JP5087514B2 - Mobile communication terminal - Google Patents

Description

  The present invention relates to a mobile communication terminal, and more particularly to a mobile communication terminal that removes noise from, for example, telephone conversation voice.

  2. Description of the Related Art Conventionally, a mobile communication terminal that removes noise from call speech is known. An example of this type of device is disclosed in Patent Document 1. This background art is a portable radio telephone provided with a noise canceller that removes (cancels) noise contained in a call voice. Specifically, in a state where a hands-free headset is connected, the transmitted voice of the speaker is collected by the microphone of the headset, and ambient noise is collected by the microphone of the portable radio telephone. The noise canceller synthesizes a pseudo noise signal from the speaker's transmitted voice and ambient noise, and cancels the ambient noise component from the speaker's transmitted voice, thereby canceling the ambient noise component included in the transmitted voice signal. The transmitted voice signal from which ambient noise has been canceled is digitally modulated and then transmitted from the antenna to the base station.

  Further, in the mobile phone disclosed in Patent Document 2, a microphone for inputting a user's voice and a sound collecting device that collects ambient noise are used as the configuration of the mobile phone without using a hands-free headset. Two microphones, a microphone, are provided, and noise is removed as in Patent Document 1.

Furthermore, the earphone cord device with a microphone connected to the mobile phone terminal disclosed in Patent Document 3 includes a noise filter having a frequency characteristic. Specifically, the noise input from the microphone of the earphone cord device with microphone is applied to a noise filter that is an LC filter, thereby attenuating the noise having a constant pitch regardless of the conversation. As a result, the mobile phone terminal can suppress audible noise at the other party of the call by transmitting the sound with attenuated noise.
JP-A-5-300209 [H04M 1/19, H04M 1/05, H04M 1/60] JP 2001-298394 A [H04B 7/26, G10L 21/02, G10L 11/00, H04M 1/247, H04M 1/60] JP 2000-31253 A [H04M 1/60, H04R 1/10]

  However, in the background art of Patent Document 1, when the distance between the microphone of the headset and the microphone of the portable radio telephone is too far away, the noise collected by the microphone of the headset by the microphone of the portable radio telephone is In addition to collecting different noises, not only can the noise be removed, but conversely, a transmitted voice signal with a lot of noise may be transmitted.

  In the background art of Patent Document 2, the same noise is collected by each microphone by providing two microphones to the mobile phone. However, if the distance from the caller is increased, the sound collecting microphone collects the same noise. The sound to be sounded has the same volume as the sound collected by the microphone, and the noise removal effect is reduced.

  Furthermore, in the background art of Patent Document 3, depending on the call environment, noise that cannot be cut by the noise filter of the frequency characteristics may occur, especially when using a mobile phone in various places while moving, The effect of high noise removal cannot be improved.

  Therefore, a main object of the present invention is to provide a novel portable communication terminal.

  Another object of the present invention is to provide a mobile communication terminal that can perform noise removal suitable for the usage state of the mobile communication terminal.

  The present invention employs the following configuration in order to solve the above problems. The reference numerals in parentheses, supplementary explanations, and the like indicate the corresponding relationship with the embodiments described in order to help understanding of the present invention, and do not limit the present invention.

  According to a first aspect of the present invention, there is provided a first microphone for collecting a caller's call voice, a second microphone for collecting surrounding voice, an output signal of the first microphone, and an output signal of the second microphone. Dual microphone noise canceling means for removing noise components contained in the output signal, single microphone noise canceling means for removing noise components contained in the output signal of the first microphone based on the output signal of the first microphone, to the caller's face When the approach detection means detects the approach to the caller's face, the dual microphone noise canceling means is selectively activated when the approach detection means detects the approach to the caller's face. Switching means for selectively activating the single microphone noise canceling means when not detected, and the output signal of the first microphone from which the noise component has been removed are transmitted A transmitting unit, a mobile communication terminal.

  In the first invention, the mobile communication terminal (10) includes a first microphone (16a) that collects a caller's voice and a second microphone (16b) that collects surrounding sounds including noise. . The noise component included in the output signal of the first microphone is dual microphone noise canceling means (20a, 20b, S43, S51, S61, S69) that removes noise based on the output signal of the first microphone and the output signal of the second microphone. , S83, S93) or single microphone noise canceling means (20a, 20b, S53, S71, S95) for removing the noise component contained in the output signal of the first microphone based on the output signal of the first microphone.

  The two noise cancellers are switched based on the detection result of the approach detection means (16a, 36) for detecting the approach to the face of the caller during a call, and the switching means (20a, S49, S67, S91) are When the approach to the caller's face is detected, the dual microphone noise canceling means is selectively activated to remove the noise component contained in the output signal of the first microphone. On the other hand, the switching means selectively activates the single microphone noise canceling means when the approach to the caller's face is not detected, thereby removing the noise component contained in the output signal of the first microphone. And a transmission means (12, 14, 20a, S15) transmits the output signal of the 1st microphone from which the noise component was removed toward the neighboring base station. In the preferred embodiment, the proximity detection means includes a proximity sensor (36).

