JP2008134557A - Mobile terminal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal device capable of reducing leak of transmitting voice and receiving voice to outside. <P>SOLUTION: The mobile terminal device includes: a microphone for detecting the transmitting voice of a user; a receiver for outputting the receiving voice from a calling place; a creating section for creating a transmission anti-phase signal of an anti-phase having the same frequency component with the transmission voice, and a receiving anti-phase signal of an anti-phase having the same frequency component with the receiving voice; and a speaker for outputting the transmission anti-phase signal and the receiving anti-phase signal, in voice. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mobile terminal device such as a mobile phone, and more particularly to a mobile terminal device capable of reducing both transmitted voice and received voice leaking to the surroundings.

  In general, when making a call with a mobile phone in a place where there is an unspecified third party such as a public place, as a manner of using the mobile phone, the voice emitted by the user of the mobile phone should not leak to the surroundings as much as possible. It is said that users should talk quietly, but if they speak quietly, it will be difficult for the other party to hear the voice, making it difficult to talk. I have to speak at a volume that can be heard.

  Therefore, in order to reduce the leakage of the transmitted voice emitted by the user to the surroundings, the mobile phone generates a voice signal having the same component as the frequency of the transmitted voice signal and having an opposite phase, and outputs it from the speaker. Thus, there is known a technique for canceling the surrounding transmitted voice and reducing the transmitted voice. For example, in Patent Document 1 described below, a portable communication terminal is configured to output an audio signal having the same frequency component and opposite phase to a transmitted voice from a speaker, and to reduce the transmitted voice audible to the surroundings by canceling the transmitted voice. In particular, a partition wall that isolates the space between the microphone and the speaker in the housing is provided, and the sound emitted from the speaker wraps around the speaker inside the housing, canceling the transmitted voice, and transmitting It is characterized by preventing the talk volume from being reduced.

In addition, for example, as disclosed in Patent Documents 2 and 3 below, in the technical field other than the mobile phone device, from the viewpoint of preventing noise to the surroundings, it has the same frequency component as the noise component that leaks to the surroundings and vice versa A configuration in which noise is reduced by outputting phase sound from a speaker is known.
JP 2006-148378 A JP-A-6-208214 JP-A-8-150621

  However, with the widespread use of mobile phones, while further improvement in manners during calls is demanded, the above-mentioned Patent Document 1 can reduce the leakage of the transmitted voice to the surroundings, but from the speaker of the mobile phone. It is not possible to reduce the leakage of the received voice.

  In addition, many of recent mobile phones have a music playback function, and reduction of sound leaking from a speaker or headphones (or earphones) accompanying music playback is also required for improving manners.

  Furthermore, as in Patent Document 1, if a partition wall is provided to prevent reverse phase sound from a speaker from entering a microphone, miniaturization of the mobile terminal device is hindered. Further, when the reverse phase sound from the speaker reaches the user's ear, the received sound from the receiver is canceled, the volume is lowered, and it becomes difficult to hear.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a mobile terminal device that can reduce leakage of sound output from the mobile terminal device to the outside, such as received voice, as well as transmitted voice.

  Another object of the present invention is to provide a portable terminal device that prevents a reverse phase sound from a speaker from reaching a user's ear or a microphone without providing a partition wall.

  FIG. 1 is a diagram showing a main configuration of a mobile terminal device according to the present invention. The mobile terminal device is, for example, a mobile phone and can be equipped with various functions such as a telephone function, an e-mail function, a music playback function, and an Internet function. FIG. 1 shows components related to the telephone function.

  The voice transmitted by the user is acquired by the microphone 1, and the analog voice signal is converted into a digital voice signal by the A / D converter 2 and further encoded by the voice encoder 3. And transmitted from the antenna 5 via the wireless unit 4. Various encoding methods such as PCM (Pulse Code Modulation), ADPCM (Adaptive Differential Pulse Modulation), MIDI (Musical Instruments Digital Interface), AAC (Advanced Audio Coding), MP3 (MPEG Audio Layer-3), etc. May be used.

