JP7588320B1 - Communication device and call control method thereof - Google Patents

Abstract

To encourage a user of a communication device to speak at an appropriate volume.
SOLUTION
The communication device 1 comprises a bone conduction microphone 11 that picks up the user's voice and generates a transmission signal, a receiver 12 that reproduces sound based on a reception signal received from a remote device, a transmission path 22 for transmitting the transmission signal from the bone conduction microphone 11 to the remote device, a reception transmission path 24 for transmitting the reception signal to the receiver 12, and a loopback circuit 25 provided between the transmission path 22 and the reception transmission path 24 for synthesizing a side tone signal generated by processing the transmission signal with the reception signal, and the loopback circuit 25 operates based on one of a plurality of operating modes prepared in advance to control at least one of the on/off and level of the side tone reproduced by the receiver 12 based on the side tone signal.
[Selected figure] Figure 3

Description

This disclosure relates to a communication device equipped with a bone conduction microphone and a receiver, which is worn on the user's ear, head, etc., and a method for controlling the communication device.

Conventionally, in telephones, a technology has been widely used to improve call quality by outputting the user's voice picked up by the transmitter as sidetone from the receiver. When talking to the other party, the user can easily adjust the quality and clarity of their own voice by listening to the sidetone output from the receiver.

Regarding the use of such sidetones, for example, there is known a telephone having a phase conversion circuit that converts the phase of an electrical audio signal sent from a transmitter and outputs a phase-converted output signal, a signal synthesis circuit that combines the phase-converted output signal with an audio signal in which the electrical audio signal of the other party and the electrical sidetone signal are combined, thereby removing only the electrical sidetone signal and extracting only the electrical audio signal of the other party, and a selection switch that selects whether or not to input the phase-converted output signal to the signal synthesis circuit (see Patent Document 1).

Japanese Utility Model Application Publication No. 3-22451

In recent years, communication devices have been developed that are inserted into the user's ear and have a housing housing a bone conduction microphone that picks up the user's voice and an air conduction receiver that plays back the received voice of the other party. The bone conduction microphones used in communication devices are less susceptible to ambient noise than air conduction microphones, and therefore have excellent sound pickup performance for relatively quiet voices.

After extensive research, the inventors of the present application discovered that in a communication device equipped with such a bone conduction microphone, by controlling the presence or absence of side tone and the level of the side tone according to the user's speaking situation (i.e., the sound picked up by the bone conduction microphone), it is possible to encourage the user to speak at an appropriate volume. Such control of the side tone makes it possible to make the user aware of insufficient speaking (i.e., speaking at a level that is too low) or excessive speaking (i.e., speaking at a level that is too high).

In contrast, the conventional technology described in Patent Document 1 allows the side tone to be switched on and off using a selection switch, but does not take into consideration controlling the side tone in response to the user's speech.

Therefore, the main objective of the present disclosure is to provide a communication device and a call control method thereof that can encourage a user to speak at an appropriate volume by controlling the presence or absence of sidetone and the level of the sidetone according to the user's speaking situation.

The communication device of the present disclosure comprises a bone conduction microphone that picks up the user's voice and generates a transmission signal, a receiver that reproduces sound based on a reception signal received from a partner device, a transmission path for transmitting the transmission signal from the bone conduction microphone to the partner device, a reception transmission path for transmitting the reception signal to the receiver, and a loopback circuit provided between the transmission path for transmitting and the reception transmission path for synthesizing a side tone signal generated by processing the transmission signal with the reception signal, and the loopback circuit is configured to control at least one of the on/off of the side tone reproduced by the receiver based on the side tone signal and the level of the side tone , based on the level of the sound picked up by the bone conduction microphone .

The call control method disclosed herein is a call control method for a calling device, the calling device comprising a bone conduction microphone that picks up a user's voice and generates a transmission signal, a receiver that plays sound based on a reception signal received from a partner device, a transmission path for transmitting the transmission signal from the bone conduction microphone to the partner device, and a reception transmission path for transmitting the reception signal to the receiver, the calling device being capable of synthesizing a side tone signal generated by processing the transmission signal into the reception signal, and at least one of the on/off of the side tone reproduced by the receiver based on the side tone signal and the level of the side tone being controlled based on the level of the sound picked up by the bone conduction microphone .

According to the present disclosure, by controlling the presence or absence of sidetone and the level of sidetone depending on the speaking situation of the user of the communication device, it is possible to encourage the user to speak at an appropriate volume.

FIG. 1 is a perspective view showing a state in which a communication device according to a first embodiment is used; FIG. 2 is an exploded perspective view of the earphone shown in FIG. 1 . FIG. 1 is a functional block diagram showing a configuration of a communication device according to a first embodiment; FIG. 1 is an explanatory diagram showing the output characteristics of sidetone in each operation mode ((A) low voice adaptation mode, (B) loud voice suppression mode, (C) mix mode) of the communication device according to the first embodiment. FIG. 13 is an explanatory diagram showing an example of a setting screen for an operation mode of the communication device according to the first embodiment; FIG. 4 is a functional block diagram showing a first modified example of the configuration of the communication device shown in FIG. FIG. 4 is a functional block diagram showing a second modified example of the configuration of the communication device shown in FIG. FIG. 13 is a functional block diagram showing the configuration of a communication device according to a second embodiment. FIG. 11 is an explanatory diagram showing side tone characteristics in each operation mode ((A) low voice adaptation mode, (B) loud voice suppression mode, (C) mix mode) of the communication device according to the second embodiment. FIG. 9 is a functional block diagram showing a first modified example of the configuration of the communication device shown in FIG. FIG. 10 is an explanatory diagram showing the comfort zone and the discomfort zone in the relationship between the amount of sidetone delay and the sidetone playback volume. FIG. 9 is a functional block diagram showing a second modified example of the configuration of the communication device shown in FIG. 8 .

