JP2005073057A - Digital speech apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital speech apparatus capable of maintaining speech quality by eliminating a voice delay. <P>SOLUTION: The digital speech apparatus is provided with: a network input circuit 17 connected to a VoIP phone (digital speech apparatus) 10 and a digital communication network 26; a packet data reception section 18 for receiving packet data; a fluctuation absorption buffer section 19 for carrying out fluctuation absorption processing of the data; a voice decoding section 20 for decoding the data; a D/A converter 21 for converting a decoded digital signal into an analog signal; a voice output circuit 22 for converting the analog signal into voice; a speaker 23 for outputting the voice; and a data buffer section 24 for storing the decoded data, and is configured that the digital speech apparatus uses the packet data reception section 18 to carry out reception processing, thereafter applies decode processing to the data in parallel with fluctuation absorption processing, stores the decoded data in the data buffer section 24, carries out the fluctuation absorption processing, and thereafter reads the data from the data buffer section 24 and applies D/A conversion to the read data. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a digital call device such as a VoIP phone using a digital communication network.

  In recent years, with the spread of the Internet, VoIP (Voice over IP), so-called “Internet phone” has been spread. This uses a technique for transmitting voice information over an IP network used on the Internet. In the case of a telephone company telephone, an expensive telephone exchange is required. However, in the case of an IP network, the cost of used equipment can be reduced by using only an inexpensive router, and the telephone service can be realized at a lower cost.

  However, although packet communication performed on the Internet is suitable for discrete data communication, communication such as telephone and broadcast that reproduces continuous data such as voice and image data immediately on the receiving side. For example, in the case of a telephone, there is a problem that voice is delayed.

Therefore, in Patent Document 1, a transmitting station that packetizes voice information transmitted from a calling telephone and sequentially transmits it to a called telephone via the Internet, and receives a packet transmitted from the transmitting station, A transmission delay time representing a delay in transmission of the voice information contained in the packet from the destination station to the called side telephone in a call system including a destination station that sequentially transmits the voice information contained in the packet to the called side telephone. A method has been proposed in which a part of audio information is deleted based on the transmission delay time.
Japanese Patent Laid-Open No. 10-164129

  Currently, voice input / output to packet transmission / reception processing is usually performed in a VoIP telephone. FIG. 3 is a flowchart showing the operation on the transmission side in the conventional VoIP telephone. While the VoIP telephone is in use, the voice is captured by the microphone in step S20, and the process proceeds to step S21, where the voice input circuit converts the voice captured by the microphone into an electrical signal.

  Then, it progresses to step S22, the analog signal from an audio | voice input circuit is converted into a digital signal in an A / D conversion part, and it progresses to step S23 and encodes a digital signal in an audio | voice encoding part.

  Next, the process proceeds to step S24, where the packet data transmission unit performs a process of transmitting the encoded data in a packet, and the process proceeds to step S25 to output the packet data from the network output circuit to the digital communication network.

  Processing of packet data transmitted from the call destination will be described with reference to FIG. When the network input circuit receives packet data from the digital communication network in step S30, the process proceeds to step S31, where the packet data receiving unit performs packet data reception processing.

  Subsequently, the process proceeds to step S32, where the fluctuation absorbing buffer unit performs fluctuation absorbing processing for the received data. Thereafter, the process proceeds to step S33, where the speech decoding unit decodes the digital signal, and the process proceeds to step S34, where the D / A conversion unit converts the decoded digital signal into an analog signal.

  Next, the process proceeds to step S35, where the audio output circuit converts the analog signal into sound, and the process proceeds to step S36 to output sound from the speaker.

  In the above reception operation, each processing time of steps S31 to S34 takes time, so that a voice delay occurs during a call. In particular, it may take time depending on the decoding method in step S33.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a digital call device that can maintain call quality by eliminating voice delay.

  In order to achieve the above object, the present invention provides a transmission means for capturing voice and A / D converting and outputting packet data to a digital communication network, and receiving voice data from the digital communication network and performing D / A conversion. In the digital communication device comprising the receiving means for outputting the received data, the receiving means is provided with a data buffer unit for storing the decoded data, and after the packet data receiving process, the decoding is performed in parallel with the fluctuation absorbing process. And storing the decoded data in the data buffer unit, and after the fluctuation absorbing process, reading out the data from the data buffer unit and performing D / A conversion.

  The present invention also provides a network input circuit connected to a digital communication network, a packet data receiving unit that receives packet data, a fluctuation absorbing buffer unit that performs fluctuation absorbing processing of the data, and a voice decoding that decodes the data Decoding in a digital communication device comprising: a D / A converter that converts the decoded digital signal into an analog signal; a voice output circuit that converts the analog signal into voice; and a speaker that outputs voice A data buffer unit for storing the converted data is provided, and after the reception process by the packet data reception unit, the decoding process is performed in parallel with the fluctuation absorbing process, and the decoded data is stored in the data buffer unit After the fluctuation absorbing process, the data is read from the data buffer unit and D / A converted.

