JP4422714B2 - Audio transmission system - Google Patents

Description

  The present invention relates to an audio transmission system that transmits an audio signal via a signal line.

Conventionally, as an audio transmission system that transmits an audio signal via a signal line, for example, an interphone master unit and a sub master unit installed in a dwelling unit, and a door phone sub unit installed in a front door outside the dwelling unit, There is an interphone system that can perform a call between an interphone master unit or a sub master unit and a door phone slave unit, or an extension call between an interphone master unit and a sub master unit or a plurality of sub master units (for example, , See Patent Document 1). In the interphone system as described above, the volume of the person who actually talks is adjusted by operating a switch or the like.
JP 7-183958 A

  However, the conventional example requires a space for providing a volume control operation switch or the like in each of the master unit and the sub master unit, and there is a problem that the shape, size, or installation location is restricted.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an audio transmission system capable of adjusting the sound output from the audio output means to an appropriate volume regardless of human operation. There is.

In order to achieve the above object, the first aspect of the present invention provides one or more voice input terminal devices including at least voice input means for inputting voice and one or more voice output means for outputting voice at least. A voice output terminal device, a voice input terminal device, and a main device connected to the voice output terminal device via a signal line made up of a pair of pair wires, and the voice output from the voice input terminal device via the main device An audio transmission system for time-division multiplexing transmission of an audio signal to a terminal device, wherein the audio output terminal device includes audio signal receiving means for receiving an audio signal transmitted in a downlink time slot via the signal line; Ambient noise detection means for detecting the level of ambient noise at the installation location, control signal transmission means for transmitting a control signal to the main unit via the signal line, and ambient noise detection Control means for notifying the main device of the ambient noise detection value detected at the stage by means of a control signal, the main device receiving the voice signal transmitted by the voice input terminal device in the uplink time slot and receiving the downlink signal. An audio signal transmitting / receiving means for transmitting an audio signal to the audio output terminal apparatus in a time slot; a control signal transmitting means for transmitting a control signal to the audio output terminal apparatus via the signal line; and the control signal. When the ambient noise detection value is received from the audio output terminal apparatus, the apparatus further comprises volume adjusting means for adjusting the volume of the audio signal transmitted to the audio output terminal apparatus according to the ambient noise detection value.

According to a second aspect of the present invention, in the first aspect of the invention, at least one of the plurality of audio input terminal devices or audio output terminal devices is an imaging unit and a modulation that modulates an image captured by the imaging unit. And a video signal transmitting means for transmitting the video signal modulated by the modulating means in a frequency band different from the frequency band of the audio signal, and the main device is transmitted by the audio input terminal device or the audio output terminal device Video signal receiving means for receiving a video signal, demodulating means for demodulating the video signal received by the video signal receiving means, and display means for displaying the video demodulated by the demodulating means.

According to the first aspect of the present invention, it is possible to adjust the sound output from the sound output means to an appropriate volume regardless of a human operation.

According to the second aspect of the present invention, the video imaged by the voice input terminal device or the voice output terminal device can be displayed on the display means of the main device, for example, the voice input terminal device or the voice output terminal device. When the door phone is installed at the entrance of the dwelling unit, the video of the visitor can be confirmed by the main device installed in the dwelling unit, which improves usability.

  Hereinafter, an embodiment in which the technical idea of the present invention is applied to an intercom system for a detached house will be described in detail.

(Embodiment 1)
As shown in FIG. 1, the audio transmission system (interphone system) of the present embodiment is connected to a plurality of audio terminal devices 2 installed indoors in a dwelling unit H, and the plurality of audio terminal devices 2 via a signal line Ls. Main unit (base unit) 1 and door phone slave unit 3 installed outside unit (exterior) of dwelling unit H and connected to base unit 1 via communication line Lx. In a room, a master device 1 as a main device is installed in the living room, and a plurality of voice terminal devices 2 are installed in other rooms (for example, private rooms of each family). Note that although a balanced line such as a pair line is used as the signal line Ls, an unbalanced line such as a coaxial line may be used. Further, a pair of enhanced category 5 or category 6 LAN cables or a pair of CPEV cables may be used for the signal line Ls.