  According to the first invention, the approach detecting means can detect the approach to the caller's face, and the noise canceling means is switched accordingly, so that noise removal suitable for the use state of the mobile communication terminal is performed. be able to. Further, the mobile communication terminal can transmit the call voice from which the noise is removed.

  A second invention is dependent on the first invention, wherein the mobile communication terminal can be in an open state and a closed state, and further comprises a state detection means for detecting the open state, and the approach detection means is a state detection Enabled to detect the approach to the caller's face when the open state is detected by the means, and not to detect the approach to the caller's face when the open state is not detected by the state detection means. Disabled.

  In the second invention, the mobile communication terminal is a folding type capable of taking an open state and a closed state, and the state detection means (20a, 38, 40, S89) detects the approach to the face of the caller. Detect open state that needs to be done. Therefore, the approach detection means is not validated unless an open state is detected. Further, the approach detection means is invalidated so as not to detect the approach to the caller's face if the open state is not detected, that is, if it is closed.

  In the preferred embodiment, the state detecting means detects the state based on the magnetism detected by the magnetic sensor (38).

  According to the second invention, in the folding portable communication terminal capable of taking the open state and the closed state, the approach detection means is effective only in the open state where it is necessary to detect the approach to the caller's face. It can be made to become.

  A third invention is dependent on the first invention or the second invention, wherein the mobile communication terminal is capable of hands-free call, is hands-free call, and the approach detection means approaches the caller's face. It further includes invalidating means for invalidating the second microphone when it is not detected.

  In the third invention, for example, the invalidation means (20a, S25) switches to the hands-free call during a call, and when the approach detection means does not detect the approach to the caller's face, the invalidation means (20a, S25) Disable it.

  According to the third aspect of the invention, the second microphone is disabled when the hands-free call is in progress and the approach detection unit does not detect the approach to the caller's face, thereby restricting the sound collection by the second microphone. Therefore, power consumption of the mobile communication terminal can be suppressed.

  A fourth invention is dependent on any one of the first to third inventions, and the approach detection means includes a light emitting element and a light receiving element, and based on an output signal of the light receiving element, Detect approach.

  In the fourth invention, the light emitting element (36a) emits infrared rays, and the light receiving element (36b) receives infrared rays reflected on the face of the caller. That is, since the infrared light emitted from the light emitting element is not received unless the caller's face approaches, the approach detection means detects the approach of the caller's face depending on whether the light receiving element receives the infrared light.

  In a preferred embodiment, the light emitting element is an LED capable of emitting infrared light, and the light receiving element is a photodiode capable of receiving infrared light. In a further preferred embodiment, the proximity detection means is a proximity sensor composed of an LED capable of emitting infrared rays and a photodiode capable of receiving infrared rays.

  According to the fourth aspect, the approach to the caller's face can be detected by using the light emitting element and the light receiving element.

  The fifth invention is dependent on any one of the first to third inventions, and the approach detecting means detects approach to the caller's face based on the output signal of the first microphone.

  In the fifth invention, the volume of sound input to the call speaker differs greatly between a call voice in a state where the caller's face is close and a call voice in which the caller's face is far away, that is, in a hands-free call state. Based on the output signal of the microphone, that is, the volume of the sound collected by the first microphone, the approach to the caller's face is detected.

  According to the fifth aspect, it is possible to detect the approach to the caller's face based on the output signal of the first microphone.

  According to this invention, since the approach to the caller's face can be detected by the approach detecting means and the noise canceling means is switched accordingly, noise removal suitable for the use state of the mobile communication terminal can be performed. it can.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

<First embodiment>
Referring to FIG. 1, mobile communication terminal 10 includes a power supply circuit 28 that supplies power to the entire system based on the voltage of a lithium ion battery 30 that is a secondary battery. Further, when the power supply circuit 28 supplies power to the entire system based on the voltage of the lithium ion battery 30 that is a secondary battery, it is referred to as a power-on state. Similarly, when the power supply circuit 28 does not supply power to the entire system based on the voltage of the lithium ion battery 30 that is a secondary battery, it is referred to as a power-off state. The power supply circuit 28 is activated when a power-on operation is performed by the key input device 22 in the power-off state, and is stopped when a power-off operation is performed by the key input device 22 in the power-on state. Further, even in the power-off state, the power supply circuit 28 is activated in response to charging of the lithium ion battery 30 and stopped in response to completion of charging of the lithium ion battery 30. The charging means that the lithium ion battery 30 stores electric energy by receiving a current supplied from an external charger (not shown).

  When a call operation is performed by the key input device 22, the CPU (also referred to as a processor or a computer) 20a of the control unit 20 controls the radio communication circuit 14 corresponding to the CDMA system and outputs a call signal. To do. The output call signal is transmitted from the antenna 12 and transmitted to the mobile communication network including the base station. Then, when the call partner performs a response operation, a call ready state is established.