  According to the present invention, the decoding that has been performed after the fluctuation absorbing process is performed in parallel with the fluctuation absorbing process, and the decoded data is stored, so that the decoding waiting state can be avoided, and the voice Call quality can be maintained without delay.

  Hereinafter, a VoIP telephone will be described as an example of a digital call device. FIG. 1 is a block diagram showing the configuration of the VoIP telephone 10, and FIG. 2 is a flowchart showing the operation of the receiving means.

  The VoIP telephone is connected to another telephone via a digital communication network such as the Internet or a public digital line. Other telephones may be fixed telephones and mobile telephones in addition to VoIP telephones.

  As shown in FIG. 1, the VoIP telephone 10 includes a transmission means for capturing voice, A / D converting and outputting the data to the digital communication network 26 as packets, and receiving voice data from the digital communication network 26 for D Receiving means for outputting after A / A conversion, and these are controlled by the control unit 25.

  The transmission means includes a microphone 11 that captures sound, a sound input circuit 12 that converts sound from the microphone 11 into an electrical signal, and an A / D converter 13 that converts an analog signal from the sound input circuit 12 into a digital signal. And a voice encoding unit 14 that encodes a digital signal, a packet data transmission unit 15 that transmits the encoded data in a packet, and a network output circuit 16 that is connected to the digital communication network 26. The transmission operation is the same as that in FIG. 3 described in the conventional example.

  On the other hand, the receiving means includes a network input circuit 17 connected to the digital communication network 26, a packet data receiving unit 18 that receives packet data, a fluctuation absorbing buffer unit 19 that performs fluctuation absorbing processing of the data, and a digital signal. Audio decoding unit 20 for decoding, data buffer unit 24 for storing the decoded data, D / A conversion unit 21 for converting the decoded digital signal into an analog signal, and converting the analog signal into audio It comprises an audio output circuit 22 for conversion and a speaker 23 for outputting audio.

  Next, processing of packet data transmitted from the call destination will be described with reference to FIG. When the network input circuit 17 receives packet data from the digital communication network 26 in step S10, the process proceeds to step S11, and the packet data receiving unit 18 performs packet data reception processing.

  Subsequently, the process proceeds to step S12, where the fluctuation absorbing buffer unit 19 performs fluctuation absorbing processing on the received data, and at the same time, the audio decoding unit 20 decodes the digital signal and stores it in the data buffer unit 24. Thereafter, the process proceeds to step S13, data is read from the data buffer unit 24, and the process proceeds to step S14, where the D / A conversion unit 21 converts the decoded digital signal into an analog signal.

  In step S15, the audio output circuit 22 converts the analog signal into sound. In step S16, the sound is output from the speaker 23.

  As described above, the decoding that has been performed after the fluctuation absorbing process is performed in parallel with the fluctuation absorbing process, and the decoded data is stored, thereby avoiding the state of waiting for decoding. That is, since the decoded data is stored in the data buffer unit 24 during the fluctuation absorbing process, the data in the data buffer part 24 can be read out quickly after the fluctuation absorbing process, so that the audio delay is eliminated. Call quality can be maintained.

  The present invention can be used for digital telephones using VoIP technology, including various telephones such as fixed telephones and mobile telephones.

It is a block diagram which shows the structure of the VoIP telephone set of this invention. It is a flowchart which shows operation | movement of the means for reception of this invention. It is a flowchart which shows the operation | movement of the transmission side in the conventional VoIP telephone. It is a flowchart which shows operation | movement of the conventional means for reception.

Explanation of symbols

10 VoIP telephone (digital communication equipment)
DESCRIPTION OF SYMBOLS 11 Microphone 12 Voice input circuit 14 Voice encoding part 15 Packet data transmission part 16 Network output circuit 17 Network input circuit 18 Packet data reception part 19 Fluctuation absorption buffer part 20 Voice decoding part 21 D / A conversion part 22 Voice output part 23 Speaker 24 Measuring unit 25 Control unit 26 Digital communication network

Claims (2)

Digital having a transmission means for capturing voice, A / D converting and outputting packet data to a digital communication network, and a reception means for receiving voice data from the digital communication network, D / A converting and outputting In the communication device,
The receiving means is provided with a data buffer unit for storing the decoded data, and after the packet data receiving process, the decoding process is performed in parallel with the fluctuation absorbing process and the decoded data is supplied to the data buffer unit. A digital communication device that stores data, and after the fluctuation absorbing process, reads data from the data buffer unit and performs D / A conversion. A network input circuit connected to the digital communication network, a packet data receiving unit for receiving packet data, a fluctuation absorbing buffer unit for performing fluctuation absorbing processing of the data, a voice decoding unit for decoding the data, and a decoding In a digital communication device comprising a D / A converter that converts the digital signal into an analog signal, an audio output circuit that converts the analog signal into audio, and a speaker that outputs audio,
A data buffer unit for storing the decoded data is provided, and after the reception process by the packet data reception unit, the decoding process is performed in parallel with the fluctuation absorbing process and the decoded data is stored in the data buffer unit. And after the fluctuation absorbing process, data is read from the data buffer unit and D / A converted.

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