JPH06252795A - Data recorder and recording and reproducing device - Google Patents

Abstract

PURPOSE:To record voice data efficiently on a semiconductor memory by eliminating easily a silence section. CONSTITUTION:Voice data and data rate information are used for recording. The data rate information is fed to a silence discrimination block 30, in which the presence/absence of voice is discriminated. in the case of absence of voice, a counter 31 is incremented and in the case of presence of voice, the counter 31 is reset. Non-voice recording data are generated at a generating block 33 based on a count of the counter 31. The data consist of a header representing non-sound and a non-sound consecutive length in succession to the header and a generating block 34 generate voice recording data. Outputs of the blocks 33, 34 are inputted to a data selection block 35 and selected by a control signal outputted from the block 30. A recording control block 36 uses a pointer 40 as an address to write data from the block 35 to a semiconductor memory 37.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to, for example, CDMA in the United States.
The present invention relates to a data recording device and a recording / reproducing device used in a recording device for digital mobile communication.

[0002]

2. Description of the Related Art In a conventional analog type telephone, call voice is recorded using a tape recorder. On the other hand, conversion to digital information is performed using an encoding device such as ADPCM or ADM and recorded in a semiconductor memory. A device using such a semiconductor memory does not have a drive part like a tape recorder, and thus is downsized, which is advantageous in terms of stability, portability, and the like.

By the way, in an apparatus using such a semiconductor memory, in order to lengthen the recording time, it is necessary to record only during a period when there is sound. In that case, the presence or absence of a voice signal must be determined. For that purpose, a method of determining whether the energy of the signal is above a certain level is usually used.

[0004]

On the other hand, digital telephones for encoding and transmitting voice signals have been implemented. In that case, in order to efficiently record the audio signal in the semiconductor memory, it is optimal to record the encoded audio data as it is. However, when the voice signal has already been encoded at the reception, in order to use the energy of the signal as in the conventional technique for determining the presence / absence of voice, it is necessary to perform decoding once using a vocoder.

By the way, in the CDMA digital mobile communication in the United States, the data rate is determined according to the energy of the voice signal, the voice coding is performed based on the data rate, and the voice data is transmitted. That is, this US C
The voice coding method used in the DMA digital mobile communication is a data transmission method using voice activity (data is not sent when there is voice, or data is sent at a high transmission rate when there is voice). If there is not, a method of sending at a low data rate) is implemented.

The present invention has been made in view of such circumstances, and for example, in a CDMA digital mobile communication, a silent section is easily removed and recorded, and voice data is efficiently recorded in a semiconductor memory. The purpose is to provide a recorder (data recording device and recording / reproducing device).

[0007]

According to a first aspect of the present invention, in a data recording device for a communication device in which a data rate of data is variable according to a voice signal, the data rate of received data or transmitted data is set. Based on the determination means (block 30) for determining whether there is sound or not, a counter 31 that measures the duration of a silence state when the determination means determines that there is no sound, a code indicating the silence and the duration. A data recording device having a recording means (semiconductor memory 37) for recording.

According to a second aspect of the present invention, in a data recording device for a communication device in which a data rate of data is variable according to a voice signal, voice / silence is generated based on a data rate of received data or transmitted data. And a means for removing the error correction code or the like from the transmitted or received data and extracting only encoded voice data (voice recording data). A data recording device having a generation block 34) and a recording means (semiconductor memory 37) for recording the audio data.

A third means according to the present invention is to record voice data and its data rate, data indicating the type of information such as invalid data when error correction is impossible, silence data, etc. as a header prior to voice data. A data recording device according to the first or second means.

According to a fourth aspect of the present invention, in a data recording / reproducing apparatus for a communication device in which a data rate of data is variable according to an audio signal, the data rate is added to the audio data as header information at the time of recording. The data recording / reproducing apparatus is characterized in that at the time of recording and reproducing, the header information is taken out and the number of data to be subsequently taken out is determined from the information.

According to a fifth aspect of the present invention, in a data recording / reproducing device for a communication device in which a data rate of data is variable according to an audio signal, at the time of recording, header information indicating sound or no sound is recorded. A data recording / reproducing apparatus is characterized in that, during reproduction, a silence or a sound is determined from the header information, the silence generating circuit is operated for the silence information, and the vocoder is operated for the speech information.

[0012]

According to this, when the data rate is low, the amount of data to be recorded is determined by determining that it is a silent section and recording only its duration, and by removing the error correction code from the transmitted and received data in the voiced section. It is possible to realize highly efficient recording by reducing.

[0013]

1 is a block diagram of a CDMA digital cellular telephone terminal according to the present invention.

First, the reception system will be described. The signal received by the antenna 10 is supplied to the receiver 12 via the antenna duplexer 11 and converted into a baseband signal. The output of the receiver 12 is input to the demodulator 14 and demodulated data is output as the output. This demodulated data is supplied to the vocoder 17 via the CPU 16. The vocoder 17 reproduces a voice sample from the encoded data, which is D /
A-converted and output from the vocoder. The output of the vocoder 17 is output from the speaker 19 via the amplifier 18.

