JP2002223268A - Voice control device and mobile telephone using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a voice control device and a mobile telephone using the same in which a received voice is not hidden in an ambient background noise, and a received voice in which a sense of discomfort due to the only increase in reception volume is improved in a conventional technique can be obtained. SOLUTION: The device is provided with a frequency analyzing means for analyzing the frequency characteristic of an ambient noise coming from a transmitter, and a frequency characteristic conversion means for converting the frequency characteristic of a received voice on the basis of the analyzed result of the frequency analyzing means during voice communication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice control device for controlling frequency characteristics of a received voice and a portable telephone using the same.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a conventional portable telephone disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 4-82331. In the figure, reference numeral 13 denotes a radio unit for transmitting / receiving a radio signal to / from a base station via an antenna 14, and 25 is disposed between the microphone 1 and the loudspeaker 9 and the radio unit 13, and performs input / output of a call signal. An audio processor to control. The microphone 1 operates as a noise sensor when the speech codec 21 connected to the microphone 1 detects noise by calculating ambient noise (background noise), in addition to operating as a telephone.

Reference numeral 15 denotes a CPU which controls the radio unit 13 and the audio processor 25 to execute processing such as calling and ending a call, and includes a threshold setting unit 26, a comparison unit 27, and a switching unit 2.
8, including a volume setting unit 29. The comparison unit 27 compares the threshold value set in the threshold value setting unit 26 with the level of the ambient noise detected by the microphone 1 and the speech codec 21, and supplies a reception volume control signal to the volume setting unit 29 based on the comparison. I do. The switching unit 28 is a keypad 30
And switches and selects one of the comparison unit 27 and the keypad 30, and supplies a reception volume control signal to the volume setting unit 29 from one of them.

A ROM 23 stores a program used by the CPU 15 and a RAM 24 used by the CPU 15 for processing. The keypad 30 is the CPU 1
5, a dial signal, a reception volume adjustment signal, and the like are input.
A display unit 22 displays a dial number and the like under the control of the CPU 15.

Next, the operation of the above-mentioned conventional portable telephone will be described. First, the user operates the keypad 30 to set the first threshold and the second threshold in the threshold setting unit 26. It is assumed that the second threshold is higher than the first threshold. FIG.
Is a flowchart showing an operation when a call is received or called from the mobile telephone set with the threshold value in this way.
When automatically adjusting the received voice, the user turns on the automatic reception volume switch, starts a calling operation when calling, and hooks up when receiving a call. The CPU 15 checks on / off of the automatic reception volume switch (step S).
31) If it is off, no automatic reception volume adjustment is performed,
If it is on, the process proceeds to step S32.

In step S 32, the comparing unit 2 compares the ambient noise detected by the microphone 1 and the speech codec 21 with the first threshold set in the threshold setting unit 26.
Compare at 7. As a result, if the level of the detected ambient noise is smaller than the first threshold value, the reception volume adjustment signal instructing the low volume setting in step S33 is output from the comparison unit 27.
Output. If the level of the detected ambient noise is equal to or higher than the first threshold value, it is compared with the second threshold value in step S34. As a result, if the ambient noise level is smaller than the second threshold value, the received sound volume adjustment signal for instructing the medium volume setting in step S35, and if the ambient noise level is equal to or more than the second threshold value, the large volume setting is instructed in step S36. The reception volume adjustment signals are output from the comparison unit 27, respectively. The received sound volume adjustment signal output in this way is input to a volume setting unit 29 via a switching unit 28, and the volume setting unit 29 controls the audio processor 25 via the wireless unit 13 based on the received sound volume adjustment signal. Control and set the receiving volume.

[0007]

The conventional portable telephone is configured as described above, and the reception volume is adjusted based on the volume of the ambient noise. However, there is a problem in that the volume is too high, which gives the user discomfort.

[0008] In addition, noise contains various kinds of frequency components. When the detected noise is not so loud as the whole sound volume but has a frequency close to the voice frequency band, the received voice is included in the noise. There was a problem that it was masked and became inaudible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is not buried in ambient noise, and it is possible to improve discomfort caused by simply increasing the volume of a received voice with respect to ambient noise as in the prior art. The present invention proposes a voice control device capable of obtaining a received voice.