  When a call termination operation is performed by the key input device 22 after shifting to a call ready state, the CPU 20a controls the wireless communication circuit 14 to transmit a call termination signal to the mobile communication network including the base station. After transmitting the call end signal, the CPU 20a ends the call process. Also, when the call end signal is received from the call partner first, the CPU 20a ends the call process. Furthermore, the CPU 20a also ends the call process when a call end signal is received from the mobile communication network regardless of the call partner.

  When the call signal from the other party is captured by the antenna 12 while the power of the mobile communication terminal 10 is on, the radio communication circuit 14 notifies the CPU 20a of an incoming call. The CPU 20a displays the caller information described in the incoming call notification on the LCD monitor 34 controlled by the LCD control circuit 32, and outputs a ringtone from the second speaker 18b. When a response operation is performed by the key input device 22, a call ready state is established.

  In the call ready state, the following processing is executed. The modulated audio signal (high frequency signal) transmitted from the other party is received by the antenna 12. The received modulated audio signal is subjected to demodulation processing and decoding processing by the wireless communication circuit 14. The received voice signal thus obtained, that is, the voice of the other party is output from the first speaker 18a. Further, the transmission voice signal captured by the first microphone 16 a, that is, the call voice of the caller is subjected to encoding processing and modulation processing by the wireless communication circuit 14. The modulated audio signal generated thereby is transmitted using the antenna 12 as described above. The first microphone 16a functions as a call microphone that collects the caller's call voice.

  2A to 2C are illustrative views showing the appearance of the mobile communication terminal 10. 2A and 2B, the mobile communication terminal 10 has a case C1 formed in a plate shape. The antenna 12 is a telescopic antenna configured to be extendable and provided to protrude from the upper side surface of the case C1. Note that the antenna 12 may be a built-in antenna or may be built in the case C1.

  The first microphone 16a and the first speaker 18a (not shown in FIG. 2A) are built in the case C1. The opening op1 leading to the built-in first microphone 16a is provided on one main surface in the length direction of the case C1, and the opening op2 leading to the built-in first speaker 18a is the other main surface in the length direction of the case C1. Is provided. A second microphone 16b and a second speaker 18b (not shown in FIGS. 2A and 2B) are also built in the case C1. The opening op4 leading to the built-in second microphone 16b is provided on the other surface in the longitudinal direction of the case C1, and the opening op3 leading to the built-in second speaker 18b is different from the opening op2 in the position of the case C1. It is provided on the other main surface in the length direction. As shown in FIG. 2C, the opening op4 that communicates with the built-in second microphone 16b may be provided on the other surface in the longitudinal direction of the case C1.

  That is, the caller inputs the transmission voice to the first microphone 16a through the opening op1, and listens to the reception voice from the first speaker 18a through the opening op2. Further, the caller hears a ring tone from the second speaker 18b through the opening op3. Then, ambient noise is input to the second microphone 16b through the opening op4. That is, the second microphone 16b functions as an environmental microphone that collects ambient sounds.

  The key input device 22 includes a plurality of keys such as a call key, a menu key, and an end call key, and is provided on the main surface of the case C1. The LCD monitor 34 is attached so that the monitor screen is exposed on the main surface of the case C1. And the proximity sensor 36 is attached so that the input of a sensor may be exposed to the main surface of case C1, so that the approach to a caller's face can be detected. Note that the proximity sensor 36 may be attached to either the length direction one side or the length direction other side of the main surface of the case C1.

  FIG. 3 is an illustrative view showing a configuration of the proximity sensor 36 that operates as an approach detecting means. Referring to FIG. 3, the proximity sensor 36 includes an LED 36a that is a light emitting element and a photodiode 36b that is a light receiving element. Then, the CPU 20a determines the approach to the caller's face from the change in the output of the photodiode 36b. Specifically, the LED 36a emits infrared rays, and the photodiode 36b receives infrared rays reflected from the caller's face and the like. That is, when the photodiode 36b is far from the caller's face, the infrared light emitted from the LED 36a is not received by the photodiode 36b. However, when the proximity sensor 36 approaches the caller's face, the infrared light emitted from the LED 36a is emitted from the photodiode. Light is received by 36b. Therefore, since the photodiode 36b changes the infrared rays received by approaching the caller's face, the CPU 20a determines the approach to the caller's face based on the amount of infrared rays received by the photodiode 36b. Can do.

  In this embodiment, an infrared type proximity sensor that uses infrared rays is used as the proximity sensor. However, a capacitive type proximity sensor that uses a change in the capacitance of the capacitor, or reflection of ultrasonic waves is used. An ultrasonic type proximity sensor or the like may be used.

  In this mobile communication terminal 10, a call (hereinafter referred to as a handy call) in which the mobile communication terminal 10 is brought close to the caller's face and a call (hereinafter referred to as a hands-free call) in which the mobile communication terminal 10 is moved away from the caller's face. The call can be performed in two states. For example, referring to FIG. 4A, in a handy call, the received voice output from the first speaker 18a is heard in the state of being close to the caller's face, and the transmitted voice is input to the first microphone 16a. . On the other hand, referring to FIG. 4B, in the hands-free call, the received voice output from the second speaker 18b is heard with the mobile communication terminal 10 kept away from the face, and the transmitted voice is sent to the first microphone 16a. Enter.