  The intercom unit 3 includes a microphone 30, a speaker 31, a microphone amplifier 32a that amplifies the output of the microphone 30, a speaker amplifier 32b that amplifies the input to the speaker 31, a call button 33 that is operated by the visitor, and a visitor. A video signal output from the camera unit 34, and audio / video demultiplexing for frequency-division multiplexing of the audio signal and 2-line 4-line conversion processing of the audio signal and transmission processing of the calling signal Part 35 and a terminal part 36 to which the communication line Lx is connected. However, since the structure of the door phone sub unit 3 is well known in the art, a detailed description thereof will be omitted.

  The audio terminal device 2 includes a microphone 20a and a speaker 20b, a microphone amplifier 21a that amplifies the output of the microphone 20a, a speaker amplifier 21b that amplifies the input to the speaker 20b, and modulates and demodulates the audio signal using a digital modulation method. A control signal is transmitted via the signal line Ls between the audio signal multiplex transmission processing unit 22 for time division multiplex transmission (TDMA <Time Division Multiple Access>) stored in the time slot and the downlink time slot, and the base unit 1. A control signal transmission processing unit 23 for transmission, a demultiplexing unit 24 for frequency-division multiplexing and demultiplexing of the control signal and the audio signal, a control unit 25 for controlling each unit with the CPU as a main component, an extension button described later, An operation unit 26 having an operation button (not shown) such as a response button and outputting an operation signal to the control unit 25 in accordance with the operation of the operation button, and a signal line L There comprises a terminal portion 27 connected, the ambient noise detector 28 for detecting the ambient noise at the installation location. That is, the voice terminal device 2 according to the present embodiment is a voice input terminal device because both the voice input means (microphone 20a) for inputting voice and the voice output means (speaker 21a) for outputting voice are provided. At the same time, it is a voice output terminal device. However, the configuration of the voice terminal device 2 is not limited to this, and a voice input terminal device having voice input means and no voice output means, or having voice output means and no voice input means. It may be configured as an audio output terminal device. Each voice terminal apparatus 2 is given a unique identification code (ID), and each terminal apparatus 2 can be identified by this identification code.

  The audio signal multiplex transmission processing unit 22 converts an analog audio signal output from the microphone 20a and amplified by the microphone amplifier 21a into a digital signal, and performs BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), 16QAM. (Quadrature Amplitude Modulation), a process of modulating by a digital modulation method such as 64QAM, and a process of demodulating the audio signal separated from the control signal by the demultiplexer 24 and converting it to an analog signal and outputting it to the speaker amplifier 21b . The control signal transmission processing unit 23 also modulates the control data given from the control unit 25 by a modulation scheme such as FSK (frequency shift keying) or PSK (phase shift keying), and the demultiplexing unit 24 performs audio signal processing. And a process of demodulating the separated control signal and passing control data to the control unit 25.

  As shown in FIG. 2, the ambient noise detection unit 28 calculates a short-time average value calculation unit Ps for calculating a short-time average value Ps of instantaneous power of an input signal (transmission signal) input from the microphone 20a via the microphone amplifier 21a. 28a, a long-time average value calculation unit 28b for calculating a long-term average value Pn of instantaneous power, and a speech signal containing a voice component by comparing the short-time average value Ps and the long-term average value Pn It has a near-end side speech section detection unit 28c that detects a section, and an ambient noise level calculation unit 28d that calculates an estimated value Pn ′ of the near-end side ambient noise level included in the transmission signal. The short-time average value calculation unit 28a multiplies the instantaneous value (absolute value) Pv (n) of the input signal by a positive constant ρ1 (<1) and the delayed short-time average value Ps (n−1). The short-time average value Ps (n) is calculated by performing a process of adding a value obtained by multiplying the value by a positive constant (1-ρ1), that is, an arithmetic process of the following expression (1).