Also, the present invention is not buried in ambient noise,
Another object of the present invention is to provide a mobile phone capable of obtaining a received voice in which the discomfort caused by simply increasing the volume of the received voice with respect to the ambient noise is reduced.

Further, the present invention provides a receiving apparatus which is not buried in ambient noise even in an environment where noise changes with time, and which has improved discomfort caused by simply increasing the receiving volume of the ambient noise with respect to conventional noise. The goal is to obtain a mobile phone that can obtain voice.

Further, according to the present invention, it is possible to obtain a received voice which is not buried in ambient noise and has improved discomfort caused by simply increasing the received sound volume with respect to the ambient noise as in the related art, with a simple configuration. It proposes a mobile phone.

Further, the present invention provides a portable telephone which is not buried in ambient noise, and which can obtain a received voice in which discomfort is improved by simply increasing the receiving volume with respect to background noise as in the prior art and which is easy to use. Is to get.

[0014]

A voice control device according to the present invention includes a transmitter, a receiver, a frequency analyzer for analyzing frequency characteristics of ambient noise input from the transmitter, and an analysis result of the frequency analyzer. Frequency characteristic conversion means for converting the frequency characteristic of the received voice output to the receiver based on the frequency characteristic, the frequency analysis means detects a high noise frequency band where the ambient noise is large, and based on the analysis result, the frequency The characteristic conversion means emphasizes a received voice band other than the high noise frequency band.

A portable telephone according to the present invention includes a transmitter and a receiver, and is capable of performing voice communication by a radio signal. The frequency analysis means analyzes frequency characteristics of ambient noise input from the transmitter. And a frequency characteristic conversion means for converting the frequency characteristic of the received voice by the radio signal based on the analysis result of the frequency analysis means at the time of the voice call.

A portable telephone according to the present invention includes a transmitter and a receiver, and is capable of performing voice communication by a radio signal. The frequency analysis means analyzes frequency characteristics of ambient noise input from the transmitter. Frequency characteristic conversion means for converting the frequency characteristic of the received voice by the radio signal, and control means for controlling the frequency characteristic conversion means based on the analysis result of the frequency analysis means during the voice call, and outputting the output from the handset Is further provided.

Further, the portable telephone according to the present invention further comprises voice detecting means for detecting the presence or absence of the transmitted voice inputted from the transmitter, wherein the frequency analyzing means detects the transmitted voice by the voice detecting means. When the noise is not detected, the frequency characteristic of the ambient noise is analyzed.

Further, in the portable telephone according to the present invention, the control means controls the frequency characteristic conversion means based on an analysis result of the frequency analysis means every time a predetermined time elapses during the voice call.

Further, in the portable telephone according to the present invention, the control means controls the frequency characteristic conversion means to be an initial set value at the end of the voice call.

Further, in the portable telephone according to the present invention, the frequency analysis means analyzes a frequency characteristic of the ambient noise at least during a call by calling or receiving a call.

Further, in the portable telephone according to the present invention, the frequency analyzing means detects a high noise frequency band in which the ambient noise is large, and based on the result of the analysis, the control means controls the received voice other than the high noise frequency band. The frequency characteristic conversion means is controlled so as to emphasize a band.

Further, in the portable telephone according to the present invention, the frequency analysis means is based on FFT analysis.

Still further, in the portable telephone according to the present invention, the frequency characteristic conversion means is an equalizer.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of a mobile phone using the voice control device according to the present invention. In the figure, reference numeral 1 denotes a microphone which is a transmitter which receives a transmission voice and outputs a transmission voice signal, and 2 denotes a microphone amplifier which is connected to the microphone 1 and amplifies the transmission voice signal with a predetermined gain. 1
Reference numeral 0 denotes a DSP for performing digital signal processing on a signal input from the microphone amplifier 2, and includes a frequency component analysis unit 3, a reception frequency characteristic control unit 4, an A / D converter 5, an equalizer 6, and a D / A A converter 7 is included. The frequency component analyzer 3 constitutes a frequency analyzer, and the equalizer 6 constitutes a frequency characteristic converter. The frequency component analysis unit 3 performs an FFT on the ambient noise input from the microphone 1 and converted into a digital signal by the A / D converter 5.
(Fast Fourier Transform) Analyzes frequency components by analysis.
The reception frequency characteristic control unit 4 controls the equalizer 6 based on the analysis result of the frequency component analysis unit 3 so as to change the frequency characteristics of the reception voice.

