setting.
[0012]
The present invention has been made in view of the above-described circumstances, and an
object thereof is to provide a voice switching device capable of reliably preventing one-sided
15-04-2019
5
collapse and transmission blocking and reception blocking.
[0013]
According to the first aspect of the present invention, in order to achieve the above object, a
loudspeaker communication terminal having a microphone and a speaker is used in the
loudspeaker communication terminal of a loudspeaker communication system in which the
loudspeaker communication terminal is connected by wire to another communication terminal or
loudspeaker communication terminal. Transmitter loss insertion means for inserting a loss into a
transmitter signal path for transmitting a transmitter signal collected by the microphone to a
channel, and a receiver side for transmitting a receiver signal received from a channel to the
speaker Receiver loss insertion means for inserting a loss into the signal path, transmission bias
amplification mode setting amplification means for extracting and amplifying a transmission
signal input to the transmission loss insertion means, and the reception loss insertion means A
transmitting signal amplified by the amplifying unit for receiving / biasing mode setting for
taking out and amplifying the incoming signal to be inputted, the amplifying unit for transmitting
/ biasing mode setting, and the amplifying unit for receiving / biasing mode setting The speech
mode is estimated based on the reception signal, and according to the estimation result, the
transmission side loss insertion means and the reception side loss insertion means control the
amount of loss to be inserted into the path to make the speech mode the transmission mode. An
insertion loss amount control means for switching to a reception mode, a near end background
noise power estimation means for estimating noise power on the near end side included in the
transmission signal, and noise power on the far end side included in the reception signal The
gains of the far-end side background noise power estimating means, and the amplifying means
for setting the transmitting / swing mode and the receiving means for the receiving / swing
mode setting according to estimated values of the far-end side background noise power and the
near-end side background noise power A first instantaneous power estimation unit for estimating
the instantaneous power of the input signal to the transmission side loss insertion means; and A
second instantaneous power estimation unit for estimating the instantaneous power of the input
signal to the side loss insertion means, and an input point to the transmission side loss insertion
means from the transmission side loss insertion means and the wraparound on the line side A
line feedback gain multiplication unit having as a coefficient a value determined according to a
gain of the system to be fed back to the input point to the receiving side loss insertion means;
and the receiving side loss insertion from the input point to the receiving side loss insertion
means Means and an acoustic feedback gain multiplication unit having as a coefficient a value
determined according to the gain of the path leading to the input point to the transmission side
loss insertion means through the wraparound on the acoustic side, and the second instantaneous
power estimation Comparator for comparing the magnitude relationship between the output
signal obtained by inputting the output signal of the input unit to the acoustic feedback gain
multiplication unit and the output signal of the first instantaneous power estimation unit, and the
first instantaneous power estimation unit Input signal to the line feedback gain multiplier A
15-04-2019
6
second comparator that compares the magnitude relationship between the output signal
obtained by the second instantaneous power estimation unit and the output signal of the second
instantaneous power estimation unit; a transmission signal speech section detection unit that
detects a speech section of the transmission signal; Based on the reception signal voice section
detection unit for detecting the voice section of the voice signal, the comparison result of the first
comparator and the second comparator, and the detection result of the transmission signal voice
section detection unit and the reception signal voice section detection unit. An insertion loss
amount distribution processing unit that determines a call state and controls an insertion loss
amount of the transmission side loss insertion means and the reception side loss insertion means,
and the uneven weight mode control means estimates the far end side background noise power
The value is greater than the estimated value of the near-end background noise power, and the
voice section is not detected by the transmission signal voice section detection unit, and the
estimated value of the near-end background noise power is greater than a predetermined value
for a certain period of time If you continue the above more The gain of the amplifier for
amplification is set larger than the gain of the amplifier for receiving deflection mode setting to
set the transmission bias mode, and the estimated value of the near-end side background noise
power is larger than the estimated value of the far-end side background noise power If the state
where no voice section is detected by the reception signal voice section detection unit continues
for a predetermined time or more, the gain of the reception bias mode setting amplification
means is increased more than the gain of the transmission bias mode setting amplification
section to receive the reception bias mode. And setting the neutral mode by not amplifying the
reception signal and the transmission signal by the amplification means for setting the reception
/ reception mode and the amplification means for transmission / reception mode setting when
none of the above conditions is satisfied. Do.
