JP2002368891A - Loudspeaking system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing costs of a loudspeaking system by decreasing the number of components. SOLUTION: A voice speech processing circuit 30 is configured with a single processor such as a digital signal processor(DSP), and a simultaneous speech block 31 and a voce generating block 32 are realized by controlling the hardware of the DSP with an exclusive software program. Since the voce speech processing circuit 30 configured by the single processor(DSP) in this way executes simultaneous speech processing and voce generating processing, the number of components of the loudspeaking system can be reduced compared with a conventional system where a plurality of integrated circuits are combined for each processing to reduce the manufacturing costs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice communication system, such as a hands-free intercom system, which is installed in an apartment house such as a detached house or condominium and enables hands-free communication with a visitor.

[0002]

2. Description of the Related Art Conventionally, an indoor call terminal (parent unit) installed in a dwelling unit in an apartment house such as a detached house or an apartment, and an outdoor call terminal (door phone handset) installed in a front door outside the dwelling unit or the like ) Is provided with a hands-free intercom system that enables a loudspeaker call (hands-free call). In recent years, in apartments and other condominiums, outdoor call terminals such as lobby intercoms installed at communal entrances and doorphone handsets installed outside the entrance doors of each dwelling unit and housing information panels installed inside each dwelling unit have been A loudspeaker system for making a loudspeaker call with such an indoor call terminal has also become widespread. FIG. 10 is a system configuration diagram schematically showing an example of a conventional voice call system.

[0003] This loudspeaker system includes a lobby intercom 102 installed at a common entrance, an alarm monitor 103 installed at a manager's office, a house information panel 100 installed at each dwelling unit, and a door at each dwelling unit. And a door phone slave unit 101 installed outdoors. Lobby intercom 102
Are connected via signal lines between the alarm monitoring panel 103 and each of the house information panels 100..., The lobby intercom 102, the alarm monitoring panel 103,
A signal can be transmitted to and from each of the house information panels 100.

Each of the doorphone slave units 101 provided outside the entrance door of each dwelling unit is connected to each of the housing information panels 100 in the corresponding dwelling unit via signal lines. Lobby intercom 102 is provided with external input means 102a such as a numeric keypad.
, A microphone 102b, a speaker 102c, a call button 102d, and the like.

[0005] Then, visitors come to lobby intercom 1
02 is input from the external input means 102a provided in the unit 02, and when the call button 102d is pressed, a call is made from the house information panel 100 installed in the dwelling unit of the inputted dwelling unit number. When a sound is emitted and the resident of the dwelling unit presses the response button of the housing information panel 100 in response to the ringing sound, the microphone 102b and the speaker 102c of the lobby intercom 102 and the housing information panel 100 are connected. A microphone and a speaker are provided so that a visitor and a resident can talk.

[0006] The alarm monitor 103 is provided with external input means 103a such as a numeric keypad, a handset 103b, an alarm issuing means (not shown), and various security sensors such as a fire detector provided at each dwelling unit. (Not shown) and the like. Then, a manager or the like operates the external input means 1 provided on the alarm monitoring panel 103.
When any house number is input from the house information board 03a, a ringing tone is emitted from the house information panel 100 installed in the dwelling unit of the dwelling unit number, and the resident of the dwelling unit responds to the ringing sound to respond to the ringing sound. When the response button is pressed, the handset 103b of the alarm monitoring panel 103 and the housing information panel 1
The telephone number between the manager and the resident can be communicated by the microphone and speaker provided in 00.

Each of the home information panels 100 is provided with a microphone, a speaker, an alarm button, and the like. Then, when, for example, the dwelling unit number of the alarm monitoring panel 103 is input from an external input means (not shown) such as a numeric keypad provided in each of the housing information panels 100, a ringing tone is emitted from the alarm monitoring panel 103, and management is performed. When a person or the like picks up the handset 103b of the alarm monitoring panel 103 in response to the ringing sound, the housing information panel 10
The microphones and speakers 0 and the handset 103b of the alarm monitoring panel 103 allow the resident and the manager to talk.

[0008] Further, the door phone slave device 101 includes a call button 10
1a, a microphone 101b, a speaker 101c, and the like. Then, the visitor presses the call button 1 of the intercom slave device 101.
When the home information panel 100 in the dwelling unit is pressed, a ringing tone is emitted from the house information panel 100... The microphone and speaker of the door phone handset 101 and the microphone and speaker of the house information panel 100 allow the visitor and the resident to talk.

The housing information panel 100 monitors one or more fire detectors provided in the dwelling unit, and when any one of the fire detectors is detected, an alarm sound or a warning sound is issued in advance. After first notifying the resident in the dwelling unit that the fire detector has been activated by outputting a stored voice message (alarm message), the fire detection panel 103 detects a fire via the signal line. It outputs a signal (fire detector activation signal) indicating that the detector has been activated.

The home information panel 100 outputs a fire detector operation signal, outputs a signal when the resident performs a predetermined fire determination operation, or outputs a fire detector operation signal.
When the resident does not perform a predetermined recovery operation within a predetermined time, a fire determination signal is output to the alarm monitoring panel 103 via a signal line. In this case, in a dwelling unit where a fire has occurred, a warning is issued by outputting a voice message stored in advance in each housing information panel 100.

On the other hand, when the alarm monitor 103 receives a fire detector operation signal from any of the dwelling units via a signal line, the alarm monitor panel 103 identifies the address added to the fire detector operation signal and outputs the signal. The dwelling unit is identified, the dwelling unit number where the house information panel 100 that outputs the fire detector operation signal is installed is displayed on the display unit, and a warning is simultaneously output to inform the manager or the like of the dwelling unit number.

When the house information panel 100 further outputs a fire determination signal, the alarm monitoring panel 103 receives the fire determination signal through a signal line. A house information panel 100 of a dwelling unit is designated, an alarm control signal is output through a signal line, and a neighboring dwelling unit (a housing information panel 1 that outputs a fire determination signal).
From the house information panel 100 installed on the same floor as the dwelling unit where 00 is installed, or on the immediately above floor, for example,
A voice message such as "Fire. Fire. A fire has occurred. Please confirm your safety and evacuate." Can be output through the speaker of the house information panel 100.

[0013]

Conventionally, a speech processing circuit such as an echo canceller and a voice switch for realizing a hands-free simultaneous call, and a voice generation circuit for generating a special sound such as an alarm sound and an alarm message have been conventionally provided. Each of them is configured as a separate integrated circuit (IC), and the plurality of integrated circuits are used in combination. Therefore, there is a problem that the number of parts increases and the manufacturing cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a voice communication system capable of reducing the number of parts and reducing the manufacturing cost.

[0015]

According to the first aspect of the present invention, there is provided an indoor communication terminal provided with a microphone and a speaker and installed inside a dwelling unit, and provided with a microphone and a speaker outside the dwelling unit to achieve the above object. One or more outdoor communication terminals are connected to each other through a communication path, and at least one of the outdoor communication terminals includes an imaging camera for imaging a caller and transmits a video signal captured by the imaging camera to the communication path. The video signal transmitted through the communication path is transmitted to the indoor call terminal, and the indoor call terminal is provided with a video signal processing means and a display means for processing the video signal transmitted through the communication path and displaying the video on the display means. Monitors the output of one or more sensors installed to detect anomalies such as fire or gas leaks, and responds to the details of the detected anomalies when any of the sensors detects an anomaly. In a loudspeaker system in which the alarm message or the alarm sound is output from the speaker and transmitted to the outdoor communication terminal via the communication path and output from the speakers of the outdoor communication terminal, the indoor communication terminal is connected to each outdoor communication terminal. Call processing block that performs processing for realizing a two-way simultaneous call via a communication path between the two, a ring tone output from a speaker in response to a call from the outdoor call terminal, and an outdoor call terminal that made a call A voice call processing circuit composed of a single processor for a back tone transmitted through a communication path, and a voice generation block for generating a warning message and a warning sound. In order to perform simultaneous call processing and voice generation processing in a voice call processing circuit composed of processors of different types, a plurality of integrated circuits are combined to perform each processing. Compared to the example it reduces the number of components attained a reduction in manufacturing cost.