The first invention made to solve the above problem is a call control method for a telephone device, the telephone device comprising a bone conduction microphone that picks up a user's voice and generates a transmission signal, a receiver that reproduces sound based on a reception signal received from a counterpart device, a transmission path for transmitting the transmission signal from the bone conduction microphone to the counterpart device, and a reception transmission path for transmitting the reception signal to the receiver, the telephone device being capable of synthesizing a side tone signal generated by processing the transmission signal into the reception signal, and at least one of the on/off of the side tone reproduced by the receiver based on the side tone signal and the level of the side tone is controlled based on the level of the sound picked up by the bone conduction microphone .

This allows the user to be encouraged to speak at an appropriate volume by using multiple operating modes to control the presence or absence (i.e., on/off) of side tone and the level of side tone depending on the user's speaking situation.

In addition, the second invention is configured to operate based on any one of a plurality of pre-prepared operating modes, the plurality of operating modes including a low-voice adaptation mode, in which the side sound is disabled only when the level of the picked-up sound is equal to or lower than a first threshold value.

According to this, when the level of the sound picked up by the bone conduction microphone is equal to or lower than the first threshold (i.e., the user's speaking volume is insufficient), the side sound is disabled (i.e., the side sound is turned off or the side sound level is set to essentially zero) to notify the user that the speaking volume is insufficient, thereby encouraging the user to speak at an appropriate volume.

In addition, a third invention is configured such that the multiple operating modes include a loud voice suppression mode, and in the loud voice suppression mode, when the level of the picked-up sound is equal to or greater than a second threshold value that is greater than the first threshold value, the level of the side sound is increased.

According to this, when the level of the sound picked up by the bone conduction microphone is equal to or higher than the second threshold (i.e., the user's speaking volume is excessive), the side sound level is increased to inhibit the user's speaking, thereby encouraging the user to speak at an appropriate volume.

In a fourth aspect of the present invention, the loopback circuit includes a microphone sound detector that detects the level of the picked-up sound based on the transmission signal from the transmission line for voice transmission.

This allows multiple operating modes to be appropriately executed based on the level of sound picked up by the bone conduction microphone.

The fifth invention further includes an input device for the user to perform input operations, and the plurality of operation modes are individually turned on and off based on the user's input operations on the input device.

This allows the user to easily select the desired operating mode and have the communication device execute it.

In the sixth aspect of the present invention, the loopback circuit includes a gain adjustment unit that adjusts the gain of the transmission signal from the transmission line.

By appropriately adjusting the gain of the outgoing signal as part of the processing of the outgoing signal, the receiver can appropriately reproduce the side tone based on the generated side tone signal.

The seventh invention further includes an ambient sound detector that detects the level of ambient sound, excluding the user's voice, picked up by the bone conduction microphone based on the transmission signal from the transmission line for transmitting speech, and the gain adjustment unit is configured to adjust the gain for the transmission signal from the transmission line for transmitting speech based on the level of the ambient sound.

This allows the receiver to properly reproduce side tones by appropriately adjusting the gain for the transmitted signal based on the level of ambient sound (excluding the user's voice) picked up by the bone conduction microphone.

The eighth invention further includes a volume adjustment unit provided in the receiving transmission path for adjusting the volume of the sound based on the receiving signal reproduced by the receiver based on the receiving signal, and the gain adjustment unit is configured to set the gain based on the degree of adjustment of the volume by the volume adjustment unit.

By doing this, the gain for the transmission signal can be appropriately set based on the degree of volume adjustment by the volume adjustment unit, allowing the receiver to appropriately reproduce the side tone.

In addition, the ninth invention is configured such that the loopback circuit further includes a speech detector that detects whether or not the user is speaking based on the transmission signal from the transmission line for speech, and executes the low voice adaptation mode when it is determined based on the detection result of the speech detector that the sound picked up by the bone conduction microphone does not include the user's speech at a predetermined level or above.

This allows the soft voice adaptation mode to be appropriately executed when the sound picked up by the bone conduction microphone does not include the user's speech at a specified level (i.e., when the user speaks but the volume is insufficient).

In addition, the tenth aspect of the present invention is configured such that the loopback circuit includes a voice extraction unit that extracts a voice signal based on the user's voice from the transmission signal from the transmission path for voice transmission, and generates the side tone signal based on the voice signal.

This allows the side tone signal to be appropriately generated (i.e., improving the quality of the side tone reproduced by the receiver) based on the audio signal extracted from the transmitted signal.

In addition, the eleventh invention is configured such that the loopback circuit includes a delay processing unit that delays the audio signal based on a predetermined delay time in the loud voice suppression mode, and generates the side tone signal based on the delayed audio signal.

This allows the timing of the side tone reproduced by the receiver to be delayed by the side tone signal generated based on the delayed audio signal (i.e., giving the user a feeling of discomfort and preventing loud speech), thereby encouraging the user to speak at an appropriate volume.

The twelfth invention further comprises a noise canceller provided in each of the transmission paths for voice transmission, which removes or reduces noise components in the voice transmission signal that is the subject of processing by the loopback circuit, and an echo canceller that removes or reduces echo components included in the voice transmission signal that is the subject of processing by the loopback circuit.

As a result, noise and echo components are removed from the transmitted signal, allowing the side tone signal to be generated appropriately (i.e., improving the quality of the side tone reproduced by the receiver).

In addition, the thirteenth aspect of the present invention is configured such that the loopback circuit includes a band expansion unit that expands the frequency band of the sidetone signal.

