JP2007159109A - Telephone conversation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a telephone conversation apparatus with which reliable conversation is possible even in noisy environment. <P>SOLUTION: The apparatus has an inner earpiece 11 having an ear pad 11a which ear is mounted inserted to the ear, and a headset 12 to which the inner earpiece 11 is connected. The headset 12 is provided with an amplifier 16 which amplifies a voice signal input through the ear pad 11a, an AD conversion circuit 17 which carries out AD conversion processing of the signal input from the amplifier 16, a signal processing circuit 18 which removes noise other than sound which vibrates the eardrum from an amplifier output signal input through the AD conversion circuit 17 and which outputs the processing signal after removal to the AD conversion circuit 17, a wireless module 20 which sends out the signal input from the AD conversion circuit 17 as a wireless signal, and a transmission/reception switching circuit 21 to which the output signal from the wireless module 20 is input and which switches transmission/reception by preferring reception. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a call device, and more particularly to a call device that can reliably make a call by removing noise associated with the call.

2. Description of the Related Art Conventionally, a communication device used for conversation at a remote place where direct conversation is not possible is known. Such a communication device is, for example, a microphone that converts sound emitted from the mouth into an electric signal, and an electric signal input from the microphone, and outputs the signal by wired or wireless, or an electric signal input by wired or wireless. It has a control device that performs control processing on the signal and outputs it, and headphones that convey the sound to the ear based on the electrical signal output from the control device.
As such a call device, for example, “Communication device for work site” (see Patent Document 1) and “Interactive terminal device, call control method thereof, and program thereof” (see Patent Document 2) are known.

  “Communicator for work site” is a helmet or headset equipped with a handset connected to a communication terminal such as a mobile phone terminal, a simple mobile phone terminal, a portable wireless communication terminal, etc. By providing noise canceling means to mute the noise, send only the voice on the sending side excluding the ambient noise on the sending side, listen to the transmitted voice with the ambient noise on the receiving side removed, both Wearers at different work locations in a noisy environment exchange very clear voices and communicate with each other.

In addition, the “interactive terminal device, its call control method, and its program” include a bone conduction microphone that picks up voice vibration from the skull of the speaker and converts it into a transmitted voice signal. A wireless means for transmitting the transmitted voice signal and receiving the received voice signal from the network; a bone conduction speaker for converting the received voice signal received by the wireless means into voice vibration and conducting to the skull of the speaker; , A normal microphone that collects the surrounding voice of the speaker, a phase inverting circuit that reverses the phase of the surrounding voice collected by the normal microphone, and a peripheral voice that is phase-inverted by the phase inverting circuit is output as a noise neutralized voice. And a normal speaker.
JP 2005-072703 A JP 2003-143253 A

However, for example, in a high noise environment such as a civil engineering construction site, a factory, an airfield, etc., the content of the call is almost inaudible due to the noise, and it is difficult to make a call.
That is, with a headset such as a conventional “workplace communication device”, noise transmitted to the eardrum through vibrations of the mouth and head cannot be removed under extremely severe noise environments. However, the sound may not be collected correctly due to the movement of the microphone position.
In addition, in a technique using a bone conduction microphone such as the conventional “interactive terminal device, its call control method, and its program”, the voice of the speaker (particularly the voice signal that has propagated through the air) Since the signal is generated by propagating the bone, there is a problem that the variation due to the physical characteristics and the degree of wearing of the individual is large.

Furthermore, noise cancellation by phase reversal, which is a common technique of these, cannot be removed in a high-environment environment where the level of ambient noise to be collected exceeds 75 dB or voice noise with the same frequency band. Met. In addition, for example, since the factory is working with both hands, in the case of voice input with a directional microphone, if the position of the microphone is moved, it is difficult to bring it near the mouth.
An object of the present invention is to provide a communication device that can make a reliable call even in a high noise environment.

  In order to achieve the above object, a communication device according to the present invention includes an inner earphone having an ear pad to be inserted into an ear, and a headset to which the inner earphone is connected, and the headset includes the ear pad. The eardrum is amplified from an amplifier that amplifies a voice signal input via the analog signal, an analog-digital conversion circuit that performs analog-digital conversion processing on the signal input from the amplifier, and an amplifier output signal input via the analog-digital conversion circuit. A signal processing circuit that removes noise other than the sound to be vibrated and outputs the processed signal after the removal to the analog-digital conversion circuit; a wireless module that sends a signal input from the analog-digital conversion circuit as a wireless signal; When the output signal from the wireless module is input, the transmission priority is changed And a circuit switched transmission received cormorants.

