JP2006038890A - Transmitter, speech transmitting method and program, receiver, speech receiving method and program, wireless microphone system, and speech transmitting and receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively reduce deterioration in speech quality during communication by performing error correction processing selectively for an important part of speech data to be transmitted by technology of a wireless microphone with an error correcting function. <P>SOLUTION: A speech data division part 143 of a processing part 14 sections digital speech data into an important part and other parts according to predetermined specified regularity and an error correcting 1st encoder 15 adds a redundant bit for error correction to the important part at a higher rate than to other parts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement in the technology of a wireless microphone having an error correction function.

In recent years, with the advancement of digital technology, the audio transmission of wireless microphone systems used in various venues has also been digitized. In digital data transmission such as voice, error detection and correction techniques are used. In this technique, a redundant bit called a checksum or the like is added to transmission data on the transmission side, and error detection or correction of reception data is performed on the reception side (see, for example, Patent Document 1). Typical examples include vertical parity check method, horizontal parity check method, Hamming code method, CRC method, Reed-Solomon code method, convolutional code method, Viterbi decoding method, turbo code method, etc. It is suitable for applications that not only detect but also correct.
JP 2000-353968 A

  By the way, the ratio of errors that can be corrected in the transmission data is related to the ratio of redundant data to the transmission data body. For example, a unit amount of data transmission in a wireless microphone system is called a symbol, but how many symbols can be error-corrected within a certain amount of data is proportional to the amount of redundant data added to that amount of data. .

  However, since the number of symbols that can be transmitted per unit time is limited due to the limit of the data transmission rate (bandwidth), the amount of redundant data that can be added is also limited. In the conventional wireless microphone system, as shown in FIG. 6A, a predetermined ratio of redundant data, that is, a checksum is allocated evenly to any part of transmission data. In other words, there is a problem that a sufficiently effective error correction process cannot be performed.

  In particular, wireless microphones have characteristics that the radio wave condition of the carrier wave is likely to change due to the frequency band used and the usage that the user walks around on the platform etc., and there are many errors in important data parts such as code bits. If it cannot be corrected, there will be acoustic inconveniences such as extreme noise and sound quality degradation including sound interruption.

  An object of the present invention is to solve the above-described problems of the prior art, and an object of the present invention is to perform error correction processing on an important part of audio data to be transmitted in a wireless microphone technology having an error correction function. Therefore, it is effective to reduce the deterioration of sound quality during communication.

  In order to achieve the above object, the invention of claim 1 includes a microphone for voice input, A / D conversion means for converting an analog voice signal inputted from the microphone into digital voice data by a computer or an electronic circuit, Based on the digital audio data, a computer or an electronic circuit creates transmission data by processing including addition of redundant bits for error correction, and transmission means for wirelessly transmitting the transmission data by a carrier wave And a means for dividing the digital audio data into an important part and another part by a predetermined predetermined regularity by the error correction coding means, and the other for the important part. And means for adding redundant bits for error correction at a rate higher than that of the portion.

  According to a fourth aspect of the invention, the invention of the first aspect is grasped from the viewpoint of a method, and a computer or an electronic circuit converts a microphone for voice input and an analog voice signal inputted from the microphone into digital voice data. A / D conversion means, based on the digital audio data, a computer or an electronic circuit creates error correction coding means for generating transmission data by processing including addition of redundant bits for error correction, and the transmission data An audio transmission method executed using a transmitter having a radio transmission method using a carrier wave, wherein the error correction coding unit causes the digital audio data to be transmitted to an important part according to a predetermined regularity. And the redundant bits for error correction are added to the important part at a higher rate than the other parts. And executing a process.

  According to a seventh aspect of the present invention, there is provided an audio transmission program that is obtained from the viewpoint of the computer program according to the first and fourth aspects of the invention, and a computer or an electronic circuit receives an audio input microphone and an analog audio signal input from the microphone. A / D conversion means for converting into digital audio data; and error correction encoding means for creating transmission data by a computer or electronic circuit based on the digital audio data by processing including redundant bit addition for error correction; A transmission means for wirelessly transmitting the data for transmission on a carrier wave, by controlling a computer or an electronic circuit of the transmitter, the digital audio data is predetermined in the error correction encoding means Processing to separate the important part from the other part by regularity, and the other part with respect to the important part And a process of adding redundant bits for error correction at a high rate.