This allows the bandwidth of the audio signal to be expanded to properly generate a sidetone signal (i.e., improve the quality of the sidetone reproduced by the receiver).

The 14th invention is a method for controlling a call device, the call device comprising a bone conduction microphone that picks up the user's voice and generates a transmission signal, a receiver that reproduces sound based on a reception signal received from a partner device, a transmission path for transmitting the transmission signal from the bone conduction microphone to the partner device, and a reception path for transmitting the reception signal to the receiver, the device is capable of synthesizing a side tone signal generated by processing the transmission signal with the reception signal, and is configured to control at least one of turning on and off the side tone reproduced by the receiver based on the side tone signal and the level of the side tone based on one of a plurality of operation modes prepared in advance.

This allows the user to be encouraged to speak at an appropriate volume by using multiple operating modes to control the presence or absence (i.e., on/off) of side tone and the level of side tone depending on the user's speaking situation.

The following describes an embodiment of the present disclosure with reference to the drawings.

First Embodiment
Fig. 1 is a perspective view showing a communication device 1 according to a first embodiment of the present disclosure in a used state. Fig. 2 is an exploded perspective view of the earphone 2 shown in Fig. 1.

As shown in FIG. 1, the communication device 1 includes an earphone 2 that constitutes the main body of the communication device, and a signal processing device 3 that performs signal processing necessary for communication. Here, an example is shown in which the earphone 2 is inserted into the right ear 5 of the user. However, the earphone 2 may also be inserted into the left ear of the user. The communication device 1 may also include a pair of earphones 2, one on the left and one on the right.

In the communication device 1, the signal processing device 3 is connected to the earphone 2 via a signal line 4. However, the earphone 2 and the signal processing device 3 may be connected to each other so as to be able to communicate with each other via a wireless signal based on Wifi (registered trademark) or Bluetooth (registered trademark), etc.

The earphone 2 may further include a function similar to that of the signal processing device 3. In other words, the communication device 1 may be configured such that the signal processing device 3 is integrated inside the housing of the earphone 2.

As shown in FIG. 2, the earphone 2 includes an exterior housing 9, a bone conduction microphone 11 housed in the exterior housing 9, an air conduction receiver 12, an internal housing 13, and a microphone rubber 15.

The exterior housing 9 forms the outer shell of the earphone 2. The exterior housing 9 includes a case 9A that forms the inner part (rear part) of the user's ear, and a cover 9B that forms the outer part of the user's ear. The exterior housing 9 is formed by overlapping the cover 9B on the case 9A from the outside. The exterior housing 9 is provided with a cable cap 10 for leading the signal line 4 to the outside.

The bone conduction microphone 11 is a device that is placed on the user's ear so as to pick up vocal cord vibrations that are mainly transmitted to the vocal cord vibration transmission area, and picks up the user's voice and ambient sounds generated around the user. The bone conduction microphone 11 is equipped with an element (e.g., a vibration detection element) for converting audio vibrations into an electrical signal (an example of a transmission signal). In other words, the bone conduction microphone 11 can pick up sounds such as the user's voice and generate an electrical signal. The electrical signal generated by the bone conduction microphone 11 is input to the signal processing device 3 via the signal line 4. The bone conduction microphone 11 picks up vocal cord vibrations that propagate inside the user's body, and therefore has the property of being less susceptible to the influence of ambient sounds other than the user's voice.

The air conduction receiver 12 converts an electrical signal (an example of a received signal) input from the signal processing device 3 via the signal line 4 into a sound such as the speech of the other party and outputs it. The air conduction receiver 12 may be configured with a known speaker. A bone conduction receiver (bone conduction receiver) may be used instead of the air conduction receiver 12. For example, when the signal processing device 3 outputs an electrical signal corresponding to the speech of the other party of the user's call, the air conduction receiver 12 outputs a sound corresponding to the speech of the other party. Note that the sound output by the air conduction receiver 12 is not limited to the speech of the other party of the call, and may include, for example, ambient sounds and on-hold sounds.

The internal housing 13 is a member for guiding the reproduced sound of the air conduction receiver 12 to the ear canal, and is provided with a passage 13A for guiding the reproduced sound of the air conduction receiver 12 to the ear canal. The air conduction receiver 12 is disposed on one end side of the passage 13A of the internal housing 13.

At the other end of the passage 13A, a cylindrical tube portion 13B is provided that extends to the outside of the exterior housing 9 through an opening 9C provided in the exterior housing 9 (specifically, the case 9A). In this embodiment, a tip rubber 16 that abuts against the user's ear canal over its entire circumference is provided at the extending end of the tube portion 13B. By having the tip rubber 16 abut against the ear canal over its entire circumference, the airtightness of the ear canal is ensured, and the reproduced sound from the air conduction receiver 12 is effectively transmitted to the user.

The microphone rubber 15 elastically holds the bone-conduction microphone 11. The microphone rubber 15 connects the bone-conduction microphone 11 to a part where vocal cord vibration is transmitted via bones near the ear 5 (hereinafter referred to as the vocal cord vibration transmission part). This allows the vocal cord vibration transmitted to the vocal cord vibration transmission part to be transmitted to the bone-conduction microphone 11, and the bone-conduction microphone 11 picks up sound by detecting the vocal cord vibration propagating to the bones and skin around the ear via the microphone rubber 15.

The signal processing device 3 generates a signal to be output to the communication device of the other party (not shown in the figure) (an example of the other party's device). Based on the characteristics of the bone conduction microphone 11, the signal processing device 3 can increase the clarity of the user's speech while suppressing the influence of ambient sound, and deliver the speech to the other party's communication device.