Reference numeral 14 denotes an antenna for transmitting and receiving radio signals to and from the base station, and reference numeral 13 denotes a high-frequency unit connected to the antenna 14, which performs up-conversion of a transmission signal, down-conversion of a reception signal, and the like. Reference numeral 12 denotes a modulation / demodulation unit that modulates and demodulates transmission and reception signals, and reference numeral 11 denotes a timing control unit that processes transmission and reception signals in accordance with communication timing with the base station. The received signal is converted into a received voice signal via an antenna 14, a high frequency unit 13, and a modulation / demodulation unit 12, and is input to the equalizer 6 via a timing control unit 11. The equalizer 6 performs weighting of the set signal strength based on the control of the reception frequency characteristic control unit 4 for the signal of each frequency band of the input reception voice signal. That is, the frequency characteristic of the received voice signal is converted. Equalizer 6
Is converted into an analog signal by a D / A converter 7, amplified by a receiver amplifier 8 at a predetermined gain, and then converted into a received voice by a receiver 9 and output. Note that the DSP 10, the timing control unit 11, the modem unit 12, and the high frequency unit 13
The central control unit (CPU) 15 controls transmission / reception, ON / OFF of noise analysis, and the like.

Next, the operation will be described. FIG. 2 is an operation flowchart of the first embodiment. First, an incoming or outgoing call operation is performed, and a two-way voice path for transmitting and receiving is turned on to start a telephone call (step S11). At the start of the call, the microphone amplifier 2 is turned on, and before the caller speaks out, the ambient noise coming from the microphone 1 is taken into the frequency component analyzer 3, and the frequency characteristics of the ambient noise are measured (step S12). At this time, the ambient noise has been amplified by the microphone amplifier 2 and converted into a digital signal by the A / D converter 5, and the frequency component analysis unit 3 analyzes the frequency of the ambient noise converted into the digital signal by FFT analysis. Is performed (step S13).

On the other hand, the voice of the other party is received from the antenna 14 in a form included in the radio signal, converted into a received voice signal via the high frequency unit 13 and the modem unit 12, and transmitted to the equalizer 6 via the timing control unit 11. Is input to The reception frequency characteristic control unit 4 adjusts and controls the equalizer 6 to perform weighting of the signal strength based on the result of the frequency component analysis in step S13 on the signal of each frequency band of the received reception voice signal (step S13). Step S14).

Ambient noise frequency measurement result and equalizer 6
FIG. 3 shows an example of a correspondence relationship with the adjustment of (1). The frequency component analyzer 3 measures the frequency characteristics of the ambient noise (step S
101), if the measurement result indicates the frequency characteristic of “large low-frequency noise” illustrated in step S102, it is analyzed that the high-noise frequency band is the low-frequency band, and the reception frequency characteristic control is performed based on the analysis result. The unit 4 adjusts the equalizer 6 to “high-frequency emphasis” so as to emphasize the high frequency band (step S105). In other words, since the high noise frequency band is the low frequency band, the high frequency band other than the low frequency band is emphasized. In addition, the measurement result of the frequency characteristics of the ambient noise is “high-frequency noise large” illustrated in step S103.
In the case where the following frequency characteristics are shown, the frequency component analysis unit 3 analyzes that the high noise frequency band is the high frequency band, and based on the analysis result, the reception frequency characteristic control unit 4 emphasizes the equalizer 6 to the low frequency band. Is adjusted to "low frequency emphasis" (step S106).

As described above, by emphasizing the frequency bands other than the high noise frequency band where the ambient noise is large, the discomfort to the caller due to simply increasing the overall volume is improved, and the contents of the call are not masked by the noise and the contents of the call are reduced. A received voice that is easy to hear can be obtained.

