JP3005459B2 - Audio data recording / reproducing method and apparatus for wireless communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to communication voice recording and reproduction of a radio communication device, and more particularly to a method and apparatus for recording and reproducing voice data in a digital communication type radio telephone using a voice code.

[0001]

2. Description of the Related Art In a conventional wireless telephone having a voice recording function, analog voice signal data is converted into digital data and stored during recording (recording), and the stored data is taken out when reproducing. It is converted to analog voice again.

FIG. 2 shows a configuration diagram in the case where a recording / reproducing function is added to a conventional analog wireless telephone.

[0003] The transmission voice is converted into a voice signal as an electric amplitude signal by a microphone 1 and then converted into a microphone amplifier 2.
And is sent to the transmission signal processing circuit 3. The transmission signal processing circuit 3 sends a control signal necessary for communication control to the control unit 5.
, The signal is superimposed on the audio signal at a frequency outside the band of the audio signal and sent to the transmitter 4. The control unit 5 is a control circuit having a built-in microprocessor, and controls a communication procedure and other parts of the mobile phone.

In order to communicate at a plurality of frequencies, a wireless telephone needs to change the frequency of wireless communication according to a required frequency. The frequency synthesizer 6 includes a control unit 5
A reference frequency corresponding to a required frequency is generated under the control of the transmitter and transmitted to the transmitter 4 and the receiver 9.

The transmitter 4 modulates the audio signal from the transmission signal processing circuit 3, converts the signal into a frequency corresponding to the reference frequency from the synthesizer 6, amplifies the power, and sends the amplified signal to the duplexer 7. The duplexer 7 is constituted by a filter circuit having a function of preventing transmission radio waves from going to the receiver and preventing reception radio waves from going to the transmitter. The transmission radio wave transmitted from the transmitter to the duplexer 7 is transmitted from the antenna 8.

[0006] The received radio wave is received by the antenna 8 and transmitted to the receiver 9 through the duplexer 7. The receiver 9 extracts only a necessary frequency based on the reference frequency from the synthesizer 6, amplifies it, demodulates it, and converts it into an audio signal. The converted audio signal is sent to the reception signal processing circuit 10.

[0007] The received signal processing circuit 10 extracts only a signal of a frequency in a voice band from the received voice signal.
Communication control data superimposed on the voice at a frequency outside the voice band is sent to the control unit 5. Received signal processing circuit 10
The audio signal extracted by the receiver is sent to the receiver amplifier 11 through the switch 35 and amplified,
Sent out.

When recording audio, the audio signal output from the reception signal processing circuit 10 is converted into a digital signal by the AD converter 13 and stored in the audio memory circuit 15. When reproducing the audio, the audio data stored in the audio memory circuit 15 is converted by the DA converter 14 into analog audio. The control of storing the voice in the voice memory circuit and extracting the voice data from the voice memory circuit is performed by the control unit 5.
It is performed by

The display operation unit 36 includes a display device and an input device. When a record button (not shown) of the display operation unit 36 is pressed, the control unit 5 detects the press and instructs the sound memory circuit 15 to fetch sound data.
In the case of reproduction, the control unit 5 switches the switch 35 to a, performs an operation of starting reproduction with respect to the audio signal memory circuit 15, and the audio data extracted from the audio signal memory circuit 15 , Is amplified by the receiver amplifier 11, and then transmitted from the receiver 12.

[0010]

When the recording / reproducing function is added to the above-mentioned analog type radio telephone, an A / D converter, a D / A converter, and a voice for exclusively recording audio data which are not originally required in the analog type. It is necessary to provide memory.

[0011] In a radio telephone communication system, a plurality of base stations are usually installed. In this system,
When the radiotelephone is used while moving, and the radio wave weakens away from the base station with which the communication is being performed and the communication state deteriorates, the communication is switched to a base station near the base station where the radio wave is strong. However, at present in Japan, in the case of a digital system, a VSELP system (vector sum excited linear prediction system) is adopted as a voice coding system depending on a base station. A different system, called a pitch synchronous innovation code excited linear prediction system, is planned to be introduced. In such a situation, when the base station changes during a call, the coding scheme is switched.