The call partner's communication device is not particularly limited, but may have a configuration similar to that of the communication device 1. For example, the call partner's communication device outputs the user's voice from an air conduction receiver built into the earphone or various speakers based on the signal received from the user's communication device 1 (i.e., the signal generated by the signal processing device 3).

The signal processing device 3 is configured by a terminal (e.g., a smartphone) equipped with a processor such as a CPU, memory such as RAM and ROM, storage such as an SSD or HDD, a display such as a touch panel, a network interface, and an audio input/output terminal. However, the configuration of the signal processing device 3 is not limited to this form, and may be configured by, for example, a tablet or various computers equipped with audio input/output terminals. Furthermore, the signal processing device 3 may also be realized by a combination of a logic device and various analog devices.

As described below, the communication device 1 can output side tone (i.e., the user's voice) from the air conduction receiver 12 when the user is talking to a call partner. The communication device 1 can encourage the user to speak at an appropriate volume by controlling the presence or absence of side tone (i.e., on/off) and the level of the side tone (sound pressure level) according to the user's speaking situation.

Figure 3 is a functional block diagram showing the configuration of the communication device 1 according to the first embodiment. Figure 4 is an explanatory diagram showing the output characteristics of the side tone in each operation mode of the communication device 1 ((A) low voice adaptation mode, (B) loud voice suppression mode, (C) mix mode). Figure 5 is an explanatory diagram showing an example of a setting screen for the operation mode of the communication device 1.

As shown in FIG. 3, in the communication device 1, an electrical signal (hereinafter referred to as a "transmitting signal") generated by the bone conduction microphone 11 is input to the signal processing device 3 via a signal line 4. The signal processing device 3 also outputs an electrical signal (hereinafter referred to as a "receiving signal") received from the other device to the air conduction receiver 12 via the signal line 4. Although not shown in the figure, the signal processing device 3 may include an AD converter that converts the transmitting signal input from the bone conduction microphone 11 into a digital signal, and a DA converter that converts the receiving signal output to the air conduction receiver 12 into an analog signal.

The signal processing device 3 has a transmission path 22 for transmitting the transmission signal from the bone conduction microphone 11 to the transmitter 21 (i.e., to the other device). The signal processing device 3 also has a reception path 24 for transmitting the reception signal from the receiver 23 (i.e., from the other device) to the air conduction receiver 12. The signal processing device 3 also has a loopback circuit 25 provided between the transmission path 22 for transmitting and the reception path 24 for receiving. The loopback circuit 25 processes the transmission signal from the transmission path 22 for transmitting and generating a side tone signal. The side tone signal is transmitted via a side tone transmission path 27 that connects the transmission path 22 for transmitting and the reception path 24, and is synthesized with the reception signal of the reception path 24.

The transmitting unit 21 and the receiving unit 23 may be configured with an antenna and a communication circuit for wireless communication with the other device. The transmitting unit 21 transmits the transmission signal from the bone conduction microphone 11 transmitted by the transmission line 22 to the other device. The receiving unit 23 receives the reception signal transmitted from the other device. The received reception signal is transmitted to the air conduction receiver 12 by the reception line 24.

In the signal processing device 3, the transmission path 22 for sending is provided with an amplifier 31 that amplifies the transmission signal. The transmission path 24 for receiving is provided with a synthesis unit 33 that synthesizes (or superimposes) the side tone signal from the loopback circuit 25 with the reception signal from the reception unit 23, and an amplifier 35 that amplifies the reception signal with which the side tone signal has been synthesized. The amplifiers 31, 35 and the synthesis unit 33 may each be configured with an electronic element or circuit.

The loopback circuit 25 has a gain adjustment unit 36, a switch unit 37, a first sound detector 38, and a controller 39.

The gain adjustment unit 36 is provided in the sidetone transmission path 27, and generates a sidetone signal by adjusting the gain applied to the outgoing voice signal from the outgoing voice transmission path 22 (one example of processing the outgoing voice signal). At this time, the level of the sidetone based on the sidetone signal (i.e., the level of the sidetone reproduced by the air conduction receiver 12) is adjusted by the gain applied to the outgoing voice signal. The gain adjustment unit 36 can perform different types of gain adjustment according to the operation mode executed by the communication device 1 described later.

The switch unit 37 is provided in the sidetone transmission path 27 and includes a switch that can switch the sidetone signal from the gain adjustment unit 36 on and off. When the switch unit 37 turns on the sidetone signal, the sidetone signal is input to the synthesis unit 33. The sidetone signal input to the synthesis unit 33 is synthesized with the received signal from the receiving unit 23, amplified by the amplifier unit 35, and then reproduced by the air conduction receiver 12. On the other hand, when the switch unit 37 turns off the sidetone, the sidetone signal input to the synthesis unit 33 is blocked. As a result, the air conduction receiver 12 does not reproduce the sidetone, and only reproduces the sound from the other device (the voice of the other party and ambient sounds).

The first sound detector 38 (an example of a microphone sound detector) acquires the transmission signal transmitted through the transmission path 22 for transmitting voice, and can detect the level (dB) of the sound picked up by the bone conduction microphone 11 based on the transmission signal.

The controller 39 obtains the detection result from the first sound detector 38, and controls the on/off operation of the switch unit 37 based on the detection result. For example, the controller 39 can compare the sound level detected by the first sound detector 38 with one or more preset thresholds, and control the on/off operation of the switch unit 37 based on the comparison result. The controller 39 can execute different types of control according to the operation mode executed by the communication device 1, which will be described later.

