KR100481274B1 - Digital Data Encoding and Decoding Method using Sound wave for data communication via Sound wave, and Communication Device using the method - Google Patents

Abstract

The present invention relates to a method and apparatus for encoding and decoding sound waves of digital data for near field communication through sound waves between a transmitter and a receiver.

In the present invention, in order to improve transmission efficiency and reliability, the frequency shift keying method is used as a data transmission method using sound waves, and the frequency used therein is to use the frequency of the pitch used in current music.

The present invention provides a decoding method of encoding digital data into sound waves and reconstructing the encoded sound waves back into digital data in order to transmit digital data using sound waves between a transmitting device and a receiving device that are separated from each other.

Generating a mapping table for associating pitch combinations with unit values of digital data;

A transmission step of converting digital data to be transmitted, which is composed of a column of digital data unit values, into a column of pitch combinations corresponding to the mapping table for each digital data unit value, and generating and transmitting the synthesized sound wave having a frequency of each pitch;

And a step of extracting a row of pitch combinations from the sound waves generated from the transmitting apparatus and converting the extracted pitch combinations into digital data composed of digital data unit values corresponding to the mapping table. Encoding, decoding method for a sound wave of the and a transmitting and receiving device using the same.

When the present invention described above is implemented, it is possible to transmit and receive a large amount of information using the pitch frequency of music already built into many devices, without using a dedicated terminal to increase the amount of digital data transmission using sound waves per unit time.

Description

Digital Data Encoding and Decoding Method using Sound wave for data communication via Sound wave, and Communication Device using the method

The present invention relates to a method and apparatus for encoding and decoding digital data for near field communication through sound waves between a transmitter and a receiver.

Existing technologies for transmitting small amounts of digital data at short distances include infrared transmission / reception (IrDA) technology, contact / contactless RF card technology, barcodes downloaded to mobile phones and barcode readers, and wristwatches. Techniques using beep sound.

In the field where a small amount of digital data is transmitted at a short distance, an infrared transceiver is used as a communication means for short distance remote control in order to transmit a simple control command. For example, an example of using a near-field two-way communication for transmitting a credit card number using infrared rays or processing a payment using a contactless RF card is also shown.

These technologies have the advantage that they can be implemented at low cost because they do not require amplification or relaying to compensate for attenuation over transmission distance compared to telecommunications, and can be implemented at a short distance such as wireless e-commerce using digital tickets or mobile phones. As the demand for transmitting and receiving digital data increases, more technology demand is expected.

The obstacle to using near field communication using an infrared transceiver is that the data storage medium must have a built-in infrared transmitter or receiver, or have a separate interface to communicate with an infrared transceiver. It is becoming a factor which hinders the spread as production cost increases.

The RF contactless card has been widely used in recent years, but it is also limited to the field where information requiring high security is used because it requires the spread of dedicated terminals and the cost increase due to the increase in the amount of information storage. have.

The barcode downloaded to a mobile phone has a limitation on the amount of data that can be transmitted at one time due to the size limitation of the display device, and the bar code of a new standard for the conventional barcode reader is low due to the light emitted from the LCD screen itself. There is a disadvantage to spreading the leader.

A method of transmitting digital data using a beep sound of a wrist watch is known from Biometrics, Inc., US Pat. No. 5,848,027. 1 attached to this patent application is a representative view of a "biometric system". The system includes a portable terminal such as a digital display wristwatch that can store and transmit data. These data can be transmitted to a personal computer in the form of an acoustic "beep" that produces sound pressure obtained by the microphone. Any kind of digital device controlled by a microprocessor, including piezoelectric elements capable of generating acoustic "beep" for data transmission, can be used as the terminal of the system.

The system uses Dual Frequency Shift Keying (DFSK) modulation and Continuous Waveform (CW) modulation to transmit binary numbers.

The DFSK modulation method assigns 0 and 1 to two specific frequencies, respectively, and decides which frequency to generate the sound waves according to which number the transmitter transmits, and transmits them as sound waves. 0 or 1 is judged as being received, and CW modulation method is 1 to keep sound over a certain intensity over a certain time regardless of frequency, and 1 to keep sound free for a certain time. It is the way of seeing.

