JP3107097B2 - Telephone equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone device, and more particularly to a portable telephone.

[0002]

2. Description of the Related Art During a telephone call, if there is noise in the surroundings, the noise is picked up by a transmitter, and the clarity of the transmitted content is significantly reduced.

In this case, depending on the use environment of the telephone,
While it is possible to devise the transmitter so that it does not pick up too much ambient noise, it may not be possible. For example, in the case of a car phone, an engine sound, a wind noise and the like may become noise.

Therefore, as a method of reducing the influence of such noise, a microphone is prepared separately from the transmitter, surrounding noise is collected, and feedback is provided by the spectrum of the noise signal to provide a microphone. A method for suppressing a noise signal included in an output signal has been considered.

[0005]

However, even if such a method is performed, there is actually a difference between the spectrum of the noise picked up by the microphone and the spectrum of the noise picked up by the microphone. Therefore, it is difficult to sufficiently suppress the noise signal included in the output signal of the transmitter and extract only the voice signal. Furthermore, it is almost impossible to make it available for hands-free use in a car phone or the like.

[0006] The present invention is to solve such a problem.

[0007]

Therefore, according to the present invention, when the reference numerals of the respective parts correspond to the embodiments described later, the audio code for extracting the characteristics of the audio waveform from the audio signal of the word uttered by the user. Encoding circuit 13, an audio waveform recording circuit 5 for recording the characteristics of the audio waveform extracted by the audio encoding circuit 13, an audio waveform characteristic extracted by the audio encoding circuit 13, and an audio waveform recording circuit 5. A comparison circuit for comparing the characteristics of the recorded speech waveform with the characteristics of the speech waveform output from the speech encoding circuit and recording in the speech waveform recording circuit in the comparison circuit during transmission; The characteristics of the voice waveform are compared with the characteristics of the voice waveform, and as a result of the comparison, the characteristics of the voice waveform having less noise signal are sent out as the signal to be transmitted.

[0008]

The characteristics of the voice waveform of the input voice signal and the characteristics of the voice waveform registered in advance are compared to check for coincidence or approximation, and a voice signal in which a noise signal is suppressed is output.

[0009]

In FIG. 1, reference numeral 10 denotes a transmission circuit, reference numeral 20 denotes a reception circuit, reference numeral 30 denotes a system controller, reference numeral 41 denotes operation buttons such as dial buttons, and reference numeral 42 denotes a display device. This is for controlling display and the like. For this reason, the system controller 30 is configured by a microcomputer, and includes the operation buttons 41 and the display device 4.
2 is connected, and a required control signal or data is accessed between each circuit.

Reference numeral 5 denotes an audio waveform characteristic recording circuit, in which various audio waveform characteristics of the user are recorded and held.

[Registration of Voice Waveform Characteristics] This is a process of registering various voice waveform characteristics of the user in the recording circuit 5, and is realized, for example, by executing the routine 60 shown in FIG. .

That is, when the portable telephone is in the standby state, for example, when the function button of the operation buttons 41 is pressed and then the registration button is pressed, the routine 60 starts from step 61 and then proceeds to step 62.
Waits for voice input.

[0013] Then, when the user speaks the specified word to the transmitter 11, the voice signal (supposed to contain no noise signal) is supplied from the transmitter 11 to the A / D converter 12. A / D converted to a digital audio signal, the signal is code-compressed in the audio encoding circuit 13 to extract the characteristics of the audio waveform, and the characteristics of the audio waveform are temporarily registered in the recording circuit 5 in step 63. Then, the process proceeds to step 64.

When the user presses a function button of the operation buttons 41 and then presses a confirmation button, this is detected in step 64, and the process proceeds to step 64.
From step 65, in which step 65
Waiting for voice input again.

Therefore, when the word input in step 62 is repeated toward the transmitter 11, the voice signal is processed in the same manner to extract the characteristics of the voice waveform. And step 63
Characteristics of the speech waveform of the word provisionally registered in step 65
Is compared with the characteristics of the voice waveform of the input word, and it is checked whether or not the characteristics of the voice waveform of the input word can be recognized by this comparison.

If the feature can be recognized, the process proceeds from step 66 to step 71. In this step 71, it is displayed on the display device 42 that the words input in steps 62 and 65 are adopted, and the process proceeds to step 71. Go to 72.