Further, when the result of measuring the frequency characteristics of the ambient noise shows the frequency characteristic of "small noise" in the entire voice frequency band as shown in step S104, the frequency component analyzer 3 determines that there is no high noise frequency band. The received frequency characteristic is analyzed, and based on the analysis result, the receiving frequency characteristic control unit 4 adjusts the equalizer 6 to “flat characteristic” so as to have a flat characteristic (step S107), and obtains the most natural received voice.

The received voice signal input to the equalizer 6 adjusted as described above is converted into a frequency characteristic by weighting the signal strength for each frequency band. The received voice signal output from the equalizer 6 is converted into an analog signal by a D / A converter 7, amplified by a receiver amplifier 8 with a predetermined gain, and then converted into a received voice by a receiver 9 and output. In FIG.
In step S15, when the end call is selected by pressing an end key (not shown) or the like, the CPU 15 controls the end of the call, and at the same time, controls to reset the frequency adjustment of the equalizer 6 to return to the default flat characteristic ( Step S16).

The frequency component analysis of the ambient noise by the frequency component analysis unit 3 and the frequency characteristic conversion of the received voice signal by the equalizer 6 are calculated and converted by the DSP 10 to determine the noise level and the frequency threshold. Range / low range threshold, step S105, step S in FIG.
The adjustment values of the equalizer as shown in 106 and step S107 are stored in advance in the CPU or in a memory (not shown) as parameters. The reception frequency characteristic control unit 4 adjusts and controls the equalizer 6 based on the stored parameter values and the analysis result of the frequency component analysis unit 3. As a result, the processing load of the DSP 10 is reduced, and quick processing is possible.

At the same time as the end of the call, the frequency characteristics of the equalizer are reset so as to return to the default flat characteristics. With this control, an advantage is obtained in that, when the user prefers to use the flat characteristics without changing the frequency characteristics, for example, during playback of the voice recorded by the voice memo function during standby, the user-friendliness is good. In addition,
With this voice memo function, it is possible to record the voice of the other party during the call, that is, the received voice.
It is also possible to record without passing through the equalizer 6 under the control of the PU 15.

In the above description, the measurement of the frequency characteristic of the ambient noise is performed after the start of the call and before the caller makes a sound. However, the measurement may be performed during the calling operation at the time of calling or receiving a call. In this case, the microphone amplifier 2 is turned on at the beginning of the incoming or outgoing call operation so that the ambient noise is taken in from the microphone 1. As a result, the time required to measure the frequency characteristics of the ambient noise increases, and more accurate analysis becomes possible. Further, when a ringing tone is sounding during a ringing operation at the time of an incoming call, a known frequency component of the ringing tone may be deleted to measure the frequency characteristics of the ambient noise. In this case, it is possible to measure the frequency characteristics of the ambient noise during a call state in which the ring tone is not sounding, and it is possible to perform more preferable frequency characteristic conversion of the received voice.

Embodiment 2 Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a block diagram showing Embodiment 2 of a mobile phone using the voice control device according to the present invention. In the figure, components having the same reference numerals as those in FIG. Reference numeral 16 denotes a transmission sound presence / absence detection unit that detects the presence / absence of a transmission sound signal in a transmission sound path through which the transmission sound input from the microphone 1 is transmitted, monitors an output of the A / D converter 5,
The detection result is notified based on a request from the CPU 15. The threshold value used by the transmitted sound presence / absence detector 16 to determine the presence or absence of transmitted sound is stored in a memory (not shown) in advance.
The CPU 15 has a timer (not shown), and controls each digital signal processing of the DSP 10 based on the count value of the timer and the detection result of the transmission sound presence / absence detection unit 16.

Next, the operation will be described. FIG. 5 is an operation flowchart of the second embodiment. First, in an incoming call or outgoing call operation, the two-way voice path of the transmission / reception system is turned on to start a call (step S21). At this time, CPU1
The timer (not shown) in 5 is reset to zero, and the counting of the elapsed time x is started. Microphone amplifier 2 at the start of the call
Is turned on, the ambient noise coming from the microphone 1 is taken into the frequency component analysis unit 3 before the caller makes a voice,
The frequency characteristics of the ambient noise are measured (step S2).
2). At this time, the ambient noise has been amplified by the microphone amplifier 2 and converted into a digital signal by the A / D converter 5, and the frequency component analysis unit 3 analyzes the frequency of the ambient noise converted into the digital signal by FFT analysis. Is performed (step S23).

