JPH11330880A - Voice output change control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly change received sound volume by coping with surrounding noises. SOLUTION: Surrounding noises are measured by a microphone 1, and when the measured noise level is larger than a prescribed threshold level, a detection signal is transmitted from a noise level detecting circuit 24. In this case, the number of times of the output of the detection signal in a preout counting period is counted by a counter circuit 23. Then, a voice output level is controlled to be changed according to the compared result of this counted result with a preset set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio output change control system, and more particularly to a system for controlling an audio output of a portable telephone or the like.

[0002]

2. Description of the Related Art A receiver such as a portable telephone incorporates a noise canceller for removing noise on a transmitting side. Even if the noise on the transmitting side is removed by this noise canceller, there are many situations where it is difficult to hear depending on the surrounding environment of the receiving side. In such a case, it can be dealt with by changing the reception volume.

However, there is a problem that it is troublesome for the user to set the receiving volume according to the place where the telephone is used. In order to solve this, the surrounding noise level may be detected, and the reception volume may be changed according to the detection result.

A technique for changing the reception volume is disclosed in Japanese Unexamined Patent Publication No.
No. 172619. In this publication, the peak value of the noise level is detected, and the received sound volume is changed according to the detection result.

[0005]

As described in the above-mentioned publication, when the receiving sound volume is changed, the peak value of the noise is detected even when a sudden large noise is generated, and the detection result is obtained. The received sound volume is changed in accordance with. Then, there is a disadvantage that the received sound volume becomes unnecessarily large in order to cope with the large peak value.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a sound output change control system capable of appropriately changing a received sound volume in response to ambient noise. It is to be.

[0007]

A sound output change control system according to the present invention is a sound output change system for changing and controlling a sound output level of a sound signal to be transmitted, comprising a noise measuring means for measuring ambient noise. Noise level detecting means for transmitting a detection signal when the measured noise level is higher than a predetermined threshold level; counting means for counting the number of times the detection signal is output within a preset counting period; And a sound output level change control means for controlling the change of the sound output level in accordance with a result of comparison between the counting result and a preset value.

[0008] In short, the present system counts the number of times of output of the detection signal transmitted when the measured noise level is higher than the predetermined threshold level within a preset counting period, and this counting result is set in advance by the counting result. The sound output level is changed and controlled in accordance with the result of comparison with the set value. Further, the counting period and the threshold level are changed and controlled according to the external command. By doing so, the received sound volume can be appropriately changed in response to the surrounding noise.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a sound output change control system according to the present invention. In the figure, the audio output change control system according to the present embodiment includes:
A microphone 1 that receives an ambient sound, a level measurement unit 2 that measures the level of the input ambient sound, a level determination circuit 3 that determines the measured level, and an output of the level determination circuit 3. It is configured to include an amplifier circuit 4 for amplifying the reception output of the receiver 5 in response thereto, and a speaker 6 for outputting the audio signal amplified by the amplifier circuit 4. The receiving unit 5 has a function of receiving a telephone voice signal.

The microphone 1 is, for example, a high sensitivity type (0.1 to 8 KHz) condenser microphone. The ambient noise includes the voice of the user in addition to the original noise (noise), so it is necessary to distinguish this voice from the noise. Therefore, it is assumed that the microphone 1 is installed at a position where the voice of the talker (user) hardly reaches the receiver of the telephone. For example, it is installed at a position symmetrical with respect to the receiving speaker.

The noise level obtained by the microphone 1 is used for controlling an amplifier circuit 4 via a level measuring section 2 and a level determining circuit 3 which will be described later.
That is, the audio signal output from the speaker 6 is changed by controlling the change of the amplification degree in the amplifier circuit 4.

Next, an example of the internal configuration of the microphone 1 and the level measuring section 2 will be described with reference to FIGS. In each of these drawings, the same parts as those in FIG. 1 are indicated by the same reference numerals.

In FIG. 2, the microphone 1 includes an audio input unit 10, a transformer 11 for amplifying the input audio, and a transistor 12.

In FIG. 1, a level measuring section 2 includes an ON / OFF circuit 22 for turning on / off the noise measurement in accordance with a set threshold level, a control circuit 21 for setting the threshold level, and an ON / OFF. The circuit includes a counter circuit 23 for counting the noise signal output from the circuit 22, and a noise level determination circuit 24 for determining a noise level based on the count value.

