JP5070073B2 - Intercom system - Google Patents

Description

  The present invention relates to an interphone system that establishes a call by transmitting and receiving an audio signal between an entrance cordless handset and a room base phone connected via a wired transmission path or a wireless transmission path, and in particular, improves call quality. Related to the intercom system.

  Conventionally, in loudspeaker devices (interphones, telephones, PHS, etc.) used in homes, offices, factories, etc., whether or not a reference signal includes an audio signal with high accuracy even under a high background noise level. An audio detector that can be detected is disclosed (for example, see Patent Document 1).

  According to this sound detector, the sound signal is included in the reference signal due to the fact that the ratio between the sound component emitted by the near-end speaker and the other background noise component in the sound signal collected by the microphone becomes small. Even if it is included, it is possible to reduce the situation where the audio signal cannot be detected, and it is possible to accurately detect whether the reference signal is an audio signal even under a situation where the background noise level is high.

  Further, as another background technology capable of accurately detecting whether or not the reference signal is an audio signal like the above-described audio detector, the power of a specific frequency of the data signal (agreeing with the reference signal) is used. An intercom system of Japanese Patent Application No. 2007-223687 has been filed that can determine whether the type of data signal is a silence signal or a (sounded) audio signal according to the number of spectrums.

JP 2000-305579 A

  According to the sound detector disclosed in Japanese Patent Laid-Open No. 2000-305579 and the interphone system disclosed in Japanese Patent Application No. 2007-223687 described in the background art, the type of the reference signal / data signal is a silent signal or a (sounded) sound signal. For example, the reference signal / data signal having a high frequency component such as a frictional sound and a low output level cannot be detected / determined as a sound signal with a certain frequency band. This caused the voice of the call to be cut off and the call quality was degraded.

  The present invention has been made to solve this problem, and by adding a frequency band characteristic to a voice signal that can be discriminated as a voiced signal, an erroneous discrimination of a voice signal that causes a headache in a call voice is performed. The purpose is to provide an intercom system that prevents call quality and improves call quality.

In order to achieve the above object, an interphone system according to a first aspect of the present invention is connected to an entrance cordless handset having a handset microphone and handset speaker via a wired transmission path or a wireless transmission path. And a room base unit having a base unit microphone and a base unit speaker for inputting / outputting a voice signal for establishing a call between the handset microphone and the handset speaker of the main unit. In the living room master unit, the analog audio signal sent to the base unit microphone is converted into a digital audio signal to be sent, and the input signal is sent to the cordless handset microphone and transmitted via the transmission path. The base unit voice codec for digital / analog conversion of the incoming digital voice signal to the received analog voice signal and output from the base unit speaker, and the transmission line transmitted from the base unit voice codec to the transmission line And a voice processing unit for varying the signal voltage of the digital voice signal and the signal voltage of the received analog voice signal transmitted through the transmission line from the transmission path to the master voice codec. The voice processing unit of the room master unit includes a transmitter attenuator for attenuating the signal voltage of the transmitted digital audio signal, a receiver attenuator for attenuating the signal voltage of the received digital audio signal, and the transmitted digital audio. A transmission side band division processing circuit for dividing a signal into a plurality of frequency bands, a reception side band division processing circuit for dividing a received digital audio signal into a plurality of frequency bands, and a transmission side band division processing circuit. A transmission-side noise level calculation circuit for calculating a noise level of a transmitted digital audio signal divided into a plurality of frequency bands based on a predetermined transmission-side threshold corresponding to the plurality of frequency bands ; computing a noise level of the received digital speech signal divided into a plurality of frequency bands on the side band division processing circuit based on the predetermined receiver side threshold corresponding to the plurality of frequency bands Receiver side noise level arithmetic circuit and transmitter side signal discrimination circuit for discriminating whether the transmitted digital voice signal is a silence signal or a voice signal based on the calculation result of the transmitter side noise level arithmetic circuit A reception side signal determination circuit for determining whether the received digital audio signal is a silence signal or a sound signal based on the calculation result of the reception side noise level calculation circuit, a transmission side signal determination circuit, and a reception side An attenuation level control circuit is provided for controlling the attenuation level of the transmission side attenuator and the attenuation level of the reception side attenuator based on the determination result of the signal determination circuit.

