JPH06350691A - Telephone set - Google Patents

Abstract

PURPOSE:To provide a telephone set which corrects the voice signal lost on the way of a line of a telephone network to clarify the indistinct voice. CONSTITUTION:The reception voice signal branched by a cross point 11 is separated into frequency bands (1) 2000 to 2250Hz, (2) 2251 to 2500Hz, (3) 2501 to 2750Hz, and (4) 2751 to 3000Hz by a frequency analysis circuit 12, and levels of the separated voice signal are detected and are outputted to a signal level comparator 13, and signal levels of frequency bands (1) to (4) are compared with that of 1000Hz, and data of the comparison result is outputted to a CPU 15 through an A/D converter 14. The CPU 15 sends such control signal to a graphic equalizer 16 which adjusts the signal level of frequency band 2000 to 3000Hz that the signal level of 1000Hz is equal to signal levels of four other frequency bands, thereby correcting the level of the reception voice signal to clarify the voice.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone, and more particularly to a telephone for correcting the clarity of received voice.

[0002]

2. Description of the Related Art Generally, a telephone connects a line between callers' telephones by a calling operation and a receiving operation via a fixed public telephone network to make a call while transmitting and receiving a voice signal. ing.

In recent years, mobile phones have been actively used by mobile communication, and there are many opportunities to talk by connecting a line to a phone connected to a fixed telephone network.

As described above, when a telephone call is made between telephones via the fixed telephone network, if the voice signal is attenuated in the middle of the line of the telephone network, the voice becomes unclear and remains inaudible. I often had to make calls. However, the conventional telephone has no means for coping with the attenuation of the voice signal.

In particular, the deterioration of the voice signal is remarkable in the case of a wireless telephone, and obscuration of voice has been a problem. Therefore, it is possible to uniformly amplify the attenuated audio signal by using an amplifier, but actually it was not so easy to hear.

[0006]

As described above, in the conventional telephone, even if the attenuation of the voice signal occurs in the middle of the line of the fixed telephone network, an appropriate means for coping with this may be provided. Since it was not equipped, there was a problem that the call had to be made with unclear voice. Therefore, an object of the present invention is to provide a telephone that corrects an unclear voice by correcting a voice signal lost in the middle of a line of a telephone network.

[0007]

A telephone of the present invention is a telephone for transmitting and receiving a voice signal via a telephone line, and signal level detecting means for detecting signal levels of a plurality of frequency bands of a received voice signal, respectively. The above object is achieved by comprising a signal level control means for controlling the signal level of the audio signal so that the detected signal levels of the plurality of frequency bands are substantially equal to each other.

In this case, for example, as described in claim 2, the signal level control means uses a predetermined one of the signal levels of the plurality of frequency bands detected by the signal level detection means as a reference level. The signal level of the audio signal may be controlled so that the signal levels of the plurality of frequency bands are substantially equal to the reference level.

Further, for example, as described in claim 3, the signal level control means uses a predetermined one of the signal levels of a plurality of frequency bands detected by the signal level detection means as a reference level. Almost 2KHz to 3K
The signal level of the audio signal may be controlled so that the signal levels in a plurality of frequency bands between Hz are substantially equal to the reference level.

Further, for example, as described in claim 4, the signal level control means uses the preset signal level as a reference level so that the signal levels of the plurality of frequency bands are substantially equal to each other. You may make it control the signal level of an audio | voice signal.

Further, for example, as described in claim 5, in claim 1 or 4, the signal level detecting means has a frequency band of an audio signal of approximately 2 KHz to 3K.
You may make it detect the signal level of several frequency bands between Hz.

Further, for example, as described in claim 6, in any one of claims 1 to 5, the signal level control means is a signal of a plurality of frequency bands of the received audio signal. A means for adjusting the level for each frequency band may be provided.

[0013]

According to the first aspect of the present invention, the signal levels of the plurality of frequency bands of the audio signal received by the signal level detecting means are respectively detected, and the signal levels of the plurality of frequency bands detected by the signal level control means are Since the signal level of the audio signal is controlled so as to be approximately equal, even if the audio signal becomes unclear due to the signal level of the audio signal being attenuated, the audio signal level becomes uniform between the predetermined frequency bands. Is corrected to clarify the voice.

According to the second aspect of the present invention, the signal level of one audio signal of the plurality of frequency bands detected by the signal level detecting means is used as a reference level, and the signal levels of the plurality of frequency bands are used as the reference levels. Since the signal level control means controls the signals so that they are substantially equal to each other, the voice signal level is made uniform and the voice is clarified.
In the invention according to claim 3, the signal level of one audio signal of the plurality of frequency bands detected by the signal level detecting means is used as a reference level, and the signal level of the frequency band between 2 KHz and 3 KHz is the reference level. Since the signal level control means controls so as to be substantially equal to, the frequency band effective for clarifying the voice is efficiently corrected and the voice is made clear.