In this modulation method, only one bit of data can be transmitted as one note. To overcome this problem, a frequency shift keying modulation method is used to allocate a specific value to two or more specific frequencies, or a continuous wave modulation method is used. The input intensity is divided into two or more sections, and when a transceiver wants to transmit more than one bit of data by one note, it should be interpreted as which sound should be generated and which value is received when a sound wave is input. As a criterion for determining whether or not to do so, the transceiver should be implemented with a correspondence table that is previously built in and promised, which has a problem of using a dedicated digital data transceiver.

In the present invention, in order to solve this problem, the frequency shift method (Frequency Shift Keying) in the data transmission method using a sound wave, to use the frequency of the pitch used in the current music to use the frequency.

The pitch used in music not only has a standardized frequency, but also a lot of devices that support it, so using it, there is no need to embed a table that corresponds to the frequency and value separately, the implementation cost is low, Since it is a standard for widespread frequencies, data transmission using sound waves is the most common.

The present invention provides a decoding method of encoding digital data into sound waves and reconstructing the encoded sound waves back into digital data in order to transmit digital data using sound waves between a transmitting device and a receiving device that are separated from each other.

Generating a mapping table for associating pitch combinations with unit values of digital data;

A transmission step of converting digital data to be transmitted, which is composed of a column of digital data unit values, into a column of pitch combinations corresponding to the mapping table for each digital data unit value, and generating and transmitting the synthesized sound wave having a frequency of each pitch;

And a step of extracting a column of pitch combinations from the sound waves generated from the transmitting device and converting the extracted pitch combinations into digital data composed of digital data unit values corresponding to the mapping table.

Encoding and decoding methods for sound waves of digital data.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a flowchart for encoding and decoding digital data according to a preferred embodiment of the present invention. The encoding method includes a mapping table generation step, a data classification step, a column construction step of a pitch combination, and a sound wave generation step;

A decoding method includes a mapping table generation step, a column extraction step of a pitch combination, a column configuration step of a data unit value, and a digital data recovery step.

3 and 4 are embodiments of a mapping table for converting digital data into a column of pitch combinations according to a preferred embodiment of the present invention, in which case the pitch combination is composed of one note and two notes. Although limited to examples, this is an example of a pitch combination consisting of one or more pitches, and the scope of the invention is not limited to the examples.

In the step of generating the mapping table, the present invention uses the pitch among various properties of the sound, because the sound is difficult to quantify, not only the accuracy of transmission and reception is low but also it is difficult to accurately extract it, and the sound length is a sound wave generator. The reverberation sound processing ability varies depending on the performance of the speaker, which makes it difficult to apply universally because the sound wave generation time variation for the same sound length is large, and the sound intensity is inversely proportional to the square of the distance depending on the propagation distance of the sound wave. To do this, the transmission distance must be constant or the transmission distance deviation must be corrected because of the problems of convenience and cost. Therefore, the present invention uses a pitch that is easy to extract among various attributes of the sound and has a small variation according to a transmission distance or a device.

An embodiment in which the decimal number 123456789 is encoded using the mapping table in which digital data values correspond to the single tone heights of FIG. 3 is as follows.

123456789 = 111010110111100110100010101 ₍₂₎

In order to encode the digital data using the mapping table of FIG. 3, the digital data is divided into digital data values in 5-bit units, which are standards of digital data unit values defined in the mapping table, as follows.

00011 10101 10111 10011 01000 10101 ₍₂₎

If you encode it using the table above, you can get a column of pitches as follows.

order One 2 3 4 5 6 1st pitch D2 # A3 B3 G3 G2 # A3

The pitch correspondence table of FIG. 4 is a correspondence table used for a transmission method in which a plurality of sounds are generated at the same time. The combination of s was excluded because it is not easy to extract frequency decomposition by sampling and Fourier transform, and some sound combinations were arbitrarily excluded in order to fit 7 bits.

An embodiment of encoding the decimal number 123456789 using a mapping table in which digital data is mapped to a combination of two pitches of FIG. 4 is as follows.

123456789 = 111010110111100110100010101 ₍₂₎

In order to encode the digital data using the corresponding table, the following is divided into digital data values in units of 7 bits.

0111010 1101111 0011010 0010101 ₍₂₎

If this is encoded using the table of FIG. 4, a combination string of the following pitches can be obtained.

order One 2 3 4 1st pitch D2 # D2 C3 # F2 2nd pitch F2 # C3 D2 D2

As shown in the above embodiment, when a pitch combination consisting of a plurality of pitches is used, the amount of data transmission per unit time is increased than when using a single tone.