  The encoded digital transmission voice signal is transmitted, decoded by the voice decoding unit 9, converted back to an analog transmission voice signal by the D / A conversion unit 10, and output from the receiver 11 as a voice. As a result, the user's own transmitted voice is output from the receiver 11, and the user can confirm his / her voice.

  Further, the encoded digital transmission voice signal is input to the antiphase waveform generator 6. The antiphase waveform generation unit 6 generates a signal (transmission antiphase signal) having the same frequency component as the input digital transmission voice signal and having an antiphase. The sound source reproduction unit 7 decodes the transmission reverse phase signal, further D / A converts it, and outputs it from the speaker 8. Thereby, the transmission voice emitted from the user's mouth and the transmission voice output from the receiver 11 are canceled by the transmission reverse phase signal output from the speaker 8, and the leakage of the transmission voice to the outside is reduced. be able to.

  On the other hand, the received voice from the call destination is received by the antenna 5 as an encoded digital received voice signal. The encoded digital reception voice signal is decoded by the voice decoding unit 9, further converted back to an analog reception voice signal by the D / A conversion unit 10, and output from the receiver 11 as a voice. Thereby, the reception voice which the other user uttered is output from receiver 11, and the user can hear reception voice.

  Then, as a leakage sound canceling function characteristic of the mobile terminal device of the present invention, the encoded digital reception voice signal is further input to the antiphase waveform generation unit 6. The reverse phase waveform generation unit 6 generates a signal having the same frequency component as that of the input digital reception voice signal and having an opposite phase (reception reverse phase signal). The sound source reproduction unit 7 decodes the received reverse phase signal, further D / A converts it, and outputs it from the speaker 8. Thereby, the received voice output from the receiver 11 is canceled by the received reverse phase signal output from the speaker 8, and the mobile terminal device of the present invention can also reduce the leakage of the received voice to the outside.

  According to the present invention, it is possible to prevent the received voice from leaking around the user by generating and outputting the reverse phase signal of the received voice together with the transmitted voice.

  Moreover, it is possible to prevent reverse phase sound from the speaker from entering the microphone without providing a partition wall between the speaker and the microphone.

  Embodiments of the present invention will be described below with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention.

  FIG. 2 is a diagram illustrating a first configuration example of the mobile terminal device according to the embodiment of the present invention. Components having substantially the same functions as those in FIG. 1 are denoted by the same reference numerals. The processing of the transmitted voice is as follows. The transmitted voice is detected by the microphone 1. The input level of the analog transmission voice signal is adjusted by a level adjustment unit (TXVOL) 21. The anti-aliasing filter (AAF) 22 is a low-pass filter for removing a signal having a frequency higher than the Nyquist frequency in order to eliminate aliasing noise. The A / D converter (ADC) 2 converts the analog transmission voice signal filtered by the anti-aliasing filter 22 into a digital transmission voice signal, and the digital transmission voice signal is converted by the band pass filter (BPF) 24. After the noise is removed, the data is encoded into the PCM format by the PCM format conversion unit 3 (9). The encoded digital transmission voice signal is transmitted as a radio signal by processing of the baseband processor 5 (6).

  The PCM format conversion unit 3 (9) decodes the encoded digital transmission voice signal. The digital transmission voice signal is denoised by the band-pass filter 26, and then the D / A conversion unit (DAC) ) 10 to return to the analog transmission voice signal. The analog transmission voice signal is smoothed by the smoothing filter (SMF), level-adjusted by the level adjustment unit (RXVOL) 30, and then output from the receiver 11. The receiver volume adjustment unit 32 is a level adjustment unit that allows the user to set the output level from the receiver 11. The transmitted voice output from the receiver 11 is for the user to confirm the transmitted voice that the user himself / herself utters.

