JP2011163725A - Remote controller for water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a remote controller for a water heater, which cancels noise not to be heard as noise even when the noise exists in the voice signal of an intercom. <P>SOLUTION: The remote controller for the water heater having an intercommunication function for allowing communication between a bath remote controller and a kitchen remote controller of the water heater, and includes a speaker and a speaker amplification means that drives the speaker, wherein the speaker amplification means does not output the voice output signal or suppresses it to less than a prescribed output level when the voice input signal is less than a prescribed input level. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a remote controller for a water heater equipped with a telephone call function between remote controllers inside and outside the bathroom.

  In order to improve the convenience of the water heater remote control, recently there has been an increase in the number of intercom functions that allow calls between the bath remote control and the kitchen remote control. In order to realize such an intercom function, in a simple configuration in the early days, transmission and reception were switched by a user's switch operation.

  However, when calling from a bathroom to a family in the kitchen using a remote control, the called family must go to the kitchen remote control and operate the kitchen remote control, which is not convenient. It was.

  Under such circumstances, an interphone with a monitor TV called a TV door phone has appeared as a front door interphone, and hands-free has become common (see, for example, Patent Document 1). Hands-free is a function that allows you to hold a handset called a handset and have a conversation without putting the handset in your ear. Of course, switching between sending and receiving is also unnecessary for user operation.

  However, such a hands-free intercom function is not the main function in the remote control of a water heater, so if you try to add an interphone function to the remote control of a water heater, you do not increase the cost as much as possible. It is necessary to install. Therefore, a water heater remote controller that has been devised to handle hands-free using half duplex bidirectional communication has been devised (see, for example, Patent Document 2).

  Such a water heater remote controller determines whether the sound pressure determination means has a sound pressure higher than a set level based on the sound signal received by the microphone, and activates the transmission means if the sound pressure is higher than the set level. , Send a message. However, since the sound pressure determination means determines the sound pressure and starts transmitting, there is a case where there is a delay of approximately 0.2 seconds in transmission and the first word of the conversation may not be heard.

  Later, by improving the voice switch technology for hands-free, an inexpensive voice switch IC was developed, and it was possible to mount it on the water heater remote control with less cost burden. Therefore, the remote controller for the water heater also adopts a voice switch IC to perform full-duplex communication, enabling simultaneous two-way calls.

  In recent years, the number of people who die while taking a bath in the bathroom is more than 10,000 people per year, and the use of equipment for preventing accidents in the bathroom, such as bathroom heating, has been promoted. However, devices that detect accidents that occur in the bathroom are either expensive or have their installation involved, or are not readily available.

  Under such circumstances, conventionally, a remote controller for a water heater is known that uses the intercom function provided in the remote controller of the water heater, monitors the sound in the bathroom, and checks the state of the bather (for example, Patent Documents). 3).

In such a remote control for a water heater, the sound of the bathroom is picked up by the microphone of the remote controller and transmitted to the kitchen remote controller, so that the sound of the bathroom can always be heard by the speaker of the kitchen remote controller. This function is called a bathroom monitor function. Furthermore, in order to make such a bathroom monitor function easy to use, a remote controller for water heaters has been devised in which automatic gain control means is provided in the microphone means of the remote control or automatic gain control means is provided in the speaker means of the kitchen remote control. (For example, see Patent Document 4).

JP 2006-50260 A JP 2006-170554 A JP 2001-208422 A JP 2007-278598 A

  However, the conventional water heater remote controller has a problem that when receiving external electromagnetic noise (hereinafter referred to as noise), the noise is heard by the user as noise. The noise will be described in detail below.

  First, as external electromagnetic noise (noise), there are noise generated from the water heater itself, noise generated from other devices, broadcast waves such as AM radio. Although noise is regulated by laws and regulations, when a weak intercom signal is amplified, even small noise that does not affect the operation of a normal device may be heard as noise.

  In the case of the configuration as in Patent Document 2, the sound pressure from the microphone is determined, and the voice is transmitted only when the sound pressure exceeds the set level. Therefore, even if there is a small noise, the sound pressure above the set level. It will be heard at the same time as the voice with. Therefore, the user is less likely to notice noise.

  However, the water heater remote control that enables simultaneous two-way communication using full-duplex communication using a voice switch IC is susceptible to noise. Hereinafter, this state will be described in detail.