In the transmission system, the audio signal input from the microphone 20 is supplied to the vocoder 17 via the amplifier 21. The audio signal input to the vocoder 17 is A / D converted, encoded, and output from the vocoder 17. Vocoder 17
Is sent to the modulator 15 via the CPU 16. The modulator 15 modulates the data and converts it into a baseband signal. The converted signal is sent from the modulator 15 to the transmitter 13. The signal input to the transmitter 13 is converted into a high frequency signal, amplified to a predetermined signal level, sent to the antenna sharing device 11, and the signal is radiated from the antenna 10 via this.

In order to record the call voice in the semiconductor memory 22, the CPU 16 intercepts the encoded voice data and writes it in the semiconductor memory 22 for both the transmission voice and the reception voice. To listen to the recorded data as an audio signal, the CPU 1
6 retrieves data from the semiconductor memory 22 and transfers it to the vocoder 17, and the vocoder 17 reproduces this into an audio signal, which is output via the amplifier 18 and the speaker 19.

FIG. 2 is an example of a block diagram for realizing means for recording voice data in a memory using the present invention.

Audio data and data rate information are used for recording. The data rate information is supplied to the silence determination block 30 and the presence / absence determination is performed. When there is no sound, the counter 31 is incremented, and when there is sound, the counter 31 is reset. Counter 3
From the value of 1, the silence data generation block 33 generates silence recording data to be recorded in the memory. This data consists of a header representing silence, followed by a silence duration.

On the other hand, the audio recording data generation block 34 is supplied with the data rate and the encoded audio data. When the data rate is different, the number of encoded voice data and the data structure are different. An error correction code is added to this data in order to detect / correct a data error in the communication path. The reliability of the semiconductor memory is very high, and error correction is almost unnecessary when recording a voice signal.

The voice recording data generation block 34 performs error correction of the data by using the error correction code in the data,
The error correction code unnecessary for recording in the semiconductor memory is removed to generate voice recording data. This data is composed of a header representing the data rate and encoded voice data from which extra information such as the error correction code is removed. It If the error cannot be corrected, the data indicating that the data is invalid is generated. This data may be composed only of a header representing invalid data, or may be added with data for explaining the invalid situation.

The outputs of the silence data generation block 33 and the voice recording data generation block 34 are the data selection block 35.
Is selected by the control signal input to the silence determination block 30. That is, the silent record data is selected in the silent section and the voice record data is selected in the sound section.

In this block diagram, in the case of silence, the silence data is made to be recorded every frame which is a processing unit of voice. Therefore, when the silence state continues, the pointer is controlled so as to overwrite the silence data. A pointer control block 32 is provided for this purpose. This block is not necessary if the silence data is written only once when the silence changes to the voice.

The recording control block 36 writes the data received from the data selection block 35 in the memory 37 using the value of the pointer 40 as an address. The number of data to be written can be known from the header, and the data counter 41
Is set. Pointer 40 increments the value,
The data counter 41 is decremented, and when the value of the data counter 41 becomes 0, writing is stopped.

Further, the recording control block 36 is provided with a memory 42 for storing the previous value of the pointer 40. When the silent state continues, the value of the memory 42 is loaded into the pointer 40 by the signal from the pointer control block 32, and the silent data is overwritten.

The above processing may be realized by the CPU. FIG. 4 shows a flow when processing is performed by the CPU. The CPU receives the encoded voice data from the demodulator 14 (for received voice) or the vocoder 17 (for transmitted voice) together with the data rate.

Then, in step [101], it is determined whether or not there is no sound based on the data rate. When there is no sound, the sound duration counter is incremented in step [102]. Next, in step [103], data for recording silent time is generated. Further, in step [104], it is determined whether or not the previous frame (voice is processed in processing units called frames) is silent. If the previous frame is silent, the pointer is returned to the beginning of the previous frame in step [105]. Then, in step [106], writing to the memory is performed.

If it is determined in step [101] that there is no sound, in step [107] data for audio signal recording is generated. Here, error correction is performed and unnecessary information (error correction code) is removed. If the error cannot be corrected by error correction, invalid data that means invalid is generated. Then, in step [106], writing to the memory is performed and the processing for one frame is completed.

FIG. 3 is a block diagram of a circuit for reproducing voice from data recorded in the memory. The recording data is taken out from the memory 60 by the reading circuit 61. Although the data in the memory has various data lengths, the number of data to be retrieved can be known by checking the header. The retrieved data is sent to the header processing block 62. Here, voice data or silence data is determined from the header.
To the silence generation circuit 64 in the case of silence data.
Send to.

In the CDMA digital mobile communication, the vocoder is provided with the processing when the voice data is erroneous and cannot be used. Therefore, the invalid data is sent to the vocoder 63. Depending on the use of the vocoder, it is conceivable that an error correction code must be attached. In that case, the header processing unit generates the error correction code and converts it into a format that the vocoder can accept.