  In addition, a reception analog-digital conversion circuit that performs analog-digital conversion processing on a reception signal that is an output signal of the wireless module, and a reception input via the reception analog-digital conversion circuit to the transmission / reception switching circuit There may be provided a reception signal processing circuit that discriminates a signal into a voice signal and background noise and performs transmission / reception switching only when there is a voice signal.

  According to this invention, it has an inner earphone having an ear pad to be inserted and worn in the ear, and a headset to which the inner earphone is connected, and an audio signal input through the ear pad is amplified by the amplifier of the headset, The signal input from the amplifier is analog-to-digital converted by the analog-to-digital conversion circuit, and the signal processing circuit removes noise other than the sound that vibrates the eardrum from the amplifier output signal input through the analog-to-digital conversion circuit. The processed signal after removal is output to the analog-to-digital conversion circuit, the signal input from the analog-to-digital conversion circuit is transmitted as a wireless signal by the wireless module, and the output signal from the wireless module is transmitted by the transmission / reception switching circuit. Is input, and transmission / reception switching with priority on reception is performed.

  Thereby, it is possible to make a call reliably even in a high noise environment. In addition, an analog-to-digital conversion circuit for receiving an analog-to-digital conversion process of an incoming signal, which is an output signal of the wireless module, and an incoming-call signal input via the analog-to-digital conversion circuit for receiving voice to the transmission / reception switching circuit Distinguishing between signal and background noise, and providing a signal processing circuit for receiving and switching the transmission and reception only when there is an audio signal, the influence of background noise is reduced and switching from the receiving side to the transmitting side is smooth It can be carried out.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a communication device according to an embodiment of the present invention, FIG. 2 shows an example of a usage state of the communication device of FIG. 1, and (a) is an explanation of a helmet wearing state. FIG. 4B is an explanatory diagram of a pocket carrying state.
As shown in FIG. 1, the communication device 10 includes an inner earphone 11 having an ear pad 11a to be inserted and worn in an ear, and a headset 12 to which the inner earphone 11 is connected. The inner earphone 11 is an earphone that has a microphone function and is inserted into an ear, and can transmit sound even without a microphone. Since it is not necessary to care about the position of the microphone, it is easy to attach.

As shown in FIG. 2, since the inner earphone 11 is easy to wear, the headset 12 is worn on the helmet H (see (a)), suspended from the neck with a strap, or attached to the neck of the outerwear. Or put in the pocket P (see (b)) does not get in the way. It can also be fixed to the ear by downsizing.
The original function of the inner earphone 11 is to convert the incoming sound as an electric signal into vibration and transmit it to the eardrum, and conversely, pick up the vibration of the eardrum with the diaphragm and convert it into an electric signal. The ear pad 11a in contact with the inner side wall of the ear wears the inner earphone 11 on the ear and simultaneously suppresses eardrum vibration due to noise from the outside. Factors that cause the eardrum to vibrate when producing sound include not only voice but also external sounds that enter through the nostrils and mouth holes and external sounds that vibrate the head itself. It's just noise.

  The headset 12 includes an earphone connector 13, a first changeover switch 14, a second changeover switch 15, an amplifier (AMP) 16, an analog-to-digital conversion circuit (CODER) 17, and signal processing inside the main body case 12 a. Circuit (Digital Signal Processor: DSP) 18, third changeover switch 19, wireless module 20, transmission / reception changeover circuit (Voice Of Exchange: VOX) 21, charging circuit 22, lithium ion battery 23, and DC input (DC-IN) ) Part 24.

On the outer surface of the main body case 12a, the connection ends of the earphone connection unit 13 and the DC input unit 24 are exposed, and a plurality of switches 25 and two LEDs (Light Emitting Diodes) 26a and 26b are provided. .
The first changeover switch 14 has a movable end connected to the earphone connector 13, a first fixed end connected to the first fixed end of the second changeover switch 15, and a second fixed end connected to the output end (OUT) of the wireless module 20. Connected. The second changeover switch 15 has a movable end connected to the amplifier 16, a first fixed end connected to the first fixed end of the first changeover switch 15, and a second fixed end connected to the ground end. The third changeover switch 19 has a movable end connected to the input end (IN) of the wireless module 20, a first fixed end connected to the analog-digital conversion circuit 17, and a second fixed end connected to the ground end.

