JPH07297887A - Mobile communication terminal - Google Patents

Abstract

PURPOSE:To improve the easiness of listening to a received voice even in the case of a large surrounding noise sound or in the case of the user being a person with geriatric hard of hearing by providing a device adjusting a sensitivity frequency characteristic of a voice signal to the terminal equipment. CONSTITUTION:The mobile communication terminal equipment is provided with an analog system sensitivity frequency characteristic adjustment device 15 for the case that a radio signal is demodulated, a digital voice signal is extracted and D/A-converted to provide an analog voice signal. The analog system sensitivity frequency characteristic adjustment device 15 selects any optional analog filter characteristic among plural kinds of analog filter characteristics and checks the sensitivity frequency characteristic of an analog voice signal by synthesizing the filter characteristic selected depending on the control signal with the characteristic of the analog voice signal input. Thus, a proper sensitivity frequency characteristic is provided depending on the environment or the operating state and a received voice of the mobile communication terminal equipment is heard easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication terminal device such as a mobile phone or a cordless phone, and more particularly to a mobile communication terminal device in which a received voice can be heard easily regardless of the usage environment or usage condition. is there.

Mobile communication terminals, such as mobile phones and cordless phones, have different usage environments and usage states, unlike wire telephones, and are often used outdoors, so the usage conditions are as follows: It is inferior to the case of a wired telephone and it is often difficult to listen to the received voice.

Therefore, in order to make it easier to listen to the received voice, there is a demand for a mobile communication terminal in which the sensitivity frequency characteristic can be easily adjusted according to the use environment and the use state.

[0004]

2. Description of the Related Art Wired telephones installed in general households are
The environment in which it is used is most often indoors. Therefore, if the sensitivity frequency characteristic for the audio signal satisfies the mask defined by the industry association standard or the like, the deterioration in the audibility of the audio can be minimized.

Conventionally, also in mobile communication terminals such as mobile phones and cordless phones, the sensitivity frequency characteristic of such a wired telephone is generally used as it is as the sensitivity frequency characteristic for the voice signal.

[0006]

However, in the case of a telephone using a wireless line, represented by a mobile telephone,
The usage environment and usage state vary depending on the user, and the received voice is not always easy to hear as long as a certain standard is satisfied. In particular, in a mobile phone that is often used outdoors, there is a problem that the received voice may be difficult to hear due to ambient noise or the like with a certain sensitivity frequency characteristic.

Further, in the case of presbycusis, it tends to be difficult to hear sounds in a high frequency range. Therefore, when a person with presbycusis uses a mobile phone and has the same voice band as a conventional wired telephone, there is a problem that the other party's words are difficult to hear.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art, and is provided with a device for adjusting the sensitivity frequency characteristic of a voice signal in a mobile communication terminal, and is used in an environment and a state of use. The purpose of the present invention is to improve the easiness of listening to the received voice by adjusting the sensitivity frequency characteristic suitable for the case even when the ambient noise is large or the user has presbycusis.

[0009]

Means for Solving the Problems (1) In a mobile communication terminal that demodulates a radio signal to extract a digital voice signal, converts the digital voice signal into an analog voice signal, and outputs the analog voice signal, an analog voice signal An analog type sensitivity frequency characteristic adjuster for adjusting the sensitivity frequency characteristic of is provided.

(2) In the case of (1), the analog type sensitivity frequency characteristic adjuster has an analog filter circuit and a control circuit for controlling the characteristic of this analog filter circuit, and responds to a control signal to the control circuit. And have a filter characteristic arbitrarily selected from a plurality of types of filter characteristics.

(3) In the case of (1), the analog type sensitivity frequency characteristic adjuster has a plurality of analog filter circuits having different characteristics, a level adjusting circuit for adjusting the output level of each analog filter circuit, and each level. A combination circuit for combining the outputs of the adjustment circuits and a control circuit for controlling the gain of each level adjustment circuit are provided, and an arbitrary filter characteristic can be set according to a control signal for this control circuit.