Ps (n) = (1−ρ1) × Ps (n−1) + ρ1 × Pv (n) (1)
The long-time average value calculation unit 28b also multiplies the instantaneous value Pv (n) of the input signal by a positive constant ρ2 (0 <ρ2 <ρ1 <1) and the delayed long-time average value Pn (n− The long-time average value Pn (n) is calculated by performing a process of adding a value obtained by multiplying 1) by a positive constant (1-ρ2), that is, an arithmetic process of the following formula (2).

Pn (n) = (1-ρ2) × Pn (n−1) + ρ2 × Pv (n) (2)
The near-end side speech section detection unit 28c compares the ratio (= Ps (n) / Pn (n)) between the short time average value Ps (n) and the long time average value Pn (n) with a predetermined threshold δ. , If δ <Ps (n) / Pn (n), it is determined as a speech segment if Ps (n) / Pn (n) ≦ δ, and if it is determined as a speech segment, a near-end speech segment is detected. The flag SDF1 is set to 1, and the near-end speech section detection flag SDF1 is set to 0 when it is determined as a non-speech section.

  The ambient noise level calculation unit 28d is a positive constant for the instantaneous value Pv (n) of the input signal when the near-end speech section detection flag SDF1 is 0, that is, when a non-speech section of the transmission signal is detected. A value obtained by multiplying ρ3 (ρ3 <1, where ρ3 may be a different value or the same value as ρ2) and a delayed ambient noise level Pn ′ (n−1) is set to a positive constant (1−ρ3). The ambient noise level Pn ′ (n) is calculated by performing a process of adding the multiplied values, that is, an arithmetic process of the following expression (3). However, when the near-end side speech section detection flag SDF1 is 1, that is, when the speech section of the transmission signal is detected, the processing of the following expression (3) is not performed and the ambient noise level Pn ′ (n) is set. It is not updated (see the following formula (4)).

Pn ′ (n) = (1−ρ3) × Pn ′ (n−1) + ρ3 × Pv (n) (3)
Pn ′ (n) = Pn ′ (n−1) (4)
On the other hand, the base unit 1 includes a terminal unit 10a to which the call line Lx is connected and a terminal unit 10b to which the signal line Ls is connected, and a video signal that is frequency-division-multiplexed and transmitted from the doorphone sub unit 3 through the call line Lx. The demultiplexing unit 11 that separates the audio signal and transmits the audio signal to the door phone sub unit 3 via the communication line Lx, and the demultiplexing unit 11 includes a display device such as a liquid crystal display or a CRT. A monitor unit 12 that demodulates and displays a video signal, a microphone 13a and a speaker 13b, a microphone amplifier 13c that amplifies the output of the microphone 13a, a speaker amplifier 13d that amplifies the input to the speaker 13b, and an echo cancellation process (audio) Processing to digitize the signal and suppress unpleasant echoes) and voice switch processing (sound volume on the transmitting side and receiving side is reduced to the low volume side) And a speech processing unit 14 that preferentially outputs a speech signal with a high volume and the like, and a speech signal is modulated and demodulated by a digital modulation method to be used as time slots in the upstream and downstream directions. An audio signal multiplex transmission processing unit 15 that stores and performs time division multiplex transmission, a control signal transmission processing unit 16 that transmits a control signal to and from each audio terminal device 2 via the signal line Ls, a control signal, and an audio signal Is provided with a demultiplexing unit 17 that frequency-division-multiplexes and demultiplexes, a control unit 18 that controls each unit using a CPU as a main component, and a storage unit 19 that stores ringing tone data and the like described later.