The encoding method using the mapping table of FIG. 4 is the same as the encoding method using the single phone, except that the pairs of pitches allocated in the same order are simultaneously generated as synthesized sound waves when generating sound waves.

The use of the mapping tables of FIGS. 3 and 4 may use not only the pitch within the audible frequency but also the pitch of the inaudible band configured according to the standard frequency allocation principle of the pitch.

5A, 5B, and 5C illustrate a synchronization pitch for synchronization between a transmitter and a receiver in order to increase reliability and efficiency of transmission in transmitting information encoded using a mapping table using a sound wave between transmission and reception apparatuses. The embodiment adds a row of combinations, and a detailed embodiment thereof is as follows.

An embodiment of a column of synchronization pitch combinations is

A column of reference pitch combinations having a specific pitch and length for synchronizing by correcting and synchronizing the deviation between the pitch and the unit time reference between the transmitting apparatus and the receiving apparatus,

There is a row of combinations of the transmission start and transmission end pitches having a specific pitch and length for synchronizing the transmission start and end points between the transmitter and the receiver.

An embodiment of improving transmission reliability using the reference tone pitch combination is as follows.

In order to correct the pitch and unit time deviation between the transmitting device and the receiving device, which may be caused by manufacturing process or quality,

The transmitting device converts the digital data to be transmitted into a column of pitch combinations, and then adds a reference sound composed of sound combinations having a specific pitch and length in the form of FIGS. 5A, 5B, and 5C, and transmits them as sound waves.

The receiving device generates a unit time correction value to be used for pitch extraction and a standard frequency correction table for each pitch by using the received reference sound, corrects the built-in frequency table for each pitch, and uses it as a reference frequency for extracting a pitch combination from sound waves. To convert the received sound waves into digital data.

An embodiment of improving transmission reliability using the transmission start sound and the transmission end sound is as follows.

In order to synchronize the transmission start and end points between the transmitting device and the receiving device,

When the transmitting device converts the digital data to be transmitted into a column of pitch combinations, adds a transmission start sound and a transmission end sound in the form of FIG. 5C, and transmits a boundary of one transmission unit sound wave.

The receiving device recognizes and receives the sound waves from the transmission start sound extracted from the transmitted sound waves to the transmission end sound as one transmission unit sound wave.

In the receiving step,

In order to extract the heat of the pitch combination transmitted in the sound wave from the sound wave,

The receiving device converts a sound wave into an electrical signal, reads it, and makes a sample file divided into unit time correction values through sampling, and then performs Fourier transform to calculate a frequency distribution of the sound wave, and then determines a pitch from the sound wave. The frequencies are found, the pitches are extracted, reconstructed into a sequence of pitch combinations, and the original transmitted digital data is extracted in the opposite way of encoding. The method of finding basal frequencies from the frequency distribution of sound waves uses the inverse principle of the synthesis of multiple sounds, a known principle of sound synthesis.

The decoding method using the mapping table of FIG. 4 is the same as the decoding method using the single tone, except that the two pitches must be decomposed and extracted from the synthesized sound wave in which two pitches are pronounced simultaneously when extracting the pitches.

6A and 6B illustrate a reference time between a transmitter and a receiver when continuous transmission of the same pitch combination is required as shown in FIG. 6A when transmitting information encoded by using a mapping table using a sound wave in the above embodiment. In order to avoid transmission errors due to deviations and to increase the reliability of transmission, an embodiment using a pitch combination consisting of A7 single tones as a continuous equal pitch surrogate combination is described in detail as follows.

The transmitting apparatus converts the digital data to be transmitted into a column of pitch combinations as shown in FIG. 6A, and then examines the column of pitch combinations and finds a pitch combination sub-string to which the same pitch combinations are continuously given. If you send a pitch surrogate combination,

The receiving device examines a row of pitch combinations as shown in FIG. 6B extracted from the transmitted sound waves, and when A7 sounds, which are successive equal pitch surrogate combinations, are found and replaced with the same pitch combinations as the previous pitch combinations, is converted into a column of pitch combinations as shown in FIG. 6A. Then decode to digital data.