(4) Adjusting the sensitivity frequency characteristic of a digital voice signal in a mobile communication terminal which demodulates a radio signal to take out a digital voice signal and digital-analog converts this digital voice signal to obtain an analog output signal. Provide a digital sensitivity frequency characteristic adjuster.

(5) In the cases of (4), the digital sensitivity frequency characteristic adjuster generates a digital filter and an R for generating an output for setting the characteristic of the digital filter.
An OM table, and has a filter characteristic arbitrarily selected from a plurality of types of filter characteristics in accordance with a control signal input to the ROM table.

(6) In the case of (4), the digital type sensitivity frequency characteristic adjuster has a plurality of digital filters having different characteristics, a coefficient multiplication amplifier for adjusting the output level of each digital filter, and each coefficient multiplication. An adder circuit for adding the outputs of the amplifiers for amplification, and a ROM table for generating an output for setting the gain of each amplifier for coefficient multiplication,
Arbitrary filter characteristics can be set according to the control signal input to the ROM table.

[0015]

[Action]

(1) In a mobile communication terminal, a radio signal is demodulated to extract a digital voice signal, the digital voice signal is converted into a digital analog signal, and an analog voice signal is output.

In this case, by providing the analog type sensitivity frequency characteristic adjuster 15 so that the sensitivity frequency characteristic of the analog audio signal can be adjusted, an appropriate sensitivity frequency characteristic is given according to the use environment and the use state. Therefore, the received voice of the mobile communication terminal can be easily heard.

(2) Analog type sensitivity frequency characteristic adjuster 1
Reference numeral 5 includes an analog filter circuit 20 and a control circuit 22 for controlling the characteristics of the analog filter circuit 20. A filter characteristic arbitrarily selected from a plurality of types of filter characteristics is selected in accordance with a control signal to the control circuit 22. It can be realized by having it.

(3) Analog type sensitivity frequency characteristic adjuster 1
5 is a plurality of analog filter circuits 32 _{1 to} 32 _N having different characteristics, level adjusting circuits 33 _{1 to} 33 _N for adjusting the output level of each analog filter circuit, and a combining circuit for combining the output of each level adjusting circuit. This can be realized by including 30 and a control circuit 31 that sets the gain of each level adjustment circuit, and setting an arbitrary filter characteristic according to a control signal to the control circuit 31.

(4) Further, in the mobile communication terminal, the digital type sensitivity frequency characteristic adjuster 18 is provided to adjust the sensitivity frequency characteristic of the digital voice signal, and similarly, according to the use environment and the use state. Therefore, it is possible to give an appropriate sensitivity frequency characteristic and make it easy to hear the received voice of the mobile communication terminal.

(5) The digital type sensitivity frequency characteristic adjuster 18 is provided with a digital filter 34 and a ROM table 35 for generating an output for setting the characteristic of this digital filter. This can be realized by having a filter characteristic arbitrarily selected from a plurality of types of filter characteristics according to the signal.

(6) The digital sensitivity frequency characteristic adjuster 18 includes a plurality of digital filters 39 _{1 to} 39 _N having different characteristics, and coefficient multiplication amplifiers 40 ₁ to 40 _N for adjusting the output level of each digital filter. , An adder circuit 42 for adding the output of each coefficient multiplying amplifier, and an R for generating an output for setting the gain of each coefficient multiplying amplifier.
This can be realized by providing the OM table 41 and setting an arbitrary filter characteristic according to the control signal input to the ROM table.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment (1) of the present invention, showing a block configuration of a receiver of a digital mobile phone, and showing a case where sensitivity frequency characteristics are adjusted by an analog system. ing. In the figure, 11 is an antenna. A radio unit 12 amplifies a radio signal received through the antenna 11 and demodulates it to extract a modulated signal formed of a digital signal. Reference numeral 13 is a digital signal processing circuit, which performs processing such as code conversion on the digital signal to extract a digital voice signal.

Reference numeral 14 is a digital-analog converter (D /
In A), the digital audio signal is converted into an analog audio signal. An analog sensitivity frequency characteristic adjuster 15 is capable of selecting arbitrary plural kinds of analog filter characteristics, and synthesizes the filter characteristics selected according to the control signal and the characteristics of the analog audio signal input. Accordingly, the sensitivity frequency characteristic of the analog audio signal is adjusted. An analog signal processing circuit 16 performs level adjustment, branching, and the like on the audio signal whose sensitivity frequency characteristic is adjusted. Reference numeral 17 denotes a receiver, which outputs voice by the output of the analog signal processing circuit 16.

