JP5291577B2 - 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, it is possible to accurately discriminate a voice part by using a cepstrum analysis method with respect to a voice signal mixed with noise, and to predict noise with respect to the voice signal mixed with noise, and to remove the noise, thereby improving the quality. An audio signal processing device is disclosed that obtains an audio signal and cuts out the audio from the audio signal so that the audio can be accurately cut out and recognized by the audio (see, for example, Patent Document 1).

  In addition, similar to the voice signal processing apparatus described in Patent Document 1, an interphone system of Japanese Patent Application No. 2008-19063 has been filed, which can recognize a voice signal and determine whether it is a silence signal or a voice signal. Yes.

Japanese Patent No. 3106543

  According to the intercom system of Japanese Patent Application No. 2008-19063 among the background arts, a digital audio signal is divided into a plurality of frequency bands, a predetermined threshold value is set for each divided frequency band, and a comparison with this threshold value is also made. For example, if the noise level in the surrounding environment outside the dwelling unit is higher than the noise level in the surrounding environment inside the dwelling unit, If the voice sent by the resident in the room is output as the incoming voice outside the dwelling unit, the voice sent by the resident needs to be higher than the noise (background noise) level. As a result, the formation of the communication path is biased, and it is difficult to secure the communication path in the transmission state.

  In addition, when a call path in the receiving state is formed for the resident, the voice received by a visitor outside the dwelling tends to be louder than necessary, while the voice received by the resident is a noise in the surrounding environment outside the dwelling. It was difficult for visitors to hear and it was difficult for listeners to ensure good call quality.

  The present invention was made in order to solve these problems, and switching the communication path formed in the master unit when transmitting and receiving voice signals to and from the entrance unit is performed around the inside and outside of the dwelling unit. It is an object of the present invention to provide an intercom system that can be executed without bias without depending on the difference in noise level in the environment, and that can secure a good call quality that is easy to hear for a listener even in various environments.

  In order to achieve the above object, an intercom system according to a first aspect of the present invention includes an entrance cordless handset having a handset microphone and handset speaker and an entrance cord via a wired transmission path or a wireless transmission path. The main unit microphone and the main unit speaker having a main unit speaker for inputting / outputting audio signals for establishing a call between the sub unit microphone and the sub unit speaker of the entrance slave unit are provided. . 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 A voice processing unit for controlling transmission / reception switching of the digital voice signal and the received digital voice signal transmitted through the transmission line from the transmission path to the master voice codec. The speech processing unit includes a transmission side attenuator for attenuating the signal voltage of the transmission digital audio signal, a transmission side noise level estimation circuit for estimating the noise level of the transmission digital audio signal, and the transmission side. Calculates the transmitted voice discrimination threshold obtained by adding the offset value set to discriminate whether the transmitted digital voice signal is a silence signal or a voice signal to the noise level estimated by the noise level estimation circuit For determining whether the transmission digital audio signal is a silence signal or a sound signal based on a comparison between the transmission side threshold control circuit and the transmission voice discrimination threshold calculated by the transmission side threshold control circuit A transmitter signal discrimination circuit, a receiver attenuator for attenuating the signal voltage of the receiver digital voice signal, and a receiver noise level estimate for estimating the noise level of the receiver digital voice signal. Received voice discrimination obtained by adding an offset value set to determine whether the received digital voice signal is a silence signal or a voice signal to the noise level estimated by the circuit and the receiver noise level estimation circuit Reception for determining whether the received digital audio signal is a silence signal or a sound signal based on a comparison between the reception side threshold control circuit for calculating the threshold and the reception voice determination threshold calculated by the reception side threshold control circuit Side signal discriminating circuit, and a comparator for comparing the signal level discriminated as a sound signal in the transmitting side signal discriminating circuit and the receiving side signal discriminating circuit, and the transmitting side attenuator and the receiving side attenuator respectively And an attenuator control circuit for controlling the attenuation level by inserting a loss. The comparator of the attenuator control circuit includes the difference between the signal voltage of the transmitted digital voice signal determined as a voiced signal on the transmitting side and the transmitted voice determination threshold value, and the received digital voice determined as a voiced signal on the receiving side. This has a function of comparing the signal voltage of the signal and the difference between the received voice discrimination thresholds.