  The interphone system according to the second aspect of the present invention is the interphone system according to the first aspect of the present invention, wherein the audio processing unit of the living room base unit includes a plurality of frequency bands divided by the transmission side band division processing circuit. A transmission side equalizer for adjusting the amplitude / frequency characteristics of the receiver, and a reception side equalizer for adjusting the amplitude / frequency characteristics of a plurality of frequency bands divided by the reception side band division processing circuit.

  According to the intercom system of the present invention, an incoming call is received from a master unit speaker of a base unit connected to the entrance unit via a wired transmission line or a wireless transmission line. Receiver digital audio signal to be output as voice, and input to the base unit microphone of the home base unit, and connected to the home base unit via a wired transmission line or a wireless transmission path. Each of the digital audio signals on the transmitting side to be output as the received voice from is divided into a plurality of frequency bands by the band division processing circuit constituting the voice processing unit of the living room master unit, and the digital divided into the plurality of frequency bands With respect to the audio signal, a silence signal or a sound signal can be determined by a signal determination circuit based on a threshold value set in advance for each frequency band. As a result, for example, even a signal having a high frequency component such as a frictional sound and a low output level can be discriminated as a sound signal with high accuracy. Occurrence of head breaks is prevented and call quality is improved.

  In addition, according to the intercom system of the present invention, the amplitude and frequency characteristics of the receiving digital audio signal and the transmitting digital audio signal divided into a plurality of frequency bands are adjusted via the respective equalizers, The operation of discriminating a silence signal or a voice signal in the signal discrimination circuit can be performed stably and with high accuracy.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments to which an intercom system of the invention is applied will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an intercom system according to an embodiment of the present invention. This intercom system is installed outside the dwelling unit, and the entrance cordless handset 1 for a visitor to call a resident in the dwelling unit to establish a call, and the dwelling unit installed in the dwelling unit, and the wired transmission line L1a or There is provided a room master unit 2 for a resident who has responded to a call from the front cordless handset 1 connected via the wireless transmission line L1b to establish a call with the visitor.

  Further, the entrance slave unit 1 includes a slave unit operation unit 100, a camera 101, a slave unit video processing unit 102, a slave unit microphone 103, a slave unit speaker 104, a slave unit audio codec 105, and a slave unit I / F (interface) 106. Is provided.

  In this entrance child device 1, the child device operation unit 100 is operated by a visitor to call a resident, and is configured by, for example, a call button.

  The camera 101 is for capturing an image of a visitor who has performed a call operation and an image in the vicinity of the outside of the dwelling unit (including a monitoring image). It is configured. The slave unit video processing unit 102 is for performing predetermined signal processing such as FM modulation and amplification on the video signal that is a video captured by the camera 101.

  The handset microphone 103 and handset speaker 104 are for inputting and outputting analog voices (transmitted voice and received voice) for a visitor to establish a call with a resident. The handset audio codec 105 performs analog / digital conversion of an analog voice signal, which is a transmission voice input to the handset microphone 103, into a digital voice signal, and inputs it to a base unit microphone 202 (to be described later) of the room base unit 2. The digital audio signal, which is the received voice transmitted via the wired transmission path L1a or the wireless transmission path L1b, is converted into an analog audio signal by digital / analog conversion and output from the handset speaker 104. .

  The slave unit I / F 106 is a signal transmission line from the slave unit operation unit 100 to the wired transmission path L1a or the wireless transmission path L1b, and from the slave unit video processing unit 102 to the wired transmission path L1a or the wireless transmission path L1b. And a signal transmission line between the cordless handset audio codec 105 and the wired transmission path L1a, or a signal transmission line between the cordless handset voice codec 105 and the wireless transmission path L1b, respectively. .