The control circuit 21 includes a threshold level setting section 211 and a threshold level variable section 212, as shown in FIG. This control circuit 21
Specifically, as shown in FIG. 3B, a plurality of resistors R1 to R3 having different resistance values from each other,
A switch SW for selecting a switch among these resistors
And a transistor Tr that receives a current from a resistor activated by the switch SW and inputs the current to a base terminal. With such a configuration, the output terminal O
The current derived from the UT is input to the ON / OFF circuit 22. The switching of the switch SW is performed by the user.

As shown in FIG. 1A, an ON / OFF circuit 22 includes an amplifier 221 having an amplification degree changed by a current output from a control circuit 21 and an amplifier 221 having an amplification degree.
21 is provided as an input, and includes a threshold level detection unit 222 that cuts off the output of a signal below a certain threshold level.

The threshold level detecting section 222 is constituted by using a diode. An output signal is derived only when the input voltage exceeds about 0.6 V, which is the forward voltage of the diode. Therefore, when the input voltage is equal to or lower than the threshold value of 0.6 V, no output signal is derived. As a result, the analog signal input to the threshold level detector 222 is converted into a digital signal and output.

The counter circuit 23 includes an ON / OFF circuit 2
2 includes an AND gate 231 to which one output is applied to one of the input terminals, a noise counter 232 that performs a count-up operation by the output and outputs a count value, and a clock generation circuit 233 that outputs a clock signal of a predetermined cycle. It is composed of The clock signal output from the clock generation circuit 233 is applied to the other input terminal of the AND gate 231.

The counter circuit 23 performs a count-up operation using the same clock signal as the above-described clock signal output from the clock generation circuit 233, and outputs a reset signal at predetermined intervals.
4, a reset time setting unit 235 for setting a cycle of outputting the reset signal of the reset counter 234,
And a reset time varying unit 236 for controlling the change of the set cycle. It is assumed that the reset time variable section 236 can change and control the set cycle in about three to five steps by manual operation.

The noise level determination circuit 24 outputs the output of the noise counter 232 to a BCD (Binary Coded).
Decimal) encoder 241 for converting the code
And a comparison value setting circuit 242 in which a comparison value to be compared in the comparison circuit is set in advance, and a comparison circuit 243 for comparing the set value with a conversion value by the encoder 241. I have.

The value converted by the encoder 241 is reset by a reset signal output from a reset counter 234. The reset signal output from the reset counter 234 is the reset time variable unit 2
36 and the reset time setting unit 235, the cycle of which is controlled to change.

The operation of the level measuring section 2 having such a configuration will be described with reference to FIGS. These figures 5
6 and FIG. 6, parts equivalent to those in FIGS. 1 to 4 are indicated by the same reference numerals.

First, in FIG. 5, it is assumed that the input signal IN including noise changes as shown. Further, it is assumed that the reset signal RST is output every seven times of the level transition of the clock signal CLK. More specifically, the clock signal CLK starts at "0" and the reset signal RST is output at "7". Similarly, when the clock signal CLK starts at “7”, the reset signal RST is output at “14”.

In the case shown in the figure, the portion of the input signal IN exceeding the threshold value Vth and the clock signal CLK are input to the AND gate 231, and this AND gate 23
The output of 1 is counted by the noise counter 232. Therefore, while the input signal IN exceeds the threshold value Vth, the count-up by the clock signal CLK is performed. In short, the count-up operation is performed only when both the input signal and the clock signal CLK are valid. Therefore, the output 2320 of the noise counter 232 is counted up when the clock signal CLK is “1”, “3”, “5” and “7”, as shown in FIG. Will be.

The output of the noise counter 232 is input to the encoder 241 and is subjected to BCD conversion. However, since the encoder 241 is reset by the reset signal RST, a signal having three pulses as shown in (1) and a signal having one pulse as shown in (2) BCD conversion will be performed.

That is, the pulse output from the noise counter 232 is converted by the encoder 241.
On the other hand, the converted value of the encoder 241 is reset by the pulse output from the reset counter 234, and the count value at that time is recognized as the number of noises. After the reset, the pulse is newly converted by the encoder 241.

Therefore, in the case of the signal (1) shown in the figure, the noise number is "3", and in the case of the signal (2), the noise number is "1". The output 2410 of the encoder 241 is input to a comparison circuit.

Here, assuming that the clock signal CLK is 50 Hz and the reset signal RST is 1 sec, the count-up operation is always performed when the level always exceeds a predetermined level (always at the "high level"). Therefore, the count value is “50”. Then, this "5
"0" is output from the encoder 241. To change this state, the set value of the threshold level by the control circuit 21 may be changed.