Analog-type sensitivity frequency characteristic adjuster 1 for adjusting the sensitivity-frequency characteristic by the analog method
The insertion position of 5 may be either the input stage or the output stage of the analog signal processing circuit 16, or may be present on both sides of the input stage and the output stage, which results in a difference in the essential operation of the present invention. There is no.

FIG. 2 shows an embodiment (2) of the present invention, showing a block configuration of a receiving portion of a digital mobile phone, showing a case where the sensitivity frequency characteristic is adjusted by the digital system. There is. In the figure, FIG.
18 is a digital type sensitivity frequency characteristic adjuster, which is capable of selecting a plurality of arbitrary kinds of digital filter characteristics, and which has a filter characteristic selected according to a control signal. , And the characteristic of the digital audio signal input are combined to adjust the sensitivity frequency characteristic of the digital audio signal.

When the sensitivity frequency characteristic is adjusted by the digital method, the digital sensitivity frequency characteristic adjuster 18 may be inserted not only in the example shown in FIG. 2 but also in another location. There is no difference in the physical effect.

FIG. 3 shows an embodiment (3) of the present invention, and shows a structural example (1) of an analog type sensitivity frequency characteristic adjuster. In the figure, reference numeral 20 denotes an analog filter circuit, which is a variable analog element 21 _1, 21 _2,
It is shown to consist of 21 ₃ . The variable analog elements 21 _1, 21 _{2, and} 21 ₃ may be all analog elements whose characteristics are variable, or some of them may be variable and others may be fixed. Reference numeral 22 is a control circuit, which supplies a control signal to each of the variable analog elements 21 _1, 21 _{2, and} 21 ₃ .

The control circuit 22 responds to a control signal from the outside.
Then, the variable analog element 21_1,21 _2,21₃ Against
Output control signal, control signal, control signal respectively
It As a result, each variable analog element 21_1,21_2,Two
1₃ However, since the values of its components are controlled,
The filter circuit 20 having a wide bandwidth filter characteristic is
The cutoff frequency of the bandpass filter changes depending on the signal.
Turn into.

FIG. 4 shows an example (1) of signals of respective parts in the analog type sensitivity frequency characteristic adjuster,
4 illustrates the case of the embodiment shown in FIG. In the figure,
(A) shows the sensitivity frequency characteristic of the input voice signal, and has, for example, a flat characteristic equivalent to that of a general wired telephone. (B) shows the filter characteristic of the sensitivity frequency characteristic adjuster, which shows that it has a characteristic of gently cutting off the high frequency range. (C) shows the sensitivity frequency characteristic of the output signal of the sensitivity frequency characteristic adjuster, and it is shown that it has a characteristic obtained by combining the characteristics shown in (a) and (b).

FIG. 5 shows an example of the configuration of a variable analog element, showing a case where the resistance value is made variable, R _1,
R _{2 and} R ₃ are resistors, 23 _1, 23 _{2 and} 23 ₃ are analog switches, and 24 is an analog switch control circuit.

When the resistance value is changed, the on / off states of the analog switches 23 _1, 23 _2, 23 ₃ are controlled in accordance with the control signal from the analog switch control circuit 24 so that the input terminals and The resistance value between the output terminals can be changed. By the same means, it is possible to configure a variable analog element that can change the values of capacitors and coils.

FIG. 6 shows a variable analog element using a variable analog element.
1 shows an example of the configuration of a bandpass filter,
An example of configuring the following bandpass filter will be illustrated, and C₁ 
~ C ₆ Is a capacitor, R_1,R₂ Is resistance, SW₁ ~ SW₆ 
Is an analog switch (ASW), A is an amplifier, 25 is a control
It is a circuit. In the figure, a capacitor C₁ ~ C_FourWhen
Analog switch SW₁ ~ SW_Four Is the first variable analog
The element 26 is formed and the capacitor C is formed._Five ,C₆ And analogs
Switch SW_Five ,SW₆ Is the second variable analog element 27
Is forming.