Then, when the function button of the operation buttons 41 is pressed and then the registration button is pressed, this is detected in step 72, and the processing is performed in step 72.
To step 73, and in this step 73,
In step 63, the characteristics of the speech waveform of the words temporarily registered are formally registered (recorded) in the recording circuit 5, and then, in step 74, the routine 60 ends.

However, if it is determined in step 66 that the characteristics of the speech waveform of the input word cannot be recognized, the process proceeds from step 66 to step 75, in which the input to the display device 42 in steps 62 and 65 is performed. It is displayed that the word cannot be adopted, and the process proceeds to step 76. Then, in step 76, the temporary registration in step 63 is canceled, and thereafter, in step 74, the routine 60 is terminated.

If a predetermined button operation is not performed in step 64 or 72, the process proceeds from step 64 or 72 to step 74, and this routine 60 ends.

Thereafter, such processing is repeated, and the characteristics of the audio waveform necessary for transmission are registered in the recording circuit 5 as a database (codebook) of audio waveform characteristics.

[Talk] A voice signal from the transmitter 11 (this voice signal may include a noise signal) is transmitted to the A / D
The digital audio signal is supplied to the converter 12 and converted into an A / D signal.
The signal is converted, the signal is code-compressed in the coding circuit 13, and the characteristics of the sound waveform are extracted.

The characteristics of the extracted audio waveform are compared with the characteristics of the audio waveform registered in the recording circuit 5, and a digital audio signal having the same or similar characteristics is extracted. That is, data indicating the degree of ambient noise is supplied from the speech encoding circuit 13 to the system controller 30,
From the encoding circuit 13, when there is little ambient noise,
A signal obtained by code-compressing an actual audio signal is output, and when there is much ambient noise, an audio waveform registered in the recording circuit 5 is output. Thus, the digital audio signal in which the noise signal is suppressed is extracted from the encoding circuit 13.

Then, the digital audio signal is supplied to an encoding circuit 14 for error correction to perform encoding processing for error correction, and the signal subjected to the encoding processing is supplied to a transmission circuit 15. The signal is converted into an uplink transmission signal, and this transmission signal is supplied to the transmission / reception antenna 43 and transmitted to the base station.

[0024] Further, a downlink transmission signal from the base station is received by the antenna 43 and supplied to the receiving circuit 21, from which a digital audio signal is extracted. The extracted signal is supplied to an error correction circuit 22 for error correction, and the error-corrected signal is supplied to an audio decoding circuit 23 and decoded into an original digital audio signal. When this signal is supplied to the D / A converter 24, the D / A
The audio signal is converted and supplied to the receiver 25.

Thus, the transmission circuit 10 and the reception circuit 20
In this case, according to the present invention, the characteristics of the waveform of the voice signal to be transmitted can be changed according to the characteristics of the voice waveform registered in the recording circuit 5 in advance. , And only the waveforms that are the same or close to each other are transmitted, so that even if the voice signal from the transmitter 11 includes a noise signal, the transmitted voice signal is a voice signal in which the noise signal is suppressed. It can be.

Further, since the noise signal can be sufficiently suppressed, a hands-free car phone or the like can be provided.

Moreover, the speech encoding circuit 13, ie,
Since the telephone using the voice codec does not require a new additional circuit, it is possible to suppress the noise of the transmitted voice signal without increasing the cost.

FIG. 3 shows an example of the audio encoding circuit 13 and the connection relationship between the audio encoding circuit 13 and the recording circuit 5. The speech encoding circuit 13 performs encoding by an analysis synthesis encoding method.
In this example, the case of the RPE-LTP method is used.
The circuits 81 to 94 are the original speech coding circuits.

That is, when registering the characteristics of the audio waveform, the digital audio signal from the A / D converter 12 is supplied from a terminal 81 to an LPC analysis circuit 82 to extract the characteristics of the audio waveform. Characteristic recording circuit 5
And recorded.

When transmitting a speech, the output signal of the LPC analysis circuit 82 is supplied to the LPC comparison and selection circuit 102, and the signal of the characteristic of the audio waveform recorded in the recording circuit 5 is compared with the comparison and selection circuit. The LPC information is separated from the noise signal included in the signal from the terminal 81 by comparing the two signals.