  According to a second aspect of the present invention, there is provided a receiving means for wirelessly receiving voice transmission data, and an error correction redundancy in which a computer or an electronic circuit is added to the transmission data based on the received transmission data. Error correction decoding means for restoring digital audio data using bits, D / A conversion means for converting the digital audio data into an analog audio signal by a computer or an electronic circuit, and audio generated by the converted analog audio signal In the receiver comprising: means for outputting to the outside of the important part and other parts included in the digital audio data by being divided by a predetermined regularity by the error correction decoding means Of these, the important part is restored using the error correction redundant bits added at a higher rate than the other part, and the other part is restored. Is restored using the error correction redundant bits added at a lower rate than the important part, and the original digital audio data is restored by combining the restored important part and the other parts. Means.

  The invention according to claim 5 is an embodiment of the invention according to claim 2 in terms of a method. A receiving means for wirelessly receiving voice transmission data and a computer or an electronic circuit based on the received transmission data. Includes error correction decoding means for recovering digital audio data using redundant bits for error correction added to the transmission data, and D / D for converting the digital audio data into an analog audio signal by a computer or an electronic circuit. In a voice receiving method executed using a receiver comprising: A conversion means; and means for outputting the converted voice based on the analog voice signal to the outside. The error correction decoding means converts the digital voice data into the digital voice data. Among important parts and other parts that are classified and included according to predetermined regularity, the important parts are more important than the other parts. Is restored using the error correcting redundant bits added at a high rate, and the other parts are restored using the error correcting redundant bits added at a lower rate than the important part, A process of restoring the original digital audio data by combining the restored important part and the other part is performed.

  An audio reception program according to an eighth aspect is obtained by grasping the inventions according to the second and fifth aspects from the viewpoint of a computer program, and includes a reception means for wirelessly receiving audio transmission data and the received transmission data. In addition, the computer or the electronic circuit restores the digital audio data using the error correction redundant bits added to the transmission data, and the digital audio data is analogized by the computer or the electronic circuit. The error correction decoding is performed by controlling a computer or electronic circuit of a receiver comprising: a D / A conversion means for converting into an audio signal; and a means for outputting the sound of the converted analog audio signal to the outside. The important part and other parts included in the digital audio data by being divided according to predetermined regularity. Of these, the important part is restored using the error correction redundant bits added at a higher rate than the other part, and the other part is added at a lower rate than the important part. The restoration is performed using the redundant bits for error correction, and the original digital audio data is restored by combining the restored important part and the other part.

  A wireless microphone system according to a third aspect captures the invention according to the first and second aspects from the viewpoint of the entire system, and is characterized by combining the transmitter according to the first aspect and the receiver according to the second aspect. To do.

  The voice transmission / reception method of claim 6 is based on the view of the invention of claim 3 as a method, and is characterized by combining the voice transmission method of claim 4 and the voice reception method of claim 5. .

  In the present invention as described above, error correction processing is performed intensively by assigning a relatively larger proportion of redundant bits for correction to important portions of audio data to be transmitted than other portions. Therefore, it is possible to effectively reduce the deterioration of sound quality during communication.

Next, the best mode for carrying out the present invention will be described with reference to the drawings. It should be noted that the assumptions such as terms common to the prior art already described are not restated.
[1. Constitution〕
First, main elements constituting the present embodiment will be described, but some components will be described later in the section of action.
[1-1. overall structure〕
As shown in FIG. 1, the present embodiment relates to a wireless microphone system that combines a wireless microphone transmitter 1 and a receiver 2 to realize error correction by a Hamming code method or the like. The antenna 3 is provided. The present embodiment can also be understood as a voice transmission method and program in the transmitter 1, a voice reception method and program in the receiver 2, and a voice transmission and reception method in the transmitter 1 and the receiver 2.

[1-2. (Configuration of transmitter)
Here, the configuration of the transmitter 1 is shown in the functional block diagram of FIG. That is, the microphone (microphone) 11 is for voice input, and the A / D conversion unit 13 is an A / D for converting an analog voice signal input from the microphone 11 and amplified by the amplifier 12 into digital voice data by a computer or an electronic circuit. It is a conversion means.

  The processing unit 14, the error correction first encoder 15 and the error correction second encoder 16 constitute error correction encoding means, and the error correction encoding means is based on the digital audio data. In addition, a computer or an electronic circuit creates transmission data by processing including redundant bit addition for error correction. The baseband processing unit 17 and the wireless unit 18 constitute a transmission unit that wirelessly transmits the transmission data using a carrier wave.

  The audio data dividing unit 143 of the processing unit 14 is a unit that divides the digital audio data into an important part and another part based on a predetermined regularity, and the error correction first encoder 15 includes: The error correcting redundant bits are added to the important part at a higher rate than the other parts.