  Further, the living room master unit 2 includes a monitor 200, a master unit video processing unit 201, a master unit microphone 202, a master unit speaker 203, a master unit audio codec 204, an audio processing unit 205, a master unit operation unit 206, a CPU 207, and a master unit. An I / F 208 is provided.

  In this room master 2, the monitor 200 is controlled by the CPU 207 to display an image, and is displayed by a call display indicating that a visitor has called from the door 1 and the camera 101 of the door 1. For example, it is configured by various image display media such as an LCD, a PDP, and an organic EL display. The master image processing unit 201 is controlled by the CPU 207, and for example, FM demodulation, amplification, etc., for video signals transmitted from the entrance unit 1 via the wired transmission path L1a or the wireless transmission path L1b. The predetermined signal processing is performed, and the image captured by the camera 101 of the front door 1 is displayed on the monitor 200.

  The base unit microphone 202 and the base unit speaker 203 are for inputting / outputting analog voices (transmitted voices, received voices) for a resident to establish a call with a visitor. In addition to the above-described call function, a call notification indicating that there is a call from the entrance cordless handset 1 by a visitor can be performed. The master unit audio codec 204 is controlled by the CPU 207 to convert an analog audio signal, which is a transmission voice input to the master unit microphone 202, into a digital audio signal, and to convert the analog unit into a digital audio signal. A digital audio signal, which is a received voice that is input to 103 and transmitted via a wired transmission path L1a or a wireless transmission path L1b, is converted from analog to digital into an analog audio signal and output from the master speaker 203. Is.

  The voice processing unit 205 is controlled by the CPU 207, and is transmitted digitally via the transmission line L2a from the main unit audio codec 204 to the wired transmission line L1a or the wireless transmission line L1b via the main unit I / F 208. The signal voltage of the audio signal, and the signal voltage of the received analog audio signal transmitted from the wired transmission line L1a or the wireless transmission line L1b to the main unit audio codec 204 via the main unit I / F 208 and the reception line L2b Is for making each variable.

  The master unit operation unit 206 detects the operation by the CPU 207, and a resident who has confirmed that a visitor has called from the entrance slave unit 1 responds, and establishes a call using the master unit microphone 202 and the master unit speaker 203. For example, a response operation for making a call or an end call operation for ending a call that has been established, for example, is constituted by a call button. As the master unit operation unit 206, a push button provided on the casing surface (not shown) of the living room master unit 2, a touch panel (not shown) provided on the front surface of the monitor 200, and the like are suitable.

  The CPU 207 is for controlling each component of the living room base unit 2. Further, the base unit I / F 208 includes a signal transmission line from the wired transmission path L1a or the wireless transmission path L1b to the base unit video processing unit 201, and the wired transmission path L1a and (the transmission line L2a or the reception line L2b). A signal transmission line between the parent device voice switch 205 or a wireless transmission path L1b and a signal transmission line between the parent device voice switch 205 (via the transmission line L2a or the reception line L2b) This is to form a signal transmission line between the transmission line L1a and the CPU 207 or a signal transmission line between the wireless transmission line L1b and the CPU 207, respectively.

  Next, a specific configuration of the voice processing unit 205 of the living room master unit 2 will be described with reference to the block diagram of FIG. The speech processing unit 205 includes a transmission side amplifier 250a, a transmission side attenuator 251a, a transmission side band division processing circuit 252a, a transmission side equalizer 253a, a transmission side noise level calculation circuit 254a, and a transmission side signal determination circuit. 255a, a reception side amplifier 250b, a reception side attenuator 251b, a reception side band division processing circuit 252b, a reception side equalizer 253b, a reception side noise level calculation circuit 254b, a reception side signal determination circuit 255b, and an attenuation level control circuit 256. It has been.