On the other hand, the voice of the other party is received from the antenna 14 in the form of being included in the radio signal, converted into the received voice signal via the high frequency unit 13 and the modem unit 12, and transmitted to the equalizer 6 via the timing control unit 11. Is input to The reception frequency characteristic control unit 4 adjusts and controls the equalizer 6 to perform weighting of the signal strength based on the result of the frequency component analysis in step S13 on the signal of each frequency band of the received reception voice signal (step S13). Step S24). The received voice signal input to the adjusted equalizer 6 is converted into a frequency characteristic by weighting the signal strength for each frequency band. The received voice signal output from the equalizer 6 is converted into an analog signal by a D / A converter 7, amplified by a predetermined gain by a receiver amplifier 8, and then converted into a received voice by a receiver 9 and output.

In step S25, the count value x of the timer in the CPU 15 is compared with a predetermined elapsed time t. If the count value x is equal to or longer than the predetermined elapsed time t, the process proceeds to step S26. In step S26, the presence / absence of a transmission voice signal is detected by the transmission voice presence / absence detecting section 16, and if no transmission voice signal is detected, the CPU 15 resets the count value of the timer to zero, and returns to step S22 to return to ambient noise. Are performed again (step S22), frequency component analysis (step S23), and equalizer adjustment (S24), and equalizer adjustment is performed based on ambient noise after a lapse of a predetermined time from the previous ambient noise measurement. If the transmission voice signal is detected in step S26, the process returns to step S25 and returns to step S26.
To detect the presence or absence of the transmission voice signal again. Step S26
When the transmitted voice signal is detected by the above, the adjustment of the equalizer 6 is not performed, and the received voice signal input to the equalizer 6 is a signal corresponding to the signal of each frequency band based on the setting of the equalizer 6 adjusted last time. The frequency characteristic is converted by weighting the intensity. The received voice signal output from the equalizer 6 is converted into an analog signal by a D / A converter 7, amplified by a receiver amplifier 8 with a predetermined gain, and then converted into a received voice by a receiver 9 and output.

At step S25, the count value x of the timer
Is shorter than the predetermined elapsed time t, the process proceeds to step S28, and if the end is not selected, the process returns to step S25.
Return to When the end call is selected by pressing an end key (not shown) in step S28, the CPU 15 performs end control, and at the same time, controls to reset the frequency adjustment of the equalizer 6 to return to the default flat characteristic (step S29). .

As described above, by repeatedly performing the frequency characteristic measurement of the ambient noise, the frequency component analysis, and the adjustment of the equalizer at every predetermined elapsed time during a call, the frequency component of the ambient noise and the like can be changed by the caller moving from place to place. Even when the volume changes, a received voice that can be easily heard without being masked by ambient noise can be obtained. In addition, since the equalizer is adjusted not every time but every time a predetermined time elapses, it is possible to avoid that the sound quality of the other party constantly changes and the caller does not feel discomfort.

[0041]

As described above, the voice control device according to the present invention converts the frequency characteristics of the received voice signal based on the frequency characteristics analysis result of the ambient noise, and emphasizes the received voice outside the high noise frequency band. Therefore, it is possible to obtain a received voice that is not buried in the surrounding background noise and that improves the discomfort caused by simply increasing the reception volume with respect to the background noise as in the related art.

Further, the portable telephone according to the present invention is configured so as to convert the frequency characteristic of the received voice signal based on the result of the analysis of the frequency characteristic of the ambient noise. It is possible to obtain a received voice in which discomfort caused by simply increasing the volume of the received voice with respect to the background noise is improved.

Further, the portable telephone according to the present invention is configured to control the frequency characteristic converting means of the received voice signal based on the frequency characteristic analysis result of the ambient noise when the transmitted voice is not detected, so that the surroundings can be more accurately detected. It is possible to analyze the frequency characteristics of the noise, to obtain a received voice that is not buried in the surrounding background noise and that improves the discomfort caused by simply increasing the reception volume with respect to the background noise as in the related art.