The control circuit 25 controls each analog switch SW.
The value of the capacitor connected to the filter circuit is made variable by controlling the on / off switching of _{1 to} SW ₆ . The selection of the capacitors C _{1 to} C ₄ by the control circuit 25 includes one capacitor, two capacitors, three capacitors, and four capacitors, and a total of two capacitors.
There are 0 ways. The likewise capacitor C _5, select the C ₆ how, and if the capacitor is one, there is the case of two, there are three in total. Therefore, by controlling the switching of each of the analog switches SW _{1 to} SW ₆ from the control circuit 25, the capacitance value formed between the input terminal and the resistor R ₁ in the first variable analog element 26,
Changing the characteristic of the primary bandpass filter formed between the input terminal and the output terminal by changing the capacitance value of the second variable analog element 27 that is connected in parallel with the resistor R _2. You can

FIG. 7 shows an embodiment (4) of the present invention, and shows a structural example (2) of an analog type sensitivity frequency characteristic adjuster. In the figure, 28 is a branching circuit for branching the audio signal into a plurality of signals, 29 is an analog filter, 30 is a combining circuit for combining a plurality of outputs, and 31 is a control circuit for controlling the characteristics of the analog filter 29.

Further, in the analog filter 29, 32
_1, 32 _{2, ...,} 32 _N are each an analog filter circuit, 33 _1, 33 _{2, ...,} 33 _N are each an analog filter circuit 32 _1, 32 _{2, ...,} the level adjusting circuit for adjusting the output level of 32 _N is there.

The control circuit 31 responds to a control signal from the outside.
Then, the level adjustment circuit 33_1,33_{2 ,}…_,33_NAgainst
Output control signals (1) to (N). This allows each
Bell adjustment circuit 33_1,33_2 ,…_,33_NOutput level of
Each level is adjusted in the synthesizing circuit 30 as it is adjusted.
Circuit 33_1,33_2 ,…_,33_NOutput based on
The output signal has a sensitivity frequency characteristic that depends on the control signal.
Change.

FIG. 8 shows an example (2) of signals of respective parts in the analog type sensitivity frequency characteristic adjuster.
8 illustrates the case of the embodiment shown in FIG. 7. In the figure,
(A) is each analog filter circuit 32 _1, 3 in FIG.
An example of characteristics of 2 _{2 ,} ... _, 32 _N is shown. (B) shows the sensitivity frequency characteristic of the input audio signal, the solid line shows the characteristic of each filter circuit, and the broken line shows the characteristic of the analog filter 29, which has a flat characteristic equivalent to that of a general wired telephone, for example. ing. (C) shows the filter characteristic of the sensitivity frequency characteristic adjuster, for example, in the low temperature range and the high range,
The characteristic that the output level of each filter circuit gradually decreases is shown. (D) shows the sensitivity frequency characteristic of the output signal of the sensitivity frequency characteristic adjuster, and it is shown that it has a characteristic obtained by combining the characteristics shown in (b) and (c).

FIG. 9 shows an embodiment (5) of the present invention and shows a structural example (1) of a digital type sensitivity frequency characteristic adjuster. In the figure, 34 is a digital filter, and 35 is a read only memory (ROM) table for outputting the filter coefficient of the digital filter 34. Further, in the digital filter 34, 36 _1-
36 ₅ is an amplifier for coefficient multiplication, 37 _{1 to} 37 ₃ are adders,
Reference numerals 38 _{1 and} 38 ₂ are delay circuits.

The ROM table 35, in accordance with the control signal, supplied to the coefficient multiplication amplifier 36 _{1-36 5,} the tap coefficients a ₀ k~a ₂ k to be multiplied, -b ₁ k, a -b ₂ k. For coefficient multiplication amplifier 36 _{1-36 3} input signals, respectively multiplied by tap coefficients a ₀ k~a ₂ k, the coefficient multiplication amplifier 36 _{4-36 5} for the output signal, the tap coefficients respectively - b ₁ k, is multiplied by the -b ₂ k.