  Further, the hands-free call can be performed when an operation for setting the hands-free call mode is performed by the key input device 22 during the call.

  In FIG. 4B, when a hands-free call is made, it is held by the caller's hand. However, a hands-free call can be made while placed on a desk or table near the caller. It may be done.

  Here, returning to FIG. 1, a DSP (Digital Signal Processor) 20b constituting the control unit 20 operates as a noise canceller for removing noise included in the transmitted voice signal. Also, noise removal for voice during a call is processed in real time.

  In this embodiment, when an approach to the caller's face is detected in a handy call or the like, the DSP 20b outputs the first microphone based on the output signal of the first microphone 16a and the output signal of the second microphone 16b. It operates as a dual microphone noise canceller (means) that removes noise components contained in the signal. Further, when no approach to the caller's face is detected in a hands-free call or the like, the DSP 20b removes a noise component included in the output signal of the first microphone based on the output signal of the first microphone. Operates as a microphone noise canceller (means). That is, the DSP 20b operates as an optimal noise canceller according to the usage state of the mobile communication terminal 10.

  The dual microphone noise canceller will be described in detail. The first microphone 16a collects ambient noise together with the call voice, and the second microphone 16b collects ambient noise. Further, the DSP 20b generates an audio signal having an antiphase that cancels the ambient noise based on the ambient noise collected by the second microphone 16b, and mixes it with the audio signal collected by the first microphone 16a. , Remove the noise. Then, the CPU 20 transmits the call voice signal from which the noise component generated by the DSP 20b is removed as a transmission voice signal to a neighboring base station. The dual microphone noise canceller provides a high noise removal effect when the mobile communication terminal 10 is close to the caller's face.

  On the other hand, when specifically explaining the single microphone noise canceller, the DSP 20b corresponds to the frequency band of the ambient noise with respect to the voice signal including the voice collected by the first microphone 16a and the ambient noise. Ambient noise is attenuated by filtering with a low pass filter (LPF). Then, the CPU 20a transmits an audio signal in which ambient noise is attenuated as a transmission audio signal to a neighboring base station. The single microphone noise canceller provides a high noise removal effect when the mobile communication terminal 10 is far away from the caller's face.

  FIG. 5 is an illustrative view showing a memory map of the RAM 26. The memory map 300 of the RAM 26 includes a program storage area 302 and a data storage area 304. A part of the program and data is read from the flash memory 24 at once or partially and sequentially as necessary, stored in the RAM 26, and processed by the CPU 20a or the like.

  The program storage area 302 stores a program for operating the mobile communication terminal 10. Programs for operating the mobile communication terminal 10 include a call program 310, a hands-free control program 312 and a noise canceller program 314. The call program 310 is a program for controlling a call by the mobile communication terminal 10 in response to a user (caller) call operation. The hands-free control program 312 is executed in response to the processing of the call program 310, and is a program for controlling the second microphone 16b and the second speaker 18b in accordance with an operation for setting the hands-free call mode. Similar to the hands-free control program 312, the noise canceller program 314 is executed in response to the processing of the call program 310, and is a program for removing noise components contained in the call voice according to the call state.

  Although illustration is omitted, the program for operating the mobile communication terminal 10 includes a program for notifying incoming calls, a program for managing an address book composed of telephone number data of other mobile communication terminals 10, and the like.

  In the data storage area 304, a call flag 320 is provided. The call flag 320 is a flag for determining whether or not the mobile communication terminal 10 is busy. For example, the call flag 320 is composed of a 1-bit register. When the call flag 320 is established (turned on), a data value “1” is set in the register, and when the call flag 320 is not established (turned off), a data value “0” is set in the register. The on / off state of the call flag 320 is switched by a call program.

  Although illustration is omitted, the data storage area 304 stores character data to be displayed on the LCD monitor 34, image data and address book data necessary for GUI display, and the like. Buffers and other flags and counters necessary for operation are also provided.

  The CPU 20a executes tasks including a call process shown in FIG. 6, a hands-free control process shown in FIG. 7, a noise canceller process shown in FIG.

  FIG. 6 is a flowchart showing call processing. Referring to FIG. 6, when a call operation is performed by the user, call flag 320 is turned on in step S1. The call flag 320 is used to determine whether or not a call is in progress in other processes executed in parallel. Therefore, the call flag 320 is turned on as soon as the call process is executed. Subsequently, in step S3, hands-free control processing is executed in parallel. That is, the call process shown in FIG. 6 and the hands-free control process shown in FIG. 7 are executed in parallel. Subsequently, noise canceller processing is executed in parallel. That is, the call process shown in FIG. 6 and the noise canceller process shown in FIG. 8 are executed in parallel.