  The call processing unit 14 includes a DSP (digital signal processor), an A / D converter, a D / A converter, a codec circuit, and the like. An analog audio signal transmitted via Lx is converted into a digital audio signal, which is caused by acoustic coupling between the microphone 30 and the speaker 31 of the door phone slave unit 3, acoustic coupling between the microphone 13a and the speaker 13b of the base unit 1, or the like. Processing is performed such as suppressing unpleasant echoes and comparing the direction of the voice by comparing the level of the voice (speech voice) input from the microphone 13a and the voice (received voice) transmitted from the doorphone slave unit 3. . Further, the call processing unit 14 generates unpleasant echoes with the voice terminal device 2 due to acoustic coupling between the microphone 20a and the speaker 20b of the voice terminal device 2, acoustic coupling between the microphone 13a and the speaker 13b of the parent device 1, or the like. Processing to suppress or switch the call direction by comparing the level of the voice (transmitted voice) input from the microphone 13a and the voice (received voice) transmitted from the voice terminal device 2 is performed. Further, when the voice terminal devices 2 talk to each other individually (extension call), the call processing unit 14 performs signal processing on the voice signals stored and transmitted from the respective voice terminal devices 2 in the uplink time slot. By doing so, unpleasant echo caused by acoustic coupling between the microphone 20a and the speaker 20b is suppressed, or the call direction is switched by comparing the level of the audio signal. Furthermore, the call processing unit 14 also performs a process of adjusting the volume of the audio signal transmitted to the audio terminal device 2 according to the ambient noise level Pn ′ notified from the audio terminal device 2 by the control signal.

  Here, in the base unit 1, the synchronization signal is sent to the signal line Ls via the demultiplexing unit 17 under the control of the control unit 18. A plurality (2n) of time slots are arranged within a period (signal transmission period) from the start of the time slot until the next synchronization signal rises. The first n time slots are in the up direction, and the second n time slots are in the down direction. Hereinafter, in order to simplify the description, an uplink time slot is referred to as an “uplink slot”, a downlink time slot is referred to as a “downlink slot”, and a combination of an uplink slot and a downlink slot is referred to as a channel. Therefore, in this embodiment, n (n channels) uplink slots and downlink slots are arranged in the signal transmission period, so that a maximum of n voice terminal apparatuses 2 can individually talk on a one-to-one basis.

  Next, the operation of this embodiment when a one-to-one call (individual call) is performed between the two voice terminal apparatuses 2 will be described with reference to FIG. In the following, a case where two units of the voice terminal device 2A and the voice terminal device 2B make an individual call will be exemplified.

  First, when an extension button (not shown) of the operation unit 26 is operated in the voice terminal device 2A, an operation signal is output from the operation unit 26 to the control unit 25, and the control unit 25 that has received the operation signal receives the extension call. Request control data is generated and given to the control signal transmission processing unit 23. The control signal transmission processing unit 23 sends the control data of the extension call request and its own identification code through the demultiplexing unit 24 and the terminal unit 27 by the control signal. The signal is sent to the signal line Ls.

  On the other hand, in base unit 1, the control signal transmitted via signal line Ls is separated by demultiplexing unit 17 and received by control signal transmission processing unit 16, and the extension call request and request source included in the received control signal. Is sent to the control unit 18. The control unit 18 reads out the ringing tone data stored in the storage unit 19 and gives it to the call processing unit 14. The control unit 18 causes the speaker 13 b to ring through the call processing unit 14 and includes the identification code of the request source. A control signal including the ringing tone data with all the identification codes as destinations is transmitted by the control signal transmission processing unit 16 via the signal line Ls.