According to a second aspect of the present invention, in the first aspect of the present invention, the simultaneous call processing block includes an acoustic echo canceller for canceling an acoustic echo generated by acoustic coupling between a microphone and a speaker of the indoor call terminal, and an outdoor call terminal. A line echo canceller for canceling a line echo generated by acoustic coupling or a signal wraparound through a communication path, and an acoustic echo path and a closed loop formed by the line echo path provided between the line echo canceller and the line echo canceller. A voice switch that suppresses howling by reducing loop gain, and an amplifier with a gain control function provided on a signal path of a transmission signal and a reception signal sandwiched between an acoustic echo canceller and a line echo canceller; The switch inserts a loss into the signal path of the transmitting side. Side loss insertion means, reception side loss insertion means for inserting a loss into the signal path on the reception side, and insertion loss amount control means for controlling the amount of loss inserted from each of the loss insertion means on the transmission side and the reception side. The insertion loss control means estimates the acoustic feedback gain of the path that returns from the output point of the receiving-side loss inserting means to the input point of the transmitting-side loss inserting means via the acoustic echo path, and Estimating the line-side feedback gain of the path that returns from the output point of the loss insertion means to the input point of the receiving-side loss insertion means via the line echo path,
A total loss amount calculation unit that calculates the total loss amount to be inserted into the closed loop based on the estimated value of each feedback gain on the sound side and the line side, and monitors a transmission signal and a reception signal to estimate a call state, An insertion loss amount distribution processing unit that determines the distribution of each insertion loss amount of the transmission side loss insertion unit and the reception side insertion loss unit according to the estimation result and the calculated value of the total loss amount calculation unit,
The total loss amount calculation unit calculates the sum of the loss amounts to be inserted into the closed loop based on the estimated values of the respective feedback gains and adaptively updates the update mode, and the fixed mode in which the total loss amount is fixed to a predetermined initial value. It has two operation modes, operates in the fixed mode during the period from the start of communication with the outdoor call terminal to the time when the acoustic echo canceller and the line echo canceler are sufficiently converged, and the sound echo canceler and the line echo canceler are sufficiently converged. It operates in the update mode during the period after the start of the call, and when the acoustic echo canceller and the line echo canceller do not converge immediately after the start of the call, the total loss amount is calculated by the total loss amount calculation unit operating in the fixed mode. Is fixed to a sufficiently large initial value, which suppresses the occurrence of unpleasant echoes and howling and realizes stable half-duplex calls Can, in a state where the acoustic echo canceller and the line echo canceler is sufficiently converged, the total loss by total loss amount calculation unit that operates in update mode can be realized simultaneous calls bidirectional in order to be updated from time to time.
Also, by setting the gains of the amplifiers with a gain control function on the transmitting side and the receiving side to appropriate values, a desired call volume can be obtained, and a gain control function is provided when an excessive level of sound is input. Due to the saturation processing of the amplifier, it is possible to prevent occurrence of a problem such as overflow in the voice communication processing circuit.

According to a third aspect of the present invention, in the second aspect of the present invention, there is provided a receiver which has an operation unit which can be operated by a caller, and controls the gain of the amplifier with a gain control function on the receiving side in accordance with the operation of the operation unit. It is characterized in that the volume gain control means is provided in the indoor call terminal, and the call can be made at a desired volume of the caller.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the gain of the amplifier with the gain control function on the receiving side controlled by the receiving volume gain control means is complementary to the gain of the amplifier with the gain control function on the receiving side. Speaking volume gain control means for controlling the gain is provided in the indoor communication terminal, and the level of the sending volume decreases complementarily even if the level of the receiving volume rises, so that the closed loop gain is always substantially equal. Because it is kept constant, howling does not occur, and when the caller of the indoor call terminal operates the operation unit to reduce the receiving sound volume because the indoor ambient noise level is low, the Since the gain of the amplifier with the gain control function complementarily increases, the transmission volume that can be heard by the caller of the outdoor call terminal can be increased to realize a comfortable call.

According to a fifth aspect of the present invention, in the second aspect of the present invention, the voice generation block is configured to perform a call when the indoor call terminal is called from another outdoor call terminal during a call with any one of the outdoor call terminals. The ringing tone generated without interrupting the call is superimposed on the reception signal and output from the speaker of the indoor communication terminal, and the generated back tone is transmitted to the calling side outdoor communication terminal via the communication path. While the ringing tone is being output when the ringing tone is superimposed, the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous call processing block and the operation of the update mode of the total loss amount calculating unit are stopped, and the total loss amount calculating unit is stopped. Is characterized in that a call processing means for holding a calculated value immediately before the operation stop of the update mode is provided in the voice call processing circuit, and a disturbance component for the acoustic echo canceller is provided. It is no call processing means during superposition of rings results in a divergence and howling of the adaptive filter by stopping the operation of the update mode of the adaptive filter coefficient update processing and total loss amount calculation section of the acoustic echo canceller comprising. Moreover, since the call processing means causes the total loss amount calculation unit to hold the calculated value immediately before the stop of the operation in the update mode, the total loss amount calculation unit can reduce the closed loop gain (echo path gain) by superimposing the ringing tone. It is possible to avoid a situation in which the estimated value of the total loss amount is not stabilized due to erroneous estimation as if it fluctuated.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the speech processing means updates the adaptive filter coefficient of the acoustic echo canceller in the simultaneous speech processing block only when the ringing tone level is equal to or higher than a predetermined threshold. The operation of the update mode of the total loss amount calculating unit is stopped, and when the ringing tone level is less than the threshold value and is a level that can be ignored by the acoustic echo canceller, the acoustic echo canceller also performs the ringing tone superimposition. The adaptive filter coefficient update process and the operation of the update mode of the total loss amount calculation unit are continued, and even if the characteristics of the echo path fluctuate due to a change in the distance to the microphone or speaker due to the movement of the talker, it can follow this. The following result is also reflected in the calculation result of the total loss amount calculation unit.

According to a seventh aspect of the present invention, in the fifth aspect of the present invention, the call processing means updates the adaptive filter coefficient of the acoustic echo canceller in the simultaneous call processing block and the total loss amount calculating section in accordance with the type of ringing tone. The update mode operation is stopped, and if the ringing tone is not of a type that does not adversely affect the adaptive filter coefficient updating process of the acoustic echo canceller, the adaptive filter coefficient updating of the acoustic echo canceller is performed even while the ringing tone is superimposed. The processing and the operation of the update mode of the total loss amount calculation unit are continued, and even if the characteristics of the echo path fluctuate due to the movement of the caller and the distance to the microphone or the speaker changing, it is possible to follow this, The follow-up result is also reflected in the calculation result of the total loss calculation unit.

According to an eighth aspect of the present invention, in the second aspect of the present invention, the voice generation block includes a special function such as an alarm message or an alarm sound when the indoor communication terminal is in communication with any of the outdoor communication terminals. A special sound generated without generating a sound and without interrupting the call is superimposed on the reception signal and output from the speaker of the indoor call terminal, and while the special sound is being output during the superposition of the special sound during the call, The speech communication processing circuit is provided with speech processing means for stopping the operation of the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous speech processing block and the update mode of the total loss amount calculation unit, and a disturbance component for the acoustic echo canceller. The speech processing means stops the adaptive filter coefficient update processing of the acoustic echo canceller and the operation of the update mode of the total loss amount calculation unit during the superposition of the special sound There is no cause divergence and howling of the adaptive filter by causing. Moreover, since the call processing means causes the total loss amount calculation unit to hold the calculated value immediately before the stop of the operation in the update mode, the total loss amount calculation unit can reduce the closed loop gain (echo path gain) by superimposing the special sound. It is possible to avoid a situation in which the estimated value of the total loss amount is not stabilized due to erroneous estimation as if it fluctuated.

According to a ninth aspect of the present invention, in the invention of the eighth aspect, the speech processing means updates the adaptive filter coefficient of the acoustic echo canceller in the simultaneous speech processing block only when the level of the special sound is equal to or more than a predetermined threshold. It is characterized in that the operation of the update mode of the total loss amount calculating unit is stopped, and when the level of the special sound is less than the threshold value and is a level that can be ignored by the acoustic echo canceller, the acoustic echo canceller is also operated during the superposition of the special sound. The adaptive filter coefficient update process and the operation of the update mode of the total loss amount calculation unit are continued, and even if the characteristics of the echo path fluctuate due to a change in the distance to the microphone or speaker due to the movement of the talker, it can follow this. The following result is also reflected in the calculation result of the total loss amount calculation unit.

According to a tenth aspect of the present invention, in the invention of the eighth aspect, the speech processing means includes an adaptive filter coefficient update process of the acoustic echo canceller in the simultaneous speech processing block and a total loss amount calculation unit in accordance with the type of the special sound. The update mode operation is stopped, and if the special sound is not of a type that does not adversely affect the adaptive filter coefficient update processing of the acoustic echo canceller, the adaptive filter coefficient of the acoustic echo canceller is updated even during the superposition of the special sound. The processing and the operation of the update mode of the total loss amount calculation unit are continued, and even if the characteristics of the echo path fluctuate due to the fact that the talker moves and the distance to the microphone or speaker changes, it is possible to follow this, The follow-up result is also reflected in the calculation result of the total loss calculation unit.

According to an eleventh aspect of the present invention, in accordance with the second aspect of the present invention, there is provided an operation unit operable by a caller, and when the operation unit is operated, the video signal processing unit is activated to display an image on the display unit. Video loss monitoring means, wherein the insertion loss control means increases the insertion loss of the transmission-side loss insertion means and increases the insertion loss of the reception-side loss insertion means when the video monitoring means activates the video signal processing means. , The voice switch is forcibly set to the receiving state, and the gain with the gain control function on the receiving side is set to a large gain as compared with the time of the call, and the image is taken by the imaging camera of the outdoor call terminal. When the displayed video is displayed on the display means of the indoor call terminal and monitored, the received sound volume is forcibly increased, so that the ambient sound of the outdoor call terminal and the voice of the caller of the outdoor call terminal can be clearly heard.

According to a twelfth aspect of the present invention, in the eleventh aspect, a near-end background noise level estimating means for estimating a near-end background noise level included in the transmission signal, The voice call processing circuit further includes a receiving volume control circuit for controlling the gain of the amplifier having a gain control function on the receiving side in accordance with the estimated value. When displaying and monitoring on the display means of the terminal, it is possible to listen to the ambient sound of the outdoor call terminal and the voice of the caller of the outdoor call terminal at an appropriate volume according to the level of the indoor ambient noise.