  Subsequently, in step S7, it is determined whether or not a call end operation has been performed. That is, it is determined whether or not a call end operation has been performed by the key input device 22. If “YES” in the step S7, that is, if a call ending operation is performed, the process proceeds to a step S17. On the other hand, if “NO”, that is, if the call end operation is not performed, it is determined whether or not the received voice is received in step S9. That is, it is determined whether or not the received voice transmitted from the mobile communication terminal 10 of the other party is received. If “YES” in the step S9, that is, if the received voice is received, the call voice is output in a step S11, and the process returns to the step S7. That is, the received voice is output from the first speaker 18a or the second speaker 18b. Since the initial call is always a handy call, a received voice is output from the first speaker 18a. When an operation for setting the hands-free call mode is performed during the handy call, the received voice is output from the second speaker 18b.

  If “NO” in the step S9, that is, if the received voice is not received, it is determined whether or not the call voice is collected in a step S13. That is, it is determined whether or not the voice of the user (caller) and ambient noise are collected by the first microphone 16a and the second microphone 16b. If “YES” in the step S13, that is, if the user's (caller) voice or ambient noise is collected by the first microphone 16a and the second microphone 16b, the call voice is transmitted to the call partner in a step S15. Send. That is, the call voice of the caller whose noise has been canceled (noise removal) by the DSP 20b is transmitted as a transmission voice signal. Since the initial state call is set to perform a handy call, the user's (caller) voice and ambient noise are collected by the first microphone 16a and the second microphone 16b. In the hands-free call, the voice of the user (caller) and ambient noise are collected only by the first microphone 16a.

  Further, when the processing of step 15 is completed or “NO” in step S13, that is, when the voice of the user (caller) and ambient noise are not collected by the first microphone 16a and the second microphone 16b. Return to step S7.

  Here, in step S17, since the call termination process has been performed, the call flag 320 is turned off and the call process is terminated.

  FIG. 7 is a flowchart showing the hands-free control process executed in step S3 of FIG. Referring to FIG. 7, in step S <b> 21, it is determined whether or not an HF (Handsfree) setting operation is performed. That is, it is determined whether or not an operation for setting the hands-free call mode has been performed by the key input device 22. If “NO” in the step S21, that is, if an operation for setting the hands-free call mode is not performed, the process proceeds to a step S27. On the other hand, if “YES”, that is, if an operation for setting a hands-free call is performed, in step S23, the received voice is set to be output from the second speaker 18b. That is, the received voice that has been output from the first speaker 18a is output from the second speaker 18b.

  Subsequently, the sound collection of the second microphone 16b is stopped in step S25. That is, in the hands-free call, noise removal is not performed using the second microphone 16b because the distance between the mobile communication terminal 10 and the caller's face is long. However, even in the hands-free call mode, if an approach to the caller's face is detected and a handy call is made, the CPU 20a starts collecting sound from the second microphone 16b, and the DSP 20b uses the second microphone 16b. Let the noise be removed. The CPU 20a that executes the process of step S25 operates as an invalidating unit.

  Accordingly, if a single microphone noise canceller is set during a hands-free call, the second microphone 16b can be disabled by restricting the sound collection by the second microphone 16b. Power can be reduced.

  Subsequently, in step S27, it is determined whether or not an HF release operation is performed. That is, it is determined whether or not an operation for canceling the setting of the hands-free call mode is performed by the key input device 22. If “NO” in the step S27, that is, if an operation for canceling the setting of the hands-free call mode is not performed, the process proceeds to a step S33. On the other hand, if “YES”, that is, if an operation to cancel the setting of the hands-free call mode is performed, in step S29, the received voice is set to be output from the first speaker 18a. That is, the reception voice that has been output from the second speaker 18b in the state where the hands-free call mode is set is output from the first speaker 18a.

  Subsequently, sound collection by the second microphone 16b is started in step S31, and the process returns to step S21. That is, since the hands-free call is canceled and the handy call is performed, the CPU 20a starts collecting the sound from the second microphone 16b.

  Here, in step S33, it is determined whether a call is in progress. That is, it is determined whether the call flag 320 is on. If “YES” in the step S33, that is, if the call flag 320 is turned on, the process returns to the step S21. On the other hand, if “NO”, that is, if the call flag 320 is OFF, the hands-free control process is terminated.

  FIG. 8 is a flowchart showing the noise canceller process executed in step S5 of FIG. Referring to FIG. 8, in step S41, the proximity sensor 36 is turned on. That is, the proximity sensor 36 is turned on in order to detect the approach to the caller's face. Subsequently, in step S43, a dual microphone noise canceller is set. That is, in the initial state of the call, since the handy call is set to be performed, the DSP 20b is operated as a dual microphone noise canceller.

  Subsequently, in step S45, it is determined whether or not the call is continued. That is, it is determined whether the call flag 320 is on. If “NO” in the step S45, that is, if the call flag 320 is turned off, the noise canceller process is ended. On the other hand, if “YES” in the step S45, that is, if the call flag 320 is turned on, it is determined whether or not the output of the proximity sensor 36 has changed in a step S47. That is, it is determined whether or not the distance between the mobile communication terminal 10 and the caller's face has changed.