According to the fourth aspect of the present invention, a preset signal level is used as a reference level, and the signal levels of a plurality of frequency bands are made substantially equal to the reference level.
Since the control is performed by the signal level control means, the reference level for correction does not change, stable signal level correction is possible, and the voice is clarified.

According to the invention of claim 5, claim 1 or 4
In the invention described above, the signal level detecting means is approximately 2K.
Since only the signal level in the frequency band of the audio signal between Hz and 3 KHz is detected, the frequency band to be corrected is limited to the band corresponding to the voice, and effective correction can be performed. Clarified.

According to the sixth aspect of the invention, since the signal levels of the plurality of frequency bands of the audio signal received by the signal level control means are adjusted for each frequency band, the audio signal level is partially attenuated. Even if it is present, this is corrected to a predetermined signal level for each frequency band, so that the signal level can be easily made uniform.

[0018]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 is an overall view showing a schematic configuration of a telephone network for connecting each telephone terminal.

As shown in FIG. 1, the telephones 2, 3, and 4 connected to the existing fixed telephone network 1 are connected to the fixed telephone network 1.
A call is made / called in via the telephone, and a call is made while mutually connecting the lines and exchanging voice signals. In addition, a mobile phone using mobile communication which has become widespread in recent years has a central transmission / reception station 5 connected to the fixed telephone network 1 and is provided from the central transmission / reception station 5 for each transmission / reception area. The peripheral transceiver stations 6 and 7 are connected by a line. When making a call in each communication area, the mobile phones 8 and 9 or the mobile phone 10 wirelessly make a call to the peripheral transceiver stations 6 and 7 in each communication area. Phone 8,
It is possible to talk with each other or with the telephones 2, 3, and 4 connected to the fixed telephone network 1.

Next, FIG. 2 is a circuit block diagram showing a partial configuration of the telephone of the present invention. The configuration of the telephone shown in FIG. 2 is the same as that of the mobile telephones 8 and 9 of FIG.
Alternatively, it can be adopted as any configuration of the telephones 2, 3, 4 connected to the fixed telephone network.

As shown in FIG. 2, the voice reception signal from the other party's telephone is branched at the cross point 11 and input to the frequency analysis circuit 12.

The frequency analysis circuit 12 separates the audio reception signal into predetermined frequency bands and detects and outputs the level of the audio signal in each of the separated frequency bands.
Here, 10 for checking the reference audio signal level
A voice signal of 00 Hz and a frequency band for correcting the level of the voice signal are 2000 to 2250 Hz, 22
51 to 2500 Hz, 2501 to 2750 Hz, 2
Audio signals in four bands of 751-3000 Hz are selectively taken out. In the present embodiment, the frequency band in which the signal level is corrected is set between 2000 Hz and 3000 Hz because it is the frequency band in which the improvement of the intelligibility of the voice is most remarkable by matching with the human hearing characteristics. . Then, the signal level information for each frequency band detected from the audio signal separated for each frequency band by the frequency analysis circuit 12 is output to the signal level comparator (comparator) 13, respectively.

The signal level comparator 13 has a signal level of 1000 Hz and 2000-2250 Hz, 2251-.
2500Hz, 2501-2750Hz, 2751
It is to compare the signal level of each audio signal of ˜3000 Hz. The data of this comparison result is A / D
After conversion by the converter 14, the CPU (Central Proc
essing Unit) 15.

The CPU 15 inputs a control signal for holding the signal level of each frequency band to a predetermined level to the graphic equalizer 16 to adjust the gain. Here, so that the signal level of each of the above-mentioned frequency bands becomes the same as the signal level of 1000 Hz,
A control signal is sent to the graphic equalizer 16 to adjust the gain. Although the CPU 15 is used as the signal level control means in the present embodiment, when a predetermined signal indicating the comparison result of the signal levels is input to the CPU 15 other than this CPU, the gain adjustment corresponding to this signal is performed. Equipped with a corresponding map that outputs a control signal for
It can be configured to perform control based on this.

The graphic equalizer 16 adjusts the signal level of the received audio signal input from the cross point 11 for each frequency band.
Based on the control signal from the signal No. 5, the signal levels in the respective frequency bands of to have predetermined signal levels (here, 1000H.
The signal level is adjusted to be the same as the signal level of z).

The receiver 17 outputs a voice when the reception voice signal whose signal level is corrected by the graphic equalizer 16 is input.