Further, the portable telephone according to the present invention is configured to control the frequency characteristic conversion means of the received voice signal based on the frequency characteristic analysis result of the ambient noise every time a predetermined time elapses. Even in a changing environment, it is possible to obtain a received voice that is not buried in the surrounding background noise and that improves the discomfort caused by simply increasing the reception volume with respect to the background noise as in the related art.

Further, the portable telephone according to the present invention has an FF
The frequency characteristics of the ambient noise are analyzed by T analysis, and the frequency characteristics of the received voice signal are converted by the equalizer, so that it is not buried in the background noise with a simple configuration. It is possible to obtain a received voice in which discomfort caused by simply increasing the reception volume is improved.

In the portable telephone according to the present invention, the frequency characteristic conversion means is controlled to the initial set value at the end of the voice call, so that it is easy to use.

Further, the portable telephone according to the present invention analyzes the frequency characteristics of the ambient noise at least during the calling by calling or receiving, so that the frequency analysis can be performed effectively prior to the calling. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a mobile phone using a voice control device according to Embodiment 1 of the present invention.

FIG. 2 is an operation flowchart of the first embodiment of the present invention.

FIG. 3 is a flowchart showing a correspondence between a measurement result of an ambient noise frequency and adjustment of an equalizer according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a mobile phone using a voice control device according to Embodiment 2 of the present invention.

FIG. 5 is an operation flow chart according to the second embodiment of the present invention.

FIG. 6 is a block diagram showing a conventional mobile phone.

FIG. 7 is an operation flowchart of a conventional mobile phone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microphone (transmitter) 3 Frequency component analysis part (frequency analysis means) 6 Equalizer (frequency characteristic conversion means) 9 Receiver (receiver) 15 CPU (control means) 16 Transmission sound presence / absence detection part (voice detection means)

Claims (10)

[Claims] 1. A transmitter, a receiver, frequency analysis means for analyzing frequency characteristics of ambient noise input from the transmitter, and a frequency of a reception voice output to the receiver based on an analysis result of the frequency analysis means. Frequency characteristic conversion means for converting characteristics, the frequency analysis means detects a high-noise frequency band in which the ambient noise is large, and based on the analysis result, the frequency characteristic conversion means detects a reception in a frequency band other than the high-noise frequency band. An audio control device for enhancing an audio band. 2. A portable telephone comprising a transmitter and a receiver and capable of voice communication using a radio signal, wherein said frequency analysis means analyzes frequency characteristics of ambient noise coming from said transmitter. A mobile telephone further comprising frequency characteristic conversion means for converting frequency characteristics of a received voice of the radio signal based on an analysis result of the frequency analysis means. 3. A portable telephone comprising a transmitter and a receiver and capable of voice communication using a radio signal, a frequency analysis means for analyzing frequency characteristics of ambient noise coming from the transmitter, a reception voice based on the radio signal. Frequency characteristic converting means for converting the frequency characteristics of the above, and control means for controlling the frequency characteristic converting means based on the analysis result of the frequency analyzing means during the voice call, and outputting the output from the receiver. A mobile phone characterized by the following. 4. A voice detecting means for detecting presence or absence of a transmitted voice input from the transmitter, wherein the frequency analyzing means detects the surrounding noise when the transmitted voice is not detected by the voice detecting means. The mobile phone according to claim 3, wherein frequency characteristics are analyzed. 5. The mobile phone according to claim 4, wherein the control unit controls the frequency characteristic conversion unit based on an analysis result of the frequency analysis unit every time a predetermined time elapses during the voice call. Phone. 6. The mobile phone according to claim 3, wherein said control means controls said frequency characteristic conversion means to an initial set value at the end of said voice call. 7. The mobile phone according to claim 3, wherein said frequency analysis means analyzes a frequency characteristic of said ambient noise at least during a call by calling or receiving a call. 8. The frequency analysis unit detects a high-noise frequency band in which the ambient noise is large, and based on the analysis result, the control unit increases the received voice band other than the high-noise frequency band. The mobile phone according to claim 3, wherein the mobile phone controls a frequency characteristic conversion unit. 9. The mobile phone according to claim 8, wherein said frequency analysis means performs FFT analysis. 10. The mobile phone according to claim 8, wherein said frequency characteristic conversion means is an equalizer.