  Further, since the mobile communication terminal 10 is held by hand, the output from the proximity sensor 36 is not always stable. Therefore, unless the amount of change in the output of the proximity sensor 36 exceeds a predetermined value, it is not determined that the output of the proximity sensor 36 has changed. For example, specifically, the output of the proximity sensor 36 is converted into a numerical value by A / D conversion and stored in a register provided in the RAM 26. The output numerical value of the proximity sensor 36 stored in this register is updated every 100 ms, and the CPU 20a obtains the difference between the value stored when updating and the value stored this time. Then, the CPU 20a determines whether or not the output of the proximity sensor 36 has changed depending on whether or not the difference exceeds a predetermined value.

  If “NO” in the step S47, that is, if the output of the proximity sensor 36 does not change, the process returns to the step S45. On the other hand, if “YES”, that is, if the output of the proximity sensor 36 changes, it is determined whether or not the vehicle is approaching in step S49. Specifically, it is determined whether or not the value from the proximity sensor 36 after A / D conversion is equal to or greater than a threshold value.

If “YES” in the step S49, that is, if the value of the proximity sensor 36 is equal to or larger than the threshold value, a dual microphone noise canceller is set in a step S51, and the process returns to the step S45. That is, the DSP 20b is operated as a dual microphone noise canceller. If “NO” in the step S49, that is, if the value of the proximity sensor 36 is less than the threshold value, a single microphone noise canceller is set in a step S53, and the process returns to the step S45. That is, the DSP 20b is operated as a single microphone noise canceller.
<Second embodiment>
In the second embodiment, a process for detecting the approach between the mobile communication terminal 10 and the caller's face from the volume of the sound collected by the first microphone 16a instead of the proximity sensor 36 will be described. Further, in the second embodiment, the illustration of the configuration of the mobile communication terminal 10 in FIG. 1 described in the first embodiment and the external view of the mobile communication terminal 10 in FIG. The same as the embodiment. Further, the usage example of the mobile communication terminal 10 shown in FIG. 4, the memory map of the RAM 26 shown in FIG. 5, the call processing flowchart shown in FIG. 6, and the hands-free processing flowchart shown in FIG. Because of this, duplicate explanation is omitted.

  FIG. 9 is a flowchart showing the noise canceller processing in the second embodiment executed in step S5 of FIG. A detailed description of the processing overlapping with the noise canceller processing of the first embodiment shown in FIG. 8 is omitted. Referring to FIG. 9, in step S61, a dual microphone noise canceller is set. Subsequently, in step S63, it is determined whether or not the call is continued. If “NO” in the step S63, the noise canceller process is ended. On the other hand, if “YES”, it is determined in step S65 whether or not the volume of the first microphone 16a has changed. That is, it is determined from the volume of the sound collected by the first microphone 16a whether or not the caller's face has approached.

  Specifically, the volume of the sound collected by the first microphone 16a is digitized by A / D conversion, and the volume value of the first microphone 16a is stored in the register of the RAM 26. The volume value stored in this register is updated every 100 ms, and the CPU 20a obtains the difference between the volume value stored in the register and the volume value stored this time when updating. Then, the CPU 20a determines whether or not the volume of the microphone has changed depending on whether or not the difference exceeds a predetermined value.

If “NO” in the step S65, that is, if the volume of the first microphone 16a does not change, the process returns to the step S63. On the other hand, if “YES”, that is, if the volume of the first microphone 16a changes, it is determined in step S67 whether or not the volume of the first microphone 16a is greater than or equal to a threshold value. That is, it is determined whether or not the volume of the A / D converted first microphone 16a is greater than or equal to a threshold value. If “YES” in the step S67, that is, if the volume of the sound collected by the first microphone 16a is equal to or higher than the threshold value, a dual microphone noise canceller is set in a step S69, and the process returns to the step S63. If “NO” in the step S67, that is, if the volume of the sound collected by the first microphone 16a is less than the threshold value, a single microphone noise canceller is set in a step S71, and the process returns to the step S63.
<Third embodiment>
In the third embodiment, a process for detecting the approach of the mobile communication terminal 10 and the caller's face when the mobile communication terminal 10 is folded in half will be described. In the third embodiment, the proximity sensor 36 is used to approach the caller's face, but it may be detected by the volume of the first microphone 16a as in the second embodiment. In the third embodiment, the configuration of the proximity sensor 36 described in the first embodiment, the usage example of the mobile communication terminal 10 shown in FIG. 4, the memory map of the RAM 26 shown in FIG. 5, and the call processing flow shown in FIG. The flowchart of the hands-free process shown in FIG. 7 and FIG. 7 is the same as that of the first embodiment, and thus the duplicate description is omitted.

  FIG. 10 is a block diagram illustrating a configuration of the mobile communication terminal 10 according to the third embodiment. Since the configuration other than the magnetic sensor 38 and the magnet 40 is the same as that of the first embodiment, detailed description thereof is omitted. The magnetic sensor 38 is a sensor that detects the magnetism of the magnet 40. Then, the CPU 20a determines whether the mobile communication terminal 10 is open or closed based on the magnetism of the magnet 40 detected by the magnetic sensor 38.