In the intercom system according to the second aspect of the present invention, in the first aspect of the present invention, the noise level estimated by the transmission-side noise level estimation circuit is small on the output side of the transmission-side attenuator. Corresponding to the above, a transmission side signal level control circuit for amplifying or attenuating the signal level of the transmission digital audio signal is provided.

In the intercom system according to the third aspect of the present invention, in the first aspect of the present invention, the output side of the reception side attenuator corresponds to the magnitude of the noise level estimated by the reception side noise level estimation circuit. Thus, a receiving side signal level control circuit for amplifying or attenuating the signal level of the received digital audio signal is provided.

  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. When the voice processing unit of the living room base unit performs transmission / reception switching control with the transmitting side digital audio signal to be output as the received voice from the voice processing unit, the attenuator control circuit of the voice processing unit is outside the dwelling unit where the entrance cordless handset is installed. Even if there is a difference between the noise level and the noise level in the dwelling unit where the master unit is installed, it is not dependent on the level difference or the level is adjusted equally by the adjuster. did Compared with the difference of the signal level of the voice signal that is determined to be a voice signal, the comparison is made by the comparator, and the switching of the speech path between the transmitting state and the receiving state in the room master unit is biased. Can be performed accurately.

  In addition, according to the intercom system of the present invention, the speaker can be made to correspond to the noise level outside the dwelling unit where the entrance cordless handset is installed and the noise level inside the dwelling unit where the base unit is installed. The signal level of the output signal from can be amplified or attenuated, and good call quality that is easy to hear for the receiver can be ensured even in various environments.

FIG. 1 is a block diagram showing an overall configuration of an intercom system according to an embodiment of the present invention. FIG. 2 is a block diagram showing a specific configuration of the audio processing unit of the living room master unit in the intercom system according to the embodiment of the present invention. 3 (A), (B), (C), and (D) respectively show the signal processing of the transmitted digital audio signal performed by the audio processing unit of the living room base unit in the interphone system according to the embodiment of the present invention. It is a signal waveform diagram which shows an example. 4 (A), (B), (C), and (D) are examples of signal processing of received digital audio signals performed in the audio processing unit of the living room master unit in the interphone system according to the embodiment of the present invention. FIG.

  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 an overall 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 used to capture a video of a visitor who has performed a call operation and a video (surveillance video) in the vicinity of the outside of the dwelling unit. The camera 101 includes various video imaging media such as a CCD and a CMOS. ing. 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 (A / D conversion) of an analog voice signal, which is a transmitted voice input to the handset microphone 103, into a digital voice signal, and will be described later of the room base unit 2. Digital / analog conversion (D / A conversion) of a digital voice signal, which is a received voice input to the base unit microphone 202 and transmitted via the wired transmission path L1a or the wireless transmission path L1b, into an analog voice signal. This is for outputting 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 unit 2, the monitor 200 is controlled by the CPU 207 (to an image output state), and not only displays the video imaged by the camera 101 of the front door unit 1, but also a call by the visitor. For example, it is composed of 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 that there is a call 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 audio processing unit 205 is controlled by the CPU 207, and transmits a digital audio signal transmitted on the transmission line L2a from the master audio codec 204 to the wired transmission path L1a or the wireless transmission path L1b, and the wired transmission path. This is for switching control of the transmission / reception operation with the received digital audio signal transmitted on the reception line L2b from the L1a or the wireless transmission line L1b to the main unit audio codec 204.