  The amplifier 16 connected to the movable end of the second changeover switch 15 has a function of amplifying a weak electric signal that enters from the inner earphone 11 and a filter that removes signals other than the audio band. Is output to the analog-digital conversion circuit 17. An analog-digital conversion circuit 17 connected to the amplifier 16 performs an analog-digital conversion process on the signal input from the amplifier 16.

The signal processing circuit 18 connected to the analog-to-digital conversion circuit 17 removes noise other than the sound that vibrates the eardrum from the output signal from the amplifier 16 input via the analog-to-digital conversion circuit 17. The processed signal is output to the analog-digital conversion circuit 17. The analog-digital conversion circuit 17 performs a digital-analog conversion process on the signal input from the signal processing circuit 18.
That is, the signal processing circuit 18 removes noise that cannot be removed only by the ear pad 11a of the inner earphone 11 by signal processing, takes in noise before sound is generated in advance, and extracts this noise from a signal that enters along with the sound. The purpose is to extract only.

  The wireless module 20 connected to the third changeover switch 19 transmits the signal input from the analog-digital conversion circuit 17 as a wireless signal from the antenna 20a. By communicating the audio signal from which noise has been removed with a PDA (Personal Digital Assistant: PDA), PC (Personal Computer), a mobile phone, a control device, etc., wirelessly, the system configuration by wire (cable) is difficult and troublesome. Can be eliminated.

  As a wireless method, weak wireless, specific low power wireless, Bluetooth, WiFi (Wireless Fidelity), PHS (Personal Handyphone System), etc. can be considered, but Bluetooth with a headset profile is easy to configure at present. It is desirable to use Bluetooth. However, in the future, ultra-wideband (UWB) and ZigBee, which is a short-range wireless communication standard with an increased communication speed, are also considered as candidates.

  The transmission / reception switching circuit 21 to which the output signal from the wireless module 20 is input performs transmission / transmission switching with priority on reception in order to enable natural conversation. The first changeover switch 14, the second changeover switch 15, and the third changeover switch 19 are switched by an output signal from the transmission / reception switch circuit 21. At the time of transmission, the movable end and the first fixed end of the first changeover switch 14 are the first fixed end and the movable end of the second changeover switch 15, and the first fixed end and the movable end of the third changeover switch 19 are When connected, the movable end and the second fixed end of the first changeover switch 14 are movable, the second fixed end and the movable end of the second changeover switch 15 are movable, and the second fixed end of the third changeover switch 19 is movable. The ends are connected to each other.

  The charging circuit 22 charges the lithium ion battery 23 with the DC power input from the DC input unit 24. Each switch 25 is connected to the wireless module 20 to perform various switching processes, the LED 26a is connected to the wireless module 20 and lights up in connection with the operation of the wireless module 20, and the LED 26b is connected to the charging circuit 22. Lights in connection with the operation of the charging circuit 22.

  When people talk, they listen with their ears and speak with their mouths, but they are difficult to hear if there is a lot of noise. In this case, conversation is possible if a microphone and a loudspeaker are used, but the device is too large, and the loudspeaker microphone is mixed with noise, so it is not suitable as speech recognition data. Therefore, using headphones for music appreciation can eliminate noise, but is troublesome. The use of earphones (inner earphones) equipped with earpads for music appreciation, which have been recently inserted and used in the ears, can be eliminated.

  When listening using earphones, the vibration of the earphone diaphragm is transmitted to the eardrum. Conversely, when vibration is applied to the earphone, an electric signal corresponding to the vibration is generated based on the same principle as the microphone. In addition, when a person speaks, his / her throat is shaken and a sound is emitted from his / her mouth. At this time, although the vibration of the generated sound is very weak, the eardrum is also vibrated. If vibrations transmitted to the earphone can be detected using this principle, sound can be emitted from the eardrum through the earphone. In the case of an inner earphone, the noise coming from the ear can be reduced to some extent by a pad that also has a function for attaching the earphone to the ear.

In addition, since noise is transmitted not only from the ear but also to the diaphragm of the earphone through vibrations of the nose, mouth and head, there is a limit to noise removal by the ear pad. However, noise can be effectively removed depending on the shape of the ear pad.
The communication device 10 described above performs digital signal processing to further reduce the noise attenuated by the ear pad, thereby enabling natural conversation in a high noise environment with a noise level of 90 dB or more and noise at a level that can be recognized by the speech recognition engine. Can be removed.