  In the voice terminal devices 2A, 2B, 2C, 2D, when the control signal transmission processing unit 23 receives the control signal transmitted from the base unit 1, and passes the ringing tone data included in the received control signal to the control unit 25, The control unit 25 converts the ringing tone data into an analog ringing tone signal, and causes the speaker 20b to ring through the voice signal multiplex transmission processing unit 22. When an extension button (not shown) of the operation unit 26 is operated in the voice terminal device 2B, an operation signal is output from the operation unit 26 to the control unit 25, and the control unit 25 that receives the operation signal receives a request. Control data of a response (extension response) indicating that the individual call with the original voice terminal apparatus 2A has been accepted is generated and given to the control signal transmission processing unit 23, and the control signal transmission processing unit 23 The self identification code is sent to the signal line Ls via the demultiplexing unit 24 and the terminal unit 27 by the control signal.

  In base unit 1, control signal transmitted from voice terminal apparatus 2 B is received by control signal transmission processing unit 16, and extension response control data and response destination identification code included in the received control signal are sent to control unit 18. Then, the control unit 18 causes the control signal transmission processing unit 16 to transmit a control signal including control data for extension response permission with the request source identification code as a destination.

  Then, in all the voice terminal devices 2 including the request source voice terminal device 2A and the response destination voice terminal device 2B, the control unit 25 stops ringing of the ringing tone by the speaker 20b. Further, in the voice terminal device 2B that is the response destination, the ambient noise detection unit 28 detects the ambient noise level Pn ′, and the detected ambient noise level Pn ′ is given from the control unit 25 to the control signal transmission processing unit 23, and the control signal The transmission processing unit 23 sends the ambient noise level Pn ′ and its own identification code to the signal line Ls via the demultiplexing unit 24 and the terminal unit 27 by the control signal. Here, it is assumed that a time slot of channel 1 is allocated to the requesting voice terminal apparatus 2A, and a time slot of channel 2 is allocated to the voice terminal apparatus 2B of the response destination. Accordingly, in the requesting voice terminal apparatus 2A, the voice (transmission voice) input from the microphone 20a is modulated by the voice signal multiplex transmission processing unit 22, and the modulated voice signal (transmission signal) is transmitted to the channel 1 upstream. The data is stored in the slot and transmitted to the base unit 1 through the signal line Ls.

  In base unit 1, a voice signal (transmission signal) transmitted from voice terminal apparatus 2 </ b> A is received by voice signal multiplex transmission processing unit 15, demodulated, and output to call processing unit 14. Then, the call processing unit 14 performs an echo suppression process, a call direction switching process, and the like (hereinafter referred to as “amplified call process”) on the voice signal, and is notified by a control signal from the answering voice terminal device 2B. The volume adjustment process is performed according to the ambient noise level Pn ′, and the processed audio signal is modulated again by the audio signal multiplex transmission processing unit 15 and stored in the downlink slot of the channel 2 toward the response destination audio terminal apparatus 2B. Then send. Here, the call processing unit 14 adjusts the volume of the audio signal to increase as the ambient noise level Pn ′ increases.

  Then, in the response destination voice terminal apparatus 2B, the voice signal stored in the downlink slot of channel 2 is taken in, demodulated by the voice signal multiplex transmission processing unit 22 and the received voice is sounded from the speaker 20b, and the microphone 20a. Is modulated by the audio signal multiplex transmission processing unit 22, the modulated audio signal (transmission signal) is stored in the upstream slot of channel 2, and the master unit 1 is connected via the signal line Ls. Transmit to. At this time, since the volume of the received voice ringed from the speaker 20b of the voice terminal device 2B is adjusted by the call processing unit 14 of the base unit 1, for example, the volume is increased even in an environment where the ambient noise level is high. Therefore, the received voice is easy to hear.

  Here, in the requesting voice terminal device 2A, the ambient noise detecting unit 28 detects the ambient noise level Pn ′, and the detected ambient noise level Pn ′ is given from the control unit 25 to the control signal transmission processing unit 23, The control signal transmission processing unit 23 sends the ambient noise level Pn ′ and its own identification code to the signal line Ls via the demultiplexing unit 24 and the terminal unit 27 by the control signal. In response destination voice terminal apparatus 2B, voice (speech voice) input from microphone 20a is modulated by voice signal multiplex transmission processing unit 22, and the modulated voice signal (speech signal) is channel 2 uplink slot. And transmitted to the base unit 1 through the signal line Ls.