In such a case, in the conventional apparatus, if the coding system is switched during recording of a call, it is not possible to determine where and how the voice coded data stored in the voice memory is based on which coding system. However, there arises a problem that audio data cannot be decoded by an appropriate decoding method.

The present invention solves the above problems, and provides a method for recording and reproducing audio data continuously even when the audio memory is small and the audio coding system is switched during a call. The purpose is to:

SUMMARY OF THE INVENTION An audio data recording / reproducing apparatus for a wireless communication apparatus according to the present invention comprises: an audio encoder for encoding audio data according to a predetermined audio encoding method; A voice decoder for voice decoding data, a buffer unit for temporarily storing voice code data, a memory for storing voice code data and a signal representing the coding scheme, and a voice coding scheme sent from the base station And sends a control signal for controlling the speech coding method to the speech coder and the speech decoder based on the signal, and adds data representing the speech coding method to the speech coded data to add these data. Is stored in a memory, voice code data is taken out from the memory, written into a buffer unit, and a voice coding method of a voice decoder is controlled in accordance with data representing the voice coding method. And a control unit. The audio data recording method of the wireless communication device is a method of adding data representing the current audio encoding scheme sent from the base station to the audio code data held in the buffer and recording the data in a memory . Audio data recording and reproducing method of the radio communications apparatus, the recording time is recorded in the memory by adding data representing the current speech coding method which is sent from the base station to the voice code data stored in the buffer, reproduction At the time, the voice code data stored in the memory and the data representing the voice coding method added thereto are read out, and the coding method of the voice decoder is switched based on the data representing the voice coding method, and the voice code data is buffered. It is a method of writing to.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a case where the recording / reproducing apparatus of the present invention is used for a general digital wireless telephone, and an embodiment of the present invention will be described with reference to FIG.

When multiplex communication is performed by a time division method in a digital communication method, for example, in the case of the RCR standard which is a Japanese standard method or the IS-54 system in North America, the frequency is 6 times as shown in FIG. It is divided into slots and is repeated. When one slot is used as one line, six lines can be used at one frequency. In Japan and North America, one line is used for two slots or one line is used for one slot. In the case of using two slots for one line, for example, when 1 in FIG. 3 is used, another slot of the line uses a slot every two slots such as four.

In Japan and North America, one frame is 40 ms.
1 slot is about 6.6 mse because of the length of c
c. That is, when one line is constituted by one slot, the voice is compressed by the voice encoder in units of 40 msec. The data is transmitted and received in units of one slot.

At the time of transmission, audio input from the microphone 16 is converted into a digital signal by the AD converter 17.
The audio data converted into the digital signal is output from the audio encoder 18.
Are collectively voice-encoded in units of 40 msec.
A digital signal processor is used for the audio encoder 18, and the audio decoder 30 can be formed on the same processor. This processor stores software for encoding and decoding according to a specific encoding method.

The voice code data is transmitted to the transmission data processing unit 19.
Is sent to the upstream buffer 20. Upstream buffer 20 is 4
The content is updated by the voice code data sent from the voice encoder 18 every 0 msec. Transmission data processing unit 19
Rearranges the voice code and the data for communication control transmitted from the control unit 21 into a data array for transmission.

The transmission data processed by the transmission data processing section 19 is sent to a transmitter 22. Frequency synthesizer 23
Generates a reference frequency corresponding to a required frequency under the control of the control unit 21 and sends it to the transmitter 22 and the receiver 26. The transmitter 22 modulates the transmission data from the transmission data processing unit 19, converts the data into a frequency corresponding to the reference frequency from the synthesizer 6, amplifies the power, and sends it to the duplexer 24. The duplexer 24 is configured by a filter circuit having a function of preventing transmission radio waves from going to the receiver 26 and preventing reception radio waves from going to the transmitter 22. The transmission radio wave transmitted from the transmitter 22 to the duplexer 24 is transmitted to the antenna 2
5 is transmitted.