  On the other hand, the baseband processor 5 (6) generates a digital transmission reverse phase signal having the same frequency component as that of the encoded digital transmission voice signal and having an opposite phase, and sends it to the multimedia processor 34. The multimedia processor 34 converts the digital transmission reverse phase signal into a format used by the sound source reproduction unit 7 and sends the digital transmission reverse phase signal to the sound source reproduction unit 7. The multimedia processor 34 and the sound source playback unit 7 have a music playback function, for example, and perform audio processing using a music playback format different from the call format (for example, PCM format). The sound source reproduction unit 7 decodes the digital transmission reverse phase signal, performs D / A conversion, and returns the analog transmission reverse phase signal. The analog transmission reverse phase signal is output from the speaker 8. The speaker level adjustment unit 36 is level adjustment means that allows the user to set the output level from the speaker 8.

  Thus, the reception voice output from the receiver 11 is canceled by the reception reverse phase signal output from the speaker 8, and the mobile terminal device of the present invention can reduce leakage of the reception voice to the outside. .

  The processing of the received voice is as follows. When the baseband processor 6 receives the encoded digital reception voice signal, it sends it to the PCM format converter 3 (9). The PCM format converter 3 (9) decodes the encoded digital received voice signal. Similarly to the digital transmission voice signal, the decoded digital reception voice signal is subjected to noise removal by the band pass filter 26 and then returned to the analog reception voice signal by the D / A converter (DAC) 10. The analog reception voice signal is smoothed by the smoothing filter (SMF), level-adjusted by the level adjustment unit (RXVOL) 30, and then output from the receiver 11. Thus, the user can hear the received voice from the receiver 11.

  On the other hand, when the baseband processor 6 receives the encoded digital reception voice signal, the baseband processor 6 generates a digital reception reverse phase signal having the same frequency component as that of the digital reception, and sends it to the multimedia processor 34. The multimedia processor 34 converts the digital reception reverse phase signal into a format used by the sound source reproduction unit 7, and sends the digital reception reverse phase signal to the sound source reproduction unit 7. The sound source reproduction unit 7 decodes the digital reception reverse phase signal, performs D / A conversion, and returns the analog reception reverse phase signal. In this way, the analog reception reverse phase signal is output from the speaker 8 and the reception voice output from the receiver 11 is canceled.

  The multimedia processor 34 determines at least one of the input voice level from the microphone 1 and the output voice level from the receiver 11 according to the level of the digital transmission reverse phase signal and the digital reception reverse phase signal received from the baseband processor 6. You may control. In the case where the reverse phase transmission voice or the output level of the reverse phase output from the speaker 8 is insufficient to the level necessary for cancellation, the transmission voice and the reception voice are reduced by reducing the levels of the original transmission voice and reception voice. Prevent outside leakage of received voice. Specifically, the multimedia processor 34 determines at least one of the level adjustment unit 20 and the level adjustment unit 30 when the levels of the digital transmission reverse phase signal and the digital reception reverse phase signal exceed a predetermined threshold. To suppress at least one of the input sound level and the output sound level.

  Alternatively, the multimedia processor 34 may perform control to output a warning sound from the receiver 11 via the sound source reproduction unit 7. Thereby, the user is informed that the output level of the transmission reverse phase signal or the reception reverse phase signal from the speaker 8 is not a sufficient level to cancel the sound leakage to the outside. The user weakens the output sound from the receiver 11 by the receiver level adjustment unit 32, or reduces the sound emitted by the user himself, thereby suppressing leakage sound to the outside.

  Further, in order to prevent the received voice or the transmitted voice from leaking to the outside, the multimedia processor 34 causes the sound source playback unit 7 to play back the sound source data stored in advance in the storage means in the mobile terminal device, thereby causing the reverse phase. It is also possible to control to output from the speaker 8 by superimposing it on the signal. When the output level of the transmission reverse phase signal or the reception reverse phase signal from the speaker 8 is not a sufficient level to cancel sound leakage to the outside, a specific pattern sound is output superimposed on the reverse phase signal. Thus, it is possible to prevent the content of the user's call from leaking outside. The pattern sound is an arbitrary noise sound or music, and can be selected by the user.