  In base unit 1, a voice signal (transmission signal) transmitted from voice terminal apparatus 2 B is received by voice signal multiplex transmission processing unit 15, demodulated and output to call processing unit 14. In addition to performing call processing, volume adjustment processing according to the ambient noise level Pn ′ notified by the control signal from the voice terminal device 2A is performed, and the voice signal after processing is again modulated by the voice signal multiplex transmission processing unit 15 to generate voice. Stored in the downlink slot of channel 1 and transmitted to the terminal device 2A. Then, in the voice terminal apparatus 2A, the voice signal stored in the downlink slot of channel 1 is taken in, demodulated by the voice signal multiplex transmission processing unit 22, and the received voice is sounded from the speaker 20b. 2A and B can transmit and receive audio signals using the time slots of channels 1 and 2 to enable individual calls. At this time, since the volume of the received voice ringed from the speaker 20b of the voice terminal device 2A is also adjusted by the call processing unit 14 of the parent device 1, for example, the volume does not increase too much even in an environment where the ambient noise level is low. The volume is adjusted to a moderate level and the received voice is easy to hear. Note that the assignment of channels to be used for all voice terminal apparatuses 2A, 2B, 2C, and 2D may be determined in advance, or the assignment is notified by a control signal from the master unit 1 when actually performing an extension call. You may make it.

  As described above, in the present embodiment, there is no need for a space for providing a volume control operation switch or the like in the voice terminal device 2 as in the conventional example, and there is no restriction on the shape, size, or installation location. In addition, there is an advantage that usability can be improved because the sound generated from the speaker 20b can be adjusted to an appropriate volume regardless of human operation.

( Embodiment 2 )
The system configuration of this embodiment shown in FIG. The present embodiment is characterized in that a voice terminal device 2E connected to the master unit 1 via a signal line Ls is installed at the outside entrance of the dwelling unit H instead of the door phone slave unit 3. However, since the basic configuration of this embodiment is common to Embodiment 1, the same components will not be further illustrated and described with the same reference numerals.

  A voice terminal device (hereinafter referred to as a “door phone terminal device”) 2E installed at the outside entrance includes a camera unit 29a and a video signal multiplex transmission processing unit in addition to the same components as the other voice terminal devices 2A to 2D. 29b. The camera unit 29a is configured by an optical system such as an individual image sensor or a lens, and images a visitor. The video signal multiplex transmission processing unit 29b converts the analog video signal output from the camera unit 29a into a digital signal and modulates the modulated video signal (video) in a frequency band different from the frequency band for transmitting the audio signal. Data) is stored in the upstream slot and transmitted. In the demultiplexing unit 24, the video signal output from the video signal multiplex transmission processing unit 29b is frequency division multiplexed with the audio signal and the control signal.

  On the other hand, in the base unit 1 in the present embodiment, the video signal transmitted via the signal line Ls is separated by the demultiplexing unit 17, and the separated video signal is demodulated by the video signal processing unit 11 and from the digital signal. An image is displayed on the monitor unit 12 by converting it into an analog signal.

  Next, the operation of the present embodiment will be described by taking as an example a case in which a video image captured by the door phone terminal device 2E is displayed on the parent device 1 at the same time that a call is made between the parent device 1 and the door phone terminal device 2E.

  First, when a call button (not shown) provided on the operation unit 26 is operated in the door phone terminal device 2E, the control unit 25 generates a call notification for calling the base unit 1 and sends it to the control signal transmission processing unit 23. Then, the control signal transmission processing unit 23 sends the call notification and its own identification code to the signal line Ls via the demultiplexing unit 24 by the control signal. Further, the control unit 25 activates the camera unit 29a to image a person (visitor) who operates the call button, and converts an analog video signal output from the camera unit 29a into a digital signal by the video signal multiplex transmission processing unit 29b. And modulate. The modulated video signal is stored in the uplink slot (for example, the uplink slot of channel 5) assigned to the intercom terminal device 2E by the demultiplexing unit 24 and transmitted to the signal line Ls.