The key input section 18 is a key input for adjusting the graphic equalizer 16 for adjusting the signal level for each frequency band.

The telephone according to this embodiment is configured as described above, and its operation will be described below.

First, as shown in FIG. 1, a mutual call between the telephones 2, 3, and 4 connected via the fixed telephone network 1,
Alternatively, during a call between the telephones 2, 3, 4 and the mobile telephones 8, 9 or the car telephone 10, if the signal level of the voice signal is attenuated in the middle of the line transmitted and received via the fixed telephone network 1, the call voice Became unclear and was very difficult to hear.

In particular, in the case of the mobile telephones 8 and 9 or the car telephone 10 that makes a telephone call by radio, the signal level of the received voice signal is likely to be attenuated, and the voice during the telephone call is often unclear. , It was often difficult to hear.

Therefore, in this embodiment, as shown in FIG. 2, the received voice signal is branched at the cross point 11, and one received voice signal is 2000 Hz to 3000 H.
The signal level of each frequency band between z is adjusted through the graphic equalizer 16 and is sent to the handset 17.

The other received voice signal branched at the cross point 11 is 1000H at the frequency analysis circuit 12.
z and 2000-2250 Hz, 2251-250
0 Hz, 2501 to 2750 Hz, 2751 to 30
Separated for each frequency band of 00 Hz, the level of the separated audio signal is detected, and the signal level comparator 13
Is output to. In this signal level comparator 13, 100
0 Hz is compared with the signal level for each frequency band up to each of the above, and the data of the comparison result is converted into a digital signal by the A / D converter 14 and output to the CPU 15, based on the output result. , CPU15 is 2000H
1000 Hz for the graphic equalizer 16 that adjusts the signal level in the frequency band of z to 3000 Hz.
The control signal is sent out so that the signal level of 4 and the signal levels of the other 4 bands are the same, and the gain of the graphic equalizer 16 is adjusted.

FIG. 3 is a diagram showing the relationship between the signal level and the frequency showing the improved state of the received voice, (a) of which is a characteristic diagram of the received voice signal before correction, and (b) of which is shown in FIG. It is a characteristic diagram of the received voice signal after correction.

As shown in FIG. 3 (a), the lower the frequency of the received voice signal, the less the signal level is attenuated and the flat characteristic is shown.
It can be seen that the signal level drastically decreases during reaching 0 Hz. As described above, the voice signal transmitted and received through the fixed telephone network is significantly attenuated particularly in a high frequency band. Therefore, the voice actually heard from the handset 17 is unclear and very difficult to hear.

For this reason, in the present embodiment, the graphic equalizer 16 is set so that the signal level of, for example, 1000 Hz, which has relatively little attenuation, is used as the reference level, and the signal level between 2000 Hz and 3000 Hz is the same as this signal level. CPU control signal to adjust the gain of
15 is sent to perform correction for improving the clarity of the received voice.

As described above, the telephone according to the present embodiment has the configuration shown in FIG.
As shown in (b), a voice signal attenuated in the middle of a fixed telephone network line is divided into a plurality of frequency bands, and the signal level is finely adjusted for each frequency band, so that the characteristic of the signal level with respect to frequency is flat. Can be corrected to improve the clarity of the received voice.

Therefore, by performing the above-mentioned correction processing so that the signal level attenuated in the middle of the line or the like is made to be a clear voice again, even the mobile phones 8 and 9 and the car phone 10 which use radio waves are very difficult. You will be able to talk with clear voice.

In this embodiment, 2000 Hz to 30 Hz
The signal level of the audio signal in the frequency band of 00 Hz is 100.
I made a correction to match the signal level of 0Hz,
This reference level is not limited to 1000 Hz in the present embodiment, and a desirable effect similar to the above can be obtained by extracting a frequency portion in the received voice signal in which attenuation is relatively unlikely to occur. .

As described above, in the above embodiment, the signal level at the predetermined frequency of the received voice signal is used as the reference level for correcting the signal level for comparison, and the correction processing is performed according to the comparison result. There is.

However, the present invention is not limited to this, and as another embodiment, for example, a reference level value for correction can be set in advance and correction can be made according to the reference level.

FIG. 4 is a circuit block diagram showing a partial configuration of a telephone according to another embodiment. The configuration of FIG. 4 different from FIG. 2 is that a reference level signal generator 19 for presetting a reference level of a signal for comparing signal levels is added. Then, when the signal level comparator 13 compares the signal levels of the received voice signals for each frequency band, the reference level signal generator 19 generates a predetermined reference level signal, and the reference level signal generator 19 generates a predetermined reference level signal. A comparison with the signal level is made.