  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). (Via) signal transmission line between base unit processing unit 205 or wireless transmission path L1b and signal transmission line between voice processing unit 205 (via transmission line L2a or reception line L2b) and wired transmission This is for forming a signal transmission line between the path L1a and the CPU 207 or a signal transmission line between the wireless transmission path 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 voice processing unit 205 includes a transmission side attenuator 250a, a transmission side noise level estimation circuit 251a, a transmission side threshold control circuit 252a, a transmission side signal determination circuit 253a, a transmission side signal level control circuit 254a, and a reception side. A side attenuator 250b, a reception side noise level estimation circuit 251b, a reception side threshold control circuit 252b, a reception side signal discrimination circuit 253b, a reception side signal level control circuit 254b, and an attenuator control circuit 255 are provided.

  In this voice processing unit 205, a transmission side attenuator 250a is provided on a transmission line L2a from the main unit audio codec 204 to the main unit I / F 208, and is a digital audio signal (resident's) transmission audio ( In attenuating the signal voltage of the transmitted digital voice signal), this signal voltage is controlled by the attenuator control circuit 255. The receiver attenuator 250b is provided on the reception line L2b from the parent device I / F 208 to the parent device voice codec 204, and is a signal voltage of a digital voice signal (received digital voice signal) which is a received voice (of a visitor). This signal voltage is controlled by the attenuator control circuit 255 when the signal is attenuated.

  The transmission side noise level estimation circuit 251a is for estimating the noise level of the transmission digital voice signal. The receiver noise level estimation circuit 251b is for estimating the noise level of the received digital audio signal.

  The transmission-side threshold control circuit 252a is an offset value that is set to determine whether the transmission digital audio signal is a silence signal or a sound signal at the noise level estimated by the transmission-side noise level estimation circuit 251a. Is used to calculate the transmitted voice discrimination threshold value obtained by adding. Further, the reception side threshold control circuit 252b sets an offset value set for determining whether the reception digital audio signal is a silence signal or a sound signal at the noise level estimated by the reception side noise level estimation circuit 251b. The received voice discrimination threshold obtained by the addition is calculated.

  The transmission side signal discrimination circuit 253a discriminates whether the transmission digital audio signal is a silence signal or a sound signal based on the comparison with the transmission audio discrimination threshold calculated by the transmission side threshold control circuit 252a. Is for. Further, the reception side signal determination circuit 253b determines whether the reception digital sound signal is a silence signal or a sound signal based on the comparison with the reception sound determination threshold value calculated by the reception side threshold control circuit 252b. Is.

  The transmission side signal level control circuit 254a corresponds to the magnitude of the noise level estimated by the transmission side noise level estimation circuit 251a, and the signal level of the transmission digital audio signal which is the output of the transmission side attenuator 250a. Is for amplifying or attenuating. Further, the receiver signal level control circuit 254b amplifies the signal level of the receiver digital audio signal that is the output of the receiver attenuator 250b in accordance with the magnitude of the noise level estimated by the receiver noise level estimation circuit 251b. Or for damping.

  The attenuator control circuit 255 includes a comparator 255a for comparing the signal level determined to be a voice signal by the transmission side signal determination circuit 253a and the reception side signal determination circuit 253b, and the transmission side attenuator 250a and the reception side. A loss is inserted into each of the side attenuators 250b to control the attenuation level, and this comparator 255a determines the signal level of the transmitted digital audio signal determined as a voice signal on the transmitting side and the transmitted audio discrimination It has a function of comparing the difference between the threshold value and the difference between the signal level of the received digital voice signal determined as a voiced signal on the receiving side and the received voice discrimination threshold value.

  The attenuator control circuit 255 not only compares the noise level estimated by the transmitting side noise level estimating circuit 251a and the receiving side noise level estimating circuit 251b with the comparator 255a, but also the comparator 255a. An adjuster 255b is provided for adjusting the level by making the signal levels of both the transmitting side and the receiving side corresponding to each other in reverse, and this adjuster 255b has a ratio corresponding to the magnitude of both estimated noise levels. The function of adjusting the level by multiplying the signal level of both the transmitting side and the receiving side input to the comparator 255a by the reciprocal number of. 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 S1 generated by the slave unit operation unit 100 is transmitted to 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. Via the CPU 207.