When recording a sound to be transmitted, when a transmission recording start button (not shown) of the display operation unit 34 is pressed, the control unit 21 detects this and records the sound stored in the upstream buffer 20. The code data is stored in the memory circuit 33.

The received radio wave is received by an antenna 25 and transmitted to a receiver 26 through a duplexer 24. The receiver 26 extracts only the necessary frequency based on the reference frequency from the synthesizer 23, amplifies it, demodulates it, and converts it into received data.

The received data is sent to the received data processing section 27, and the received data processing section 27 extracts voice data from the received data. Communication control data other than the audio data is passed to the control unit 21.

The data for communication control transmitted from the base station includes data related to an encoding method and the like, and is transmitted together with voice data or independently at the start of data reception from the base station.

The audio data extracted by the reception data processing section 27 is sent to the down buffer 28 and to the audio decoder 30 through the switch 29. The content of the downlink buffer 28 is updated by the voice code data transmitted from the reception data processing unit 27 every 40 msec.

The audio data sent to the audio decoder 30 is decoded into a digital audio signal by a predetermined method and sent to the DA converter 31. The digital audio signal sent to the DA converter 31 is converted into an analog audio signal and transmitted from the speaker 32.

When recording the received voice, the display operation unit 34
Is pressed, the control unit 21 detects this and stores the voice code data stored in the down buffer 28 in the memory circuit 33.

In the case of reproducing sound, when the reproduction button (not shown) of the display operation unit 34 is pressed, the control unit 21 detects that the reproduction button is pressed, and the control unit 21 records the sound stored in the memory circuit 33. The data is taken out and written to the downstream buffer 28. The control unit 21 switches the switch 29 to a, and the recorded data written in the down buffer 28 is converted into digital audio data by the audio decoder, and then sent to the DA converter 31 to be converted into analog audio. It is transmitted from the receiver 32.

In the above configuration, an AD and DA converter for recording in the audio memory and reproducing from the audio memory becomes unnecessary. Also, since the audio data is encoded by the audio encoder, it is compressed to about 1/9 to 1/18 of the normal digital audio data, so that a memory having a small storage capacity is sufficient. For this reason, a part of the memory conventionally used by the control unit in normal processing can be used for recording audio data, and there is little need to newly provide a dedicated memory.

Next, another embodiment of the present invention will be described.

First, reception will be described. The process until the reception data processing unit 27 extracts the audio data from the reception data is as described above. Here, the communication control data other than the voice data is information such as a communication procedure and a voice coding method, and is transmitted to the control unit 21. The data related to the coding method and the like are sent together with the voice data at the start of data reception or independently from the base station. The control unit 21 controls the voice encoder 18 and the voice decoder 30 to operate in the voice coding scheme transmitted at this time. The control unit 21 stores a signal indicating the audio encoding system sent from the base station, and stores the signal in the ROM in the digital signal processor constituting the audio decoder 30 according to the audio encoding system. The corresponding software is selected by the control signal (C1). The decoding process is performed by the software of the selected audio encoding method.

When the base station changes to another speech coding system, the control unit 21 stores a signal representing the new speech coding system, and controls the speech encoder 18 and the speech decoder 30 according to the new system.

When recording the received voice, the display operation unit 34
When the receiver recording start button (not shown) is pressed, the control unit 21 detects this, and the voice code data stored in the down buffer 28 includes bit data (voice coding method) representing the voice coding method. If there are two types, 1 or 0 may be added to a predetermined position (for example, the head) of the slot and stored in the memory circuit 33. However, as the bit data, data of 2 bits or more is used when there are more than two types of audio coding systems.

The transmission is as described above. The control unit 21 stores a signal representing the audio encoding system sent from the base station, and stores the signal in the ROM in the digital signal processor constituting the audio encoder 18. Control signal for corresponding software (C1)
Switch by. The encoding process is performed by software of the selected audio encoding method. When recording the transmission voice, the voice code data stored in the upstream buffer 20 is added with bit data indicating the current coding scheme, and is stored in the memory circuit 33.