According to a thirteenth aspect of the present invention, in the second aspect, the operation modes of the acoustic echo canceller and the line echo canceller are set to a coefficient update mode in which an adaptive filter coefficient update process is performed and a coefficient fixed mode in which an adaptive filter coefficient is fixed. The indoor call terminal is provided with an echo canceller operation control means for stopping the adaptive filter coefficient update process and switching to any of the through modes for passing an input signal, and the operation test of the acoustic echo canceller and the line echo canceller is performed. Easy to do.

According to a fourteenth aspect of the present invention, in the second aspect, the operation state of the voice switch is set to an update state in which the total loss amount calculation section operates in the update mode, and a fixed state in which the total loss amount calculation section operates in the fixed mode. The state, the insertion loss amount distribution processing unit forcibly increases the distribution of the insertion loss amount to the receiving side insertion loss means, the forced transmission state, the insertion loss amount distribution processing unit, the insertion loss amount to the transmission side insertion loss means The voice call processing circuit is provided with voice switch operation control means for switching to any one of the forced listening states in which the distribution of the voice switch is forcibly increased, so that the voice switch operation test can be easily performed.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail by embodiments with reference to the drawings. The loudspeaker system of each embodiment signals at least an indoor call terminal M such as a base unit or a house information panel and an outdoor call terminal (not shown) such as a door phone handset or a lobby intercom as in the conventional example. Although it is configured by connecting with a communication path consisting of a line, an outdoor call terminal such as a door phone handset or a lobby intercom is common to the conventional example, and therefore illustration and description are omitted, and an indoor call terminal according to the gist of the present invention is provided. Only M will be described.

(Embodiment 1) FIG. 1 is a block diagram showing a main part of an indoor communication terminal M in this embodiment. The indoor call terminal M includes a microphone 1 and a speaker 2, and C
A monitor unit 3 which is composed of an RT, a liquid crystal display, or the like, and which displays an image captured by an imaging camera of the outdoor telephone terminal; and a monitor unit which performs signal processing on a video signal transmitted from the outdoor telephone terminal via a signal line. A video display circuit 4 serving as a video signal processing means for displaying a video on the transmission line 3;
A signal separating unit 6 for separating an audio signal and a video signal multiplexed and transmitted from an outdoor call terminal, and a process for realizing a two-way simultaneous call between the outdoor call terminal and a signal line. , A call tone output from the speaker 2 in response to a call from the outdoor call terminal, a back tone transmitted through the signal line to the called outdoor call terminal, an alarm message and an alarm Voice call processing circuit 3 having voice generation block 32 for generating sound
0, a microphone amplifier 7 for amplifying an output signal (transmission signal) of the microphone 1, a first A / D converter 8 for converting an analog transmission signal amplified by the microphone amplifier 7 into a digital signal, and a voice call. A first D / A converter 9 for converting a digital transmission signal output from the processing circuit 30 into an analog signal, and a transmission signal amplifier for amplifying the analog transmission signal converted by the first D / A converter 9 10 and
A receiving signal amplifier 11 for amplifying the audio signal (receiving signal) separated by the signal separating unit 6, a second A / D converting unit 12 for converting an analog receiving signal amplified by the receiving signal amplifier 11 into a digital signal, A second D / A converter 13 for converting a digital reception signal output from the voice call processing circuit 30 into an analog signal, and a first speaker amplifier for amplifying the analog reception signal converted by the second D / A converter 13 14 and the voice generation block 32 of the voice call processing circuit 30
A third D / A converter 15 for converting a digital voice signal such as a ringing tone generated in step 3 into an analog signal, and a second speaker amplifier 16 for amplifying the analog voice signal converted by the third D / A converter 15 A first analog signal multiplexing unit 17 that multiplexes a reception signal amplified by the first speaker amplifier 14 and a voice signal such as a ringing tone amplified by the second speaker amplifier 16 and outputs the multiplexed signal to the speaker 2; Circuit 3
The fourth D / A converter 18 converts a digital voice signal such as a ringing tone generated by the voice generation block 32 into an analog signal, and amplifies the analog voice signal converted by the fourth D / A converter 18. Audio signal amplifier 19, the transmission signal amplified by the transmission signal amplifier 10, and the audio signal amplifier 1
And a second analog signal multiplexing unit 20 that multiplexes the voice signal such as a ring tone amplified in 9 and outputs the multiplexed signal to the transmission processing unit 5. However, means for monitoring the outputs of sensors such as a fire detector and a gas leak detector described in the conventional example is not the gist of the present invention, and the configuration and the configuration are well known in the related art, so that illustration and description are omitted.

On the other hand, in an outdoor telephone terminal equipped with an imaging camera, an audio signal and a video signal are transmitted through a signal line composed of a pair of pairs by multiplexing an FM signal with an audio signal to be transmitted in baseband. It is transmitted to the indoor call terminal M. However, since the outdoor call terminal performing such an operation is conventionally known as a door phone handset with a camera or the like, a detailed description is omitted.

In the indoor communication terminal M, the multiplexed audio signal and video signal received by the transmission processing unit 5 are separated by the signal separation unit 6, and the video signal demodulated by the video display circuit 4 is output to the monitor unit 3. By doing so, the image captured by the imaging camera of the outdoor call terminal is displayed on the screen of the monitor unit 3.

The simultaneous call processing block 31 is, as shown in FIG. 2, an acoustic echo canceller 33 for eliminating an acoustic echo generated by acoustic coupling between the microphone 1 and the speaker 2.
A line echo canceller 34 for canceling a line echo caused by acoustic coupling or a signal wraparound via a signal line in an outdoor call terminal, and an acoustic echo canceller 33
A sound switch 35 provided between the acoustic echo path and the closed loop (echo path) formed by the acoustic echo path and the line echo path to suppress howling, and an acoustic echo canceller 33
And amplifiers 36 and 37 with gain control functions on the transmitting side and the receiving side provided on the signal paths of the transmission signal and the reception signal sandwiched between the line echo cancellers 34, respectively.

The acoustic echo canceller 33 has a conventionally well-known configuration including an adaptive filter 33a and a subtractor 33b.
The impulse response of the feedback path (acoustic echo path) formed by the acoustic coupling between the speaker 2 and the microphone 1 is adaptively identified by the adaptive filter 33a and estimated from the reference signal (the received signal output from the voice switch 35). The echo component (acoustic echo) is first subtracted by the subtractor 33b into the first signal.
The subtraction is performed from the output signal (sending signal) of the / D conversion unit 8 to cancel out the echo component and delete it. The line echo canceller 34 also has a conventionally well-known configuration including an adaptive filter 34a and a subtractor 34b, and performs reflection due to impedance mismatch between the transmission processing unit 5 and a signal line, and a signal between a speaker and a microphone in an outdoor telephone terminal. Return path (line echo path) formed by acoustic coupling
Is adaptively identified by the adaptive filter 34a, and the echo component (line echo) estimated from the reference signal (the transmission signal output to the first D / A conversion unit 9) is subtracted from the reception signal by the subtractor 34b. By doing so, the echo component is canceled out.

The voice switch 35 is a transmission signal attenuator 38 which is a transmission side loss insertion means for inserting a loss in a transmission side signal path, and a reception side loss insertion means which is for inserting a loss in a reception side signal path. The received signal attenuator 39 and the amount of loss inserted from each of the attenuators 38 and 39 on the transmitting side and the receiving side (each attenuator 3
Attenuator gain control unit 40, which is an insertion loss amount control unit for controlling the gains of 8, 39. Further, the attenuator gain control unit 40 controls the sound of a path (hereinafter, referred to as “sound-side feedback path”) that returns from the output point of the reception signal attenuator 39 to the input point of the transmission signal attenuator 38 via an acoustic echo path. A path for estimating the side feedback gain and returning from the output point of the transmission signal attenuator 38 to the input point of the reception signal attenuator 39 via the line echo path (hereinafter, referred to as “line side feedback path”).
And the sum of the loss amounts to be inserted into the closed loop (the insertion loss amount of the transmission signal attenuator 38 and the reception signal) based on the estimated values α and β of the acoustic side and line side feedback gains. A total loss amount calculator (not shown) for calculating the sum of the insertion loss amounts of the attenuators 39, a communication state is estimated by monitoring the transmission signal and the reception signal, and the estimation result and the total loss amount calculation unit The transmission signal attenuator 38 and the reception signal attenuator 3
9, and an insertion loss distribution processor (not shown) for determining the gain.

The total loss calculator estimates the short-time average power of the input signal of the transmission signal attenuator 38 using a rectifier smoother, a low-pass filter, or the like. Received signal attenuator 39 using a filter or the like
Estimating the time-average power of the output signal of
The minimum value of the estimated value of the time average power of the output signal of the reception signal attenuator 39 is obtained at the maximum delay time assumed in the acoustic feedback path, and the time average of the input signal of the transmission signal attenuator 38 is calculated using this minimum value. The value obtained by dividing the estimated value of the power is used as the estimated value α of the feedback gain on the acoustic side, and the time average power of the input signal of the received signal attenuator 39 in a short time is estimated using a rectifier smoother or a low-pass filter. And a transmission signal attenuator 3 using a rectifier smoother and a low-pass filter.
8 to estimate the shortest time average power of the output signal of the transmission signal attenuator 38 in the maximum delay time assumed in the line-side feedback path, With this minimum value, the reception signal attenuator 39
The value obtained by dividing the estimated value of the time average power of the input signal is used as the estimated value β of the line-side feedback gain. Then, the total loss amount calculation unit calculates the estimated values α,
The total loss required to obtain a desired gain margin is calculated from β, and the value is output to the insertion loss distribution processing unit.