  First, when there is no audio in both the bathroom remote control and the kitchen remote control in the call state, the voice enters the idle state, and the audio signal from the bathroom remote control to the kitchen remote control is the audio signal from the kitchen remote control to the kitchen remote control. Are both attenuated by -20 dB. In other words, the volume of the call is reduced, and the audio signal is not completely cut off. If either of them has an audio signal, the audio is amplified by +6 dB, and the reverse direction is attenuated by -46 dB so that the audio signal is clearly transmitted and howling is prevented.

  In the idling state described above (when there is no audio signal in both remote controllers), although the attenuation of −20 dB is applied, the speaker amplifier is in an operating state. When noise enters in this state, attenuation of −20 dB is applied on the input side of the voice switch IC, but noise is input to the speaker amplifier as it is on the output side of the voice switch IC.

  In this case, there is no sound signal originally and no sound can be heard from the speaker, so only noise due to noise is heard by the user. In other words, the adoption of the voice switch IC enables simultaneous two-way calls, which enables more natural calls, and improves usability, but has the problem of being easily affected by noise.

  Also, as in Patent Document 3 and Patent Document 4, when the intercom function is used and the bathroom monitor function is realized, the kitchen remote control always sets the speaker amplifier to the operating state, and the audio signal sent from the full remote control As it continues to ring from the speaker. Even in this situation, if there is noise, there is a problem that it is heard as noise from the speaker of the kitchen remote control.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a water heater remote controller that prevents a voice signal of an interphone from being heard as noise even if the noise is present.

  In order to solve the above-mentioned conventional problems, a hot water heater remote control according to the present invention is a water heater remote control having an interphone function capable of making a call between a bath remote control of a water heater and a kitchen remote control, and drives a speaker and a speaker. The speaker amplifying unit includes a speaker amplifying unit. When the audio input signal is less than a predetermined input level, the speaker amplifying unit does not output the audio output signal or suppresses the audio output signal to be less than the predetermined output level. In the case of an input signal, the audio signal is not output or is suppressed to a level lower than a predetermined level, so that it can be reduced to a level at which noise cannot be heard from the speaker or noise is not a concern.

  INDUSTRIAL APPLICABILITY The present invention can provide a water heater remote control that prevents a voice signal of an interphone from being heard as noise even if the noise is present.

Block diagram of a water heater provided with a water heater remote controller in Embodiment 1 of the present invention Detailed block diagram of speaker amplifying means 5 and speaker amplifying means 15 of the water heater remote controller in the first embodiment Characteristic diagram of audio input signal vs. audio output signal in the first embodiment Detailed block diagram of speaker amplifying means 5 and speaker amplifying means 15 of the water heater remote controller in Embodiment 2 of the present invention Characteristic diagram of audio input signal vs. audio output signal in the second embodiment Detailed block diagram of speaker amplifying means 5 and speaker amplifying means 15 of the water heater remote controller in Embodiment 3 of the present invention Characteristic diagram of audio input signal vs. audio output signal in the third embodiment Detailed block diagram of speaker amplifying means 5 and speaker amplifying means 15 of the water heater remote controller in Embodiment 4 of the present invention Characteristic diagram of audio input signal vs. audio output signal in the fourth embodiment

  A water heater remote controller according to a first aspect of the present invention is a water heater remote controller having an interphone function capable of making a call between a bath remote controller of a water heater and a kitchen remote controller, and includes a speaker and speaker amplification means for driving the speaker. When the voice input signal is less than the predetermined input level, the voice output signal is not output, or when the voice input signal is lower than the predetermined output level, there is no voice of the call and only the noise is included in the voice input signal. In addition, since the audio signal is not output or is suppressed to a level lower than a predetermined level, it can be reduced to a level at which noise cannot be heard from the speaker or the noise is not a concern.

The water heater remote control according to the second invention is the remote controller according to the first invention, particularly in the first invention, wherein the speaker amplifying means is a speaker amplifier, a level determining means for determining the magnitude of the audio input signal of the speaker amplifier, and a determination result of the level determining means. If the level determination means determines that the audio input signal is less than the predetermined input level, the switching means stops the operation of the speaker amplifier so that there is no original audio signal. Even if only noise is input to the speaker amplifying means as an audio input signal, the audio signal, that is, noise is determined to be less than a predetermined input level by the level determining means, and the speaker amplifier is turned off. Is not output and the noise is heard by the user as noise No.