In the case of reproducing sound, when the reproduction button (not shown) of the display operation unit 34 is pressed, the control unit 21 detects the depression and switches the switch 29 to a. Next, the control unit 21 takes out the recording data stored in the memory circuit 33, reads out the bit data indicating the audio encoding method, switches the encoding method of the audio decoder 30 accordingly, Write 28.
The recording data written in the downstream buffer 28 is converted into digital audio data by the audio decoder 30, sent to the DA converter 31, converted into analog audio, and transmitted from the receiver 32.

In the above description, the recording start button is separately described as the reception recording start button and the transmission recording start button, but it may be a single recording start button having both functions. Also, the memory circuit is formed in an LSI together with the control unit, or the DRA is separate from the LSI including the control unit.
M, SRAM, etc. in some cases.

According to the above method, even when the coding method is switched when the base station changes during a call, the audio data can be continuously recorded and reproduced.

As described above, the present invention relates to a digital radio telephone, a buffer unit for temporarily recording audio data, an audio memory unit for recording audio data recorded in the buffer unit, Since a control unit for controlling these components is provided, an AD and DA converter for recording and reproduction is not required, and a memory can be reduced. When recording the audio data, the data representing the encoding method is recorded together with the audio data in the memory, and during reproduction, the audio is reproduced according to the recorded encoding method. However, there is a great effect that audio data stored in the audio memory can be appropriately recorded and reproduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a wireless telephone showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional analog wireless telephone.

FIG. 3 is a diagram showing the structure of time-division data.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 16 Microphone 2 Microphone amplifier 3 Transmission signal processing circuit 4, 22 Transmitter 5, 21 Control part 6, 23 Frequency synthesizer 7, 24 Demultiplexer 8, 25 Antenna 9, 26 Receiver 10 Reception signal processing circuit 11 Receiver amplifier 12, 32 Receiver 13, 17 AD converter 14, 31 DA converter 15 Audio memory circuit 18 Audio encoder 19 Transmit data processing unit 20 Up buffer 27 Receive data processing unit 28 Down buffer 29, 35 Switch 30 Audio composite unit 33 Memory circuit 34 , 36 Display operation unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04M 11/00 H04B 7/26

Claims (6)

(57) [Claims] 1. An audio data recording / reproducing apparatus for a wireless communication device, comprising: an audio encoder for encoding audio data according to a predetermined audio encoding method; and audio decoding of audio data according to a predetermined audio encoding method. A buffer for temporarily storing voice code data, a memory for storing voice code data and data indicating the voice coding method, and a signal indicating the voice coding method sent from the base station And sends a control signal for controlling the audio encoding method to the audio encoder and the audio decoder based on the signal, adds data representing the audio encoding method to the audio code data, and stores these data in the memory. It stores the voice code data from the memory, writes it in the buffer unit, and controls the voice coding system of the voice decoder according to the data representing the voice coding system. A control unit having the function, the audio data recording and reproducing apparatus of a radio communication device, characterized in that it comprises a. 2. The audio data recording / reproducing apparatus for a wireless communication device according to claim 1, wherein the control unit adds data representing the audio encoding method to a head of the audio encoded data. 3. The audio data recording / reproducing apparatus for a wireless communication device according to claim 1, wherein the buffer unit includes a downlink buffer unit for received audio data and an uplink buffer unit for transmitted audio data. 4. The voice of the wireless communication device according to claim 3, wherein voice code data from the received data processing unit is sent to the downstream buffer unit, and voice code data from the voice encoder is sent to the upstream buffer unit. Data recording and playback device. 5. The voice data recording of a wireless communication device, wherein data representing a current voice coding system sent from a base station is added to voice code data held in a buffer and recorded in a memory. Method. 6. At the time of recording, the data representing the current audio encoding system sent from the base station is added to the audio code data held in the buffer, and the data is recorded in the memory. At the time of reproduction, the data is held in the memory. Wirelessly reading voice code data and data representing a voice coding method added thereto, switching a coding method of a voice decoder based on the data representing the voice coding method, and writing voice code data into a buffer; A method for recording and playing back audio data in communication equipment