  In the voice processing unit 205, the transmission side amplifier 250a is provided on the transmission line L2a from the master unit audio codec 204 to the master unit I / F 208, and is a digital voice signal (send digital audio signal) that is a transmission voice. ). The receiver-side amplifier 250b is provided on the reception line L2b from the master unit I / F 208 to the master unit voice codec 204, and amplifies a digital voice signal (received digital voice signal) that is a received voice. .

  The transmission side attenuator 251a is provided on the transmission line L2a from the transmission side amplifier 250a to the base unit I / F 208, and attenuates the signal voltage of the digital audio signal (transmission digital audio signal) which is the transmission audio. In this case, the attenuation level is controlled by the attenuation level control circuit 256. In addition, the reception side attenuator 251b is provided on the reception line L2b from the reception side amplifier 250b to the base unit audio codec 204, and this attenuates the signal voltage of the digital voice signal (received digital voice signal) that is the reception voice. The attenuation level is controlled by the attenuation level control circuit 256.

  The transmission side band division processing circuit 252a converts the transmission digital audio signal amplified via the transmission side amplifier 250a into a plurality of frequency bands, for example, “300 Hz <F1a ≦ 500 Hz” of the low frequency band F1a, medium frequency The frequency F2a is divided into three frequency bands such as “500 Hz <F2a ≦ 2 kHz” and the high frequency band F3a “2 kHz <F3a ≦ 5 kHz”. The high frequency band F3a “5 kHz” A half value of the sampling frequency is shown. Further, the reception side band division processing circuit 252b converts the received digital audio signal amplified via the reception side amplifier 250b into a plurality of frequency bands, for example, “300 Hz <F1b ≦ 500 Hz” of the low frequency band F1b, medium frequency band This is for dividing into three frequency bands such as “500 Hz <F2b ≦ 2 kHz” of F2b and “2 kHz <F3b ≦ 5 kHz” of high frequency band F3b. “5 kHz” of high frequency band F3b is sampling. A half value of the frequency is shown. The division processing into a plurality of frequency bands performed by the transmission side band division processing circuit 252a and the reception side band division processing circuit 252b is limited to the above-described division into the three frequency bands. If it is two or more frequency bands, it can be arbitrarily divided into a plurality of frequency bands.

  The transmission side equalizer 253a is for adjusting the amplitude and frequency characteristics of the three frequency bands divided by the transmission side band division processing circuit 252a, and is integrated with the transmission side band division processing circuit. Can be provided. The receiver-side equalizer 253b is for adjusting the amplitude / frequency characteristics of the three frequency bands divided by the receiver-side band division processing circuit 252b, and is provided integrally with the reception-side band division processing circuit. be able to.

  The transmission side noise level calculation circuit 254a is divided into three types of frequency bands by the transmission side band division processing circuit 252a, and the transmission digital sound whose amplitude and frequency characteristics are adjusted via the transmission side equalizer 253a. This is for calculating the noise level of the signal. In addition, the receiving side noise level calculation circuit 254b is divided into three types of frequency bands by the receiving side band division processing circuit 252b, and the received digital audio signal whose amplitude and frequency characteristics are adjusted via the receiving side equalizer 253b. This is for calculating the noise level.

  The transmission side signal discrimination circuit 255a is a silent signal obtained by adjusting the amplitude / frequency characteristics of the transmission side audio level signal via the transmission side equalizer 253a based on the calculation result of the transmission side noise level calculation circuit 254a. Or it is for discriminating whether it is a sound signal. In addition, the receiver side signal discrimination circuit 255b receives a received digital audio signal whose amplitude and frequency characteristics are adjusted via the receiver side equalizer 253b based on the calculation result of the receiver side noise level calculation circuit 254b. This is to determine whether it is a sound signal.