[0014]
According to the invention of claim 2, in the invention of claim 1, the sound of the path returning
from the output point of the receiving side loss insertion means to the input point of the
transmission side loss insertion means via the acoustic echo path on the near end side. Acoustic
side feedback gain estimating means for estimating the side feedback gain, wherein the biased
mode control means does not shift to the transmission biased mode unless the estimated value of
the acoustic side feedback gain is less than a predetermined threshold value. Do.
[0015]
In the invention of claim 3, according to the invention of claim 1 or 2, the gains of the biased
mode control amplification means and the biased transmission mode setting amplification means
are near-end background noise power and It is characterized in that it is gradually increased or
decreased according to the estimated value of the far-end side background noise power.
15-04-2019
7
[0016]
According to the invention of claim 1, the biased mode control means is configured such that the
estimated value of the far-end side background noise power is larger than the estimated value of
the near-end side background noise power and the voice section is detected by the receiving
signal voice section detector. If it is not detected and the state where the estimated value of the
near-end side background noise power is larger than the predetermined value continues for a
fixed time or longer, the gain of the transmitting bias setting amplifier is increased compared to
the gain of the receiving bias setting amplifier. By setting the transmission bias mode to the
transmission bias mode, for example, when the background noise on the near end side is very
small, the transmission bias mode is not set by the slight background noise on the far end side.
And transmission blocking and reception blocking can be reliably prevented.
[0017]
According to the invention of claim 2, the biased mode control means prevents the reception
blocking more reliably by not transitioning to the transmission biased mode unless the estimated
value of the acoustic side feedback gain is less than a predetermined threshold value. be able to.
[0018]
According to the invention of claim 3, a comfortable call can be made according to the magnitude
of the background noise power.
[0019]
In this embodiment, since the basic configuration is the same as that of the conventional
example, the same reference numerals are given to the common components and the description
will be omitted.
[0020]
In this embodiment, as shown in FIG. 1, a first instantaneous power estimating unit 31 for
estimating the instantaneous power of the input signal to the transmitting side loss insertion
means 1 and the instantaneous of the input signal to the receiving side loss insertion means 2 A
second instantaneous power estimation unit 32 for estimating power, an input point to the
transmission side loss insertion means 1, an input to the reception side loss insertion means 2
through the transmission side loss insertion means 1 and a wraparound on the line side Line
feedback gain multiplication unit 33 having a value determined according to the gain of the
system returning to the point as a coefficient, reception side loss insertion means 2 from the
input point to reception side loss insertion means 2 and sound side wraparound An acoustic
15-04-2019
8
feedback gain multiplication unit 34 having as a coefficient a value determined according to the
gain of the path reaching the input point to the transmitting side loss insertion means 1 through
the acoustic signal output from the second instantaneous power estimation unit 32 An output
signal obtained by being input to the feedback gain multiplication unit 34 Output obtained by
inputting the output signal of the first instantaneous power estimating unit 31 to the first
feedback power multiplying unit 33 by comparing the first comparator 35 that compares the
magnitude relationship with the output signal of the instantaneous power estimating unit 31 of
FIG. The second comparator 36 that compares the magnitude relation between the signal and the
output signal of the second instantaneous power estimation unit 32, the transmission signal
speech section detection unit 37 that detects the speech section of the transmission signal, and
the reception signal A voice receiving section 38 for detecting a voice section, and a sound of a
path returning from an output point of the receiving side loss insertion means 2 to an input point
of the transmitting side loss insertion means 1 via an acoustic echo path on the near end side.