The insertion loss distribution processor monitors the input and output signals of the transmission signal attenuator 38 and the input and output signals of the reception signal attenuator 39, and determines the magnitude relationship between the power levels of these signals and the presence or absence of a voice signal. Is determined from the information of (1), and the total loss is distributed to the transmission signal attenuator 38 and the reception signal attenuator 39 at a rate corresponding to the determined communication state. Each attenuator 38, 39
The amount of insertion loss (gain) of.

Incidentally, the adaptive filters 33a and 34 of the acoustic echo canceller 33 and the line echo canceller 34 are provided.
It takes a learning time of several seconds for a to identify the impulse response of each return path on the acoustic side and the line side. In other words, the acoustic echo canceller 33 and the line echo canceller 34 cannot cut off the respective return paths for a few seconds immediately after the start of the call, and a closed loop is formed in the communication system. In such a state, the voice uttered by the caller is audible to the caller as an echo, which causes discomfort. Also, howling occurs if the gain of the amplifier is large.

Therefore, even in a state where the echo cancellers 33 and 34 have not converged immediately after the start of a call (a learning state for identifying an impulse response), in order to prevent howling from occurring, the loop gain of the closed loop exceeds 1 ×. It is necessary to design the gain of each amplifier so that it does not occur. this is,
Obviously, the call volume is limited, and when the indoor call terminal M has a housing having a large acoustic coupling gain due to a short distance between the speaker 2 and the microphone 1, a sufficient call volume that does not hinder practical use. May not be obtained.

The above description is based on the adaptive filters 33a, 33a of the acoustic echo canceller 33 and the line echo canceller 34.
It is assumed that the coefficient of 4a is all reset to 0 at the start of a call. On the other hand, the adaptive filter 33
Although a method in which initial values of coefficients are given to a and 34a is also conceivable, since the characteristics of each return path on the acoustic side and the line side to be identified by the adaptive filters 33a and 34a differ depending on the installation environment of the housing, With the initial value set in advance, there is a possibility that the canceling effect of each return path on the sound side and the line side may not be obtained at all. Therefore, even in such a system, it is unavoidable that the call volume is restricted.

Therefore, in the present embodiment, an update mode in which the total loss amount calculating section calculates the total sum of the loss amounts to be inserted into the closed loop based on the estimated values α and β of the feedback gains as described above, And two operation modes of a fixed mode for fixing the total loss amount to a predetermined initial value. During a period from the start of communication with the outdoor call terminal to the time when the acoustic echo canceller 33 and the line echo canceller 34 sufficiently converge, It operates in the fixed mode and operates in the update mode during a period after the acoustic echo canceller 33 and the line echo canceller 34 have sufficiently converged. That is,
In the total loss amount calculation unit, the estimated values α and β of the acoustic feedback gain and the line feedback gain both continue for a predetermined time (several hundred milliseconds) or more from the start of the call and have a predetermined threshold ε (for example, It is considered that the acoustic echo canceller 33 and the line echo canceller 34 have sufficiently converged at a point in time when the estimated value α is smaller than the estimated values α and β by 10 dB to 15 dB, and the total loss is fixed to the initial value before the above point. The operation mode is switched to an update mode in which the total loss amount is adaptively updated based on the estimated values α and β after the time point. Note that the initial value of the total loss amount in the fixed mode is set to a value sufficiently larger than the total loss amount updated as needed in the update mode.

When the acoustic echo canceller 33 and the line echo canceler 34 do not sufficiently converge immediately after the start of a call, the value is set to a sufficiently large value by the total loss calculator operating in the fixed mode. Since the total loss amount of the initial value is inserted in the closed loop, unpleasant echo (acoustic echo and line echo) and howling can be suppressed, and a stable half-duplex call can be realized.
When the acoustic echo canceller 33 and the line echo canceler 34 have sufficiently converged after a lapse of time from the start of the call, the operation mode of the total loss calculator is switched from the fixed mode to the update mode and inserted into the closed loop. Since the total loss decreases to a value sufficiently lower than the initial value,
Two-way simultaneous communication can be realized. In addition, by setting the initial value of the total loss amount to an appropriate value, the closed loop gain is increased by a factor of 1 to prevent howling when the acoustic echo canceller 33 and the line echo canceller 34 do not converge immediately after the start of a call. Is eliminated so that the gain of each amplifier is not exceeded, and the gain of the amplifier is adjusted so that a desired call volume can be obtained irrespective of the shape and structure of the housing (not shown) of the indoor call terminal M. Can be designed.

In this embodiment, amplifiers 36 and 37 with gain control functions (AGC) for varying the gain in accordance with the level of an input signal (transmitting signal or receiving signal) are used as sound volume adjusting amplifiers. It is provided on the signal path of the transmission signal and the reception signal sandwiched between the canceller 33 and the line echo canceller 34, respectively. The configuration and operation of the amplifier with a gain control function are well known in the art, and a detailed description thereof will be omitted.

For example, as gain control characteristics of the amplifiers 36 and 37 with gain control functions on the transmitting side and the receiving side, the gain is G1 [dB] in a range where the input signal level is equal to or less than the minimum value of the input signal that can be regarded as voice. When the input signal level is in the range from the minimum value to the assumed maximum value of the call voice level, the gain is set to G2 [dB], and when the input signal level is equal to or higher than the maximum value, the gain is set to G3 [dB]. A gain G1 in a range below the minimum value of the signal and a gain G3 in a range above the maximum value of the signal
Is set to a relatively small value, and the gain G2 in the range from the minimum value to the maximum value of the input signal is set to G1, G
If set to a value sufficiently larger than 3, microphone 1
If the sound signal collected by the telephone call can be regarded as a call voice, the gain becomes G2 necessary to obtain a desired call volume. Sound, construction noise, automobile noise, etc.), the gain G1 or G3 is small, so that an appropriate call volume can be obtained while reducing the feedback gains α and β. When an excessively high level speech signal is input, it is possible to prevent the occurrence of problems such as overflow in the speech communication processing circuit 30 by saturation processing of the amplifiers 36 and 37 with gain control functions.

On the other hand, the voice generating block 32 includes a ringing tone generator (not shown) for generating a digital ringing tone by appropriately selecting from a plurality of ringing sounds prepared in advance. And a plurality of voice message data compressed and stored in a built-in or external memory. A voice message decompression unit (not shown) for generating a digital voice message by reading and decompressing, and selecting and reading and decompressing a plurality of melody sound data similarly compressed and stored in the memory. And a melody sound expansion unit (not shown) that generates the melody sound of Here, the alarm sound is for notifying the resident of the occurrence of an abnormality such as a fire or gas leak, the voice message is a message (alarm message) for notifying the above-mentioned abnormality, and the melody sound is a ring tone. Is used as

The voice generation block 32 generates a specific sound as an excuse to stop the telephone conversation with the other party, and expands the specific sound data compressed and stored in the memory. It has at least one of the sound extension parts. For example, when a resident answers a call from an outdoor call terminal (lobby intercom, etc.), the other party (call partner) is an uninvited visitor such as a salesman, so the call is stopped immediately and the visit is stopped. There is a case where a resident wants to take care of the person. In such a case, it is possible to create an excuse to stop the call by letting the other party hear a sound such as a telephone ringing sound or a child's cry (this is called a "specific sound"). You can immediately cancel the call with the other party you do not want to talk to by saying, "Please pick it up because your child is crying and you can't release your hand."

The voice signal of the special sound such as a ringing tone, a warning tone, or a voice message generated by the voice generating block 32 is output to the first or second analog signal multiplexing unit 17 or 2.
At 0, the signal is time-division multiplexed with the call signal (transmitted signal and received signal) output from the simultaneous call processing block 31, and output to the speaker 2 or the transmission processing unit 5.

In this embodiment, the voice communication processing circuit 30 is constituted by a single processor such as a digital signal processor (DSP), and the hardware of the DSP is controlled by dedicated software. A call processing block 31 and a voice generation block 32 are realized. Thus a single processor (DSP)
In order to perform simultaneous call processing and voice generation processing in the voice call processing circuit 30 constituted by the above, the number of parts is reduced as compared with the conventional example in which each processing is performed by combining a plurality of integrated circuits, thereby reducing the manufacturing cost. Reduction can be achieved.

(Embodiment 2) FIG. 3 is a block diagram showing a main part of an indoor communication terminal M of this embodiment. However, components common to the first embodiment are denoted by the same reference numerals, and illustration and description are omitted.

This embodiment has an operation section which can be operated by a caller, and a reception volume control means for controlling the gain of the amplifier 37 with a gain control function on the reception side in accordance with the operation of the operation section. It is characterized in that it is provided in M.