  On the other hand, in the base unit 1, the control unit 18 that has received the control signal for the call notification via the signal line Ls causes the speaker 13 b to ring and uses all the identification codes including the identification code of the request source as the destination. A control signal including ringing tone data is transmitted by the control signal transmission processing unit 16 via the signal line Ls. Also, a video signal transmitted from the door phone terminal device 2E via the signal line Ls is taken into the video signal processing unit 11 via the demultiplexing unit 17, demodulated by the video signal processing unit 11, and converted into an analog signal, An image is displayed on the monitor unit 12. Then, when a resident who has viewed the video on the monitor unit 12 operates a response button (not shown) of the base unit 1, the control unit 18 activates the call processing unit 14 to enable a call, and further the door phone terminal device 2E. The control signal transmission processing unit 16 causes the control signal transmission processing unit 16 to transmit the control signal including the control data including the control data to the notification that the telephone call is started (call start notification).

  In the intercom terminal device 2E, when the control signal of the call start notification is received by the control signal transmission processing unit 23, the control unit 25 activates the audio signal multiplex transmission processing unit 22 to enable a call, and the collected sound is collected by the microphone 20a. The audio signal output from the multiplex transmission processing unit 22 is multiplexed with the video signal by the demultiplexing unit 24 (frequency division multiplexing), stored in the assigned channel 5 uplink slot, and transmitted to the base unit 1. Further, the audio signal stored and transmitted from the base unit 1 in the downlink slot of channel 5 is separated by the demultiplexing unit 24, and the separated audio signal is input to the audio signal multiplex transmission processing unit 22 and is transmitted from the speaker 24b. Ring.

  In the base unit 1, the audio signal (received signal) and the video signal transmitted from the door phone terminal device 2E are separated by the demultiplexing unit 24, received by the audio signal multiplex transmission processing unit 15, and demodulated to be processed by the call processing unit 14. Output to. Then, the call processing unit 14 performs loudspeaking call processing on the voice signal (received signal) and causes the speaker 13b to ring with the processed voice signal (analog signal). Further, the voice signal (transmission signal) output from the microphone 13 a is subjected to the voice call processing by the call processing unit 14, and then converted and modulated by the voice signal multiplex transmission processing unit 15. Store and transmit to door phone terminal apparatus 2E. The video signal separated by the demultiplexing unit 17 is demodulated by the video signal processing unit 11, converted from a digital signal to an analog signal, and output to the monitor unit 12. In this way, a video signal is transmitted from the door phone terminal device 2E to the parent device 1, and a voice signal is transmitted bidirectionally between the door phone terminal device 2E and the parent device 1, thereby making a call. Note that the case where one of the other voice terminal devices 2A to 2D answers the call from the door phone terminal device 2E is basically the same as the extension call between the voice terminal devices 2A to 2D described in the first embodiment. Since this is an operation, the description is omitted.

Thus, in this embodiment, since the voice terminal device (door phone terminal device) 2E is installed at the outside entrance of the dwelling unit H in place of the door phone slave unit 3, it is used only for calls with the door phone slave unit 3. Since the demultiplexing unit 11 and the terminal unit 10a are not required, the configuration of the base unit 1 can be simplified, and further, a telephone call (intercom call) inside and outside the dwelling unit H and a call (extension call) inside the dwelling unit H can be performed simultaneously. This has the advantage of improving usability. For example, in a case where a doorphone sub-unit is individually installed in the outer entrance of a parent household and a child household in a so-called two-family house, in Embodiment 1, during a call with one doorphone sub-unit, the other Although it is not possible to make a call with the doorphone slave unit and to view the image captured by the other doorphone slave unit, in this embodiment, the images are individually and simultaneously communicated and captured by each doorphone terminal device 2E. Can be seen. In addition, since the door phone terminal device 2E is generally installed outdoors where the ambient noise is larger than that of the other voice terminal devices 2A to 2D installed indoors, the volume is set according to the ambient noise level as in the first embodiment. improve the degree of call performance by the tone pollock Rukoto the increases.