The comparison results of the acoustic feedback gain estimation means 11 for estimating the
feedback gain α, and the comparison results of the first comparator 35 and the second
comparator 36 with the transmission signal speech section detection unit 37 and the reception
signal speech section detection unit 38. Determine the call status based on the detection result
and send it The insertion loss amount control means 3 comprises an insertion loss amount
distribution processing unit 30 for controlling the insertion loss amount of the side loss insertion
means 1 and the reception side loss insertion means 2 and the unbalanced mode control means 8
comprises far end background noise The state where the estimated value of power is larger than
the estimated value of near-end background noise power and the speech section is not detected
by the transmission signal voice section detection unit 37, and the estimated value of near-end
background noise power is larger than a predetermined value If it continues for a fixed time or
more, the gain GT of the transmission polarization mode setting amplifier 6 is made larger than
the gain GR of the reception polarization mode setting amplifier 7 to set the transmission
polarization mode, and estimation of the near-end background noise power If the state where the
value is larger than the estimated value of the far-end side background noise power and the
speech section is not detected by the reception signal speech section detection unit 38 continues
for a predetermined time or more, the gain GR of the reception biased mode setting amplifier 7
The gain GT of the talk biased mode setting amplifier 6 is increased to set the receiver biased
mode, and when neither of the above conditions is satisfied, each gain of the transmitter biased
mode set amplifier 6 and the receiver biased mode set amplifier 7 It is characterized in that GT
and GR are set to be substantially equal (for example, 0 [dB]) in the neutral mode.
[0021]
In the first comparator 35, the output signal from the first instantaneous power estimation unit
31 and the output signal from the second instantaneous power estimation unit 32 (first
15-04-2019
9
instantaneous power estimation value) are sent to the acoustic feedback gain multiplication unit
34. The output signal C1 becomes 1 when the estimated value of the instantaneous power is
greater than the output signal of the acoustic feedback gain multiplication means 34, and the
estimated value of the instantaneous power is the acoustic feedback gain multiplication. When
the output signal of the means 34 is less than the output signal C1 is zero.
In the second comparator 36, an output signal obtained by inputting the output signal of the first
instantaneous power estimation unit 31 to the line feedback gain multiplication unit 33 and an
output signal of the second instantaneous power estimation unit 32 And the output signal C2
becomes 1 when the output signal of the line-side feedback gain multiplication means 33 is equal
to or greater than the second instantaneous power estimate value, and the line-side feedback
gain multiplication means 33 The output signal C2 becomes 0 when the output signal of the
signal is less than the second instantaneous power estimated value.
[0022]
The first and second instantaneous power estimation units 31 and 32 are realized by an
integration circuit or a digital filter having a sharp rise and a slow fall characteristic, and input
signals to the transmission side loss insertion means 1 respectively. The instantaneous power of
the signal amplified by the transmission bias mode setting amplifier 6 and the reception bias
mode setting amplifier 7 is estimated for the input signal to the receiver side loss insertion
means 2 respectively.
[0023]
FIG. 2 is a block diagram showing a specific configuration of the transmission signal speech
section detection unit 37 and the reception signal speech section detection unit 38. As shown in
FIG.
The transmission signal voice section detection unit 37 refers to the transmission signal (the
reception signal in the reception signal voice section detection unit 38, and the parenthesis in the
following represents the case of the reception signal voice section detection unit 38), and the
near end side ( Background noise power estimation unit 37a (38a) for estimating the background
noise level at the far end side, and the instantaneous power estimated value Ps estimated by the
first instantaneous power estimation unit 31 (32) and the background noise power estimation
unit 37a ( Input signals to the transmitter or receiver loss insertion means 1 and 2 based on the
background noise power estimated value Pn estimated in 38a) (hereinafter collectively referred
15-04-2019
10
to as “reference signal”) in If it is determined to be a voice signal, the determination result
(determination flag) SDF1 (SDF2) is set to 1, and if it is determined to be a non-voice signal, the
determination result SDF1 (SDF2) Together with the 0, the determination result SDF1 (sdf2) is
and a voice / non-voice determining section 37b (38b) for holding the previous determination
result SDF1 (sdf2) to update.