As shown in FIG. 3B, the housing 60 of the indoor communication terminal M is formed of a synthetic resin into a rectangular box shape.
The screen of the monitor unit 3 is exposed at the upper front, and a response button 61 for starting a telephone call in response to a ringing tone is provided at the center of the lower front. Further, the housing 60
An operation unit 62 for operating a rotary switch (not shown) is rotatably disposed at one end of a lower part of the front surface. This rotary switch has three switching positions, and each switching position corresponds to the level of the received sound volume (three levels of large, medium, and small).

The rotary switch is connected to a detection circuit 41, which outputs detection signals of three voltage levels corresponding to three switching positions. The detection signal output from the detection circuit 41 is an A / D converter 42
Is converted into a digital signal and output to the main control unit 50. The main control unit 50 includes a CPU, and performs functions other than those performed by the voice call processing circuit 30, such as monitoring the output of a sensor and controlling the output of an alarm, or a call transmitted from an outdoor call terminal via a signal line. Various functions such as controlling the voice call processing circuit 30 to output a ringing tone or the like when a signal is received are realized by executing dedicated software. That is, in this embodiment, the rotary switch, the operation unit 62, the detection circuit 41, the A / D converter 42, and the main control unit 50 constitute a receiving sound volume gain control unit. The main control unit 50 and the voice call processing circuit 30 including a DSP can communicate with each other via a serial interface.

Thus, the main controller 50 controls the A / D converter 42
When any of the large, medium, and small volume setting data corresponding to the digital detection signal converted in step (1) is transmitted to the voice call processing circuit 30, the voice call processing circuit 30 Is set to a value corresponding to the volume setting data, the reception volume (the volume of the sound audible from the speaker 2) is set to one of the high, medium, and low levels. Therefore, by operating the operation unit 62, a call can be made at a desired volume of the caller, and the usability is improved.

By the way, when the level of the received sound volume is increased, there is a possibility that the loop gain of the closed loop is also increased and howling occurs. Therefore, the transmission volume gain control means for controlling the gain of the amplifier 36 with the gain control function on the transmission side complementarily with the gain of the amplifier 37 with the gain control function on the reception side, which is controlled by the reception volume gain control means, is used. It is desirable to provide the terminal. Here, “complementary” refers to the gain Gr of the receiver-side gain control function amplifier 37 as shown in FIG.
When the gain Gr is increased, the gain Gt is decreased, and when the gain Gr is decreased, the gain Gt is decreased so that the sum of the gains Gt of the amplifiers 36 with gain control functions on the transmitting side is always constant.
This means increasing t.

As shown in the flowchart of FIG. 5, the main control unit 50 reads the detection signal output from the A / D converter 42 at a predetermined cycle (step 1). It is determined whether or not the read detection signal has changed (step 2). If the detection signal has changed, a gain Gr according to the detection signal is calculated (step 3), and the gain of FIG. The gain Gt is calculated based on the relationship (step 4). Then, the calculated setting data (volume setting data) of the gains Gr and Gt is transmitted from the main control unit 50 to the voice call processing circuit 30 (step 5). The gain of each of the amplifiers with gain control function 37, 36 is set in the setting data Gr, Gt, and the volume is adjusted. In addition,
If the currently read detection signal has not changed from the previously read detection signal, the detection signal is read again. That is, in this embodiment, the rotary switch, the operation unit 62, the detection circuit 41, the A / D converter 42, and the main control unit 50 constitute a transmission volume gain control unit.

Since the transmission volume gain control means controls the gain of the amplifier 36 with gain control function on the transmission side complementarily to the gain of the amplifier 37 with gain control function on the reception side,
Even if the level of the receiving sound volume increases, the level of the transmitting sound volume decreases complementarily and the loop gain of the closed loop is always kept substantially constant, so that no howling occurs and the ambient noise level indoors is reduced. When the caller of the indoor communication terminal operates the operation unit 62 to reduce the reception volume because of the small size, the gain of the amplifier 36 with the gain control function on the transmitting side complementarily increases, so that the communication of the outdoor communication terminal can be performed. A comfortable call can be realized by increasing the transmission volume heard by the user.

(Embodiment 3) FIG. 6 is a block diagram showing a main part of an indoor communication terminal M of this embodiment. However, components common to the first and second embodiments are denoted by the same reference numerals, and illustration and description are omitted.

In the present embodiment, a command such as a special sound transmission request or a special sound stop request sent from the main control unit 50 in response to a call from an outdoor call terminal or the like is received, and a call sound or a sound in the voice generation block 32 is received. A process for generating or stopping a special sound such as a melody sound or a specific sound or a voice message is started or stopped, and a response indicating a processing state is received from the voice generation block 32 in response to a processing state response (generating or completing generation of the special sound). A command receiving / response message sending unit 43 for returning a message to the main control unit 50; and an adaptive filter coefficient update of the acoustic echo canceller 33 in the simultaneous call processing block 31 while the special sound is output when the special sound is superimposed during the call. The processing and the operation of the update mode of the total loss amount calculation unit are stopped, and the operation of the update mode is performed in the total loss amount calculation unit. And call processing means serving call control unit 44 for holding the calculated value of the stop just before is provided to the voice communication processing circuit 30.

Here, when an indoor call terminal M is called from any other outdoor call terminal (for example, a door phone handset) during a call with any one of the outdoor call terminals (for example, a lobby intercom), the main control unit 50 A request to send a ringing tone (including a melody tone) is output to the command receiving / response message sending unit 43, and the ringing tone generated by the voice generation block 32 is superimposed on the reception signal without interrupting the call, and the indoor call terminal M is output. And a caller's outdoor call terminal (in this case, a door phone handset) transmits the generated back tone via a signal line. However, the special sound such as a ringing tone superimposed on the received signal during the call becomes a disturbance component for the acoustic echo canceller 33 and the voice switch 35, and thus there is a possibility that the adaptive filter 33a diverges and howling occurs.

Therefore, in the present embodiment, the command receiving / response message sending unit 43 determines whether or not a call is in progress based on the operation of the call control unit 44, and based on the processing status response received from the voice generation block 32. It is determined whether or not the special sound is being generated and output. If it is determined that the telephone is talking and the special sound is being generated and output, the call control unit 44 controls the simultaneous call processing block 31 to control the adaptive filter coefficient of the acoustic echo canceller 33. The update process and the operation of the total loss amount calculation unit in the update mode are stopped, and the total loss amount calculation unit holds the calculated value immediately before the operation of the update mode is stopped. For this reason, the speech control unit 44 stops the adaptive filter coefficient updating process of the acoustic echo canceller 33 and the operation of the update mode of the total loss amount calculating unit during the superposition of the special sound such as the ringing tone which becomes a disturbance component for the acoustic echo canceller 33. By doing so, divergence and howling of the adaptive filter 33a do not occur. Moreover, the call control unit 44 causes the total loss amount calculation unit to hold the calculated value immediately before the stop of the operation in the update mode.
It is possible to avoid a situation in which the total loss amount calculation unit makes an erroneous estimation as if the loop gain of the closed loop fluctuates due to the superposition of the special sound and the calculated value of the total loss amount is not stabilized.

When the special sound is superimposed during a call, the call controller 44 unconditionally controls the simultaneous call processing block 31 to update the adaptive filter coefficient of the acoustic echo canceller 33 and to operate the update mode of the total loss amount calculator. Instead, the simultaneous call processing block 31 is controlled only when the level (volume) of the special sound is equal to or more than a predetermined threshold to update the adaptive filter coefficient of the acoustic echo canceller 33 and update the total loss amount calculation unit. The mode operation may be stopped. In this way, when the level of the special sound is less than the threshold value and is a level that can be ignored by the acoustic echo canceller 33, the adaptive filter coefficient update processing of the acoustic echo canceller 33 and the calculation of the total loss amount even during the superposition of the special sound. The operation of the update mode of the unit can be continued, and even if the characteristics of the echo path fluctuate due to a change in the distance from the microphone 1 or the speaker 2 due to the movement of the caller, the following result can be obtained. There is an advantage that the result is reflected in the calculation result of the total loss amount calculation unit.

Alternatively, the call control unit 44 controls the simultaneous call processing block 31 in accordance with the type of the special sound to stop the adaptive filter coefficient update processing of the acoustic echo canceller 33 and the operation of the update mode of the total loss amount calculation unit. You may do so. That is, the acoustic echo canceller 3 has a special sound superimposed on the received signal like a narrow band signal having a high level.
3 and the operation of the voice switch 35 are determined to be of a type that adversely affects the operation of the voice switch 35 as a disturbance. 31 to stop the adaptive filter coefficient update processing of the acoustic echo canceller 33 and the operation of the total loss amount calculation unit in the update mode. In this way, if the special sound is not of a type that does not adversely affect the adaptive filter coefficient updating process of the acoustic echo canceller 33, the acoustic echo canceller 3 can be used even during the superposition of the special sound.
The adaptive filter coefficient update process of No. 3 and the operation of the update mode of the total loss amount calculation unit are continued, and even if the distance of the microphone 1 or the speaker 2 changes due to the movement of the talker, the echo path characteristics may change. Can follow,
There is an advantage that the follow-up result is reflected also in the calculation result of the total loss amount calculation unit.

(Embodiment 4) FIG. 7 is a block diagram showing a main part of an indoor communication terminal M of this embodiment. However, components common to the first to third embodiments are denoted by the same reference numerals, and illustration and description are omitted.