The outputs of the vocoder 63 and the silence generation circuit 64 are supplied to the selection circuit 65. Which signal to select is determined by the silence / voice output of the header processing block. The output signal selected by the selection circuit 65 is the amplifier 6
It is output from the speaker 67 via 6. The silence generating circuit 64 can be included in the vocoder 63.

FIG. 5 shows a flow in the case where the CPU performs the process of reproducing the voice from the data recorded in the memory.

In the initialization (step [201]), the data pointer of the memory is initialized. Next, in step [202], the header is read. Then, in step [203], it is determined from the header information whether or not there is silence, and if there is no sound, the silence time data is read in step [206], and then the silence state for the time designated in step [207] is output. . Then, the process proceeds to step [208].

If it is determined that there is sound in step [203], the encoded voice data is read in step [204] and the voice signal is reproduced using the vocoder in step [205]. . Step [205]
When the above process is completed, the process proceeds to step [208]. In step [208], it is determined whether or not there is print data in the memory, and if there is any print data, the process returns to step [202] and the same processing is repeated. If there is not, the reproduction process of the recorded data ends.

FIG. 6 shows a format of data written in the memory. The data is composed of a header and a data section, and the header indicates which data rate of the data is voice data, silent data, or invalid data.
In the data section, in the case of voice data, voice coded data of the number of data corresponding to each data rate is stored, and in the case of silence data, silence time is stored. In the case of invalid data, there is no data section or data indicating the invalid situation is added.

FIG. 7 shows an example of data recorded in the memory. Since only the minimum necessary data is recorded in the memory by this method, it is possible to record voice for a long time if the memory size is constant. When reproducing sound, the size of the data part can be known from the header, and there is no inconvenience in taking out.

[0036]

As is apparent from the above description, according to the audio recording apparatus of the present invention, the silent state is determined based on the data rate, and the silent state records only the duration time, and the voiced state. Then, it is possible to improve the memory usage efficiency by removing unnecessary information such as error correction code to be recorded in the semiconductor memory and recording only the minimum necessary information according to the data rate. Can record the voice of time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a data flow in a CDMA digital mobile communication telephone terminal.

FIG. 2 is a block diagram showing a means for recording encoded audio data in a semiconductor memory.

FIG. 3 is a block diagram showing means for reproducing an audio signal from information recorded in a semiconductor memory.

FIG. 4 is a flow chart diagram when a process of recording audio data in a semiconductor memory is performed by software.

FIG. 5 is a flow chart diagram when a process of reproducing an audio signal from information recorded in a semiconductor memory is performed by software.

FIG. 6 is a diagram illustrating a format of data recorded in a semiconductor memory.

FIG. 7 is a diagram showing an example of data recorded in a semiconductor memory.

[Explanation of symbols]

 10 Antenna 11 Antenna Sharing Device 12 Receiver 13 Transmitter 14 Demodulator 15 Modulator 16 CPU 17 Vocoder (Voice Signal Coding / Decoding Device) 18 Voice Signal Amplifier 19 Speaker 20 Microphone 21 Microphone Input Signal Amplifier 22 Semiconductor Memory 30 Silence determination block 31 Silence duration measuring counter 32 Semiconductor memory recording data pointer control block 33 Silence data generation block 34 Voice recording data generation block 35 Data selection block 36 Recording control block 37 Semiconductor memory 60 Semiconductor memory 61 Data reading circuit 62 Header Processing block 63 Vocoder 64 Silence generation circuit 65 Output signal selection block 66 Audio signal amplifier 67 Speaker

Claims (5)

[Claims] 1. A data recording device for a communication device, wherein a data rate of data is variable according to an audio signal, and a determining means for determining whether sound is present or not based on a data rate of received data or transmitted data. A data recording device comprising: a counter for measuring the duration of a silent state when the determination means determines that there is no sound; and a recording means for recording the code indicating the silence and the duration. 2. A data recording device for a communication device, wherein a data rate of data is variable according to an audio signal, and a determining means for determining whether sound is present or not based on the data rate of received data or transmitted data. When the determination means determines that there is sound, it has a means for removing error correction codes from the transmitted or received data and extracting only encoded voice data, and a recording means for recording the voice data. Characteristic data recording device. 3. The audio data and data rate thereof, data indicating the type of information such as invalid data when error correction is impossible, silence data, etc. are recorded as a header prior to the audio data, or 2. The data recording device according to 2. 4. A data recording / reproducing device for a communication device, wherein a data rate of data is variable according to an audio signal, wherein the data rate is added to audio data as header information at the time of recording, and at the time of reproducing, A data recording / reproducing apparatus characterized in that the header information is taken out and the number of data to be taken out subsequently is determined from the information. 5. A data recording / reproducing device for a communication device, wherein a data rate of data is variable according to an audio signal, wherein header information indicating voiced or silent is recorded during recording, and the header information is recorded during reproduction. Determines whether or not there is silence,
A data recording / reproducing apparatus which operates a silence generating circuit for silent information and a vocoder for speech information.