The adder 37 ₁ is a coefficient multiplication amplifier 36 _{3 ,}
The outputs of 36 ₅ are added, and the delay circuit 38 ₁ is added by the adder 37 ₁
The output of the 1 sampling period delay, adder 37 ₂ is delayed to the output of the coefficient multiplication amplifier 36 _2, 36 ₄ circuit 38 ₁
, The delay circuit 38 ₂ delays the output of the adder 37 ₂ by one sampling period, and the adder 37 ₃ adds the output of the coefficient multiplying amplifier 36 _{1 and} the output of the delay circuit 38 _2. , Generate an output signal.

Therefore, the digital filter 34 is
The cutoff frequency is changed according to the tap coefficient data from the M table 35, and a plurality of types of filter characteristics having a relatively wide bandwidth are realized corresponding to the control signal. Although FIG. 9 shows an example of a 2D type digital filter, such a filter may be further connected in cascade.

FIG. 10 shows an embodiment (6) of the present invention,
The structural example (2) of a digital type sensitivity frequency characteristic adjuster is shown. In the figure, 39 _{1 to} 39 _N are digital filters each having a narrow band pass characteristic, and 40 ₁
To 40 _N respectively digital filters 39 ₁ ~ 39 _N
A coefficient multiplication amplifier for multiplying the output of ₁ by the coefficients k ₁ to k _N ,
Reference numeral 41 designates coefficient multiplication amplifiers 40 ₁ to 40 according to the control signal.
Read-only memory (RO to output a factor for the _N
M) A table.

An adder circuit 42 adds the outputs of the coefficient multiplying amplifiers 40 ₁ to 40 _N. Reference numeral 43 is a power calculation unit that calculates the power of the input signal. An amplitude correction coefficient calculation unit 44 generates a correction coefficient for correcting the amplitude of the output signal according to the calculated power. An amplitude correction amplifier 45 corrects the output amplitude of the adder circuit 42 according to the correction coefficient to generate an output signal having a desired amplitude.

The digital type sensitivity frequency characteristic adjuster shown in FIG. 10 has basically the same operation principle as the analog type sensitivity frequency characteristic adjuster shown in FIG. 7, and the ROM table according to the control signal. 41 output from coefficient k ₁
By controlling and adding the gains of the coefficient multiplying amplifiers 40 ₁ to 40 _N corresponding to k _N , the output levels of the digital filters 39 _{1 to} 39 _N are changed, and the sensitivity frequency characteristics in the voice band are changed. Change. Further, since the amplitude correction amplifier 45 corrects the level of the addition output according to the amplitude correction coefficient calculated according to the input power to generate the output signal, it is always required even if the power of the input signal changes. An output signal having an amplitude of can be obtained.

[0045]

As described above, according to the present invention, the mobile communication terminal is provided with the device for adjusting the sensitivity frequency characteristic of the audio signal, so that the sensitivity frequency suitable for the use environment and the use state can be obtained. It is possible to impart characteristics, and thus make it easy to hear the voice received from the mobile communication terminal even when it is used outdoors in a place where there is a large amount of ambient noise, or when it is used by a person with deafness. .

The adjustment of the moving frequency characteristics in the mobile communication terminal of the present invention may be performed by an analog circuit or a digital circuit. Alternatively, the characteristics of a single filter with a wide frequency band may be changed to obtain the required sensitivity frequency characteristics, or multiple filters with a relatively narrow frequency band may be used to adjust the level of each output signal. Can be changed to obtain the required sensitivity frequency characteristic.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment (1) of the present invention.

FIG. 2 is a diagram showing an embodiment (2) of the present invention.

FIG. 3 is a diagram showing an embodiment (3) of the present invention.

FIG. 4 is a diagram showing an example (1) of signals of respective parts in the analog type sensitivity frequency characteristic adjuster, wherein (a) is a sensitivity frequency characteristic of an input audio signal, and (b) is a filter characteristic of the sensitivity frequency characteristic adjuster. , (C) show the sensitivity frequency characteristic of the output signal of the sensitivity frequency characteristic adjuster.