This embodiment has an operation section which can be operated by a caller, and comprises an image monitor means for activating the image display circuit 4 and displaying an image on the monitor section 3 when the operation section is operated. When the video display circuit 4 is started by the monitor means, the attenuator gain control unit 40 increases the insertion loss of the transmission signal attenuator 38 and decreases the insertion loss of the reception signal attenuator 39 to switch the audio switch 35. It is characterized in that the receiver is forcibly set to the receiving state, and the gain of the amplifier 37 with the gain control function on the receiving side is set to a value larger than that during a call.

That is, the indoor call terminal M displays the image picked up by the image pickup camera of the outdoor call terminal on the monitor section 3 without making a call, and outputs the sound collected by the microphone of the outdoor call terminal from the speaker 2. A so-called monitor function for monitoring the situation near the outdoor call terminal.
A monitor button (operation unit) 63 for activating a monitor function is provided on the housing 60 of the indoor communication terminal M (FIG. 3).
(B), when the monitor button 63 is pressed, a push button switch (not shown) is turned on, and a monitor start signal is input to the main control unit 50 which is a video monitor unit. The control unit 50 activates the image display circuit 4 and causes the monitor unit 3 to display an image.

Further, the main control unit 50 to which the monitor start signal is input gives a command for instructing the voice call processing circuit 30 to operate in the monitor mode. The command reception / response message transmission unit 43 transmits the received command to the call control unit 44. Then, the call control unit 44 controls the simultaneous call processing block 31 according to the command, and the attenuator gain control unit 40 increases the insertion loss of the transmission signal attenuator 38 and decreases the insertion loss of the reception signal attenuator 39. Thus, the voice switch 35 is forcibly set to the receiving state, and the gain of the amplifier 37 with the gain control function on the receiving side is set to a larger value than that during the telephone call. Here, the set value of the gain of the amplifier with gain control function 37 on the receiving side is, for example, a level at which so-called sound leakage is negligible, in which the voice of the other party can be clearly heard and the sound in the dwelling unit can be heard from the speaker of the outdoor communication terminal. And

Since the present embodiment is configured as described above, when the image picked up by the imaging camera of the outdoor call terminal is displayed on the monitor unit 3 of the indoor call terminal M and monitored, the reception volume is forcibly set. The ambient sound of the outdoor call terminal and the voice of the caller of the outdoor call terminal can be clearly heard.

When the gain setting value of the amplifier 37 with the gain control function on the receiving side in the monitor mode is fixed to a predetermined value, if the noise level of the indoor call terminal M in the dwelling unit is large, the ambient sound of the outdoor call terminal or the outdoor There is a possibility that the voice of the caller of the call terminal cannot be clearly heard.

Therefore, as shown in FIG. 8, a near-end side background noise level estimating section 45 for estimating the near-end side (microphone 1 side) background noise level included in the transmission signal, It is desirable that the simultaneous call processing block 31 be provided with a reception volume control section 46 for controlling the gain of the amplifier 37 with a gain control function on the reception side according to the estimated value. The near-end side background noise level estimating unit 45 is realized by an integrator or a digital filter or the like having a characteristic that the rise is gradual and the fall is sharp, and the transmission signal output from the amplifier 36 with the transmission side gain control function. This is for estimating the background noise level that constantly exists in the inside.

If the estimated value of the near-end background noise level is large, the reception volume gain control section 46 increases the gain of the amplifier 37 with the gain control function on the reception side and increases the estimated value of the near-end background noise level. If is smaller, the gain of the amplifier 37 with the gain control function on the receiving side is reduced, so that the image captured by the imaging camera of the outdoor telephone terminal can be used for the indoor telephone terminal M.
In the case of displaying and monitoring on the monitor unit 3, the ambient sound of the outdoor call terminal and the voice of the caller of the outdoor call terminal can be heard at an appropriate volume according to the level of the indoor ambient noise.

(Embodiment 5) FIG. 9 is a block diagram showing a main part of an indoor communication terminal M of this embodiment. However, components common to the first to fourth embodiments are denoted by the same reference numerals, and illustration and description are omitted.

The present embodiment is characterized in that an echo canceller operation control section 47 and a voice switch operation control section 48 are provided in the voice call processing circuit 30.

The echo canceller operation control unit 47 sets the operation mode of the acoustic echo canceller 33 and the line echo canceller 34 to a coefficient update mode in which adaptive filter coefficient update processing is performed, a coefficient fixed mode for fixing adaptive filter coefficients, an adaptive filter coefficient The update process is stopped and the mode is switched to one of the through modes in which the input signal is passed.

The voice switch operation control section 48 determines the operation state of the voice switch 35 as an update state in which the total loss amount calculation section operates in the update mode, a fixed state in which the total loss amount calculation section operates in the fixed mode, and an insertion state. The loss amount distribution processing unit forcibly increases the distribution of the insertion loss amount to the reception signal attenuator 39, and the insertion loss amount distribution processing unit performs the transmission signal attenuator 3 operation.
8 is switched to any one of the forced listening state in which the distribution of the insertion loss amount to the forcible listening position 8 is forcibly increased.

That is, when performing an operation test on the echo cancellers 33, 34, the operation mode of the echo cancellers 33, 34 is set to one of the coefficient update mode, the fixed coefficient mode, and the through mode according to the type of the operation test. There is a need to. Similarly, when performing an operation test on the voice switch 35, the voice switch 3 is set to any of the update state, the fixed state, the forced transmission state, and the forced reception state.
It is necessary to set the operation state of No. 5.

The type (test mode) of the operation test for the echo cancellers 33 and 34 and the voice switch 35 is specified by the command by the main control unit 50, and the command received via the command reception / response message transmission unit 43 Since the echo canceller state control unit 47 and the voice switch state control unit 48 set the operation mode of the echo cancellers 33 and 34 and the operation state of the voice switch 35 in accordance with the test mode specified in the above, the acoustic echo canceller 33 and the line echo There is an advantage that the operation test of the canceller 34 and the operation test of the voice switch 35 can be easily performed.

[0077]

According to the first aspect of the present invention, there is provided an indoor call terminal provided with a microphone and a speaker and installed in a dwelling unit,
A communication path connected to one or more outdoor communication terminals having a microphone and a speaker and installed outside the house, wherein at least one outdoor communication terminal includes an imaging camera for imaging a caller and an imaging camera A video signal processing means for displaying a video signal transmitted through the communication path to the video signal signal transmitted through the communication path and displaying the video on the display means; Means for monitoring the output of one or more sensors installed in the dwelling unit for detecting an abnormality such as a fire or gas leak, and detecting the abnormality when any of the sensors detects the abnormality. Loudspeaker system that outputs an alarm message or an alarm sound corresponding to a voice from a speaker, transmits the message to an outdoor call terminal via a communication path, and outputs from the speaker of the outdoor call terminal. The indoor call terminal includes a simultaneous call processing block for performing a process for realizing a two-way simultaneous call with each outdoor call terminal via a communication path, and a speaker for receiving a call from the outdoor call terminal. , A back tone transmitted via a communication path to a calling outdoor call terminal, and a voice generation block for generating an alarm message and an alarm sound, which are constituted by a single processor. Since it is equipped with a call processing circuit, the simultaneous call processing and voice generation processing are performed by a voice call processing circuit composed of a single processor, so that it is compared with the conventional example in which each processing is performed by combining a plurality of integrated circuits. As a result, there is an effect that the number of parts can be reduced and the manufacturing cost can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the simultaneous call processing block comprises: an acoustic echo canceller for canceling an acoustic echo generated by acoustic coupling between a microphone and a speaker provided in the indoor call terminal; A line echo canceller for canceling a line echo generated by acoustic coupling or a signal wraparound through a communication path, and an acoustic echo path and a closed loop formed by the line echo path provided between the line echo canceller and the line echo canceller. A voice switch that suppresses howling by reducing loop gain, and an amplifier with a gain control function provided on a signal path of a transmission signal and a reception signal sandwiched between an acoustic echo canceller and a line echo canceller; The switch inserts a loss into the signal path of the transmitting side. Side loss insertion means, reception side loss insertion means for inserting a loss into the signal path on the reception side, and insertion loss amount control means for controlling the amount of loss inserted from each of the loss insertion means on the transmission side and the reception side. The insertion loss control means estimates the acoustic feedback gain of the path that returns from the output point of the receiving-side loss inserting means to the input point of the transmitting-side loss inserting means via the acoustic echo path, and Estimating the line-side feedback gain of the path that returns from the output point of the loss insertion means to the input point of the receiving-side loss insertion means via the line echo path,
A total loss amount calculation unit that calculates the total loss amount to be inserted into the closed loop based on the estimated value of each feedback gain on the sound side and the line side, and monitors a transmission signal and a reception signal to estimate a call state, An insertion loss amount distribution processing unit that determines the distribution of each insertion loss amount of the transmission side loss insertion unit and the reception side insertion loss unit according to the estimation result and the calculated value of the total loss amount calculation unit,
The total loss amount calculation unit calculates the sum of the loss amounts to be inserted into the closed loop based on the estimated values of the respective feedback gains and adaptively updates the update mode, and the fixed mode in which the total loss amount is fixed to a predetermined initial value. It has two operation modes, operates in the fixed mode during the period from the start of communication with the outdoor call terminal to the time when the acoustic echo canceller and the line echo canceler are sufficiently converged, and the sound echo canceler and the line echo canceler are sufficiently converged. In the period after the operation, the operation is performed in the update mode. Therefore, in a state where the acoustic echo canceller and the line echo canceller have not converged immediately after the start of the call, the total loss amount is sufficiently increased by the total loss amount calculation unit operating in the fixed mode. Since it is fixed to a large initial value, unpleasant echo and howling can be suppressed to achieve stable half-duplex calls, In a state where Kokyansera and line echo canceller is sufficiently converged, the total loss by total loss amount calculation unit that operates in the update mode has the effect of simultaneous calls bidirectional in order to be updated from time to time can be realized. Also, by setting the gains of the amplifiers with a gain control function on the transmitting side and the receiving side to appropriate values, a desired call volume can be obtained, and a gain control function is provided when an excessive level of sound is input. There is an effect that the saturation processing of the amplifier can prevent a problem such as an overflow in the voice communication processing circuit from occurring.