  According to a third aspect of the present invention, in the first aspect, the speaker amplifying unit includes a speaker amplifier, a level determining unit that determines the magnitude of the audio input signal of the speaker amplifier, and a determination result of the level determining unit. Switching means for switching the amplification factor of the speaker amplifier, and when the level determination means determines that the audio input signal is less than the predetermined input level, the switching means switches the amplification factor of the speaker amplifier to the lower side, Even if there is no audio signal and only noise is input to the speaker amplifying means as an audio input signal, the audio signal, that is, noise is determined to be less than a predetermined input level by the level determining means, and the amplification factor of the speaker amplifier is low Therefore, the audio output signal is not amplified greatly, but is output small. 'S is less likely to be heard as noise to the user, it is difficult to notice.

  The water heater remote control according to a fourth aspect of the invention is particularly the first aspect of the invention, wherein the speaker amplifying means comprises a speaker amplifier and a signal blocking means provided on the voice input signal side of the speaker amplifier, and the signal blocking means is a voice input signal. By blocking the audio input signal when the signal is less than a predetermined level, even if only the noise is input to the speaker amplification means as the audio input signal without the original audio signal, the audio signal, that is, the noise is Therefore, since the signal blocking means blocks noise, no noise is output as an audio output signal from the speaker amplifier, and the noise is not heard by the user.

  The water heater remote control according to a fifth aspect of the present invention is the remote controller of the fifth aspect, particularly in the first aspect, wherein the speaker amplifying means comprises a speaker amplifier and a signal attenuating means provided on the audio input signal side of the speaker amplifier. By attenuating the audio input signal when the noise level is less than the predetermined level, even if only the noise is input to the speaker amplifying means as the audio input signal without the original audio signal, the audio signal, that is, the noise is Since it is determined that the input level is lower than the predetermined input level and the sound signal is attenuated by the attenuating means and transmitted to the speaker amplifier, the sound output signal is output largely and not amplified, so that the noise is heard as noise by the user. Difficult to notice.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram of a water heater provided with a water heater remote controller according to the first embodiment of the present invention.

  In FIG. 1, in the remote controller 1, the microphone 2, the microphone amplifying means 3, the speaker 4, the speaker amplifying means 5, and the communication means 6 constitute an interphone function. The microphone means 9 includes a microphone 2 and a microphone amplifying means 3, and the speaker means 10 includes a speaker 4 and a speaker amplifying means 5. Further, the microcomputer 7 inputs the call switch 8 and activates / stops the communication means 6.

  In the kitchen remote controller 11, the microphone 12, the microphone amplifying means 13, the speaker 14, the speaker amplifying means 15, the voice switch means 22, and the communication means 16 constitute an interphone function. The microphone unit 19 includes a microphone 12 and a microphone amplification unit 13, and the speaker unit 20 includes a speaker 14 and a speaker amplification unit 15. Further, the microcomputer 17 inputs the call switch 18 and activates / stops the communication means 16. The bathroom water heater 21 is connected to the bath remote controller 1 and the kitchen remote controller 11.

  The microphone means 9, speaker means 10 and communication means 6 of the remote controller 1 and the microphone means 19, speaker means 20, communication means 16 and voice switch means 22 of the kitchen remote control 11 constitute a voice call function.

  FIG. 2 shows a detailed block diagram of the speaker amplifying means 5 and the speaker amplifying means 15 of the water heater remote controller according to the first embodiment of the present invention.

  In FIG. 2, the audio input signal is input to the speaker amplifier 23 and also input to the level determination unit 24. The determination result of the level determination unit 24 is input to the switching unit 25, and the switching unit 25 turns on and off the operation of the speaker amplifier 23.

  The operation and action of the water heater remote controller configured as described above will be described below.

  First, the operation of the intercom function using the voice switch means 22 will be described. When the user presses the call switch 8 of the remote controller 1 or when the user presses the call switch 18 of the kitchen remote controller 11, the intercom function is activated. The voice switch means 22 is a kind of means for switching between intercom reception and transmission. Compare the incoming and outgoing volume, and convey the louder sound.

  For example, the microphone 2 of the remote controller 1 receives sound, is amplified by the microphone amplifying means 3, and transmits the audio signal to the kitchen remote controller 11 by the communication means 6. In the kitchen remote controller 11, the communication means 16 receives the audio signal from the remote controller and transmits it to the voice switch means 22. For the voice switch means 22, this voice signal becomes the reception volume.