[1-3. Receiver configuration)
The configuration of the receiver 2 is shown in the functional block diagram of FIG. That is, the wireless unit 28 and the baseband processing unit 27 constitute a receiving unit that wirelessly receives audio transmission data. The error correction first decoder 25, the error correction second decoder 26, and the processing unit 24 constitute error correction decoding means, and the error correction decoding means converts the received transmission data. Basically, a computer or an electronic circuit restores digital audio data using error correction redundant bits added to the transmission data.

  The D / A conversion unit 23 is D / A conversion means for converting the digital audio data into an analog audio signal by a computer or an electronic circuit, and the amplifier 22 and the speaker 21 are audio signals based on the converted analog audio signal. Is a means for outputting to the outside.

  Then, the error correction first decoder 25 includes the important part included in the digital audio data by being divided according to a predetermined regularity, and the other important part. This is a portion to be restored using the error correction redundant bits added at a higher rate than the portion. On the other hand, the second error correction decoder 26 is a part that restores the other part by using the error correction redundant bits added at a lower rate than the important part. Furthermore, the audio data restoration unit 243 is a means for restoring the original digital audio data by combining the restored important part and the other part.

[2. Action)
The present embodiment as described above operates as follows.
[2-1. Send)
First, in the present embodiment, a processing procedure when the transmitter transmits voice is shown in the flowchart of FIG.

[2-1-1. (Until digitalization)
At the time of transmission, first, the transmitter 1 converts the sound input to the microphone (microphone) 11 into an electrical analog audio signal, and the amplifier 12 amplifies the analog audio signal to a predetermined level. The amplified analog audio signal is converted into digital audio data according to conditions such as a predetermined sampling frequency and the number of quantization bits by an A / D (analog-to-digital) converter 13 (step 01). Are collected for each predetermined amount of sampling signal and additional data, and error correction coding processing is performed (steps 02 to 08).

[2-1-2. compression〕
Specifically, first, the audio codec (CODEC) 141 of the processing unit 14 performs audio compression coding processing based on the digital audio data converted by the A / D conversion unit 13 (step 02). , Process into compressed data.

[2-1-3. Split〕
Each time the buffer 142 accumulates a predetermined number, that is, several tens of samples at a time as unit audio data for transmission (step 03), the audio data dividing unit 143 selects the unit audio data according to the importance. Are divided (divided) into several parts (step 04). In this case, typically, an important part that has a large influence if mistaken, such as a sign bit of audio data, is divided into another part that has a relatively small influence, and rearrangement is performed as necessary.

  As an example, when PCM coding or ADPCM is used, the data is divided into communication data such as higher bits including codes having a large sound change amount and lower bits having a relatively small change amount. In the case of the sub-band ADPPCM, the low frequency divided in the frequency band is set to “high” importance, and the high frequency importance is set to “low”. In addition, although it classify | categorized into 2 types with high and low importance here, the kind of division may be 3 or more types.

[2-1-4. (Addition of control data)
Further, the attached data first adding unit 144 adds important control data such as the ID of the transmission signal and the remaining battery level to the highly important audio data classified as described above ( Step 05). This added data is called an important data group. On the other hand, the attached data second adding unit 145 adds control data with low importance among various control data to the voice data with low importance among the audio data classified as described above (step 07). The added data is called a normal data group.

[2-1-5. Error correction coding
For the important data group divided as described above, the error correction first encoder 15 that realizes a relatively high error correction capability encodes the error correction code such as a checksum with respect to the data amount. A relatively higher rate is added than in the case of the normal data group (step 06). On the other hand, the normal data group is encoded by the error correction second encoder 16 that realizes a relatively low error correction capability, and redundant bits such as checksums, that is, error correction codes are important for the data amount. Encoding is performed at a relatively smaller rate than in the case of the data group (step 08).

  For example, when a total of 10 symbols can be corrected per 100 symbols of the transmission data body, as shown in FIG. 6B, the transmission data body of 100 symbols is preliminarily divided into 20 symbols that are important data and 80 symbols that are not so important. Among the total 10 symbols that can be corrected (20 checksum data amount), a correctable number of 8 symbols (16 checksum data amount) is assigned to 20 important symbols, while the remaining 80 symbols are assigned to the remaining 80 symbols. Therefore, only the remaining 2 symbols (4 symbols of checksum data amount) of the correctable number are allocated. Thereby, the reception sensitivity of an important part improves, and as a result, deterioration of sound quality can be reduced.

[2-1-6. (Wireless transmission)
As described above, the important data group and the normal data group, which are audio data to which attached data and error correction codes are added, are necessary for interleaving (step 09), frame addition (step 10), IQ signal output, etc. After that, the baseband processing unit 17 places the carrier wave and transmits it from the radio unit 18 equipped with an antenna (steps 11 and 12).