Then, the separated noise signal is supplied to the subtraction circuit 101, and the digital audio signal from the terminal 81 is supplied to the subtraction circuit 101, and the noise signal mixed in the digital audio signal from the terminal 81. Is canceled by the noise signal from the comparison and selection circuit 102, and the audio signal with the noise signal suppressed is extracted from the subtraction circuit 101.

Further, the extracted audio signal is supplied to an inverse filter 83 and a comparison / selection circuit 102
, One of the LPC information from the analysis circuit 82 and the LPC information from the recording circuit 5 is selected and taken out,
The extracted LPC information is supplied to the inverse filter 83. Thus, the inverse filter 83 predicts the audio signal.

The predicted audio signal is sequentially supplied to a subtraction circuit 84, a weight filter 85, a drive pulse downsampler 86, and an APCM quantization circuit 87, and drive pulse vibration information is extracted. 88. Also, long-term prediction filter information is extracted by the long-term prediction filter 91 and the pitch analysis circuit 92 and supplied to the multiplexing circuit 88. Here, 93 is a local decoding circuit, and 94 is an addition circuit.

Further, drive pulse position information is extracted from the downsampler 86 and supplied to the multiplexing circuit 88, and LPC information from the comparison and selection circuit 102 is supplied to the multiplexing circuit 88.

Thus, the multiplexing circuit 88 outputs the RPE-
A digital audio signal encoded by the LTP method is extracted, and this signal is supplied to the error correction encoding circuit 14 as described above.

In this case, since the noise signal of the audio signal supplied to the inverse filter 83 is suppressed by the signal from the comparison and selection circuit 102, the audio signal output from the multiplexing circuit 88 is also a noise signal. Has been suppressed.

In the above description, when a specific one of the operation buttons 41 is operated, the characteristics of the voice waveform are registered. However, a learning function is provided so that a call can be made in an environment with little ambient noise. If so, the characteristics of the voice waveform can be automatically registered or updated during the call.

Further, when registering the portable telephone, the operator of the contractor registers the characteristic of the speech waveform of the user in the recording circuit 5 or registers the characteristic of the speech waveform in the IC card used for the portable telephone. You may make it.

[0039]

According to the present invention, the characteristics of the waveform of the voice signal to be transmitted are compared with the characteristics of the voice waveform registered in the recording circuit 5 in advance, and only the waveform that is identical or close is transmitted. Therefore, even if the voice signal from the transmitter 11 includes a noise signal, the voice signal to be transmitted can be a voice signal in which the noise signal is suppressed.

Further, since a noise signal can be sufficiently suppressed, a hands-free car phone or the like can be provided.

Moreover, the speech encoding circuit 13, ie,
Since the telephone using the voice codec does not require a new additional circuit, it is possible to suppress the noise of the transmitted voice signal without increasing the cost.

[Brief description of the drawings]

FIG. 1 is a system diagram of an example of the present invention.

FIG. 2 is a flowchart illustrating an example of an audio waveform characteristic registration routine.

FIG. 3 is a flowchart illustrating an example of a speech encoding circuit.

[Explanation of symbols]

 Reference Signs List 5 voice waveform characteristic recording circuit 10 transmission circuit 11 transmitter 12 A / D converter 13 voice coding circuit 14 error correction coding circuit 15 transmission circuit 20 reception circuit 21 reception circuit 22 error correction circuit 23 voice decoding circuit 24 D / A converter 25 receiver 30 system controller 41 operation button 42 display device

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G10L 13/00 G10L 15/00-17/00 G10L 19/00-19/14

Claims (1)

(57) [Claims] 1. An audio encoding circuit for extracting characteristics of an audio waveform from an input audio signal, an audio waveform recording circuit for recording characteristics of the audio waveform extracted by the audio encoding circuit, A comparison circuit for comparing the characteristics of the voice waveform extracted by the circuit with the characteristics of the voice waveform recorded in the voice waveform recording circuit; The characteristics of the audio waveform output from the circuit are compared with the characteristics of the audio waveform recorded in the audio waveform recording circuit, and as a result of the comparison, the characteristic of the audio waveform with a small noise signal is transmitted. A telephone device designed to be sent as a spoken signal.