  A camera unit 28 that outputs a digital video signal may be used as the camera unit 28 of the door phone terminal device 2E, and a monitor unit 12 that can input a digital signal may be used as the monitor unit 12 of the base unit 1. Since the imaging to display can be performed by so-called full digital, there is an advantage that deterioration due to analog and digital signal conversion is eliminated.

Here, as shown in FIG. 5 , by simply connecting the connector of the functional module 108 to the connection port of the gate device 103, the power path and the information path of the functional module 108 can be secured at the same time. There is a wiring system that can be connected also to the gate device 103 and is excellent in workability. In this wiring system, one or a plurality of switch boxes 102 embedded and disposed at appropriate positions in a building are provided, and a power line 110 and an information line 111 that are wired in advance in a wall surface between the switch boxes 102 are sent and wired. At the same time, with respect to the switch box 102 at the starting end, a field line 110 drawn indoors through the main breaker MB and the branch breaker BB drawn into the wiring board 101, and a gateway 120 ( Information line 111 connected via a router and a hub is connected. It is also possible to incorporate the audio transmission system according to the present invention into such a wiring system.

1 is a system configuration diagram showing Embodiment 1 of the present invention. It is a block diagram of the surrounding noise detection part in the same as the above. It is operation | movement explanatory drawing at the time of the extension call in the same as the above. It is a system block diagram which shows Embodiment 2 of this invention. It is a system configuration diagram of a wiring system incorporating the same.

Explanation of symbols

1 Master unit (main unit)
2A, 2B, 2C, 2D Voice terminal device 14 Call processing unit 18 Control unit 28 Ambient noise detection unit

Claims (2)

One or more voice input terminal devices provided with at least voice input means for inputting voice, one or more voice output terminal devices provided with voice output means for outputting at least voice, voice input terminal devices, and voice output terminals An audio transmission system comprising: a main apparatus connected to the apparatus via a signal line composed of a pair of pair wires; and a time division multiplexing transmission of an audio signal from the audio input terminal apparatus to the audio output terminal apparatus via the main apparatus. There,
The audio output terminal device includes: an audio signal receiving unit that receives an audio signal transmitted in a downlink time slot via the signal line; an ambient noise detecting unit that detects the magnitude of ambient noise at an installation location; Control signal transmission means for transmitting a control signal to and from the main apparatus via the signal line, and control means for notifying the main apparatus of the ambient noise detection value detected by the ambient noise detection means,
The main apparatus receives the audio signal transmitted by the audio input terminal device in the uplink time slot and transmits the audio signal to the audio output terminal device in the downlink time slot; and the signal line Control signal transmission means for transmitting a control signal to and from the voice output terminal device via the voice signal volume of the voice signal transmitted to the voice output terminal device when the ambient noise detection value is received from the voice output terminal device by the control signal And a sound volume adjusting means for adjusting the sound volume according to the ambient noise detection value. At least one of the plurality of audio input terminal devices or audio output terminal devices includes an imaging unit, a modulation unit that modulates video captured by the imaging unit, and a video signal modulated by the modulation unit as an audio signal Video signal transmitting means for transmitting in a frequency band different from the frequency band of
The main apparatus is a video signal receiving means for receiving the video signal transmitted by the audio input terminal apparatus or the audio output terminal apparatus, a demodulating means for demodulating the video signal received by the video signal receiving means, and demodulated by the demodulating means. voice transmission system according to claim 1, characterized by comprising a display means for displaying an image.

Images