The first sound detector 38 (an example of a speech detector) may detect the presence or absence of the user's speech (i.e., speech and silence) based on the speech signal, instead of detecting the level of the sound picked up by the bone conduction microphone 11. Such detection of the presence or absence of a predetermined level of speech by the user can be performed, for example, by detecting the intensity of the voice signal and comparing it with a predetermined threshold (an example of a first threshold). The controller 39 can also determine, for example, based on the detection result of the first sound detector 38, whether a predetermined level of speech by the user has been detected, and control the switch unit 37 to turn on the side tone signal if the user's speech is detected. On the other hand, the controller 39 can control the switch unit 37 to turn off the side tone signal if a predetermined level of speech by the user is not detected.

The hardware used to configure each component of such a loopback circuit 25 can be a publicly known processor or electronic circuit.

Next, we will explain the multiple operating modes (including low voice adaptation mode, high voice suppression mode, and mix mode) that are prepared in advance in the communication device 1. Based on one of these operating modes, the communication device 1 can control at least one of the side tone on/off and the level of the side tone reproduced by the air conduction receiver 12.

In the soft voice adaptation mode, when the user's voice picked up by the bone conduction microphone 11 is insufficient (i.e., when the voice level is relatively low), the communication device 1 essentially disables the side tone reproduced by the air conduction receiver 12 (i.e., turns off the side tone or sets the side tone level to essentially zero). This allows the communication device 1 to notify a user who can no longer hear the side tone that the voice volume is insufficient, thereby encouraging the user to speak at an appropriate volume (i.e., encouraging them to speak louder).

In the soft voice adaptation mode, the controller 39 controls the operation of the switch unit 37 to turn off the side sound (one example of disabling the side sound) only when the level of the sound picked up by the bone conduction microphone 11 is equal to or lower than Va1 (dB) (one example of a first threshold value) based on the detection result of the first sound detector 38. As a result, as shown in FIG. 4(A), when the level of the sound picked up by the bone conduction microphone 11 (see the horizontal axis) is equal to or lower than Va1 (dB), the level of the side sound output from the air conduction receiver 12 (see the vertical axis) is set to substantially zero (i.e., zero or a negligible value).

On the other hand, when the level of the sound picked up by the bone conduction microphone 11 exceeds Va1 (dB), the controller 39 controls the operation of the switch unit 37 to turn on the side sound. As a result, a predetermined level of side sound is output from the air conduction receiver 12, as shown in FIG. 4(A).

Here, in FIG. 4(A), the dashed line L indicates the standard output characteristics of the side tone based on the standard gain adjustment performed by the gain adjustment unit 36 (similarly in FIG. 4(B) and (C)). In the soft voice adaptation mode, when the level of the sound picked up by the bone conduction microphone 11 is Va2 (dB) or less, the gain adjustment unit 36 performs gain adjustment to attenuate the side tone signal. As a result, the level of the side tone output from the air conduction receiver 12 is reduced by a certain amount from the standard output level (see dashed line L). On the other hand, when the level of the sound picked up by the bone conduction microphone 11 exceeds Va2 (dB), the gain adjustment unit 36 performs gain adjustment to maintain the side tone level at the sound level Va2 as it is (i.e., to keep the output of the side tone constant).

For example, the low-voice adaptation mode allows the user to understand what level of speech is appropriate in a call environment where it is preferable to speak in a low voice, such as in a place where there are other people around (e.g., on a train or other public transport). The low-voice adaptation mode also allows the user to understand what level of speech is appropriate in a call environment where there is a lot of ambient noise (a situation in which it is difficult to recognize the user's own voice).

In loud voice suppression mode, when the user's voice picked up by the bone conduction microphone 11 is excessively loud (i.e., when the voice volume level is relatively high), the communication device 1 increases the level of the side tone reproduced by the air conduction receiver 12 (i.e., outputs a side tone that is louder than standard). This allows the communication device 1 to inhibit the user's voice with the side tone, encouraging the user to speak at an appropriate volume (i.e., encouraging the user to suppress the voice volume).

In the loud voice suppression mode, the controller 39 controls the operation of the switch unit 37 to turn off the side sound only when the level of the sound picked up by the bone conduction microphone 11 is equal to or lower than Vb1 (dB) (an example of a second threshold value) based on the detection result of the first sound detector 38. As a result, as shown in FIG. 4(B), when the level of the sound picked up by the bone conduction microphone 11 is equal to or lower than Vb1 (dB), the level of the side sound output from the air conduction receiver 12 is set to substantially zero (i.e., zero or a negligible value).

On the other hand, when the level of the sound picked up by the bone conduction microphone 11 exceeds Vb1 (dB), the controller 39 controls the operation of the switch unit 37 to turn on the side sound. As a result, a predetermined level of side sound is output from the air conduction receiver 12, as shown in FIG. 4(B).

In loud voice suppression mode, the gain adjustment unit 36 performs gain adjustment to amplify the side sound signal, and increases the level of the side sound output from the air conduction receiver 12 by a certain amount from the standard output level (see dashed line L). As a result, when the level of the sound picked up by the bone conduction microphone 11 is equal to or higher than Vb1 (dB), the air conduction receiver 12 outputs a side sound at a level higher than the standard.

In the mixed mode, the communication device 1 selectively executes (i.e., uses both) the quiet voice adaptation mode and the loud voice suppression mode depending on the user's speaking situation (i.e., the level of the speaking volume). In the mixed mode, the communication device 1 executes the quiet voice adaptation mode when the level of the sound picked up by the bone conduction microphone 11 is less than Vb1 (dB), as shown in FIG. 4(C). Also, in the mixed mode, the communication device 1 executes the loud voice suppression mode when the level of the sound picked up by the bone conduction microphone 11 is equal to or greater than Vb1 (dB).