  FIG. 3 is a diagram illustrating a second configuration example of the mobile terminal device according to the embodiment of the present invention. Components having substantially the same functions as those in FIG. 1 are denoted by the same reference numerals. The second configuration example is a configuration in which leakage of sound output from the headphones (including earphones) 42 to the outside is reduced by the music playback function of the mobile terminal device. The portable terminal device includes a headphone terminal to which headphones 42 are connected. The mobile terminal device of the second configuration example may include the call function in the first configuration example.

  The sound source reproduction unit 7 reproduces the sound source data designated by the user under the control of the multimedia processor 34. The reproduced sound signal of the sound source data is output as sound from the headphones 42. The headphone level adjustment unit 40 is level adjustment means that allows the user to set the output level of the headphones 42. The sound source data is stored in advance in storage means in the mobile terminal device.

  If the sound source data to be reproduced is not in the PCM format, the multimedia processor 34 converts the sound source data into the PCM format and sends the sound source data to the baseband processor 6. The baseband processor 6 uses the same frequency component as the received sound source data. A digital anti-phase acoustic signal having and anti-phase is generated.

  The PCM format conversion unit 3 (9) decodes the digital anti-phase signal, and the decoded digital anti-phase acoustic signal is denoised by the band pass filter 26 and then analog by the D / A conversion unit (DAC) 10. Returned to the anti-phase acoustic signal. The analog anti-phase acoustic signal is smoothed by the smoothing filter (SMF) 28, level-adjusted by the level adjusting unit (RXVOL) 30, and then output from the speaker 8 as anti-phase audio. Thus, the sound leaking from the headphones 42 is canceled by the antiphase sound output from the speaker 8.

  In the above-described embodiment, the multimedia processor 34 preferably performs a so-called 3D surround process on the transmission voice, the reception voice, and the predetermined sound source data reproduced by the sound source reproduction unit 7. When the reverse phase sound output from the speaker 8 reaches the user's ear during a call, the sound emitted by the user or the sound output from the receiver 11 and the headphones 42 is canceled. Further, when the microphone 1 picks up the reverse phase sound, the level of the transmitted voice detected by the microphone 1 becomes small. By the microphone 3D surround processing, it is possible to prevent the reverse phase sound output from the speaker 8 from reaching the user's ear and the microphone, and to eliminate the inconvenience that the sound cannot be heard.

  The 3D surround technology is a process of creating three-dimensional stereophonic sound higher than stereo sound using two speakers. A sound signal that makes a user perceive that a virtual sound source exists at a predetermined position in a three-dimensional space. This is an acoustic process to be generated.

  The human ear unconsciously feels the difference in volume, the time difference or phase difference in which the sound travels, and the frequency characteristics.For example, when there is a noise in the front left, the volume difference is that the left ear is heard louder. , I instantly feel the time difference that it was transmitted to the left ear earlier. In addition, the sound from the sound source does not reach the ear linearly, but reaches the eardrum while reflecting off various objects including the human body. That is, the way of reflection differs depending on whether the sound arrives from the front or the rear. Since the person remembers the difference in transmission (called a transfer function), the direction of the sound source of the sound can be recognized. By applying this human perceptual processing capability, a pseudo acoustic signal having the same characteristics as perception in human memory is generated and emitted from the sound source. Even though it is in front, it is possible to make an illusion that the virtual sound source is in the rear and to recognize the sound as being output from the rear. Thus, the position of the sound source and the output direction (directivity) of the sound from the sound source can be virtually controlled by the 3D surround processing.

  Such 3D surround processing is a known technique and is realized as a dedicated LSI or software, and a mobile terminal device equipped with the 3D surround function has been put into practical use.