  Upon receiving the call signal S1 from the entrance child device 1, the CPU 207 of the living room parent device 2 outputs a ringing sound or a voice message indicating that there is a call by a visitor from the parent device speaker 203, and issues a call notification. Control is performed so that the monitor 200 and the parent device image processing unit 201 and the camera 101 and the child device image processing unit 102 of the entrance child device 1 become active.

  The camera 101 of the entrance cordless handset 1 starts capturing images of the visitor who has performed the call operation (including images near the outside of the dwelling unit) and generates a video signal S2. The video signal S2 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, It is transmitted to the parent device video processing unit 201 via the parent device I / F 208 of the living room parent device 2. In addition, the master video processing unit 201 performs predetermined signal processing such as FM demodulation and amplification on the received video signal S2, for example, so that a video of the visitor captured by the camera 101 of the entrance cordless handset 1 ( The image of the vicinity of the outside outside the dwelling unit is displayed on the monitor 200. Note that the monitor 200 can display not only the above-described video image display but also a call message or picture data indicating that there is a call by a visitor under the control of the CPU 207.

  Thereafter, the resident who has confirmed that the visitor has called from the entrance cordless handset 1 together with the discrimination of the visitor uses the base unit operation unit 206 of the room base unit 2 to perform a predetermined response operation. When the CPU 207 detects this operation, the CPU 207 controls the base unit audio codec 204 and the audio processing unit 205 and the sub unit audio codec 105 of the front door unit 1 to be active.

  As a specific audio signal transmission / reception operation, an analog audio signal of a voice transmitted by a resident input to the main unit microphone 202 of the living room main unit 2 shown in FIG. The digitally-converted transmission digital audio signal S20 is transmitted to the transmission-side attenuator 250a, the transmission-side noise level determination circuit 251a, and the transmission-side signal determination circuit 253a of the audio processing unit 205 shown in FIG. Here, the transmission-side noise level estimation circuit 251a calculates an average value with a long constant of several hundred milliseconds to several seconds for a predetermined frequency band of the received transmission digital audio signal S20, for example, a band of 300 to 7000 Hz. The noise level is calculated and estimated. For example, the transmission-side noise level Vn2 of the signal voltage shown in FIG. 3A is converted into the transmission-side threshold control circuit 252a, the transmission-side signal determination circuit 253a, and The data is sent to the transmission side signal level control circuit 254a. Note that the transmission-side noise level Vn2 is variable under the surrounding environment of the base unit microphone 202, that is, in accordance with the level of the noise level in the dwelling unit where the living room base unit 2 is installed.

  Further, in the voice processing unit 205 of the living room master unit 2, the transmission side threshold value control circuit 252a causes the transmission digital audio signal S20 to be silenced at the transmission side noise level Vn2 estimated by the transmission side noise level estimation circuit 251a. A transmission voice discrimination threshold Vt2 of the signal voltage shown in FIG. 3 (B) obtained by adding a predetermined offset value set to discriminate whether the signal is a signal or a voice signal is calculated. The data is sent to the determination circuit 253a and the attenuator control circuit 255, respectively.

  Further, in the voice processing unit 205 of the living room master unit 2, the transmission side signal determination circuit 253 a calculates the average value of the signal voltage in the predetermined frequency band of the transmitted digital voice signal S 20 from the base unit voice codec 204. Then, the calculated signal level V20 is compared with the transmission voice discrimination threshold Vt2 calculated by the transmission-side threshold control circuit 252a, and the comparison result is “V20 < If the relationship is “Vt2”, it is determined that the transmitted digital audio signal S20 is a silence signal, while the relationship “V20 ≧ Vt2” as shown in FIG. It is determined that the transmitted digital audio signal S20 is a sound signal. Further, the transmission side signal determination circuit 253a detects the peak signal voltage level of the transmission digital audio signal S20 determined to be sound, and transmits the transmission side detection level V20a to the attenuator control circuit 255.