When starting a call with a call partner, the user of the communication device 1 can select a desired operation mode. For example, as shown in FIG. 5, the user can select a desired operation mode (low voice adaptation mode in this case) on an operation mode setting screen 41 displayed on a touch panel 40 (an example of an input device) of the signal processing device 3. The user can also select to turn off the operation mode (i.e., not to execute any operation mode). In addition, the communication device 1 may automatically select an operation mode regardless of the user's selection.

In this way, the communication device 1 can encourage the user to speak at an appropriate volume by using multiple operation modes to control the presence or absence (i.e., on/off) of sidetone and the level of sidetone (i.e., adjusting the gain) depending on the user's speaking situation. Note that, for example, as shown in FIG. 5, the communication device 1 may display an explanation of each operation mode on a display or the like so that the user can understand the purpose of selecting each operation mode.

The method of selecting each operation mode in the communication device 1 is not limited to the example of the operation mode setting screen 41 shown in FIG. 5. For example, as a modified example of the setting screen 41, only two items, the low voice adaptation mode and the high voice self-restraint mode, may be displayed, and the user may turn on and off these two items individually. In this case, the user essentially selects the "mixed mode" shown in FIG. 5 by performing an operation to turn on both the low voice adaptation mode and the high voice self-restraint mode. Also, the user essentially selects the "off" shown in FIG. 5 by performing an operation to turn off both the low voice adaptation mode and the high voice self-restraint mode. Also, the selection of each operation mode by the user is not limited to the operation of the touch panel 40, but may be performed by the user operating other known input devices (operation buttons, keyboards, etc.).

Figure 6 is a functional block diagram showing a first modified example of the configuration of the communication device 1 shown in Figure 3. In the first modified example shown in Figure 6, components similar to those of the communication device 1 shown in Figure 3 are given the same reference numerals. Furthermore, matters regarding the first modified example that are not specifically mentioned below are similar to those of the communication device 1 according to the first embodiment described above.

As shown in FIG. 6, in the first modified example, the loopback circuit 25 of the signal processing device 3 further includes a second sound detector 48 (an example of an ambient sound detector). The second sound detector 48 acquires a transmission signal from the transmission path 22 for transmission of speech, and based on the transmission signal, can detect the level (dB) of the ambient sound, excluding the user's voice, picked up by the bone conduction microphone 11.

The gain adjustment unit 36 obtains the detection result from the second sound detector 48, and based on the detection result, can fine-tune (i.e., correct) the gain applied to the transmission signal from the transmission path for voice transmission 22. For example, the gain adjustment unit 36 can compare the level of the ambient sound detected by the second sound detector 48 with a predetermined threshold, and if the level of the ambient sound exceeds the threshold, can increase the gain from the initial value.

Figure 7 is a functional block diagram showing a second modified example of the configuration of the communication device 1 shown in Figure 3. In the second modified example shown in Figure 7, the same components as those of the communication device 1 shown in Figures 3 and 6 are given the same reference numerals. Furthermore, with regard to the second modified example, matters not specifically mentioned below are the same as those of the communication device 1 according to the first embodiment described above or its first modified example.

As shown in FIG. 7, in the second modified example, a volume adjustment unit 51 is provided upstream of the synthesis unit 33 in the receiving transmission path 24. The volume adjustment unit 51 can adjust the volume of the sound based on the received signal by adjusting the gain applied to the received signal from the receiving unit 23.

The gain adjustment unit 36 acquires information on the gain applied to the received signal (an example of the degree of volume adjustment) from the volume adjustment unit 51. The gain adjustment unit 36 can further fine-tune (i.e., correct) the gain fine-tuned according to the level of the ambient sound detected by the second sound detector 48 as described above, based on the gain information from the volume adjustment unit 51. For example, the gain adjustment unit 36 can adjust the gain applied to the transmission signal from the transmission line 22 so as to be linked with the adjustment of the gain applied to the received signal (i.e., amplification or attenuation of the received signal). As a result, for example, when the level of the sound (i.e., sound other than the side tone) of the voice of the other party reproduced by the air conduction receiver 12 becomes large, the level of the side tone becomes large so as to correspond to the level of that sound. The gain adjustment unit 36 may fine-tune the gain applied to the transmission signal based on either the detection result from the second sound detector 48 or the gain information from the volume adjustment unit 51.

Second Embodiment
Fig. 8 is a functional block diagram showing the configuration of the communication device 1 according to the second embodiment. Fig. 9 is an explanatory diagram showing the output characteristics of the side tone in each operation mode ((A) low voice adaptation mode, (B) loud voice suppression mode, (C) mixed mode) of the communication device 1 according to the second embodiment. In the communication device 1 shown in Fig. 8, the same components as those of the communication device 1 according to the first embodiment (including the first and second modified examples) are given the same reference numerals. In addition, matters not specifically mentioned below regarding the communication device 1 according to the second embodiment are similar to those of the communication device 1 according to the first embodiment.

As shown in FIG. 8, in the communication device 1 according to the second embodiment, the loopback circuit 25 has a gain adjustment unit 36 and an auto gain controller (hereinafter referred to as "AGC") 55. The AGC 55 can function in the same manner as the switch unit 37, the first sound detector 38, and the controller 39 of the communication device 1 according to the first embodiment. The AGC 55 can control the level of the side tone reproduced by the air conduction receiver 12 by controlling the gain applied to the side tone signal. For example, the AGC 55 can substantially block the side tone signal input to the synthesis unit 33 (i.e., substantially turn off the side tone) by controlling the gain applied to the side tone signal from the gain adjustment unit 36 (one example of disabling the side tone). The gain control applied to the side tone signal by the AGC 55 can be performed according to the level of the sound picked up by the bone conduction microphone 11.