  In the kitchen remote controller 11, the microphone 12 inputs sound, is amplified by the microphone amplification means 13, and is transmitted to the voice switch means 22. For the voice switch means 22, this signal becomes the transmission volume.

  When both the reception volume and the transmission volume are equal to or lower than the set volume (referred to as an idling state), the voice switch means 22 gives −20 dB attenuation to the transmission volume and −20 dB attenuation to the reception volume. Therefore, when neither the remote controller 1 nor the kitchen remote controller 11 is speaking, the other party's sound is a small sound attenuated by -20 dB, but this is not a problem because it is not speaking.

  When talking is started on the side of the remote controller 1, it is determined that the received volume of the voice switch means 22 exceeds the set volume, and that the received volume is large in comparison between the received volume and the transmitted volume. In this case, the voice switch means 22 gives an amplification of +6 dB to the reception volume, and conversely gives a large attenuation of -46 dB to the transmission volume. Therefore, the sound on the side of the remote controller 1 is amplified by +6 dB by the voice switch means 22, further amplified by the speaker amplification means 15, and output as a loud sound from the speaker 14. Thereby, the sound on the side remote controller 1 side is transmitted to the kitchen remote controller 11 side. At this time, the sound output from the speaker 14 is input to the microphone 12, but is not howling because the voice switch means 22 is attenuated by −46 dB.

  On the contrary, when starting to talk on the kitchen remote controller 11 side, the voice switch means 22 gives +6 dB of amplification to the transmission volume and gives a large attenuation of −46 dB to the reception volume as described above.

  As described above, the voice switch means 22 is used as means for switching between reception and transmission of the interphone and preventing howling.

  Next, a case where noise comes into an audio signal will be described. For example, the remote control cable for connecting the communication means 6 of the bath remote control 1 and the communication means 16 of the kitchen remote control 11 is about 50 m at the longest. If there is a device that generates noise near the remote control cable, noise called induction noise is superimposed on the remote control cable. The audio signal including the noise is input to the speaker amplifying unit 5 via the communication unit 6 on the remote controller 1 side. Conventionally, the audio input signal input to the speaker amplifying means 5 is amplified as it is and is heard from the speaker 4. Naturally, the noise contained in the audio input signal was amplified as it was and was heard from the speaker.

  FIG. 3 is a characteristic diagram of an audio input signal versus an audio output signal. The dotted line indicated as “conventional general amplification means characteristic” in FIG. 3 indicates that the audio output signal is output in proportion to the audio input signal.

  In the speaker amplifying unit 5 according to the first embodiment of the present invention, an audio input signal is input to the speaker amplifier 23 and also input to the level determining unit 24 as shown in FIG. The level determination unit 24 outputs a low level signal to the switching unit 25 when it is determined that the input voice input signal is less than the predetermined input level. The switching means 25 receives the low level signal and turns off the operation of the speaker amplifier 23. As a result, the audio input signal below the predetermined input level is not amplified by the speaker amplifier 23, and the audio output signal is not output. Therefore, no sound can be heard from the speaker 4 or the speaker 14. When there is no original audio signal in the audio input signal and only noise is carried, the audio input signal is small. If the predetermined input level is set to a level slightly higher than the small audio input signal, noise will not be heard from the speaker 4 or the speaker 14.

  Further, in a normal call, when the voice input signal is equal to or higher than the predetermined input level, the level determination unit 24 determines that the input level is equal to or higher than the predetermined input level, and outputs a high level signal to the switching unit 25. The switching means 25 receives the high level signal and turns on the operation of the speaker amplifier 23. As a result, an audio input signal having a predetermined input level or higher is amplified by the speaker amplifier 23, and an audio output signal is output. Accordingly, sound can be heard from the speaker 4 or the speaker 14. At this time, even if noise is mixed in with the sound, the sound is louder and is often not noticed by the human ear, which is not a problem in practical use.

  The amplification means characteristic in this state is as shown by the thick line in FIG. The predetermined input level may be set to a level slightly higher than the noise that comes on the audio input signal. Further, the predetermined output level is a level that is worrisome when noise is heard from a speaker. That is, if the audio input signal is at a noise level (= below the predetermined input level), it indicates that the audio output signal is not output (= below the predetermined output level).