  On the other hand, it is an analog voice signal of a voice sent by a visitor input to the handset microphone 103 of the entrance handset 1 shown in FIG. The signal S10 is transmitted through the slave unit I / F 106, the wired transmission path L1a or the wireless transmission path L1b, the master unit I / F 208 of the living room master unit 2, and the receiver attenuator 250b of the voice processing unit 205 shown in FIG. The data are transmitted to the receiving side noise level discrimination circuit 251b and the receiving side signal discrimination circuit 253b, respectively. Here, the reception side noise level estimation circuit 251b calculates an average value with a long constant of several hundred milliseconds to several seconds for a predetermined frequency band of the received reception digital voice signal S10, for example, a band of 300 to 7000 Hz. The noise level is estimated and, for example, the reception side noise level Vn1 of the signal sound pressure shown in FIG. 4A is received as the reception side threshold control circuit 252b, reception side signal determination circuit 253b, and reception side signal level. Each is sent to the control circuit 254b. Note that the receiver side noise level Vn1 varies in the ambient environment of the handset microphone 103, that is, in accordance with the noise level outside the dwelling unit where the entrance handset 1 is installed.

  Further, in the voice processing unit 205 of the living room master unit 2, the reception side threshold control circuit 252b receives the received digital voice signal S10 as a silence signal or a sound signal at the reception side noise level Vn1 estimated by the reception side noise level estimation circuit 251b. 4 is obtained by adding a predetermined offset value set to determine whether or not the received signal is received, and the received signal discrimination threshold value Vt1 shown in FIG. 4B is calculated, and the received signal discrimination circuit 253b and the attenuator control circuit 255 are each subjected to the calculation. Send it out.

  Further, in the voice processing unit 205 of the living room master unit 2, the receiver-side signal discrimination circuit 253 b calculates the average value of the signal voltage in the predetermined frequency band of the received receiver digital voice signal S 10, and the calculated signal The level V10 is compared with the received voice discrimination threshold Vt1 calculated by the receiver threshold control circuit 252b, and the comparison result has a relationship of “V10 <Vt1” as shown in FIG. In this case, it is determined that the received digital audio signal S10 is a silence signal. On the other hand, as shown in FIG. 4D, when the relationship of “V10 ≧ Vt1” is satisfied, the received digital audio signal S10 is a voice signal. Determine that there is. In addition, the reception side signal determination circuit 253b detects the peak signal voltage level of the reception digital audio signal S10 determined to be sound, and sends the transmission side detection level V10a to the attenuator control circuit 255.

  Thereafter, in the voice processing unit 205 of the living room master unit 2, the attenuator control circuit 255, as a first control example, as shown in FIG. 3D and FIG. The difference Δ2 between the transmission side detection level V20a (of the transmission digital audio signal S20) detected by the circuit 253a and the transmission voice discrimination threshold Vt2 calculated by the transmission side threshold control circuit 252a, and the reception side signal discrimination The comparator 255a compares the reception side detection level V10a (of the reception digital voice signal S10) detected by the circuit 253b and the difference Δ1 between the reception voice discrimination threshold Vt1 calculated by the reception side threshold control circuit 252b. .

  Here, when the comparison result of the comparator 255a of the attenuator 255 has a relationship of “Δ2> Δ1,” the attenuator control circuit 255 not only suppresses the attenuation level of the transmission side attenuator 250a but also reduces the parent level. The room base unit 2 enters the transmission state by inserting a loss that is a value dependent on the amount of audio feedback from the base unit speaker 203 to the base unit microphone 202 and that does not generate howling into the receiver side attenuator 250b. On the other hand, when the relationship of “Δ2 <Δ1” is satisfied, the attenuator control circuit 255 not only suppresses the attenuation level of the reception side attenuator 250b but also from the child device speaker 104 of the front child device 1 to the child device microphone 103. The room base unit 2 is in a receiving state by inserting a loss that is a value depending on the amount of voice feedback to the terminal and that does not generate howling into the transmitting side attenuator 250a.