[2-2. Receive)
Further, in the present embodiment, a processing procedure when the receiver receives audio is shown in a flowchart of FIG. As an outline, the information transmitted by the transmitter 1 as described above is received by the receiver 2, error correction processing is performed, and the audio data restored by placing the divided data in the original state is D / A converted and output.

[2-2-1. (Reception and error correction decoding)
Specifically, first, the received data is demodulated by the baseband processing (step 21 in FIG. 5) by the baseband processing unit 27 from the carrier wave received by the radio device 28 equipped with the antenna (FIG. 3), and necessary frame removal is performed. The important data group and the normal data group, which are the transmitted data for transmission, are extracted by (Step 22), interleave processing (Step 23), and the like.

  Among these, the important data group is decoded by the error correction first decoder 25 that realizes a relatively high error correction capability, and at that time, the ratio of the data amount is relatively larger than that of the normal data group. Error correction is performed using an error correction code such as a checksum added in step (step 24 in FIG. 5). On the other hand, for the normal data group, the error correction second decoder unit 26 that realizes a relatively low error correction capability decodes the data, and at this time, a check that was added at a relatively small ratio to the data amount. Error correction is performed using an error correction code such as a thumb (step 26).

[2-2-2. (Separation of attached data)
Then, from the important data group decrypted as described above, the attached data first separation unit 244 extracts important control data from various control data (step 25), while from the decrypted normal data group, The attached data second separation unit 245 extracts control data with low importance from various control data (step 27).

[2-2-3. Data reconstruction
Then, the voice data restoration unit 243 restores, that is, reconstructs the original digital voice data from the important data group and the normal data group (step 28). In this case, for example, from the important data group, a part having a large influence if a mistake is made in the sign bit of the voice data, and the other part having a relatively small influence are taken out from the normal data group and rearranged to obtain the original digital data. Get audio data.

  In the example already mentioned, in the case of PCM coding and ADPCM, the upper bit group including a code having a large sound change amount is included in the important data group, and the lower bit group having a relatively small change amount is included in the normal data group. Are taken out and integrated. In the case of subband ADPPCM, the low frequency band divided by the frequency band is obtained from the important data group, and the high frequency band is obtained from the normal data group.

[2-2-4. Stretch and play)
The audio data restored in this way is compressed, and whenever the buffer 242 accumulates a predetermined number, that is, several tens of samples at a time as unit audio data (step 29), the compressed unit audio is compressed. The audio codec (CODEC) 241 of the processing unit 24 restores the data to uncompressed digital data for reproduction (step 30).

  The D / A (digital-to-analog) conversion unit 23 D / A converts this digital data into an analog audio signal according to conditions such as a predetermined sampling frequency and the number of quantization bits (step 31), and the amplifier 22 Through the speaker 21 (step 32).

[3. effect〕
In the present embodiment as described above, error correction processing is focused on important portions of audio data to be transmitted by assigning a relatively larger proportion of redundant bits for correction than other portions. As a result, deterioration in sound quality during communication can be effectively reduced.

[4. Other embodiments]
In addition, this invention is not limited to the said embodiment, Other embodiments containing what is illustrated below and other than that are included. For example, the configurations and processing procedures shown in the drawings are merely examples, and the present invention can be appropriately modified. Therefore, as an example, the attached data first adding unit 144 and the attached data second adding unit 145 of the transmitter 1 are used. The attached data first separation unit 244 and the attached data second separation unit 245 of the receiver 2 can be omitted, and depending on the transmission method, interleaving processing, frame addition, and the like are not essential. Further, the amplifier 22 and the speaker 21 may be configured separately from the receiver 2 that constitutes the present invention.

The block diagram which shows embodiment of this invention. The functional block diagram which shows the structure of the transmitter in embodiment of this invention. The functional block diagram which shows the structure of the receiver in embodiment of this invention. The flowchart which shows the process sequence of the transmission side in embodiment of this invention. The flowchart which shows the process sequence of the receiving side in embodiment of this invention. The conceptual diagram which shows the relationship between transmission / reception data and a checksum.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transmitter 2 ... Receiver 3 ... Antenna 11 ... Microphone 12, 22 ... Amplifier 13 ... A / D conversion part 14, 24 ... Processing part 141, 241 ... Voice codec 142, 242 ... Dozens of samples (minutes) buffer 143 ... Audio data division unit 144 ... Attachment data first addition unit 145 ... Attachment data second addition unit 15 ... Error correction first encoder 16 ... Error correction second encoder 17, 27 ... Baseband processing unit 18,28 ... Wireless section 21 ... Speaker 23 ... D / A conversion section 243 ... Audio data restoration section 244 ... Attached data first separation section 245 ... Attached data second separation section 25 ... Error correction first decoder 26 ... Error correction second Decoder