Also, a case where noise on the remote control cable enters the kitchen remote control 11 side will be described. In this case, the noisy voice signal is input to the voice switch means 22 via the communication means 16. When there is no voice and only noise, the voice switch means 22 gives an attenuation of −20 dB to the transmission volume and an attenuation of −20 dB to the reception volume since both the reception volume and the transmission volume are below the set volume. give. That is, a signal attenuated by −20 dB is input to the speaker amplifying unit 15. Therefore, the audio input signal of the speaker amplifying means 15 is smaller than the input of the speaker amplifying means 5 of the remote controller 1, and it is difficult to hear noise. However, the speaker amplifying means 15 can be made less affected by noise by adopting the configuration of FIG.

  Also, in the case of a kitchen remote control, it is often installed side by side with the main unit of the entrance doorphone. In recent entrance doorphones, the parent device and the child device communicate with each other wirelessly, and the electromagnetic waves are carried as noise on the kitchen remote controller 11. Since this electromagnetic wave noise flies through the air, the noise between the voice switch means 22 and the speaker amplifying means 15 may be present. In this case, since the previous -20 dB attenuation of the voice switch means 22 is not received, noise is input to the speaker amplifying means 15 as a voice input signal. Even in this case, with the configuration of FIG. 2, noise is not output as noise from the speaker 14, and usability is improved.

(Embodiment 2)
FIG. 4 is a detailed block diagram of the speaker amplifying means 5 and the speaker amplifying means 15 of the water heater remote controller according to the second embodiment of the present invention. Since the structure of the whole water heater is the same as that of FIG. 1 shown in Embodiment 1, the same reference numerals as those in FIG.

  In FIG. 4, the speaker amplifier 23 and the level determination means 24 are the same as those in FIG. The switching unit 26 inputs the determination result of the level determination unit 24 and outputs an output for switching the amplification factor of the speaker amplifier 23. The operation and action of the water heater remote controller configured as described above will be described below.

  FIG. 5 is a characteristic diagram of an audio input signal versus an audio output signal. The dotted line indicated as “conventional general amplification means characteristic” in FIG. 5 indicates that the audio output signal is output in proportion to the audio input signal.

  In the speaker amplifying unit 5 according to the second embodiment of the present invention, an audio input signal is input to the speaker amplifier 23 and also input to the level determining unit 24 as shown in FIG. When the level determination unit 24 determines that the input voice input signal is less than the predetermined input level, a level low signal is output to the switching unit 26. The switching means 26 receives the low level signal and switches the amplification factor of the speaker amplifier 23 to the low side. As a result, the audio input signal below the predetermined input level is not greatly amplified by the speaker amplifier 23, and the audio output signal becomes smaller than that of the conventional general amplification means. Therefore, the sound heard from the speaker 4 or the speaker 14 is reduced. When there is no original audio signal in the audio input signal and only noise is carried, the audio input signal is small. If the predetermined input level is set to a level slightly higher than the small audio input signal, noise cannot be clearly heard from the speaker 4 or the speaker 14. That is, noise can be reduced to a level that is not noticed by the user.

  Further, in a normal call, when the voice input signal is equal to or higher than the predetermined input level, the level determination unit 24 determines that the input level is equal to or higher than the predetermined input level, and outputs a high level signal to the switching unit 26. The switching means 26 receives the high level signal and switches the amplification factor of the speaker amplifier 23 to the higher side. As a result, an audio input signal having a predetermined input level or higher is amplified by the speaker amplifier 23, and an audio output signal is output. Accordingly, sound can be clearly heard from the speaker 4 or the speaker 14. At this time, even if noise is mixed in with the sound, the sound is louder and is often not noticed by the human ear, which is not a problem in practical use.

The amplification means characteristic in this state is as shown by the thick line in FIG. The predetermined input level may be set to a level slightly higher than the noise that comes on the audio input signal. Further, the predetermined output level is a level that is worrisome when noise is heard from a speaker. That is, if the audio input signal is at a noise level (= below the predetermined input level), it indicates that the audio output signal is below the predetermined output level.

  Also, when noise on the remote control cable enters the kitchen remote control 11 side or when electromagnetic wave noise is applied between the voice switch means 22 and the speaker amplification means 15, noise reduction is performed as in the first embodiment. There is an effect.