  The attenuation level control circuit 256 controls the attenuation level of the transmission side attenuator 251a and the attenuation level of the reception side attenuator 251b based on the determination results of the transmission side signal determination circuit 255a and the reception side signal determination circuit 255b, respectively. It is.

  In the intercom system according to the embodiment of the present invention configured as described above, a specific operation will be described below.

  In order to call a resident in the room where the room base unit 2 shown in FIG. 1 is installed, a visitor outside the house uses the handset operating unit 100 of the front door unit 1 to perform a predetermined call. When the operation is performed, the call signal generated by the slave unit operation unit 100 passes through the slave unit I / F 106, the wired transmission path L1a or the wireless transmission path L1b, and the master unit I / F 208 of the living room master unit 2. Are transmitted to the CPU 207, and the camera 101 and the slave image processing unit 102 are activated. In addition, the camera 101 starts capturing an image of a visitor who has performed a call operation (including an image near the outside of the dwelling unit) and generates a video signal. This video signal is subjected to predetermined signal processing such as FM modulation and amplification in the slave unit video processing unit 102, and then the slave unit I / F 106, a wired transmission path L1a or a wireless transmission path L1b, a living room The data is transmitted to the parent device video processing unit 201 via the parent device I / F 208 of the parent device 2.

  When the CPU 207 of the living room master unit 2 shown in FIG. 1 receives the call signal transmitted from the entrance slave unit 1 connected via the wired transmission line L1a or the wireless transmission line L1b, the entrance child by the visitor. A ringing tone or a voice message indicating that there is a call from the machine 1 is output from the parent machine speaker 203 to make a call notification, and the monitor 200 and the parent machine video processing unit 201 are controlled to be active. By this control, the monitor 200 is imaged by the base unit video processing unit 201, for example, a video signal subjected to predetermined signal processing such as FM demodulation and amplification, that is, captured by the camera 101 of the entrance unit 1. Visitors' images (including images near the outside of the dwelling unit) will be displayed. Note that the monitor 200 displays not only the image of the visitor captured by the camera 101 of the entrance cordless handset 1 (including the image of the vicinity in the vicinity of the outside of the dwelling unit) but also from the entrance cordless handset 1 by the visitor. A call message indicating that there is a call, picture data, and the like can be displayed under the control of the CPU 207.

  Thereafter, in FIG. 1, a resident who has confirmed that the visitor has called from the entrance cordless handset 1 together with the visitor discrimination is determined using the base unit operating unit 206 of the room base unit 2. When the response operation is performed, the CPU 207 that detects this operation controls the base unit voice codec 204 and the voice processing unit 205 and the slave unit voice codec 105 of the front door unit 1 to be active.

  Here, in the voice processing unit 205 of the living room master unit 2 shown in FIG. 2, the transmitting side amplifier 250a is an analog voice signal of the sent voice inputted by the resident to the base unit microphone 202 shown in FIG. After the transmission digital audio signal that has been subjected to analog / digital conversion is amplified via the machine audio codec 204, it is transmitted to the transmission side attenuator 251a and the transmission side band division processing circuit 252a on the transmission line L2a. Here, the transmission side band division processing circuit 252a converts the transmission digital audio signal amplified via the transmission side amplifier 250a into a plurality of frequency bands, for example, “300 Hz <F1a ≦ 500 Hz” of the low frequency band F1a. The frequency band is divided into three frequency bands, such as “500 Hz <F2a ≦ 2 kHz” in the middle frequency band F2a and “2 kHz <F3a ≦ 5 kHz” in the high frequency band F3a, and the amplitude and frequency are transmitted via the transmitting-side equalizer 253a. The three types of transmitted digital audio signals whose characteristics are adjusted are transmitted to the transmission side noise level calculation circuit 254a and the transmission side signal determination circuit 255a, respectively.