  In the portable terminal device according to the embodiment of the present invention, 3D surround processing software is stored in a storage unit in the device, and the multimedia processor 34 executes the software. The multimedia processor 34 performs a 3D surround process on the audio signal output from the speaker 8 so that it does not reach the user's ear, the microphone 1 and the receiver 11 but can be heard only in the vicinity of the user. By outputting the audio signal having the opposite phase from the speaker 8, the above inconvenience is solved.

  FIG. 4 is a diagram illustrating a state in which antiphase audio is output only around the user by the 3D surround processing. A microphone 1 and a receiver 11 are provided on the side of the portable terminal device facing the user's ear. The speaker 8 is provided on the surface opposite to the side facing the user's ear. FIG. 4A shows a state in which the reverse phase sound from the mobile terminal device is output only around the user so as not to reach the mobile terminal device having the user's ear, microphone, and receiver. Moreover, FIG.4 (b) shows a mode that the antiphase audio | voice from a portable terminal device is output in the direction away from a user so that it may not reach the portable terminal device which has a user's ear, a microphone, and a receiver.

  In the above-mentioned Patent Document 1, by providing a partition wall that isolates the space between the microphone and the speaker in the housing, the sound emitted from the speaker wraps around the speaker inside the housing, canceling the transmitted voice, Although the invention for preventing the transmission volume from being reduced is disclosed, this partition wall is an obstacle to downsizing the portable terminal device. In the mobile terminal device of the present invention, it is possible to prevent the reverse phase sound from reaching the user's ear or the microphone 1 by the 3D surround processing. Therefore, there is no need to add a physical member for the sound of the opposite phase to wrap around the user's ear or microphone, so the size of the portable terminal device is not increased in order to realize the leakage sound canceling function of the present invention. It's okay.

  In addition, the leakage sound canceling function of the present invention can be realized by using a normal call circuit and processor and a music playback circuit and processor that have been conventionally installed in a portable terminal device, and increase the cost. Can be suppressed.

(Appendix 1)
In a mobile terminal device that transmits a user's transmitted voice and receives a received voice from a call destination,
A microphone for detecting the transmitted voice;
A receiver for outputting the received voice;
A generation unit that generates a transmission reverse phase signal having the same frequency component as that of the transmission voice and a reverse phase transmission signal having the same frequency component as that of the reception voice;
A portable terminal device comprising: a speaker that outputs the transmission reverse phase signal and the reception reverse phase signal generated by the generation unit.

(Appendix 2)
In a mobile terminal device having a music playback function,
A headphone jack to which headphones are connected;
A generation unit that generates the opposite phase acoustic signal having the same frequency component as the acoustic signal output to the headphone terminal and having the opposite phase;
A portable terminal device comprising: a speaker that outputs the sound of the antiphase acoustic signal generated by the generation unit.

(Appendix 3)
In Appendix 1,
With headphone jack,
The generation unit generates an anti-phase acoustic signal having the same frequency component as the acoustic signal output to the headphone terminal and having an opposite phase,
The portable terminal device, wherein the antiphase acoustic signal is output as a sound from the speaker.

(Appendix 4)
In Appendix 1,
The transmission reverse phase signal and the reception reverse phase signal output by the speaker are not output near the user's ear, the microphone and the receiver, and are output only around the user. An acoustic processing unit that acoustically processes the speech reverse phase signal and the reception reverse phase signal;
The mobile terminal apparatus, wherein the transmission-reverse phase signal and the reception-reverse phase signal subjected to the acoustic processing are output from the speaker.

(Appendix 5)
In Appendix 2 or 3,
The anti-phase acoustic signal is acoustically processed so that the anti-phase acoustic signal output from the speaker does not reach the user's ear, the microphone, and the receiver, and is output only around the user. Equipped with an acoustic processing unit,
The portable terminal apparatus, wherein the sound processing-processed antiphase acoustic signal is output from the speaker.