In the soft voice adaptation mode, the AGC 55 adds gain to the side tone signal to turn off the side tone (i.e., to attenuate the side tone signal) only when the level of the sound picked up by the bone conduction microphone 11 is equal to or lower than Va1' (dB) (an example of a first threshold value). As a result, as shown in FIG. 9(A), when the level of the sound picked up by the bone conduction microphone 11 is equal to or lower than Va1' (dB), the level of the side tone output from the air conduction receiver 12 is set to substantially zero.

When the level of the sound picked up by the bone-conduction microphone 11 exceeds Va1' (dB) and is equal to or lower than Va1 (dB), the AGC 55 controls the gain applied to the side tone signal so as to gradually suppress the attenuation of the side tone signal (i.e., to approach the standard output level). Also, when the sound level exceeds Va1 (dB) and is equal to or lower than Va2 (dB), the AGC 55 stops controlling the gain. Furthermore, when the level of the sound picked up by the bone-conduction microphone 11 exceeds Va2 (dB), the AGC 55 controls the gain so as to maintain the side tone level at the sound level Va2.

In loud voice suppression mode, the AGC 55 adds gain to the side tone signal to turn off the side tone (i.e., to attenuate the side tone signal) only when the level of the sound picked up by the bone conduction microphone 11 is equal to or lower than Vb1' (dB) (an example of a second threshold value). As a result, as shown in FIG. 9(B), when the level of the sound picked up by the bone conduction microphone 11 is equal to or lower than Vb1' (dB), the level of the side tone output from the air conduction receiver 12 is set to substantially zero.

When the level of the sound picked up by the bone conduction microphone 11 exceeds Vb1' (dB) and is equal to or lower than Vb1 (dB), the AGC 55 controls the gain applied to the side tone signal so as to gradually suppress the attenuation of the side tone signal (i.e., to approach the standard output level). In addition, the AGC 55 stops controlling the gain when the sound level exceeds Vb1 (dB).

In loud voice suppression mode, the gain adjustment unit 36 performs gain adjustment to amplify the side sound signal, and increases the level of the side sound output from the air conduction receiver 12 by a certain amount from the standard output level (see dashed line L). As a result, when the level of the sound picked up by the bone conduction microphone 11 is equal to or higher than Vb1 (dB), the air conduction receiver 12 outputs a side sound at a level higher than the standard.

In the mixed mode, the communication device 1 selectively executes the quiet voice adaptation mode and the loud voice suppression mode depending on the user's speaking situation. In the mixed mode, the communication device 1 executes the quiet voice adaptation mode when the level of the sound picked up by the bone conduction microphone 11 is less than Vb1' (dB), as shown in FIG. 9 (C). Also, in the mixed mode, the communication device 1 executes the loud voice suppression mode when the level of the sound picked up by the bone conduction microphone 11 is equal to or greater than Vb1' (dB).

Figure 10 is a functional block diagram showing a first modified example of the configuration of the communication device 1 shown in Figure 8. Figure 11 is an explanatory diagram showing the comfort zone and discomfort zone in the relationship between the amount of side tone delay and the side tone playback volume. In the first modified example shown in Figure 10, the same components as those in the communication device 1 shown in Figure 8 are given the same reference numerals. Furthermore, matters in the first modified example that are not specifically mentioned below are the same as those in the communication device 1 according to the second embodiment described above.

As shown in FIG. 10, in the first modified example, the loopback circuit 25 of the signal processing device 3 further includes an audio extraction unit 61 and a delay processing unit 62.

The voice extraction unit 61 includes a low-pass filter for extracting a voice signal related to the user's voice from the transmission signal from the transmission path 22 for voice transmission (i.e., eliminating ambient sound and echo components). The voice signal extracted by the voice extraction unit 61 is input to the gain adjustment unit 36. The gain adjustment unit 36 generates a side tone signal by adjusting the gain applied to the voice signal from the voice extraction unit 61 (an example of processing the transmission signal).

In loud voice suppression mode, the delay processing unit 62 performs delay processing on the side tone signal from the AGC 55. In the air conduction receiver 12, the side tone based on the side tone signal that has been subjected to such delay processing is reproduced with a predetermined delay (e.g., 200 ms or more) compared to the normal side tone (i.e., the side tone without delay processing). There is a relationship between the delay amount of the side tone in the air conduction receiver 12 and the playback volume of the side tone as shown in FIG. 11. When it is necessary to encourage the user to speak at an appropriate volume in the communication device 1 (e.g., to encourage the user to suppress speaking), the delay processing unit 62 may perform delay processing so that the combination of the side tone delay amount and the playback volume of the side tone is located in the uncomfortable area indicated by the level of the sound picked up by the bone conduction microphone. However, the delay processing unit 62 may be omitted in the communication device 1.

Figure 12 is a functional block diagram showing a second modified example of the configuration of the communication device 1 shown in Figure 8. In the second modified example shown in Figure 12, the same components as those of the communication device 1 shown in Figures 8 and 10 are given the same reference numerals. Furthermore, with regard to the second modified example, matters not specifically mentioned below are the same as those of the communication device 1 according to the second embodiment described above or its first modified example.

As shown in FIG. 12, in the second modified example, the transmission path 22 for voice transmission is provided with an echo canceling/noise canceling unit 71 (an example of an echo canceller or a noise canceller). In addition, the loopback circuit 25 of the signal processing device 3 further includes a band expanding unit 72.

The echo cancellation/noise cancellation unit 71 performs an echo cancellation process to remove or reduce the echo components of the transmission signal, and a noise cancellation process to remove or reduce the noise components. The gain adjustment unit 36 generates a side tone signal by adjusting the gain applied to the transmission signal from which the echo components and noise components have been removed or reduced (an example of processing the transmission signal).