As described above, when the audio signal level is corrected, the signal levels of the received audio signals are compared based on a predetermined reference level. Therefore, the reference signal level for correction is received. Since it is not influenced by the condition and the correction is always performed at a constant level, the voice can be surely clarified.

Further, in the present embodiment, the frequency band of 2000 Hz to 3000 Hz, which is particularly effective in improving the intelligibility of the voice, is selected and the signal level correction processing for this band is performed. The present invention is not limited to this, and a band wider than this frequency band can be divided into a plurality of bands to perform the same signal level correction as above.

[0045]

According to the telephone set of the present invention, the signal level detecting means detects the signal levels of a plurality of frequency bands of the received voice signal, and the signal level control means detects the plurality of frequency bands. Since the signal level of the voice signal is controlled so that the signal level of the voice signal becomes almost equal, even if the voice signal is attenuated and the voice becomes unclear, the voice signal between the predetermined frequency bands The level can be uniformly corrected to make the voice clear.

According to the telephone set of the second aspect, the signal level of one audio signal of the plurality of frequency bands detected by the signal level detecting means is used as the reference level, and the signal levels of the plurality of frequency bands are set to the reference level. Since the signal level control means controls the signal level to be substantially equal to the reference level, the voice signal level can be made uniform and the voice can be clarified.

According to the telephone set of the third aspect, the signal level of one audio signal in the plurality of frequency bands detected by the signal level detecting means is set as the reference level and 2K.
Since the signal level control means controls the signal level in the frequency band between Hz and 3 KHz to be substantially equal to the reference level, it is efficiently corrected using the frequency band effective for clarifying the voice. Can be performed to clarify the voice.

According to the telephone set of the fourth aspect, the signal level control means controls the signal level set in advance so that the signal levels in a plurality of frequency bands become substantially equal to the reference level. I decided to do so,
It is possible to perform stable level correction by always using a constant reference level, and to clarify the voice.

According to the telephone set of claim 5, claim 1
Alternatively, in the invention described in 4, the signal level detecting means detects only the signal level of the frequency band of the audio signal between approximately 2 KHz and 3 KHz, so that the frequency band to be corrected is limited to a band corresponding to the audio. As a result, effective correction can be performed, and the voice can be made clear.

According to the telephone set of the sixth aspect, the signal levels of the plurality of frequency bands of the voice signal received by the signal level control means are adjusted for each frequency band.
Even if the audio signal level is partially attenuated, it can be corrected to a predetermined signal level for each frequency band, and the signal level can be easily made uniform.

[Brief description of drawings]

FIG. 1 is an overall view showing a schematic configuration of a telephone network for connecting respective telephone terminals.

FIG. 2 is a circuit block diagram showing a partial configuration of a telephone according to the present invention.

FIG. 3 is a diagram showing a relationship between a signal level and a frequency showing an improved state of received voice.

FIG. 4 is a circuit block diagram showing a partial configuration of a telephone according to another embodiment.

[Explanation of symbols]

 11 Cross Point 12 Frequency Analysis Circuit 13 Signal Level Comparator 14 A / D Converter 15 CPU 16 Graphic Equalizer 17 Handset

Claims (6)

[Claims] 1. In a telephone for transmitting and receiving a voice signal via a telephone line, signal level detecting means for detecting signal levels of a plurality of frequency bands of a received voice signal, and signals of the detected plurality of frequency bands. And a signal level control means for controlling the signal level of the voice signal so that the levels are substantially equal to each other. 2. The signal level control means uses a predetermined one of the signal levels of a plurality of frequency bands detected by the signal level detection means as a reference level, and the signal levels of the plurality of frequency bands are reference levels. 2. The telephone according to claim 1, wherein the signal level of the audio signal is controlled so as to be substantially equal to. 3. The signal level control means uses approximately one of the signal levels of a plurality of frequency bands detected by the signal level detection means as a reference level, and is approximately 2 KH.
2. The telephone set according to claim 1, wherein the signal level of the voice signal is controlled so that the signal levels in a plurality of frequency bands are substantially equal to the reference level between z and 3 KHz. 4. The signal level control means controls the signal level of the audio signal so that the signal levels of the plurality of frequency bands are substantially equal to the reference level, using a preset signal level as a reference level. The telephone set according to claim 1, wherein: 5. The telephone according to claim 1, wherein said signal level detecting means detects the signal levels of a plurality of frequency bands in the frequency band of the audio signal between approximately 2 KHz and 3 KHz. . 6. The signal level control means comprises means for adjusting the signal levels of a plurality of frequency bands of the received audio signal for each frequency band. The phone described in Crab.