  2 is transmitted from the transmission-side band division processing circuit 252a via the transmission-side equalizer 253a. The transmission-side noise level calculation circuit 254a included in the voice processing unit 205 of the living room master unit 2 shown in FIG. Based on the transmitted digital audio signals in the three frequency bands whose amplitude and frequency characteristics are adjusted, the noise levels of the transmitted digital audio signals in the three frequency bands are calculated. More specifically, a predetermined threshold value (hereinafter referred to as a first transmitter-side threshold value) A1 is also set for a transmission digital audio signal in a middle frequency band or a low frequency band like a normal transmission voice by a resident. Then, the noise level is calculated, and the calculation result is sent to the transmission side signal discrimination circuit 255a. On the other hand, for a transmitted digital audio signal having a low frequency in a high frequency band with a high frequency component such as a frictional sound, a predetermined threshold (hereinafter referred to as a second transmitter threshold) that is different from the first transmitter threshold A1 described above. The noise level is calculated based on A2, and the calculation result is sent to the transmitting side signal discriminating circuit 255a.

  Further, the transmission side signal discriminating circuit 255a constituting the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 passes through the transmission side equalizer 253a based on the calculation result of the transmission side noise level calculation circuit 254a. Then, it is determined whether the transmitted digital audio signals in the three frequency bands with adjusted amplitude and frequency characteristics transmitted from the transmission side band division processing circuit 252a are silence signals or voice signals. Here, since the first and second transmission side threshold values A1 and A2 are set in advance in the transmission side signal discrimination circuit 255a so as to have a relationship of “A1> A2”, Based on the transmitted digital audio signals of the three frequency bands with adjusted amplitude and frequency characteristics transmitted from the transmission side band division processing circuit 252a via the side equalizer 253a, the discrimination sensitivity of sound is increased. Without changing, it is possible to discriminate not only a normal transmission voice by a resident but also a frictional sound as a sound signal with high accuracy, and the discrimination result is sent to the attenuation level control circuit 256.

  On the other hand, it is an analog audio signal of a transmission voice inputted by the visitor to the slave microphone 103 of the entrance cordless handset 1 shown in FIG. The signal is transmitted to the receiver amplifier 250b of the voice processing unit 205 shown in FIG. 2 via the slave unit I / F 106, the wired transmission path L1a or the wireless transmission path L1b, and the master unit I / F 208 of the living room master unit 2. Is done. The receiver-side amplifier 250b amplifies the received transmission digital voice signal as a received digital voice signal, and then transmits the amplified signal to the receiver-side attenuator 251b and the receiver-side band division processing circuit 252b on the reception line L2b. Here, the reception side band division processing circuit 252b converts the received digital audio signal amplified via the reception side amplifier 250b into a plurality of frequency bands, for example, “300 Hz <F1b ≦ 500 Hz” in the low frequency band F1b, medium frequency It is divided into three frequency bands such as “500 Hz <F2b ≦ 2 kHz” in the band F2b and “2 kHz <F3b ≦ 5 kHz” in the high frequency band F3b, and the amplitude / frequency characteristics are adjusted via the receiver equalizer 253b. The three types of received digital audio signals are sent to the receiving side noise level calculation circuit 254b and the receiving side signal discrimination circuit 255b, respectively.

  Further, the reception side noise level calculation circuit 254b that constitutes the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 has the amplitude / frequency transmitted from the reception side band division processing circuit 252b via the reception side equalizer 253b. Based on the received digital audio signals in the three frequency bands whose characteristics are adjusted, the respective noise levels are calculated for the received digital audio signals in the three frequency bands. Specifically, for a received digital voice signal in a middle frequency band or a low frequency band like a normal received voice by a visitor, noise based on a predetermined threshold (hereinafter referred to as a first receiver threshold) B1. The level is calculated, and the calculation result is sent to the receiver signal discrimination circuit 255b. On the other hand, for a received digital audio signal having a low frequency in a high frequency band with a high frequency component such as a frictional sound, a predetermined threshold value (hereinafter referred to as a second receiver side threshold value) different from the first receiver side threshold value B1 described above. The noise level is calculated based on B2, and the calculation result is sent to the receiver signal discrimination circuit 255b.