  As described above, according to the present invention, there is provided an inner earphone having an ear pad to be inserted into the ear and a headset to which the inner earphone is connected, and an audio signal input through the ear pad by an amplifier of the headset. The signal input from the amplifier is analog-to-digital converted by the analog-to-digital conversion circuit, and the signal output from the amplifier output signal input through the analog-to-digital conversion circuit is not audio that vibrates the eardrum. Noise is removed, the processed signal after removal is output to the analog-digital conversion circuit, the signal input from the analog-digital conversion circuit is transmitted as a wireless signal by the wireless module, and the wireless module is transmitted by the transmission / reception switching circuit. When the output signal from is input, the transmission / reception switching with priority on reception is performed. Since the, it can be reliably call under high noise environments or noise 90 dB.

Next, a call device according to another embodiment of the present invention will be described.
FIG. 3 is a block diagram showing a configuration of a call device according to another embodiment of the present invention. As shown in FIG. 3, the communication device 30 has a headset 31 instead of the headset 12 of the above-described communication device 10 (see FIG. 1). The headset 31 includes a digital transmission / reception switching circuit 32 instead of the analog transmission / reception switching circuit 21 of the headset 12 inside the main body case 31a, and the first changeover switch 14 and the wireless module. Some of the 20 connection states have been changed. Other configurations and operations are the same as those of the communication device 10. For this reason, the same number is attached | subjected to the same component and description is abbreviate | omitted.

  The transmission / reception switching circuit 32 includes a reception analog-digital conversion circuit (CODEC) 33 and a reception signal processing circuit (DSP) 34. The receiving analog-digital conversion circuit 33 has an input side connected to the output end (OUT) of the wireless module 20 and an output side connected to the second fixed end of the first changeover switch 14. The reception signal processing circuit 34 is connected to the reception analog-digital conversion circuit 33. Note that the second fixed end of the first changeover switch 14 and the output end (OUT) of the wireless module 20 are not directly connected.

  The reception analog-digital conversion circuit 33 of the transmission / reception switching circuit 32 performs analog-digital conversion processing on the reception signal which is the output signal of the wireless module 20. The reception signal processing circuit 34 connected to the reception analog-digital conversion circuit 33 discriminates the analog-digital conversion reception signal input via the reception analog-digital conversion circuit 33 into a voice signal and background noise. The transmission / reception switching is performed only when there is an audio signal. That is, the first changeover switch 14, the second changeover switch 15, and the third changeover switch 19 are switched by the output signal from the reception signal processing circuit 34.

Here, the discrimination of the reception signal and the transmission / reception switching method will be described in detail.
4A and 4B illustrate a transmission / reception switching method (part 1), where FIG. 4A is an explanatory diagram illustrating a relationship between a voice signal level and time when there is no background noise, and FIG. It is a timing chart which shows a switching state. FIG. 5 shows a transmission / reception switching method (part 2), where (a) is an explanatory diagram showing the relationship between the audio signal level in the presence of background noise, the background noise, a fixed threshold and time, and (b) is a graph. It is a timing chart which shows the switching state of reception and transmission. FIG. 6 shows a transmission / reception switching method (No. 3), where (a) is an explanatory diagram showing the relationship between the audio signal level, background noise, variation threshold and time in the presence of background noise, and (b) is a graph. It is a timing chart which shows the switching state of reception and transmission.

  For example, as shown in FIG. 4, it is assumed that transmission / reception switching is performed when the audio signal level a exceeds a fixed threshold value b. In this case, when the audio signal level a is equal to or less than the fixed threshold value b (see (a)), the transmission state is set (see (b)), but the other party starts speaking and the audio signal level a is fixed. When the threshold value b is exceeded (see (a)), the transmission / reception switching signal c is switched to the reception state (see (b)). When the voice signal level a becomes equal to or less than the fixed threshold value b (see (a)) after the other party has finished speaking, the state is switched to the transmission state after a preset off-delay time (β) has elapsed ( (See (b)).

Since priority is given to reception, when the user and the other party start talking at the same time, the state is switched to the reception state. When there is no background noise, a good call can be made even if the fixed threshold value b is used.
However, as shown in FIG. 5, when the background noise level d is large, the background noise level d exceeds the fixed threshold value b even if the audio signal level a is smaller than the fixed threshold value b (see (a)). That is, it becomes impossible to discriminate between an audio signal and background noise. In this state, even if the other party's talk is finished, it remains in the received state and does not enter the state of sending (see (b)), and it is impossible to send from itself.