A decoding method for encoding digital data into sound waves and reconstructing the encoded sound waves back into digital data in order to transmit digital data using sound waves between the transmitting apparatus and the receiving apparatus separated from each other.

An embodiment of simultaneously transmitting a plurality of digital data is as follows.

The transmitting device allocates a plurality of mapping tables using mutually exclusive pitch bands to the plurality of digital data to be transmitted, and converts the plurality of digital data into columns of a combination of pitches. When a plurality of digital data are simultaneously transmitted and added in the form of FIGS. 5A, 5B, and 5C, and a plurality of pitch combinations are simultaneously generated and transmitted,

The receiving device reads information on the transmission method from the column of the transmission method indication pitch combination included in the transmitted synthesized sound wave, generates a plurality of mapping tables used for transmission accordingly, and uses the extracted information from the transmission method indication pitch combination. According to the pitch band separation criterion, a plurality of pieces of digital data are received in correspondence with the mapping table used for the columns of the respective pitch combinations by decomposing the extracted rows of the pitch combinations into columns of the plurality of pitch combinations.

When the present invention described above is implemented, a large amount of information can be transmitted and received by using a pitch frequency of music that is already built into many devices, without using a dedicated terminal to increase the amount of digital data transmission using sound waves per unit time.

In addition, when a plurality of sounds are generated at the same time and a plurality of sounds are input at the same time, a transmission / reception apparatus capable of decomposing them into their respective pitches may further increase the amount of data transmission per unit time using sound waves.

1 is a schematic diagram of a digital data transmission system using sound waves.

2 is an encoding and decoding flowchart for transmitting and receiving digital data according to a preferred embodiment of the present invention.

3 is a mapping table for converting digital data into a monotonic pitch column;

4 is a mapping table for converting digital data into columns of pitch combinations consisting of two pitches.

5A is an embodiment of a row of pitch combinations added in front of a column of pitch combinations corresponding to digital data to which a row of synchronization pitch combinations is to be transmitted;

FIG. 5B is an embodiment of a row of pitch combinations added after a column of pitch combinations corresponding to digital data to which a row of synchronization pitch combinations is to be transmitted;

5C is an embodiment of a row of pitch combinations added before and after a row of pitch combinations corresponding to digital data to which a row of synchronization pitch combinations is to be transmitted;

Claims (19)