  FIGS. 11A and 11B are illustrative views showing the appearance of the mobile communication terminal 10 in the closed state, and FIG. 12 is an illustrative view showing the appearance of the mobile communication terminal 10 in the open state. The mobile communication terminal 10 of the third embodiment has a case C2 and a case C3 each formed in a plate shape. The thickness of case C2 and case C3 is substantially the same. Further, the antenna 12 is built in the case C1, and is not shown in FIGS. 11 (A), 11 (B) and FIG.

  In FIG. 11A, the second speaker 18b (not shown) is built in the case C2, and the opening op5 leading to the built-in second speaker 18b is provided on one outer surface in the length direction of the case C2. Similarly, the second microphone 16b (not shown) in FIG. 11B is built in the case C3, and the opening op6 leading to the built-in second microphone 16b is provided on the other outer surface in the longitudinal direction of the case C3.

  The hinge mechanism H is formed on one side surface in the length direction of the case C2. Further, the case C3 is coupled to the hinge machine term H on one main surface in the length direction. The hinge mechanism H is movable with reference to an axis AX parallel to the short side of the case C2 in a state where the case C2 is stacked on the case C3. That is, the case C2 and the case C3 are opened and closed by rotation with the axis AX as a reference.

  Referring to FIG. 12, in the opened state of mobile communication terminal 10, first microphone 16a (not shown) is built in case C3, and opening op7 leading to built-in first microphone 16a is the other in the length direction of case C3. Provided on the inner surface. Similarly, the first speaker 18a (not shown) is built in the case C2, and the opening op8 leading to the built-in first speaker 18a is provided on the other inner surface in the lengthwise direction of the case C2.

  The key input device 22 is provided on the inner side surface of the case C3. The LCD monitor 34 is attached so that the monitor screen is exposed on the inner surface of the case C2. And the proximity sensor 36 is attached so that the input of a sensor may be exposed inside case C3 so that the approach to a caller's face can be detected. The proximity sensor 36 may be attached to the inner side surface of the case C2. The magnetic sensor 38 is built in the case C3, and the magnet 40 is built in the case C2 so as to be closest to the magnetic sensor 38 in the state of FIGS.

  Therefore, the magnetic sensor 38 outputs 0 which is the minimum value in the state shown in FIG. 12, and outputs 255 which is the maximum value in FIGS. 11A and 11B. That is, in the closed state shown in FIGS. 11A and 11B, the magnetic sensor 38 outputs a maximum value, and in the open state shown in FIG. 12, the magnetic sensor 38 outputs a minimum value.

  FIG. 13 is a flowchart showing the noise canceller process in the third embodiment executed in step S5 of FIG. A detailed description of the processing overlapping with the noise canceller processing of the first embodiment shown in FIG. 8 is omitted. Referring to FIG. 13, in step S81, the proximity sensor 36 is turned on. Subsequently, in step S83, a dual microphone noise canceller is set. Subsequently, in step S85, it is determined whether or not the call is continued. If “NO” in the step S85, the noise canceller process is ended. On the other hand, if “YES” in the step S85, it is determined whether or not the output of the proximity sensor has changed in a step S87. If “NO” in the step S87, the process returns to the step S85. On the other hand, if “YES”, it is determined in a step S89 whether or not it is open. That is, it is determined whether or not the output of the magnetic sensor 38 is the minimum value. The process of step S89 is performed in order to detect the approach to the caller's face only in the open state. That is, in a situation where it is difficult for the caller's voice to be collected by the first speaker 16a, it is more effective to bring the face closer to the open state than to bring the face closer to the closed state. Detects approach to face. The CPU 20a that executes the process of step S89 operates as a state detection unit.

  If “NO” in the step S89, that is, if the output of the magnetic sensor 38 is the minimum value, the process proceeds to a step S95. On the other hand, if “YES”, that is, if the output of the magnetic sensor 38 is not the minimum value, it is determined in step S91 whether or not it is approaching. If “YES” in the step S91, a dual microphone noise canceller is set in a step S93, and the process returns to the step S85. If “NO” in the step S91, a single microphone noise canceller is set in a step S95, and the process returns to the step S85.

  In the case of detecting the approach to the caller's face even in the closed state, the determination may be made from the volume of the sound collected by the first microphone 16a shown in the second embodiment. Furthermore, when the mobile communication terminal 10 is in the open state, the noise canceller process (see FIG. 8) shown in the first embodiment is executed, and in the closed state, the noise canceller process (see FIG. 9) shown in the second embodiment is executed. Also good.

  As can be seen from the above description, the mobile communication terminal 10 including the first microphone 16a that is a call microphone and the second microphone 16b that is an environment microphone is connected to the DSP 20b using an output signal from the first microphone 16a and an output from the second microphone 16b. Dual microphone noise canceling means for removing the noise component contained in the output signal of the first microphone 16a based on the signal, or single removing the noise component contained in the output signal of the call microphone based on the output signal of the first microphone 16a based on the signal. Operate as a microphone noise canceling means. The operation of the DSP 20b is switched based on the detection result of the proximity sensor 36 which is an approach means for detecting the approach to the caller's face.