Turning to FIG. 6, the output 24 of the encoder 241
10 is input to the comparison circuit 243, and is compared with the comparison value preset in the comparison value setting circuit 242.
In this example, the number-of-noises “8,
7, 6, "5, 4, 3", and "2, 1, 0" are respectively set. Then, since the number of noises is “3” in the case of the signal of (1), the comparison circuit 243
Output "010". In the case of the signal (2) described above, since the number of noises is “1”, the comparison circuit 2
43 outputs “001”.

Here, the repetition period of the clock signal is 0.
In the case of 1 sec, the reset time is 0.5 sec, 1 s
ec and 3 sec. In this case, a maximum of 30 (3/0.
Since the noise of 1) is counted, "0"
0110000 ". Therefore, if an 8-bit comparison circuit is employed, an AND gate is provided for each bit, and a circuit for giving priority to the upper bit is assembled, it is possible to obtain several levels of noise level judgment outputs.

The output of the comparison circuit 243 is input to the D / A converter 31 in the level determination circuit 3 shown in FIG. 1 and is converted from a digital amount to an analog amount. The above-described amplifier circuit 4 in FIG. 1 is controlled by this analog amount.

As described above, in the present system, the number of outputs of the detection signal transmitted when the measured noise level is higher than the predetermined threshold level is counted within a preset counting period. The audio output level is controlled to change in accordance with the result of comparison between the audio output level and the preset value. By doing so, the received sound volume can be appropriately changed in response to the surrounding noise.

A configuration is also conceivable in which a signal in a frequency band other than the human voice frequency band is extracted by using a known filter circuit, and the extracted signal is processed as noise in the same manner as described above. However, such a configuration is not advantageous because the addition of the filter circuit hinders downsizing of the entire device.

In the above example, the case where the present system is applied to a telephone has been described. However, the present invention is not limited to this, and it is apparent that the present system can be applied to various devices.

The present invention can take the following aspects in connection with the description of the claims.

(1) The sound output change control system according to any one of claims 1 to 6, wherein a threshold level of the noise level detecting means is determined according to a threshold value of a diode.

(2) The threshold level change control means includes a plurality of resistors having different resistance values from each other, and a switch for selecting this resistor. 7. The audio output change control system according to claim 1, wherein a control signal for controlling the change of the threshold level is generated.

[0039]

As described above, according to the present invention, the number of outputs of the detection signal transmitted when the measured noise level is higher than the predetermined threshold level is counted within a preset counting period. By controlling the change of the audio output level according to the result of the comparison between the counting result and the preset value, there is an effect that the received sound volume can be appropriately changed in response to the surrounding noise. Further, by controlling the change of the counting period and the threshold level according to the external command, there is an effect that the received sound volume can be more appropriately changed in response to the surrounding noise.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an audio output change control system according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an example of an internal configuration of a level measurement unit and the like in FIG. 1;

FIG. 3 shows a control circuit and ON / O of a level measuring unit in FIG. 2;
FIG. 3 is a block diagram illustrating a more detailed configuration example of an F circuit.

FIG. 4 is a block diagram showing a more detailed configuration example of a counter circuit and a noise level determination circuit of a level measurement unit in FIG. 2;

FIG. 5 is a diagram showing an operation of the audio output change control system.

FIG. 6 is a diagram showing an operation of the audio output change control system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microphone 2 Level measurement part 3 Level judgment circuit 4 Amplification circuit 5 Receiving part 6 Speaker

Claims (6)

[Claims] 1. An audio output changing system for controlling an audio output level of an audio signal to be transmitted, comprising: a noise measuring means for measuring ambient noise; A noise level detecting means for transmitting a detection signal at a certain time, a counting means for counting the number of outputs of the detection signal within a preset counting period, and a comparison result between the counting result and a preset setting value. And a sound output level change control means for changing and controlling the sound output level in response thereto. 2. The audio output change control system according to claim 1, further comprising a count period change control means for changing and controlling the count period in response to an external command. 3. The audio output change control system according to claim 1, further comprising a threshold level change control means for changing and controlling said predetermined threshold level in response to an external command. 4. The sound output change control system according to claim 1, wherein said noise measuring means measures said ambient noise by a microphone provided in a handset of a telephone. 5. The audio output change control system according to claim 1, wherein the audio signal is transmitted from a speaker provided in a handset of the telephone. 6. The apparatus according to claim 1, wherein said counting means counts up only when said detection signal and a clock signal having a predetermined repetition frequency are both valid.
6. The audio output change control system according to any one of 5.