  As is clear from the above description, according to the first control example of the attenuator control circuit 255 constituting the voice processing unit 205 of the living room master unit 2, the noise level outside the dwelling unit where the entrance cordless handset 1 is installed and If there is a difference in the noise level inside the dwelling unit where the living room master unit 2 is installed, for example, the noise level outside the dwelling unit is larger than that inside the dwelling unit, and the noise level on the transmitting side and the receiving side is “Vn1> Vn2”. Even when a call having a relationship is established, a comparison is made by directly corresponding to the difference in the signal level of the voice signal determined to be a voice signal without depending on the level difference. The comparison is performed by the device 255a, and the switching of the speech path in the transmitting state or the receiving state in the living room base unit 2 can be performed accurately without any deviation.

  Next, in the voice processing unit 205 of the living room master unit 2, the attenuator control circuit 255 is first started by the transmission side noise level detection circuit 251 a as a second control example different from the first control example described above. The estimated noise level Vn2 on the transmission side and the noise level Vn1 on the reception side estimated by the reception-side noise level detection circuit 251b are discriminated.

  Here, when there is a difference between the noise level outside the dwelling unit where the entrance cordless handset 1 is installed and the noise level inside the dwelling unit where the living room base unit 2 is installed, for example, the noise level outside the dwelling unit is higher than that inside the dwelling unit. When the relationship of “Vn1> Vn2” is large and the ratio of the noise levels on the transmitting side and the receiving side is “Vn1: Vn2 = 4: 1”, When a transmitted voice of the same level is input to the child device microphone 103 of the entrance child device 1 and the parent device microphone 203 of the living room parent device 2, the received sound calculated by the receiving side threshold control circuit 252b of the sound processing unit 250 is received. The voice discrimination threshold Vt1 is set larger, and the room master unit 2 is likely to be in the transmission state. For this reason, there is a tendency for visitors to transmit at a louder volume than when the noise level outside the dwelling is low, and this is detected by the transmitter signal discrimination circuit 253a input to the attenuator control circuit 255 ( The transmission side detection level V20a (for the transmission digital audio signal S20) becomes larger than the reception side detection level V10a (for the reception digital audio signal S10) detected by the reception side signal discrimination circuit 253b. When the master unit 2 transitions to the receiving state, even if the resident sends a sound with a loud volume corresponding to the noise level outside the dwelling unit, it is difficult to enter the transmitting state.

  Therefore, as an example of the adjustment operation, the adjuster 255b of the attenuator 255 multiplies the aforementioned transmission side detection level V20a by “4”, which is the inverse of the ratio of the transmission side, and transmits the transmission side adjustment detection level V20b. By calculating (= 4 · V20a), the comparator 255a compares “V20b” and “V10a” under the assumption that the noise (background noise) level inside and outside the dwelling unit is equivalent.

  According to the above-described example, as the adjustment operation by the adjuster 255b of the attenuator 255, the transmission side detection level V20a is multiplied by “4” which is the reciprocal of the ratio of the transmission side. However, the present invention is not limited to this. Rather than multiplying the reception detection level V10a by "1/4" which is the reciprocal of the ratio of the reception side to calculate the reception side adjustment detection level V10b (= 1/4 · V10a), Comparing “V10b” and “V20a” can be performed by the comparator 255a under the assumption that the noise (background noise) level is the same.