A method of encoding digital data for encoding digital data into sound waves to transmit digital data using sound waves from a transmitting device that is located near each other to a receiving device, A mapping table generation step of generating a mapping table for associating pitch combinations with unit values of digital data; A data classification step of dividing the digital data into columns of digital data unit values; A column construction step of the pitch combinations configured by mapping the separated column of digital data unit values to columns of pitch combinations corresponding to the mapping table; A sound wave generation step of generating a series of synthesized sound waves of unit time length having the frequency of each pitch combination of the configured pitch combinations Encoding method of digital data comprising a. The method of claim 1, The mapping table generating step, A method of encoding digital data, comprising using a pitch combination consisting of one or more pitches. delete The method of claim 1, The mapping table generating step, A method of encoding digital data, characterized in that it uses a pitch combination of an audible band, or a pitch combination of an inaudible band constructed in accordance with a standard frequency allocation principle. The method of claim 1, The column of the pitch combination of the column configuration step of the pitch combination, And at least one sequence of synchronization pitch combinations for synchronization between a transmitting device and a receiving device. The method of claim 5, wherein The column of the synchronization pitch combination is And a column of reference tone pitch combinations having a specific pitch and length for correcting the deviation of the pitch and the unit time reference between the transmitting device and the receiving device. The method of claim 5, wherein The column of the synchronization pitch combination is And a sequence of combinations of transmission start and transmission end pitches having a specific pitch and length for synchronizing transmission start and end points between the transmitter and the receiver. The method of claim 1, The column configuration step of the pitch combination, In the case of continuous transmission of the same pitch combination between the transmitting device and the receiving device, instead of the even-numbered pitch combinations of the repeated pitch combination sub-columns among the transmitted pitch combinations, the specific pitch combinations not used in the mapping table are successively equal pitch surrogate combinations. And encoding the digital data. A method of encoding digital data for encoding digital data into sound waves to transmit digital data using sound waves from a transmitting device that is located near each other to a receiving device, A mapping table generating step of generating two or more mapping tables that correspond to a combination of pitches and unit values of digital data so as to use mutually exclusive bands of pitches; A data division step of dividing two or more digital data into columns of digital data unit values, respectively; A column construction step of the pitch combinations that constitutes the divided column of digital data unit values into columns of pitch combinations corresponding to the different mapping tables; A sound wave generation step of synthesizing a series of two or more pitch combinations into sound waves of unit time length each having a frequency of pitch combinations and generating one continuous sound wave. Encoding method of digital data comprising a. A decoding method of digital data for decoding sound waves into digital data to transmit digital data using sound waves from a transmitting device that is far from each other to a receiving device, A mapping table generation step of generating a mapping table for associating pitch combinations with unit values of digital data; A column extraction step of extracting a pitch combination from the received synthesized sound waves; A column constituting step of data unit values constituting the extracted column of pitches as a column of unit values of digital data corresponding to the mapping table; Digital data restoration step of restoring the configured column of digital data unit values to digital data Decoding method of digital data comprising a. The method of claim 10, The heat extraction step of the pitch, And a synchronization step of extracting a synthesized sound wave generated from a sequence of synchronization pitch combinations and synchronizing for transmission and reception between a transmitter and a receiver. The method of claim 11, The synchronization step, A method of decoding digital data comprising extracting a transmission start sound and a transmission end sound having a specific pitch and length, and recognizing sound waves from the received synthesized sound wave to the transmission end sound in one transmission sound wave unit. . The method of claim 11, The synchronization step, Extracting a reference sound having a specific pitch and length to generate a table of unit time correction values and standard frequency correction values for each sound level, and correcting the extracted pitches using the unit time correction values and the frequency correction value table. Characterized in that the decoding method of digital data. The method of claim 11, The synchronization step, And extracting a synthesized sound wave for detecting and correcting a transmission error having a specific pitch combination and length, and detecting and correcting the transmission error from the received sound wave. The method according to claim 10 or 13, The heat extraction step of the pitch, A method of decoding digital data, comprising extracting a pitch combination at unit time intervals of a predetermined sound wave. The method of claim 10, The heat extraction step of the pitch, And replacing successive equal pitch surrogate combinations included in the column of pitch combinations with the previous pitch combinations in the column of pitch combinations. A decoding method of digital data for decoding sound waves into digital data to transmit digital data using sound waves from a transmitting device that is far from each other to a receiving device, A mapping table generating step of generating two or more mapping tables that correspond to a combination of pitches and unit values of digital data so as to use mutually exclusive bands of pitches; A step of extracting heat of pitches for extracting two or more combinations of pitches according to a band of mutually exclusive pitches per unit time from the received synthesized sound waves; A column constituting step of data unit values constituting the extracted two or more pitch columns as columns of unit values of respective digital data corresponding to the corresponding mapping table; Digital data restoration step of restoring the configured column of each digital data unit value to each digital data Decoding method of digital data comprising a. An encoding apparatus for digital data, which encodes digital data into sound waves so that transmission apparatuses separated from each other are used to transmit digital data using sound waves to a receiving apparatus. A mapping table storage unit for storing a mapping table for associating unit values and pitch combinations of digital data; A digital data separator for dividing the input digital data into columns of digital data unit values and outputting them; A pitch combination component configured to receive a column of digital data unit values outputted from the digital data separator and to configure and output a column of pitch combinations corresponding to each digital data unit value by referring to a mapping table of the mapping table storage unit; A sound wave generation unit for generating a series of synthesized sound waves of unit time length having the frequency of each pitch combination, the column of the pitch combination output from the pitch combination configuration unit Device for encoding digital data comprising a. A decoding apparatus of digital data for decoding sound waves into digital data to transmit digital data using sound waves to a receiving apparatus from transmitting apparatuses located near each other. A mapping table storage unit for storing a mapping table for associating pitch combinations with unit values of digital data; A pitch extraction unit which receives the received synthesized sound waves and extracts pitch combinations and outputs a column of the pitch combinations; A digital data unit value constructing unit configured to receive a column of pitches output from the pitch extracting unit and output a column of unit values of digital data corresponding to the pitch by referring to the mapping table of the mapping table storage unit; Digital data restoration unit for receiving the column of the digital data unit value output from the digital data unit value configuration unit to restore the digital data Decoding device for digital data comprising a.