According to a third aspect of the present invention, in the second aspect of the present invention, there is provided a receiver which has an operation section operable by a caller and controls the gain of the amplifier with a gain control function on the receiving side in accordance with the operation of the operation section. Since the volume gain control means is provided in the indoor call terminal, there is an effect that a call can be made at a desired volume of the caller.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the gain of the amplifier with the gain control function on the receiving side controlled by the receiving volume gain control means is complementary to the gain of the amplifier with the gain control function on the transmitting side. Since the transmission volume gain control means for controlling the gain is provided in the indoor communication terminal, even if the reception volume increases, the transmission volume level decreases complementarily and the closed loop gain is always kept substantially constant. There is no howling due to dropping, and the gain control function on the transmitting side when the talker of the indoor call terminal operates the operation unit to reduce the receiving volume because the indoor ambient noise level is low. By increasing the gain of the amplifier in a complementary manner, it is possible to increase the transmission sound volume that can be heard by the caller of the outdoor call terminal, thereby achieving a comfortable call.

According to a fifth aspect of the present invention, in the second aspect of the present invention, the voice generation block is configured to perform a call when an indoor call terminal is called from another outdoor call terminal during a call with any one of the outdoor call terminals. The ringing tone generated without interrupting the call is superimposed on the reception signal and output from the speaker of the indoor communication terminal, and the generated back tone is transmitted to the calling side outdoor communication terminal via the communication path. While the ringing tone is being output when the ringing tone is superimposed, the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous call processing block and the operation of the update mode of the total loss amount calculating unit are stopped, and the total loss amount calculating unit is stopped. Is provided in the voice call processing circuit with the call processing means for holding the calculated value immediately before the stop of the operation in the update mode, so that the call which becomes a disturbance component for the acoustic echo canceller The speech processing means stops the adaptive filter coefficient update processing of the acoustic echo canceller and the operation of the update mode of the total loss amount calculation unit during the superimposition of the acoustic echo canceller, thereby preventing divergence and howling of the adaptive filter. In order to cause the total loss amount calculation unit to hold the calculated value immediately before the stop of the operation in the update mode, whether the total loss amount calculation unit fluctuates the closed loop gain (echo path gain) as a result of the superposition of the ringing tone Thus, there is an effect that it is possible to avoid a situation where the erroneous estimation is performed and the calculated value of the total loss amount is not stabilized.

According to a sixth aspect of the present invention, in the invention of the fifth aspect, the speech processing means updates the adaptive filter coefficient of the acoustic echo canceller in the simultaneous speech processing block only when the ringing tone level is equal to or higher than a predetermined threshold. Since the operation of the update mode of the total loss amount calculation unit is stopped, if the ringing tone level is less than the threshold value and is a level that can be ignored by the acoustic echo canceller, the adaptive filter coefficient of the acoustic echo canceller even during the superposition of the ringing tone The update process and the operation in the update mode of the total loss amount calculation unit are continued, so that even if the characteristics of the echo path fluctuate due to a change in the distance between the microphone and the speaker due to movement of the caller, it is possible to follow the change. This has the effect that the follow-up result is also reflected in the calculation result of the total loss amount calculation unit.

According to a seventh aspect of the present invention, in the fifth aspect of the present invention, the speech processing means updates the adaptive filter coefficient of the acoustic echo canceller in the simultaneous speech processing block and the total loss amount calculation section in accordance with the type of ringing tone. Since the operation in the update mode is stopped, if the ringing tone is not of a type that does not adversely affect the adaptive filter coefficient updating process of the acoustic echo canceller, the adaptive filter coefficient updating process of the acoustic echo canceller and the overall The operation of the update mode of the loss amount calculation unit is continued, and even if the characteristics of the echo path fluctuate due to a change in the distance between the microphone and the speaker due to movement of the caller, it can follow the change, and the result of the follow-up Is also reflected in the calculation result of the total loss amount calculation unit.

According to an eighth aspect of the present invention, in the second aspect of the present invention, the voice generation block includes a special function such as an alarm message or an alarm sound when the indoor communication terminal is in communication with any of the outdoor communication terminals. A special sound generated without generating a sound and without interrupting the call is superimposed on the reception signal and output from the speaker of the indoor call terminal, and while the special sound is being output during the superposition of the special sound during the call, The voice call processing circuit is provided with a call processing means for stopping the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous call processing block and the operation of the update mode of the total loss amount calculation unit. The speech processing means stops the operation of the adaptive filter coefficient update processing of the acoustic echo canceller and the operation of the update mode of the total loss amount calculation unit during the superposition of the sound. There is no divergence or howling of the adaptive filter, and the call processing means causes the total loss amount calculation unit to hold the calculated value immediately before the stop of the operation in the update mode. However, there is an effect that it is possible to avoid a situation in which the erroneous estimation is performed as if the loop gain (echo path gain) of the closed loop fluctuates and the calculated value of the total loss amount is not stabilized.

According to a ninth aspect of the present invention, in the invention of the eighth aspect, the speech processing means updates the adaptive filter coefficient of the acoustic echo canceller in the simultaneous speech processing block only when the level of the special sound is equal to or higher than a predetermined threshold. Since the operation of the update mode of the total loss amount calculation unit is stopped, if the level of the special sound is less than the threshold value and is a level that can be ignored by the acoustic echo canceller, the adaptive filter coefficient of the acoustic echo canceller even during the superposition of the special sound. The update process and the operation in the update mode of the total loss amount calculation unit are continued, and even if the characteristics of the echo path fluctuate due to a change in the distance between the microphone and the speaker due to the movement of the caller, it can be followed. This has the effect that the follow-up result is also reflected in the calculation result of the total loss amount calculation unit.

According to a tenth aspect of the present invention, in the invention of the eighth aspect, the speech processing means includes an adaptive filter coefficient update process of the acoustic echo canceller in the simultaneous speech processing block and a total loss amount calculation unit in accordance with the type of the special sound. Since the operation in the update mode is stopped, if the special sound is not of a type that does not adversely affect the adaptive filter coefficient update processing of the acoustic echo canceller, the adaptive filter coefficient update processing of the acoustic echo canceller and the total The operation of the update mode of the loss amount calculation unit is continued, and even if the characteristics of the echo path fluctuate due to movement of the caller and change in the distance to the microphone or speaker, it is possible to follow the change.
There is an effect that the following result is reflected also in the calculation result of the total loss amount calculation unit.

According to an eleventh aspect of the present invention, in accordance with the second aspect of the present invention, there is provided an operation unit operable by a caller, and when the operation unit is operated, the video signal processing unit is activated to display an image on the display unit. Video loss monitoring means, wherein the insertion loss control means increases the insertion loss of the transmission-side loss insertion means and increases the insertion loss of the reception-side loss insertion means when the video monitoring means activates the video signal processing means. And the voice switch is forcibly set to the receiving state, and the amplifier with the gain control function on the receiving side is set to a large gain as compared with the time of the telephone call. When displaying and monitoring on the display means of the indoor call terminal, the reception volume is forcibly increased so that the ambient sound of the outdoor call terminal and the voice of the caller of the outdoor call terminal can be clearly heard.

In a twelfth aspect of the present invention, in the eleventh aspect, a near-end side background noise level estimating means for estimating a near-end side background noise level included in the transmission signal, Since the voice communication processing circuit is provided with a reception volume control circuit for controlling the gain of the amplifier having a gain control function on the reception side in accordance with the estimated value, the image captured by the imaging camera of the outdoor communication terminal is displayed on the indoor communication terminal. When displaying and monitoring on the means, there is an effect that the ambient sound of the outdoor call terminal and the voice of the caller of the outdoor call terminal can be heard at an appropriate volume according to the level of the indoor ambient noise.

According to a thirteenth aspect of the present invention, in the second aspect, the operation modes of the acoustic echo canceller and the line echo canceller are changed to a coefficient update mode in which an adaptive filter coefficient update process is performed, and a coefficient fixed mode in which an adaptive filter coefficient is fixed. Since the indoor call terminal is provided with the echo canceller operation control means for stopping the adaptive filter coefficient update process and switching to any of the through modes for passing the input signal,
There is an effect that operation tests of the acoustic echo canceller and the line echo canceller can be easily performed.