  Here, when the comparison result of the comparator 255a constituting the audio processing unit 205 of the living room master unit 2 has a relationship of “V20b> V10a” and “V20a> V10b”, the attenuator control circuit 255 Not only is the attenuation level of the talk side attenuator 250a kept low, but a loss that is a value that depends on the amount of voice feedback from the master speaker 203 to the master microphone 202 and does not cause howling is inserted into the receiver attenuator 250b. Thus, the living room master unit 2 is in a transmission state. On the other hand, in the case of the relationship of “V20b <V10a” and “V20a <V10b”, the attenuator control circuit 255 not only keeps the attenuation level of the receiving side attenuator 250b low but also the slave unit speaker of the entrance unit 1 By inserting a loss that is dependent on the amount of voice feedback from 104 to the child microphone 103 and that does not cause howling into the transmitting side attenuator 250a, the in-room master unit 2 enters the transmitting state.

  As is clear from the above description, according to the second control example of the attenuator control circuit 255 constituting the audio processing unit 205 of the living room master unit 2, the noise level outside the dwelling unit where the entrance cordless handset 1 is installed and If there is a difference in the noise level inside the dwelling unit where the living room master unit 2 is installed, for example, the noise level outside the dwelling unit is larger than that inside the dwelling unit, and the noise level on the transmitting side and the receiving side is “Vn1> Vn2”. Even when a call having the relationship "is established, the level is adjusted equally by the adjuster 255b and then directly matched to the difference in the signal level of the voice signal determined to be a sound signal. Thus, the comparator 255a performs the comparison, and the switching of the speech path in the transmitting state or the receiving state in the living room master unit 2 can be performed accurately without any deviation.

  Next, when there is a difference between the noise level outside the dwelling unit where the entrance cordless handset 1 is installed and the noise level inside the dwelling unit where the living room base unit 2 is installed, for example, outside the dwelling unit compared to inside the dwelling unit , The transmitter side signal level control circuit 254a of the voice processing unit 205 is connected to the transmitter side when the noise level of the transmitter side and the receiver side has a relationship of “Vn1> Vn2”. After amplifying the signal level of the transmission digital audio signal S20 that is an output signal from the attenuator 250a, the transmission line L2a, the master unit I / F 208, the wired transmission path L1a or the wireless transmission path L1b, and the entrance unit 1 By transmitting to the child device speaker 104 via the child device I / F 106 and the child device voice codec 105, the reception voice of the resident output from the child device speaker 104 is not canceled by the noise outside the dwelling unit. To visitors The easy good signal level to hear me. On the other hand, the reception side signal level control circuit 254b attenuates the signal level of the reception digital audio signal S10 that is an output signal from the reception side attenuator 250, and then passes through the reception line L2b and the main unit audio codec 204 to the main unit speaker 203. , The received voice of the visitor output from the main unit speaker 203 becomes a good signal level that is easy for the resident to hear rather than a louder volume than necessary.

  Further, for example, when the noise level in the dwelling unit is larger than that outside the dwelling unit and the noise levels on the transmitting side and the receiving side have a relationship of “Vn1 <Vn2”, the transmission of the voice processing unit 205 is performed. The speech signal level control circuit 254a attenuates the signal level of the transmitted digital audio signal S20, which is an output signal from the transmit side attenuator 250a, and then transmits the transmission line L2a, the master unit I / F 208, and the wired transmission line L1a. Alternatively, the resident's received voice output from the slave unit speaker 104 is transmitted to the slave unit speaker 104 via the wireless transmission path L1b, the slave unit I / F 106 of the front door unit 1 and the slave unit audio codec 105. However, the signal level is not louder than necessary, and the signal level is easy to hear for visitors. On the other hand, the reception side signal level control circuit 254b amplifies the signal level of the reception digital audio signal S10, which is an output signal from the reception side attenuator 250, and then passes through the reception line L2b and the main unit audio codec 204 to the main unit speaker. By transmitting to 203, the reception voice of the visitor output from the main unit speaker 203 is not canceled by the noise in the dwelling unit, and has a good signal level that is easy for the resident to hear.

  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, for example, as long as the effects of the present invention are obtained, for example, Even an intercom system having the entrance cordless handset incapable of image capturing / processing functions (101, 102) and the living room base unit incapable of image output / processing functions (200, 201). It goes without saying that it can be adopted.