The background noise power estimation unit 37a (38a) is composed of an integration circuit or
digital filter having a characteristic that the rising is gradual and the falling is steep, and the
background noise power estimated value is sequentially referred to the reference signal in. Until
Pn is updated, the previous estimated value Pn is held.
[0024]
On the other hand, the voice / non-voice determination unit 37b (38b) compares, for example,
the instantaneous power estimated value Ps output from the first instantaneous power estimation
unit 31 (32) with a predetermined threshold value Ps0. The ratio Ps / Pn of Ps to the background
noise power estimated value Pn output from the background noise power estimating unit 37a
(38a) is compared with a predetermined threshold value δ, and the instantaneous power
estimated value Ps is greater than the threshold value Ps0. Is determined to be an audio signal
when the ratio Ps / Pn is larger than the threshold value δ (Ps / Pn> δ), and the determination
result SDF1 (SDF2) is 1, otherwise And the determination result SDF1 (SDF2) is set to 0.
Here, the threshold value Ps0 is a threshold value that defines the minimum level of the audio
signal, and the threshold value δ is a threshold that defines the minimum ratio of the audio
signal level to the background noise level.
[0025]
The sound side feedback gain estimation means 11 estimates the time average power of the
input signal (transmission signal) of the transmission side loss insertion means 1 in a short time,
and at the same time the input signal (reception signal) of the reception side loss insertion means
2 Estimate the time average power in a short time, and further determine the minimum value of
the estimated value of the time average power of the output signal of the receiving side loss
insertion means 2 at the maximum delay time assumed in the acoustic side feedback path HAC
The value obtained by dividing the estimated value of the time average power of the input signal
of the transmitting side loss insertion means 1 is taken as the estimated value | α ′ | of the
acoustic side feedback gain α.
15-04-2019
11
[0026]
In the insertion loss amount distribution processing unit 30 in the present embodiment, the
comparison results C1 and C2 of the first and second comparators 35 and 36 and the detection
results of the transmission signal voice section detection unit 37 and the reception signal voice
section detection unit 38 The speech state is determined with reference to SDF1 and SDF2, and
the insertion loss amount of the transmission side loss insertion means 1 and the reception side
loss insertion means 2 is determined.
That is, the insertion loss amount distribution processing unit 30 refers to the four binary signals
C1, C2, SDF1 and SDF2 to determine the call state, and the insertion loss of the transmission side
loss insertion means 1 and the reception side loss insertion means 2 Determine the amount.
Here, if C1 = C2 = 1 and SDF1 = 1, the transmitting mode, if C1 = C2 = 0 and SDF2 = 1, the
receiving mode, C1 ≠ C2 and both SDF1 and SDF2 are not 0, fast idle In mode and other states,
it is determined to be slow idle mode, and when the determination result is the transmission
mode, the insertion loss amount of the transmitting loss insertion means 1 is the minimum value,
and the insertion loss amount of the receiving loss insertion means 2 is the maximum value
When the judgment result is the reception mode, the insertion loss amount of the transmission
side loss insertion means 1 is set to the maximum value, and the insertion loss amount of the
reception side loss insertion means 2 is set to the minimum value, and the judgment result is the
high speed idle mode. Sometimes the insertion loss amounts of the transmitting side loss
insertion means 1 and the receiving side loss insertion means 2 are made equal to each other in a
short transition time, and when the determination result is in the slow idle mode, transmission is
performed in a long transition time To equal the insertion loss of the loss insertion means 1 and
the receiving side loss insertion means 2.