The band expansion unit 72 performs band expansion processing (i.e., signal processing to expand the band of the sidetone) on the sidetone signal from the AGC 55. The sidetone signal that has been band expanded by the band expansion unit 72 is input to the synthesis unit 33. This band expansion processing makes the sidetone reproduced by the air conduction receiver 12 a more natural sound. However, the band expansion unit 72 may be omitted in the communication device 1.

As described above, the embodiments have been described as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to this, and can also be applied to embodiments in which modifications, substitutions, additions, omissions, etc. have been made. It is also possible to combine the components described in the above embodiments to create new embodiments.

The communication device according to the present disclosure can encourage the user to speak at an appropriate volume by controlling the presence or absence of sidetones and the level of the sidetones depending on the user's speaking situation, and is useful as a communication device that is equipped with a bone conduction microphone and receiver and is worn on the user's ear, head, etc.

1: Communication device 2: Earphone 3: Signal processing device 4: Signal line 5: Ear 9: Exterior housing 9A: Case 9B: Cover 9C: Opening 10: Cable cap 11: Bone conduction microphone 12: Air conduction receiver 13: Internal housing 13A: Passage 13B: Cylinder 15: Microphone rubber 16: Tip rubber 21: Transmitter 22: Transmission path for sending voice 23: Receiver 24: Transmission path for receiving voice 25: Loopback circuit 27: Transmission path for side tone 31: Amplifier 33: Synthesis unit 35: Amplifier 36: Gain adjustment unit 37: Switch unit 38: First sound detector 39: Controller 41: Setting screen 48: Second sound detector 51: Volume adjustment unit 55: AGC
61: Audio extraction unit 62: Delay processing unit 71: Echo cancellation/noise cancellation unit 72: Band expansion unit

Claims (14)

A bone conduction microphone that picks up the user's voice and generates a speech signal;
A receiver that reproduces sound based on a call signal received from a remote device;
a transmission line for transmitting the transmission signal from the bone conduction microphone to the other device;
a receiving transmission path for transmitting the receiving signal to the receiver;
a loopback circuit provided between the transmission line for transmitting voice and the transmission line for receiving voice, for synthesizing a side tone signal generated by processing the transmission signal with the reception signal,
The loopback circuit controls at least one of the on/off of the side tone reproduced by the receiver based on the side tone signal and the level of the side tone based on the level of the sound picked up by the bone conduction microphone . Operates based on one of a plurality of operation modes prepared in advance,
The plurality of operation modes includes a quiet voice adaptation mode;
The communication device of claim 1 , wherein in the quiet voice adaptation mode, the sidetone is disabled only if the level of the picked -up sound is equal to or lower than a first threshold. The plurality of operation modes includes a loud noise suppression mode;
The communication device according to claim 2 , wherein in the loud voice suppression mode, when the level of the picked-up sound is equal to or higher than a second threshold value that is higher than the first threshold value, the level of the side tone is increased. 4. The communication device according to claim 3, wherein the loopback circuit includes a microphone sound detector that detects a level of the picked-up sound based on the transmission signal from the transmission path for voice transmission. An input device for the user to perform an input operation is further provided,
The communication device according to claim 3 , wherein the plurality of operation modes are individually turned on and off based on an input operation of the user on the input device. The communication device according to claim 1, wherein the loopback circuit includes a gain adjustment unit that adjusts the gain of the transmission signal from the transmission line. an ambient sound detector that detects a level of an ambient sound, excluding the user's voice, collected by the bone conduction microphone based on the transmission signal from the transmission line;
The communication device according to claim 6 , wherein the gain adjustment section adjusts the gain for the transmission signal from the transmission path for voice transmission based on a level of the ambient sound. a volume adjustment unit that is provided in the receiving transmission path and adjusts the volume of a sound based on the receiving signal that is reproduced by the receiver based on the receiving signal,
The communication device according to claim 7 , wherein the gain adjustment unit sets the gain based on a degree of adjustment of the volume by the volume adjustment unit. The communication device according to claim 2, further comprising a speech detector that detects whether the user is speaking based on the transmission signal from the transmission line, and executes the low voice adaptation mode when it is determined based on the detection result of the speech detector that the sound picked up by the bone conduction microphone does not include the user's speech at a predetermined level or above. The communication device according to claim 3, wherein the loopback circuit includes a voice extraction unit that extracts a voice signal based on the user's voice from the transmission signal from the transmission line for voice transmission, and generates the side tone signal based on the voice signal. The communication device according to claim 10, wherein the loopback circuit includes a delay processing unit that delays the audio signal based on a predetermined delay time in the loud voice suppression mode, and generates the side tone signal based on the delayed audio signal. The communication device according to claim 3, further comprising a noise canceller provided in each of the transmission paths for voice transmission, which removes or reduces noise components in the voice transmission signal to be processed by the loopback circuit, and an echo canceller which removes or reduces echo components included in the voice transmission signal to be processed by the loopback circuit. The communication device according to claim 12, wherein the loopback circuit includes a band expansion unit that expands the frequency band of the sidetone signal. A call control method for a call device, comprising:
The communication device includes:
A bone conduction microphone that picks up the user's voice and generates a speech signal;
A receiver that reproduces sound based on a call signal received from a remote device;
a transmission line for transmitting the transmission signal from the bone conduction microphone to the other device;
a receiving transmission path for transmitting the receiving signal to the receiver,
A side tone signal generated by processing the transmitted signal can be synthesized into the received signal;
A call control method, comprising controlling at least one of turning on and off a side tone reproduced by the receiver based on the side tone signal and a level of the side tone based on a level of sound picked up by the bone conduction microphone .

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