  The CPU 20a that executes the processes of steps S49, S67, and S91 operates as a switching unit, and the DSP 20b is activated as a dual microphone noise canceling unit when the proximity sensor 36 detects an approach to the caller's face. When the sensor 36 does not detect the approach to the caller's face, it is activated as a single microphone noise canceling means. And CPU20a which processes step S15 which operate | moves as a transmission means transmits the call voice from which noise was removed.

  Accordingly, since the usage state of the mobile communication terminal 10 can be determined by the approach to the caller's face detected by the proximity sensor 36, the mobile communication terminal can be switched between the single microphone noise canceller and the dual microphone noise canceller. Noise removal suitable for 10 usage conditions can be performed.

  In addition, the present invention has a great effect because, when a conference call is performed in the hands-free call mode, a noise canceller suitable for the use state is selected even if a speech is made in a handy call in consideration of ambient noise and the like. Will be raised.

  Note that the communication method of the mobile communication terminal 10 is not limited to the CDMA method, the W-CDMA method, and the TDMA method, but may be a PHS method or the like. Moreover, although the lithium ion battery 30 was employ | adopted as a secondary battery, a lead acid battery, a nickel hydride battery, a sodium ion battery, a metal air battery, a zinc bromine battery, etc. may be sufficient. Furthermore, not only the secondary battery but also a fuel cell or a manganese battery as a primary battery may be used. Further, the shape of the embodiment of the portable communication terminal 10 of the present invention is limited to the so-called straight type (FIG. 2) or the so-called folding type (FIGS. 11 and 12) described in the above embodiment. In addition, any other shape such as a so-called biaxial hinge type, a slide type, and a revolver (rotation) type can be used as appropriate.

FIG. 1 is a block diagram showing a portable communication terminal according to a first embodiment of the present invention. FIG. 2 is an illustrative view showing an appearance of the mobile communication terminal shown in FIG. FIG. 3 is an illustrative view showing one example of a detailed configuration of the proximity sensor shown in FIG. 1. FIG. 4 is an illustrative view showing one example of a usage example of the mobile communication terminal shown in FIG. FIG. 5 is an illustrative view showing one example of a memory map of the RAM shown in FIG. FIG. 6 is a flowchart showing call processing of the CPU shown in FIG. FIG. 7 is a flowchart showing a hands-free control process of the CPU shown in FIG. FIG. 8 is a flowchart showing the noise canceller processing of the first embodiment in the CPU shown in FIG. FIG. 9 is a flowchart showing the noise canceller processing of the second embodiment in the CPU shown in FIG. FIG. 10 is a block diagram showing a portable communication terminal according to the third embodiment of the present invention. FIG. 11 is an illustrative view showing an appearance of the mobile communication terminal of the third embodiment shown in FIG. FIG. 12 is an illustrative view showing another appearance of the mobile communication terminal of the third embodiment shown in FIG. FIG. 13 is a flowchart showing the noise canceller processing of the third embodiment in the CPU shown in FIG.

DESCRIPTION OF SYMBOLS 10 ... Mobile communication terminal 16a ... 1st microphone 16b ... 2nd microphone 18a ... 1st speaker 18b ... 2nd speaker 20a ... CPU
20b ... DSP
36 ... Proximity sensor 38 ... Magnetic sensor 40 ... Magnet

Claims (5)

A first microphone for collecting the caller's voice,
A second microphone that collects ambient audio,
Dual microphone noise cancellation means for removing a noise component contained in the output signal of the first microphone based on the output signal of the first microphone and the output signal of the second microphone;
Single microphone noise canceling means for removing a noise component contained in the output signal of the first microphone based on the output signal of the first microphone;
An approach detection means for detecting an approach to the face of the caller;
The dual microphone noise canceling means is selectively activated when the approach detecting means detects the approach to the caller's face, and the approach detecting means does not detect the approach to the caller's face. A portable communication terminal comprising: a switching unit that selectively activates the single microphone noise canceling unit; and a transmission unit that transmits an output signal of the first microphone from which the noise component has been removed. The mobile communication terminal can be in an open state and a closed state,
Further comprising state detecting means for detecting the open state;
The approach detection means is enabled to detect an approach to the caller's face when an open state is detected by the state detection means, and when the open state is not detected by the state detection means, The portable communication terminal according to claim 1, wherein the portable communication terminal is invalidated so as not to detect an approach to the face of the caller. The mobile communication terminal is capable of hands-free calling,
3. The mobile communication according to claim 1, further comprising: a disabling unit that disables the second microphone when the call is a hands-free call and the approach detection unit does not detect an approach to the caller's face. 4. Terminal. The approach detection means includes a light emitting element and a light receiving element,
The mobile communication terminal according to claim 1, wherein an approach to the face of the caller is detected based on an output signal of the light receiving element.   The portable communication terminal according to claim 1, wherein the approach detection unit detects an approach to the face of the caller based on an output signal of the first microphone.

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