  Further, the receiver side signal discriminating circuit 255b constituting the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 receives the amplitude / frequency transmitted from the transmitter side band division processing circuit 252b via the receiver side equalizer 253b. It is determined whether the received digital audio signals in the three frequency bands whose characteristics are adjusted are silence signals or voice signals. Here, in the receiver side signal discriminating circuit 255b, the first and second receiver thresholds B1 and B2 are set in advance so as to have a relationship of “B1> B2”, and therefore the receiver equalizer 253b. Without changing the sensitivity for detecting voice based on the received digital audio signals in the three frequency bands with the adjusted amplitude and frequency characteristics transmitted from the receiving side band division processing circuit 252b via It is possible to discriminate not only a normal received voice by a visitor but also a frictional sound as a sound signal with high accuracy, and this discrimination result is sent to the attenuation level control circuit 256.

  Next, as an example of the control, the attenuation level control circuit 256 that constitutes the audio processing unit 205 of the living room master unit 2 shown in FIG. 2 has a determination result of the transmission side signal determination circuit 255a as a sound and a reception side signal. When the determination result of the determination circuit 255b is silent, the attenuation level of the transmission side attenuator 251a is suppressed to a low level, while the attenuation level of the reception side attenuator 251b is controlled to be high. By this control, the signal voltage of the transmitted digital audio signal which is determined to be sound by the transmission side signal determination circuit 255a and amplified via the transmission side amplifier 250a on the transmission line L2a is the transmission side. After the attenuation is suppressed to a low level by the attenuator 251a, the slave unit is passed through the master unit I / F 208, the wired transmission path L1a or the wireless transmission path L1b, and the slave unit I / F 106 of the entrance slave unit 1 shown in FIG. It is transmitted to the audio codec 105. Here, handset audio codec 104 digital / analog converts the received voice transmission digital audio signal, and the frictional sound accurately identified as the voice signal as described above as well as the normal voice by the resident. Can also be output from the handset speaker 104 as an incoming voice of a voice signal. As a result, it is possible to prevent the head of the call voice output from the handset speaker 104 from being cut off and to improve the call quality.

  Further, as another example of the control, the attenuation level control circuit 256 constituting the voice processing unit 205 of the living room master unit 2 shown in FIG. 2 is that the determination result of the transmission side signal determination circuit 255a is silent and the reception side signal determination is performed. When the determination result of the circuit 255b is sound, control is performed so that the attenuation level of the transmitting side attenuator 251a is increased while the attenuation level of the receiving side attenuator 251b is decreased. By this control, the signal voltage of the received digital audio signal which is determined to be sound by the receiving side signal determining circuit 255b and amplified via the receiving side amplifier 250b on the receiving line L2b is attenuated by the receiving side attenuator 251b. After the level is suppressed to a low level, it is transmitted to the master audio codec 204 shown in FIG. Here, the main unit audio codec 204 performs digital / analog conversion on the received voice-received digital audio signal, and not only the normal voice of the visitor but also the frictional sound accurately determined as the voiced signal as described above. Also, it can be outputted from the parent speaker 203 as the voice of the voice signal. As a result, it is possible to prevent the head of the call voice output from the main unit speaker 203 from being cut off and to improve the call quality.

  Although the interphone system of the present invention has been described with a specific embodiment, the present invention is not limited to this embodiment, and any intercom system known so far can be used as long as the effects of the present invention are achieved. For example, there is an intercom system having the entrance cordless handset incapable of image capturing / processing functions (101, 102) and the living room base unit inadequate for image output / processing functions (200, 201). However, it goes without saying that it can be adopted.