FIG. 5 is a diagram showing a configuration example of a variable analog element.

FIG. 6 is a diagram showing a configuration example of a variable bandpass filter using a variable analog element.

FIG. 7 is a diagram showing an embodiment (4) of the present invention.

FIG. 8 is a diagram showing an example (2) of signals of respective parts in the analog type sensitivity frequency characteristic adjuster, wherein (a) is an example of characteristics of each analog filter circuit, and (b) is a sensitivity frequency characteristic of an input audio signal. , (C) shows the filter characteristic of the sensitivity frequency characteristic adjuster, and (d) shows the sensitivity frequency characteristic of the output signal of the sensitivity frequency characteristic adjuster.

FIG. 9 is a diagram showing an embodiment (5) of the present invention.

FIG. 10 is a diagram showing an embodiment (6) of the present invention.

[Explanation of symbols]

15 analog type sensitivity frequency characteristic adjuster 18 digital type sensitivity frequency characteristic adjuster 20 analog filter circuit 22 control circuit 30 synthesis circuit 31 control circuit 32 _{1 to} 32 _N analog filter circuit 33 _{1 to} 33 _N level adjustment circuit 34 digital filter 35 ROM Table 39 _{1 to} 39 _N Digital filter 40 ₁ to 40 _N Coefficient multiplying amplifier 41 ROM table 42 Adder circuit

Claims (6)

[Claims] 1. A mobile communication terminal for demodulating a radio signal to extract a digital voice signal, converting the digital voice signal into a digital analog signal and outputting an analog voice signal, the sensitivity frequency characteristic of the analog voice signal is adjusted. A terminal for mobile communication, comprising: an analog sensitivity frequency characteristic adjuster (15). 2. The analog-type sensitivity frequency characteristic adjuster (15) comprises an analog filter circuit (20) and a control circuit (22) for controlling the characteristics of the analog filter circuit (20). The mobile communication terminal according to claim 1, wherein the mobile communication terminal has a filter characteristic arbitrarily selected from a plurality of types of filter characteristics according to the control signal for (22). 3. The analog sensitivity frequency characteristic adjuster
(15) is a plurality of analog filters having different characteristics
Circuit (32₁ ~ 32_N) And the analog filter times
Road (32₁ ~ 32_N) To adjust the output level
Adjustment circuit (33 ₁ ~ 33_N) And the respective level adjusting circuits (3
Three₁ ~ 33_N), A synthesis circuit (30) for synthesizing the outputs of
Each level adjusting circuit (33₁ ~ 33_N) Gain
And a control circuit (31) for operating the control circuit (31).
Any filter characteristic can be set according to the control signal
The mobile communication terminal according to claim 1, characterized in that
End machine. 4. In a mobile communication terminal for demodulating a radio signal to extract a digital voice signal, converting the digital voice signal into an analog signal to obtain an analog output signal, the sensitivity frequency characteristic of the digital voice signal is adjusted. A mobile communication terminal comprising a digital sensitivity frequency characteristic adjuster (18). 5. The digital sensitivity frequency characteristic adjuster (18) comprises a digital filter (34) and a ROM table (35) for generating an output for setting the characteristic of the digital filter (34). 5. The mobile communication terminal according to claim 4, wherein the mobile communication terminal has a filter characteristic arbitrarily selected from a plurality of types of filter characteristics according to a control signal input to the ROM table (35). 6. The digital sensitivity frequency characteristic adjustment
The device (18) includes a plurality of digital filters having different characteristics.
Filter (39₁ ~ 39_N) And each digital filter
(39₁ ~ 39_N) For coefficient multiplication to adjust output level
Amplifier (40 ₁ ~ 40_N) And an amplifier for multiplying each coefficient
(40₁ ~ 40_N) Adder circuit (42) for adding the outputs of
And each coefficient multiplication amplifier (40₁ ~ 40_N) Gain
ROM table (41) that produces output for setting
And the control input to the ROM table (41)
Arbitrary filter characteristics can be set according to the signal
The mobile communication terminal according to claim 4, wherein the mobile communication terminal is a mobile communication terminal.