[0027]
The biased mode control means 8 in the present embodiment, as shown in FIG. 3, uses a
multiplier 82 for obtaining the product of the estimated value PFn of the far-end side background
noise power and a predetermined first noise power ratio coefficient X1. , And a comparison result
of the first comparator 81 with the first comparator 81 comparing the estimated value PNn of
the near-end side background noise power, an inverter 83 inverting the detection result SDF1 of
the transmission signal voice section detection unit 37, and AND gate 84 for obtaining the logical
product i of the detection result SDF1 inverted by the inverter 83, clocking means 85 comprising
15-04-2019
12
a counter which is incremented when the logical product i is 1 and reset when it is 0, clock
means A second comparator 86 for comparing the duration (count value) T 'clocked by 85 and
the first predetermined time T1, and estimation of the near-end background noise power A
multiplier 82 'for obtaining a product of PNn and a predetermined second noise power ratio
coefficient X2, a third comparator 81' for comparing the product with an estimated value PFn of
far-end side background noise power, and a reception signal An inverter 83 'for inverting the
detection result SDF2 of the voice section detection unit 38, an AND gate 84' for obtaining a
logical product i 'of the comparison result of the third comparator 81' and the detection result
SDF2 inverted by the inverter 83 '; A clock means 85 'comprising a counter which is incremented
when the logical product i' is 1 and is reset when the logical product i 'is 0, a clocking time (count
value) T "by the clocking means 85' and a second predetermined time T2. According to the
comparison result Z of the fourth comparator 86 'and the second comparator 86, and the
comparison result Z' of the fourth comparator 86 '. Titration, the amplifier 6 for gain GT and the
gain GR of the receiving unbalance mode setting amplifier 7, respectively; and a gain setting unit
87 for setting the G [dB] or 0 [dB].
[0028]
The operation of the uneven weight mode control means 8 will be specifically described.
First, the product of the far-end side background noise power estimated value PFn and the first
noise power ratio coefficient X1 is compared with the near-end side background noise power
estimated value PNn in the first comparator 81, and PFn × X1 <PNn The comparison result of 0
is output to the AND gate 84 when 1 and when PFn × X1 ≧ PNn.
The output of the AND gate 84 (logical AND only when the estimated value PNn of the near-end
side background noise power is a value larger than the product and the voice section is not
detected by the transmission signal voice section detection unit 37 I) becomes 1 and the duration
T 'in the clock means 85 is incremented, and the estimated value PNn of the near-end side
background noise power becomes less than the product or the voice section is detected by the
transmission signal voice section detection unit 37 If either condition is satisfied, the output i of
the AND gate 84 becomes 0, and the duration T 'in the clock means 85 is reset.
The duration T 'by the clock means 85 is compared with the first predetermined time T1 in the
second comparator 86, and when the duration T' exceeds the first predetermined time T1, the
second comparator 86 If the output (comparison result) Z is 1 and the duration T 'does not
15-04-2019
13
exceed the first predetermined time T1, the output Z is 0.
[0029]
On the other hand, the product of the estimated value PNn of the near-end side background noise
power and the second noise power ratio coefficient X2 and the estimated value PFn of the farend side background noise power are compared in the third comparator 81 ′ and PNn × X2 <
The comparison result of 1 at PFn and 0 at PNn × X2PNPFn is output to the AND gate 84 ′.
Then, the output of the AND gate 84 '(logical AND only when the estimated value PFn of the farend side background noise power is a value larger than the product and the speech section is not
detected by the reception signal speech section detection unit 38. I) becomes 1 and the duration
T ′ ′ in the clock means 85 ′ is incremented, and the estimated value PFn of the far-end side
background noise power is not larger than the product, or the voice section is detected by the
reception signal voice section detector 38 Is detected, or when any of the conditions is satisfied,
the output i 'of the AND gate 84' becomes 0, and the duration T "in the clock means 85 'is reset.
The duration T ′ ′ by the clocking means 85 ′ is compared with the second predetermined
time T2 by the fourth comparator 86 ′, and the fourth comparator when the duration T ′ ′
exceeds the second predetermined time T2 If the output (comparison result) Z 'of 86' becomes 1
and the duration T "does not exceed the second predetermined time T2, the output Z 'becomes 0.
[0030]
When the output Z of the second comparator 86 is 1 and the output Z 'of the fourth comparator
86' is 0, the gain setting unit 87 sets the gain GT of the transmission polarization mode setting
amplifier 6 to 0 [dB], The receiver deflection mode is set by setting the gain GR of the receiver
deflection mode setting amplifier 7 to G [dB].