(Embodiment 3)
FIG. 6 is a detailed block diagram of the speaker amplifying means 5 and the speaker amplifying means 15 of the water heater remote control according to the third embodiment of the present invention. Since the structure of the whole water heater is the same as that of FIG. 1 shown in Embodiment 1, the same reference numerals as those in FIG.

  In FIG. 6, the speaker amplifier 23 is the same as that in FIG. The signal blocking means 27 inputs a voice input signal and outputs or blocks the voice input signal to the speaker amplifier 23 according to the level of the voice input signal. The operation and action of the water heater remote controller configured as described above will be described below.

  FIG. 7 is a characteristic diagram of an audio input signal versus an audio output signal. The dotted line indicated as “conventional general amplification means characteristic” in FIG. 7 indicates that the audio output signal is output in proportion to the audio input signal.

  In the speaker amplifying unit 5 according to the third embodiment of the present invention, as shown in FIG. 6, the audio input signal is first input to the signal blocking unit 27 without being input to the speaker amplifier 23 as it is. If the input sound input signal is less than a predetermined input level, the signal blocking means 27 blocks the sound input signal and does not transmit the sound signal to the speaker amplifier 23. As a result, an audio input signal having a level lower than the predetermined input level is not input to the speaker amplifier 23, and therefore no audio output signal is output. Therefore, no sound can be heard from the speaker 4 or the speaker 14. When there is no original audio signal in the audio input signal and only noise is carried, the audio input signal is small. If the predetermined input level is set to a level slightly higher than the small audio input signal, noise will not be heard from the speaker 4 or the speaker 14.

  In a normal call, when the voice input signal is equal to or higher than the predetermined input level, the signal blocking means 27 determines that the input voice input signal is equal to or higher than the predetermined input level, and transmits the voice input signal to the speaker amplifier 23 as it is. . As a result, an audio input signal having a predetermined input level or higher is amplified by the speaker amplifier 23, and an audio output signal is output. Accordingly, sound can be heard from the speaker 4 or the speaker 14. At this time, even if noise is mixed in with the sound, the sound is louder and is often not noticed by the human ear, which is not a problem in practical use.

  The amplification means characteristic in this state is as shown by a thick line in FIG. The predetermined input level may be set to a level slightly higher than the noise that comes on the audio input signal. Further, the predetermined output level is a level that is worrisome when noise is heard from a speaker. That is, if the audio input signal is at a noise level (= below the predetermined input level), it indicates that the audio output signal is not output (= below the predetermined output level).

  Also, when noise on the remote control cable enters the kitchen remote control 11 side or when electromagnetic wave noise is applied between the voice switch means 22 and the speaker amplification means 15, noise reduction is performed as in the first embodiment. There is an effect.

(Embodiment 4)
FIG. 8 is a detailed block diagram of the speaker amplifying means 5 and the speaker amplifying means 15 of the water heater remote control according to the fourth embodiment of the present invention. Since the structure of the whole water heater is the same as that of FIG. 1 shown in Embodiment 1, the same reference numerals as those in FIG.

  In FIG. 8, the speaker amplifier 23 is the same as FIG. The signal attenuating means 28 receives an audio input signal, attenuates the audio input signal according to the level of the audio input signal, and outputs the attenuated audio input signal to the speaker amplifier 23, or directly attenuates the audio input signal without attenuating the audio input signal. Output to. The operation and action of the water heater remote controller configured as described above will be described below.

  FIG. 9 is a characteristic diagram of an audio input signal versus an audio output signal. The dotted line shown as “conventional general amplification means characteristic” in FIG. 9 indicates that the audio output signal is output in proportion to the audio input signal.

  In the speaker amplifying unit 5 according to the fourth embodiment of the present invention, as shown in FIG. 8, the audio input signal is first input to the signal attenuating unit 28 without being input to the speaker amplifier 23 as it is. If the input audio input signal is less than a predetermined input level, the signal attenuation means 28 attenuates the audio input signal and transmits the attenuated audio signal to the speaker amplifier 23. As a result, since the audio input signal below the predetermined input level is attenuated and input to the speaker amplifier 23, the amplification factor of the speaker amplifier does not change, but the input signal is attenuated and reduced, so the audio output signal is small. Become. Therefore, the sound heard from the speaker 4 or the speaker 14 is reduced. When there is no original audio signal in the audio input signal and only noise is carried, the audio input signal is small. If the predetermined input level is set to a level slightly higher than the small audio input signal, noise will not be heard clearly from the speaker 4 or the speaker 14. That is, noise can be reduced to a level that is not noticed by the user.