Claims (8)

A microphone for voice input;
A / D conversion means for converting an analog audio signal input from the microphone into digital audio data by a computer or electronic circuit;
Based on the digital audio data, a computer or an electronic circuit creates transmission data by processing including redundant bit addition for error correction, and error correction coding means;
Transmitting means for wirelessly transmitting the data for transmission on a carrier wave;
In a transmitter with
By the error correction coding means,
Means for dividing the digital audio data into an important part and another part according to predetermined regularity;
Means for adding the redundant bits for error correction to the important part at a higher rate than the other parts;
A transmitter characterized by realizing. Receiving means for wirelessly receiving voice transmission data;
Based on the received transmission data, a computer or an electronic circuit restores digital audio data using error correction redundant bits added to the transmission data, error correction decoding means,
D / A conversion means for converting the digital audio data into an analog audio signal by a computer or electronic circuit;
Means for outputting the sound of the converted analog sound signal to the outside;
In a receiver with
By the error correction decoding means,
Of the important part and other parts classified and included in the digital audio data according to predetermined regularity, the important part is added with a higher ratio than the other part. Recovered using redundant bits for correction, and restored using the error-correcting redundant bits added at a rate lower than that of the important part for the other parts. Means to restore the original digital audio data by combining
A receiver characterized by realizing.   A wireless microphone system, wherein the transmitter of claim 1 and the receiver of claim 2 are combined. A microphone for voice input;
A / D conversion means for converting an analog audio signal input from the microphone into digital audio data by a computer or electronic circuit;
Based on the digital audio data, a computer or an electronic circuit creates transmission data by processing including redundant bit addition for error correction, and error correction coding means;
Transmitting means for wirelessly transmitting the data for transmission on a carrier wave;
In a voice transmission method executed using a transmitter equipped with
By the error correction coding means,
A process of dividing the digital audio data into an important part and another part according to predetermined regularity;
A process of adding the error correction redundant bits at a higher ratio to the important part than the other parts;
The voice transmission method characterized by performing. Receiving means for wirelessly receiving voice transmission data;
Based on the received transmission data, a computer or an electronic circuit restores digital audio data using error correction redundant bits added to the transmission data, error correction decoding means,
D / A conversion means for converting the digital audio data into an analog audio signal by a computer or electronic circuit;
Means for outputting the sound of the converted analog sound signal to the outside;
In a voice receiving method executed in a receiver comprising:
By the error correction decoding means,
Of the important part and other parts classified and included in the digital audio data according to predetermined regularity, the important part is added with a higher ratio than the other part. Recovered using redundant bits for correction, and restored using the error-correcting redundant bits added at a rate lower than that of the important part for the other parts. Processing to restore the original digital audio data by combining
The voice receiving method characterized by performing.   6. A voice transmission / reception method comprising a combination of the voice transmission method according to claim 4 and the voice reception method according to claim 5. A microphone for voice input;
A / D conversion means for converting an analog audio signal input from the microphone into digital audio data by a computer or electronic circuit;
Based on the digital audio data, a computer or an electronic circuit creates transmission data by processing including redundant bit addition for error correction, and error correction coding means;
Transmitting means for wirelessly transmitting the data for transmission on a carrier wave;
By controlling a computer or electronic circuit of a transmitter equipped with the error correction coding means,
A process of dividing the digital audio data into an important part and another part according to predetermined regularity;
A process of adding the error correction redundant bits at a higher ratio to the important part than the other parts;
The voice transmission program characterized by performing. Receiving means for wirelessly receiving voice transmission data;
Based on the received transmission data, a computer or an electronic circuit restores digital audio data using error correction redundant bits added to the transmission data, error correction decoding means,
D / A conversion means for converting the digital audio data into an analog audio signal by a computer or electronic circuit;
Means for outputting the sound of the converted analog sound signal to the outside;
By controlling the computer or electronic circuit of the receiver provided with the error correction decoding means,
Of the important part and other parts that are classified and included in the digital audio data according to predetermined regularity, the important part is added at a higher rate than the other part. Recovered using redundant bits for correction, and restored using the error correcting redundant bits added at a rate lower than the important part for the other parts, and restored important parts and other parts respectively. Processing to restore the original digital audio data by combining
A voice receiving program characterized in that

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