Further, when the output Z of the second comparator 86 is 0 and the output Z 'of the fourth
comparator 86' is 1, the gain setting unit 87 'sets the gain GT of the transmission polarization
mode setting amplifier 6 to G [dB]. The transmission polarization mode is set by setting the gain
GR of the reception polarization mode setting amplifier 7 to 0 [dB].
15-04-2019
14
Furthermore, when both the output Z of the second comparator 86 and the output Z 'of the
fourth comparator 86' are 0, the gain setting unit 87 sets the gain GT of the transmission
deviation mode setting amplifier 6 and the reception deviation mode setting amplifier The
neutral mode is set by setting the gains GR of 7 to 0 [dB].
[0031]
Here, when the estimated value PNn of the near-end background noise power is very small, even
if the estimated value PFn of the far-end background noise power is considerably small, the far
end side noise is set to the transmission biased mode by a slight noise. Because of this, it is likely
to cause reception blocking.
[0032]
Therefore, the biased mode control means 8 in the present embodiment executes the comparison
operation by the first comparator 81 only when the estimated value PNn of the near-end side
background noise power is larger than a predetermined value.
That is, if the estimated value PNn of the near-end side background noise power is larger than a
predetermined value, it becomes difficult to be set to the transmission polarization mode when
the far-end side background noise power estimated value PFn is relatively small as described
above It is possible to prevent the occurrence of earpiece blocking.
In the case where the transmission side biased mode is set, reception blocking tends to occur as
the acoustic side feedback gain α increases. Therefore, in the biased mode control means 8 of
this embodiment, the estimated value of the near-end side background noise power The biased
mode control means 8 executes the comparison operation by the first comparator 81 only when
PNn is larger than the predetermined value and the estimated value | α ′ | of the acoustic side
feedback gain α is smaller than the predetermined threshold α0. ing.
[0033]
When the bias mode control means 8 switches from the neutral mode to the transmission bias
15-04-2019
15
mode or the reception bias mode, the gains GR and GT of the receiver bias mode setting amplifier
7 and the transmit bias mode setting amplifier 6 are set on the near end side. It is also possible to
increase or decrease stepwise according to the background noise power and the estimated values
PNn and PFn of the far-end side background noise power. For example, assuming that the gain
GT is increased or decreased in two steps, in the neutral mode, the biased mode control means 8
GT = G1 [dB] when the estimated value PNn of the near-end side background noise power is
PNn> W1, further When the estimated value PNn of the near-end side background noise power is
PNn> W2 (> W1) when it is set to = G1, GT = G2 (> G1) [dB], and GT = G2 is set When the
estimated value PNn of the near-end side background noise power is PNn <W2, GT = G1 [dB], and
further, when the GT = G1 is set, the estimated value PNn of the near-end side background noise
power is PNn < If W1 is reached, the gain G of the transmission bias mode setting amplifier 6 is
increased or decreased so that GT = 0 [dB]. The same applies to switching from the neutral mode
to the receiving / biasing mode. As described above, by gradually increasing or decreasing the
gains GT and GR of the transmission polarization deviation mode setting amplifier 6 and the
reception polarization deviation mode setting amplifier 7, it is possible to make a comfortable
conversation according to the magnitude of the background noise power.
[0034]
1 is a block diagram illustrating an embodiment of the present invention. It is a block diagram of
a transmission signal voice section detection means in the same as the above. FIG. 6 is a block
diagram of the uneven weight mode control means in the above. It is a block diagram which
shows a prior art example.
Explanation of sign
[0035]
DESCRIPTION OF SYMBOLS 1 transmitter side loss insertion means 2 receiver side loss insertion
means 3 insertion loss amount control means 4 near end side background noise power
estimation means 5 far end side background noise power estimation means 6 amplifier for
transmission bias mode setting 7 reception bias mode setting Amplifiers 8 Weighted Mode
Control Means
15-04-2019
16
Документ
Категория
Без категории
Просмотров
0
Размер файла
30 Кб
Теги
description, jp2007208923
1/--страниц
Пожаловаться на содержимое документа