According to a fourteenth aspect of the present invention, in the second aspect of the present invention, the operation state of the voice switch is set to an update state in which the total loss amount calculation section operates in the update mode, and a fixed state in which the total loss amount calculation section operates in the fixed mode. The state, the insertion loss amount distribution processing unit forcibly increases the distribution of the insertion loss amount to the receiving side insertion loss means, the forced transmission state, the insertion loss amount distribution processing unit, the insertion loss amount to the transmission side insertion loss means Is provided in the voice call processing circuit, so that the operation test of the voice switch can be easily performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main part of an indoor call terminal according to a first embodiment.

FIG. 2 is a block diagram showing a simultaneous call processing block in the embodiment.

FIG. 3 shows an indoor call terminal according to the second embodiment,
(a) is a block diagram of a main part, and (b) is an external view.

FIG. 4 is an explanatory diagram of the operation of the indoor call terminal in the above.

FIG. 5 is a flowchart for explaining the operation of the indoor call terminal in the above.

FIG. 6 is a block diagram illustrating a main part of an indoor call terminal according to a third embodiment.

FIG. 7 is a block diagram illustrating a main part of an indoor call terminal according to a fourth embodiment.

FIG. 8 is a block diagram showing a simultaneous call processing block in the embodiment.

FIG. 9 is a block diagram illustrating a main part of an indoor call terminal according to a fifth embodiment.

FIG. 10 is a system configuration diagram of a voice communication system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microphone 2 Speaker 3 Monitor part 4 Video display circuit 30 Voice call processing circuit 31 Simultaneous call processing block 32 Voice generation block

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yuko Maeda 1048 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Works Co., Ltd. Terms (reference) 5D020 CC06 5D045 AB26 5K027 AA09 BB14 FF12 HH03 JJ03 JJ07 5K038 AA01 CC03 CC13 DD01 DD18 EE13 FF10 GG02

Claims (14)

[Claims] 1. An indoor communication terminal provided with a microphone and a speaker and installed in a dwelling unit, and one or more outdoor communication terminals provided with a microphone and a speaker and installed outside a dwelling unit connected by a communication path. And at least one
The two outdoor call terminals include an imaging camera for imaging the caller and transmit a video signal captured by the imaging camera to the indoor call terminal via the communication path, and the indoor call terminal transmits the video signal transmitted via the communication path. And a display means for displaying an image on the display means by signal processing, and monitors the output of one or more sensors installed in the dwelling unit and detecting an abnormality such as a fire or gas leak. ,
When an abnormality is detected by any of the sensors, an alarm message or an alarm sound corresponding to the content of the detected abnormality is output from the speaker and transmitted to the outdoor call terminal via the communication path to be transmitted from the speaker of the outdoor call terminal. In the loudspeaker call system that is output, the indoor call terminal includes a simultaneous call processing block for performing a process for realizing a two-way simultaneous call via the communication path with each of the outdoor call terminals; The ring tone output from the speaker upon receiving the call, the back tone transmitted via the communication path to the calling outdoor calling terminal, and the voice generation block for generating the alarm message and the alarm sound are a single unit. A voice call system comprising a voice call processing circuit constituted by a processor. 2. The simultaneous call processing block includes: an acoustic echo canceller for canceling an acoustic echo generated by acoustic coupling between a microphone and a speaker included in the indoor call terminal;
A line echo canceller for canceling a line echo caused by acoustic coupling in an outdoor call terminal or a signal wraparound via a communication path; and an acoustic echo canceller and a line echo canceller. A voice switch that suppresses howling by reducing the loop gain of a closed loop, and an amplifier with a gain control function provided on a signal path of a transmission signal and a reception signal sandwiched between an acoustic echo canceller and a line echo canceller. The voice switch includes a transmitting-side loss inserting unit that inserts a loss into the transmitting-side signal path, a receiving-side loss inserting unit that inserts a loss into the receiving-side signal path,
Insertion loss amount control means for controlling the amount of loss inserted from each of the loss insertion means on the transmission side and the reception side, and the insertion loss amount control means is provided via an acoustic echo path from an output point of the reception side loss insertion means. Of the acoustic feedback gain of the path returning to the input point of the transmitting-side loss inserting means, and returning from the output point of the transmitting-side loss inserting means to the input point of the receiving-side loss inserting means via the line echo path. A total loss amount calculating unit for estimating a line-side feedback gain of a path to be transmitted, and calculating a total of loss amounts to be inserted into a closed loop based on the estimated values of the feedback gains on the acoustic side and the line side; A signal is monitored to estimate a communication state, and an insertion loss for determining a distribution of each insertion loss amount of the transmitting-side loss inserting unit and the receiving-side insertion loss unit according to the estimation result and the value calculated by the total loss amount calculating unit. Volume distribution processing section, and the total loss The output unit performs two operations: an update mode in which the sum of the loss amounts to be inserted into the closed loop is calculated based on the estimated values of the respective feedback gains and an adaptive update is performed, and a fixed mode in which the total loss amount is fixed to a predetermined initial value. A fixed mode during the period from the start of communication with the outdoor call terminal to the time when the acoustic echo canceller and the line echo canceler are sufficiently converged, and after the sound echo canceller and the line echo canceler are sufficiently converged. The voice call system according to claim 1, wherein the system operates in an update mode during a period. 3. An indoor communication terminal having an operation unit operable by a caller and receiving sound volume gain control means for controlling the gain of an amplifier with a gain control function on the receiving side according to operation of the operation unit. 3. The loudspeaker system according to claim 2, wherein: 4. A transmission volume gain control means for controlling the gain of an amplifier with a gain control function on the transmission side complementarily to the gain of an amplifier with a gain control function on the reception side controlled by the reception volume gain control means. 4. The loudspeaker system according to claim 3, wherein the loudspeaker system is provided in a call terminal. 5. A voice generating block comprising: a ringing signal generated without interrupting a call when an indoor call terminal is called from another outdoor call terminal during a call with one of the outdoor call terminals; Is output from the speaker of the indoor call terminal while being superimposed on the call, and the generated back tone is transmitted to the caller's outdoor call terminal via the communication path. During the period, the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous call processing block and the operation of the update mode of the total loss amount calculation unit are stopped, and the calculated value immediately before the stop of the update mode operation is held in the total loss amount calculation unit. 3. A loudspeaker system according to claim 2, wherein said call processing means is provided in said voice call processing circuit. 6. The call processing means stops the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous call processing block and the operation in the update mode of the total loss amount calculation unit only when the ringing tone level is equal to or higher than a predetermined threshold value. The voice call system according to claim 5, wherein 7. The speech processing means according to the type of ringing tone, stops the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous speech processing block and the operation of the update mode of the total loss amount calculation unit. The voice call system according to claim 5. 8. The voice generation block generates a special sound such as an alarm message or an alarm sound as needed during a call between the indoor call terminal and any of the outdoor call terminals, and does not interrupt the call. The generated special sound is superimposed on the reception signal and output from the speaker of the indoor call terminal, and the adaptive filter coefficient of the acoustic echo canceller in the simultaneous call processing block while the special sound is output when the special sound during the call is superimposed. 3. A loudspeaker system according to claim 2, wherein said speech processing circuit includes a speech processing means for stopping the updating process and the operation of the update mode of said total loss amount calculator. 9. The call processing means stops the operation of the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous call processing block and the operation of the update mode of the total loss amount calculation unit only when the level of the special sound is equal to or higher than the predetermined threshold value. 9. The loudspeaker system according to claim 8, wherein: 10. The speech processing means stops the operation of the adaptive filter coefficient update processing of the acoustic echo canceller in the simultaneous speech processing block and the operation of the update mode of the total loss amount calculation unit in accordance with the type of the special sound. Claim 8
Loudspeaker call system as described. 11. An insertion loss amount control means, comprising: an operation part operable by a caller; and video monitor means for activating a video signal processing means to display an image on a display means when the operation part is operated. Means that when the video signal processing means is activated by the video monitor means, the insertion loss of the transmission side loss insertion means is increased and the insertion loss amount of the reception side loss insertion means is reduced, so that the voice switch is forcibly set to the receiving state. 3. The loudspeaker communication system according to claim 2, wherein the gain of the amplifier with the gain control function on the receiving side is set to be larger than that of the amplifier during a call. 12. A near-end background noise level estimating means for estimating a near-end background noise level included in a transmission signal, and a receiver-side gain control function according to an estimated value of the near-end background noise level. 2. The voice call processing circuit according to claim 1, further comprising a receiving volume control means for controlling a gain of the amplifier.
1. The loudspeaker system according to 1. 13. The operation modes of an acoustic echo canceller and a line echo canceller are: a coefficient update mode in which adaptive filter coefficient update processing is performed, a coefficient fixed mode in which adaptive filter coefficients are fixed, and an input signal by stopping adaptive filter coefficient update processing. 3. The loudspeaker communication system according to claim 2, wherein an echo canceller operation control means for switching to any one of a through mode for passing the signal is provided in the indoor communication terminal. 14. The operation state of the voice switch is: an update state in which the total loss amount calculation section operates in the update mode; a fixed state in which the total loss amount calculation section operates in the fixed mode; In the forced transmission state in which the distribution of insertion loss to the loss means is forcibly increased, and in the forced reception state in which the insertion loss distribution processing unit forcibly increases the distribution of insertion loss to the transmitting side insertion loss means. 3. The loudspeaker communication system according to claim 2, wherein the voice switch operation control means for switching to any one is provided in the voice call processing circuit.