  In a normal call, when the voice input signal is equal to or higher than the predetermined input level, the signal attenuating means 28 transmits the voice input signal as it is to the speaker amplifier 23 if the input voice input signal is equal to or higher than the predetermined input level. . As a result, an audio input signal having a predetermined input level or higher is amplified by the speaker amplifier 23, and an audio output signal is output as usual. Accordingly, sound can be heard from the speaker 4 or the speaker 14. At this time, even if noise is mixed in with the sound, the sound is louder and is often not noticed by the human ear, which is not a problem in practical use.

  The amplification means characteristic in this state is as shown by a thick line in FIG. The predetermined input level may be set to a level slightly higher than the noise that comes on the audio input signal. Further, the predetermined output level is a level that is worrisome when noise is heard from a speaker. That is, if the audio input signal is at a noise level (= below a predetermined input level), it indicates that the audio output signal is less than a predetermined output.

  Also, when noise on the remote control cable enters the kitchen remote control 11 side or when electromagnetic wave noise is applied between the voice switch means 22 and the speaker amplification means 15, noise reduction is performed as in the first embodiment. There is an effect.

Needless to say, the same effect can be obtained when the speaker amplifier 23, the level determination unit 24, and the switching unit 25 shown in the first embodiment are integrated to form an IC. Needless to say, the same effect can be obtained when the speaker amplifier 23, the level determination unit 24, and the switching unit 26 shown in the second embodiment are integrated to form an IC. Needless to say, the same effect can be obtained when the speaker amplifier 23 shown in the third embodiment and the signal blocking means 27 are integrated to form an IC. Needless to say, the same effect can be obtained when the speaker amplifier 23 and the signal attenuating means 28 shown in Embodiment 4 are integrated into an IC.

  There are various ways to turn the speaker amplifier operation on and off with switching means, such as turning the speaker amplifier power on and off, using the mute function of the speaker amplifier, and forcibly shorting the output of the speaker amplifier. However, the same effect can be obtained by any method.

  The water heater remote control according to the present invention can make it difficult for the user to notice electromagnetic noise as noise in the intercom function, so that the electromagnetic noise may be output as noise, such as voice guidance, etc. It can be applied to other uses.

DESCRIPTION OF SYMBOLS 1 Remote control 4 Speaker 5 Speaker amplification means 11 Kitchen remote control 14 Speaker 15 Speaker amplification means 23 Speaker amplifier 24 Level determination means 25 Switching means 26 Switching means 27 Signal interruption means 28 Signal attenuation means

Claims (5)

A water heater remote controller having an interphone function capable of making a call between a bath remote controller of a water heater and a kitchen remote controller, comprising a speaker and speaker amplifying means for driving the speaker, wherein the speaker amplifying means has an audio input signal predetermined. A water heater remote control characterized by not outputting an audio output signal when the level is lower than the input level, or suppressing the level to be lower than a predetermined output level. The speaker amplifying means is composed of a speaker amplifier, a level determining means for determining the magnitude of an audio input signal of the speaker amplifier, and a switching means for switching on and off the operation of the speaker amplifier according to the determination result of the level determining means. 2. The water heater remote control according to claim 1, wherein when the level determination means determines that the voice input signal is less than a predetermined input level, the switching means turns off the operation of the speaker amplifier. The speaker amplifying means includes a speaker amplifier, a level determining means for determining the magnitude of an audio input signal of the speaker amplifier, and a switching means for switching the amplification factor of the speaker amplifier according to the determination result of the level determining means. 2. The water heater remote control according to claim 1, wherein when the level determination unit determines that the audio input signal is less than a predetermined input level, the switching unit switches the amplification factor of the speaker amplifier to a lower side. The speaker amplification means includes a speaker amplifier and a signal blocking means provided on the voice input signal side of the speaker amplifier, and the signal blocking means blocks the voice input signal when the voice input signal is less than a predetermined level. The water heater remote control according to claim 1. The speaker amplifying means includes a speaker amplifier and a signal attenuating means provided on the sound input signal side of the speaker amplifier, and the signal attenuating means attenuates the sound input signal when the sound input signal is less than a predetermined level. The water heater remote control according to claim 1.

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