(Appendix 6)
In any one of supplementary notes 1 to 5,
An acoustic processing unit for detecting the levels of the antiphase transmission signal and the antiphase reception signal;
The acoustic processing unit generates a warning sound and outputs the warning sound from the speaker when the levels of the reverse phase transmission signal and the reverse phase reception signal are larger than a predetermined threshold value. Mobile terminal device.

(Appendix 7)
In any one of supplementary notes 1 to 5,
An acoustic processing unit for detecting the levels of the antiphase transmission signal and the antiphase reception signal;
The acoustic processing unit adjusts the detection level at the microphone and the output level of the receiver to a predetermined level when the levels of the reverse phase transmission signal and the reverse phase reception signal are greater than a predetermined threshold value. A portable terminal device.

(Appendix 8)
In any one of appendices 1 to 7,
An acoustic processing unit that reproduces sound data of a predetermined pattern is provided,
A portable terminal device characterized in that an audio signal obtained by reproducing the audio data is output from the speaker together with the transmission reverse phase signal and the reception reverse phase signal.

(Appendix 9)
In the mobile terminal device that receives the incoming voice from the other party,
A receiver for outputting the received voice;
A generating unit that generates a reception reverse phase signal having the same frequency component as that of the reception voice and having an opposite phase;
A portable terminal device comprising: a speaker that outputs the received reverse phase signal generated by the generation unit as a voice.

It is a figure which shows the principal part structure of the portable terminal device of this invention. It is a figure which shows the 1st structural example of the portable terminal device in embodiment of this invention. It is a figure which shows the 2nd structural example of the portable terminal device in embodiment of this invention. It is a figure which shows the state from which antiphase audio | voice is output only to a user's periphery by 3D surround processing.

Explanation of symbols

  1: microphone, 2: A / D conversion unit, 3: audio encoding unit, 4: wireless unit, 5: antenna, 6: antiphase waveform generation unit, 7: sound source reproduction unit, 8: speaker, 9: audio decoding 10: D / A converter 11: Receiver

Claims (6)

In a mobile terminal device that transmits a user's transmitted voice and receives a received voice from a call destination,
A microphone for detecting the transmitted voice;
A receiver for outputting the received voice;
A generation unit that generates a transmission reverse phase signal having the same frequency component as that of the transmission voice and a reverse phase transmission signal having the same frequency component as that of the reception voice;
A portable terminal device comprising: a speaker that outputs the transmission reverse phase signal and the reception reverse phase signal generated by the generation unit. In a mobile terminal device having a music playback function,
A headphone jack to which headphones are connected;
A generation unit that generates the opposite phase acoustic signal having the same frequency component as the acoustic signal output to the headphone terminal and having the opposite phase;
A portable terminal device comprising: a speaker that outputs the sound of the antiphase acoustic signal generated by the generation unit. In claim 1,
With headphone jack,
The generation unit generates an anti-phase acoustic signal having the same frequency component as the acoustic signal output to the headphone terminal and having an opposite phase,
The portable terminal device, wherein the antiphase acoustic signal is output as a sound from the speaker. In claim 1,
The transmission reverse phase signal and the reception reverse phase signal output by the speaker are not output near the user's ear, the microphone and the receiver, and are output only around the user. An acoustic processing unit that acoustically processes the speech reverse phase signal and the reception reverse phase signal;
The mobile terminal apparatus, wherein the transmission-reverse phase signal and the reception-reverse phase signal subjected to the acoustic processing are output from the speaker. In claim 2 or 3,
The anti-phase acoustic signal is acoustically processed so that the anti-phase acoustic signal output from the speaker does not reach the user's ear, the microphone, and the receiver, and is output only around the user. Equipped with an acoustic processing unit,
The portable terminal apparatus, wherein the sound processing-processed antiphase acoustic signal is output from the speaker. In the mobile terminal device that receives the incoming voice from the other party,
A receiver for outputting the received voice;
A generating unit that generates a reception reverse phase signal having the same frequency component as that of the reception voice and having an opposite phase;
A portable terminal device comprising: a speaker that outputs the received reverse phase signal generated by the generation unit as a voice.

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