The block diagram which shows the structure of the intercom system by the Example of this invention. The block diagram which shows the specific structure of the audio | voice processing part of a living room main | base station in the intercom system by the Example of this invention.

DESCRIPTION OF SYMBOLS 1 ... Entrance cordless handset 103 …… Slave unit microphone 104 …… Slave unit speaker 2 …… Home base unit 202 …… Base unit microphone 203 …… Base unit speaker 204 …… Base unit voice codec 205 …… Sound processing unit 251a ...... Send side attenuator 251b …… Receive side attenuator 252a …… Send side bandwidth split processing circuit 252b …… Receive side bandwidth split processing circuit 253a …… Send side equalizer 253b …… Receive side equalizer 254a …… Send side Noise level calculation circuit 254b …… Receiver side noise level calculation circuit 255a …… Send side signal discrimination circuit 255b …… Reception side signal discrimination circuit 256 …… Attenuation level control circuit L1a …… Wired transmission line L1b …… Wireless transmission Road L2a …… Send line L2b …… Receive line

Claims (2)

The entrance slave unit (1) having the slave unit microphone (103) and the slave unit speaker (104) is connected to the entrance slave unit via a wired transmission path (L1a) or a wireless transmission path (L1b). A master unit microphone (202) for inputting and outputting a voice signal for establishing a call between the slave unit microphone and the slave unit speaker, and a room master unit (2) having a master unit speaker (203);
The living room master unit performs analog / digital conversion of a transmission analog voice signal input to the base unit microphone into a transmission digital voice signal, and is also input to the slave unit microphone of the entrance slave unit. A base unit voice codec (204) for digitally / analog converting a received digital voice signal transmitted via the digital signal into a received analog voice signal and outputting it from the base unit speaker; and the transmission path from the base unit voice codec Signal voltage of the transmitted digital voice signal transmitted through the transmission line (L2a) to the receiver, and signal of the received analog voice signal transmitted through the transmission line (L2b) from the transmission path to the master voice codec An audio processing unit (205) for varying each voltage,
The voice processing unit of the office master unit includes a transmitting side attenuator (251a) for attenuating the signal voltage of the transmitted digital audio signal and a receiving side for attenuating the signal voltage of the received digital audio signal. An attenuator (251b), a transmission side band division processing circuit (252a) for dividing the transmitted digital audio signal into a plurality of frequency bands, and an incoming call for dividing the received digital audio signal into a plurality of frequency bands A noise level of the transmitted digital audio signal divided into the plurality of frequency bands by the side band division processing circuit (252b) and the transmission side band division processing circuit; and a predetermined transmission level corresponding to the plurality of frequency bands. dividing the talk side threshold and transmitting end noise level calculating circuit for calculating the original (254a), said plurality of frequency bands at the receiving side band division processing circuit The above and receiving end noise level calculating circuit for the noise level of the received digital audio signal to calculate on the basis of predetermined reception side threshold corresponding to the plurality of frequency bands (254b), said transmitter side noise level calculation A transmission side signal determination circuit (255a) for determining whether the transmission digital audio signal is a silence signal or a sound signal based on the calculation result of the circuit, and the calculation result of the reception side noise level calculation circuit A receiving side signal discriminating circuit (255b) for discriminating whether the received digital audio signal is a silence signal or a voiced signal based on the above, and discrimination of the transmitting side signal discriminating circuit and the receiving side signal discriminating circuit An attenuation level control circuit (256) for controlling the attenuation level of the transmitting side attenuator and the attenuation level of the receiving side attenuator based on the result; Intercom system to be characterized.   The voice processing unit of the living room master unit includes a transmission side equalizer (253a) for adjusting amplitude and frequency characteristics of the plurality of frequency bands divided by the transmission side band division processing circuit, The intercom system according to claim 1, further comprising: a receiver-side equalizer (253b) for adjusting amplitude and frequency characteristics of the plurality of frequency bands divided by the receiver-side band division processing circuit.

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