DESCRIPTION OF SYMBOLS 1 ... Entrance child machine 103 ... Child machine microphone 104 ... Child machine speaker 2 ... Living room parent machine 202 ... Parent machine microphone 203 ... Parent machine speaker 204 ... Parent machine voice codec 205 ... Voice processing part 250a ...... Sending side attenuator 250b ...... receiving side attenuator 251a …… sending side noise level estimation circuit 251b …… receiving side noise level estimation circuit 252a …… sending side threshold control circuit 252b …… receiving side threshold control circuit 253a… ... Send-side signal discriminating circuit 253b ... Receiving-side signal discriminating circuit 254a ... Send-side signal level control circuit 254b ... Receiving-side signal level control circuit 255 ... Attenuator control circuit 255a ... Comparator 255b ... Adjuster L1a …… Wired transmission line L1b …… Wireless transmission line L2a …… Send line L2b …… Receive line

Claims (3)

An entrance cordless handset (1) having a handset microphone (103) and a handset speaker (104) and a wired transmission path (L1a) or a wireless transmission path (L1b) are connected to the entrance cordless handset, A room base unit (2) having a base unit microphone (202) and a base unit speaker (203) for inputting and outputting audio signals for establishing a call between the handset microphone and the handset speaker of the entrance handset ) And
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 The transmission digital voice signal transmitted through the transmission line (L2a) to and the reception digital voice signal transmitted through the transmission line (L2b) from the transmission path to the master voice codec are controlled for transmission / reception switching. An audio processing unit (205) for
The voice processing unit includes a transmission side attenuator (250a) for attenuating the signal voltage of the transmission digital voice signal, and a transmission side noise level estimation for estimating the noise level of the transmission digital voice signal. An offset value set to determine whether the transmitted digital audio signal is a silence signal or a sound signal at the noise level estimated by the circuit (251a) and the transmission-side noise level estimation circuit; Based on the comparison between the transmission side threshold control circuit (252a) for calculating the transmission voice discrimination threshold obtained by addition and the transmission voice discrimination threshold calculated by the transmission side threshold control circuit, the transmission side A transmitting side signal discriminating circuit (253a) for discriminating whether the digital audio signal is a silent signal or a voiced signal, and a receiving side apparel for attenuating the signal voltage of the received digital audio signal. A receiver (250b), a receiving side noise level estimating circuit (251b) for estimating a noise level of the received digital voice signal, and the received digital voice signal at a noise level estimated by the receiving side noise level estimating circuit. A reception side threshold control circuit (252b) for calculating a reception voice discrimination threshold obtained by adding an offset value set to determine whether the signal is a silence signal or a sound signal; and the reception side threshold control circuit A receiving side signal discriminating circuit (253b) for discriminating whether the received digital audio signal is a silent signal or a voiced signal based on the comparison with the received voice discriminating threshold calculated in the above, a transmitting side signal discriminating circuit, A comparator (255a) for comparing the signal voltage determined to be a voice signal by the receiver side signal determination circuit, the transmitter attenuator; A attenuator control circuit for controlling the attenuation level by inserting a loss each serial receiver side attenuator (255),
The comparator of the attenuator control circuit includes a difference between a signal voltage of the transmitted digital voice signal determined as a voiced signal on the transmitting side and a threshold value of the transmitted voice determination threshold, and a voiced signal on the receiving side. An intercom system having a function of comparing a signal voltage of the received digital audio signal determined and a difference between the received audio determination thresholds. The output side of the transmission side attenuator is for amplifying or attenuating the signal level of the transmission digital audio signal in accordance with the magnitude of the noise level estimated by the transmission side noise level estimation circuit. The intercom system according to claim 1, further comprising a transmitter signal level control circuit (254a). On the output side of the reception side attenuator, a reception side signal for amplifying or attenuating the signal level of the reception digital audio signal in correspondence with the magnitude of the noise level estimated by the reception side noise level estimation circuit The intercom system according to claim 1, further comprising a level control circuit (254b).

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