  Therefore, as shown in FIG. 6, the communication device 30 discriminates the voice signal from the background noise using the fluctuation threshold e. The fluctuation threshold e is a value obtained by taking an average value of the received signal level in the past certain time (τ) and adding a certain value (α) thereto. Since the average level of background noise within a certain time is substantially constant, this fluctuation threshold e is not exceeded (see (a)). When the level of the received signal in which the audio signal is added to the background noise exceeds the fluctuation threshold e, the call device 30 determines that there is an audio signal and switches from transmitting to receiving (see (b)).

  Since the fluctuation threshold e is an average value of the level of the received signal, it increases when an audio signal is added. That is, there is a high possibility that the voice signal level a falls below the fluctuation threshold e during a call, which delays the switch to the transmission state by increasing the preset off-delay time (β). Can be avoided (see (b)). That is, by appropriately setting three parameters, a constant time (τ) for determining the fluctuation threshold e, a constant value (α) for determining the fluctuation threshold level, and an off-delay time (β), transmission is performed. Can be switched at an appropriate timing. For this reason, it is possible to prevent the reception from being interrupted and the transmission from being disabled, and half duplex communication in which transmission and reception cannot be performed simultaneously can be performed smoothly.

In this way, the communication device 30 can reduce the influence of background noise and smoothly switch from the reception side to the transmission side, and thus can make a reliable call even in a high noise environment.
In the above description and FIG. 3, the analog-to-digital conversion circuit 17 for transmission and the analog-to-digital conversion circuit 33 for reception are separate circuits. The circuit may be formed on the same IC. Similarly, the signal processing circuit 18 for transmission and the signal processing circuit 33 for reception are separate circuits, but the same effect can be obtained even if each processing is performed by independent software on the same processor. it can.

It is a block diagram which shows the structure of the telephone apparatus which concerns on one embodiment of this invention. An example of the usage state of the telephone apparatus of FIG. 1 is shown, (a) is explanatory drawing of a helmet mounting state, (b) is explanatory drawing of a pocket carrying state. It is a block diagram which shows the structure of the telephone apparatus which concerns on other embodiment of this invention. The transmission / reception switching method (part 1) will be described. (A) is a diagram illustrating the relationship between the audio signal level and time when there is no background noise, and (b) is a switching state between reception and transmission. It is a timing chart. A transmission / reception switching method (part 2) is shown. (A) is an explanatory diagram showing the relationship between a voice signal level in the presence of background noise, a background noise, a fixed threshold, and a time, and (b) is a reception and transmission. It is a timing chart which shows the switching state of. The transmission / reception switching method (No. 3) is shown. (A) is an explanatory diagram showing the relationship between the voice signal level in the presence of background noise, the background noise, the fluctuation threshold value and time, and (b) is the reception and transmission. It is a timing chart which shows the switching state of.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,30 Communication apparatus 11 Inner earphone 11a Ear pad 12,31 Headset 12a, 31a Body case 13 Earphone connection part 14 1st changeover switch 15 2nd changeover switch 16 Amplifier 17 Analog-digital conversion circuit 18 Signal processing circuit 19 3rd changeover Switch 20 Wireless module 21 Transmission / reception switching circuit 22 Charging circuit 23 Lithium ion battery 24 DC input unit 25 Switch 26a, 26b LED
32 Transmission / reception switching circuit 33 Analog / digital conversion circuit for reception 34 Signal processing circuit for reception a Voice signal level b Fixed threshold c Transmission / reception switching signal d Background noise level e Fluctuation threshold

Claims (2)

An inner earphone having an ear pad to be inserted and worn in the ear, and a headset to which the inner earphone is connected;
The headset is
From an amplifier that amplifies an audio signal input via the earpad, an analog-digital conversion circuit that performs analog-digital conversion processing on the signal input from the amplifier, and an amplifier output signal input via the analog-digital conversion circuit A signal processing circuit that removes noise other than sound that vibrates the eardrum and outputs the processed signal after the removal to the analog-digital conversion circuit; and a radio that transmits a signal input from the analog-digital conversion circuit as a radio signal A communication apparatus comprising: a module; and a transmission / reception switching circuit that receives an output signal from the wireless module and performs transmission / reception switching with priority on reception. The transmission / reception switching circuit is:
A reception analog-digital conversion circuit for analog-digital conversion processing of a reception signal which is an output signal of the wireless module, and a reception signal input via the reception analog-digital conversion circuit are discriminated into a voice signal and background noise. 2. A communication apparatus according to claim 1, further comprising: a signal processing circuit for receiving and receiving that switches the transmission and reception only when there is a voice signal.

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