JP7011308B2 - Sound signal transmitter, sound signal receiver, and sound signal transmission system - Google Patents

Description

The present invention relates to a sound signal transmitting device, a sound signal receiving device, and a sound signal transmission system for transmitting a sound signal.

Conventionally, a technique for wirelessly transmitting a sound signal is known. Patent Document 1 discloses a technique of correcting an error generated during wireless transmission and then reproducing the sound signal by encoding the sound signal using an error correction code and then transmitting the sound signal.

Special Table 2012-517782

Even if an error correction code is used, the error cannot be corrected when the frequency of data errors occurs frequently. In the sound signal, there is a problem that the influence of the error is large depending on the bit position where the error occurs, and when the sound signal in which the error occurs is reproduced, it is heard as a large noise.

Therefore, the present invention has been made in view of these points, and is a sound signal transmitting device, a sound signal receiving device, and a sound signal transmission system capable of reducing the influence of data errors that occur during sound signal transmission. The purpose is to provide.

The sound signal transmission device of the first aspect of the present invention includes a first coded data based on a sampled value of a sound signal, a coding unit that generates a second coded data obtained by inverting the first coded data, and a coding unit. A first mixed signal including one or more first frequency signals assigned to the first encoded data and a second mixed signal including one or more second frequency signals assigned to the second encoded data. It has a mixed signal generation unit that generates a mixed signal including the above, a modulated signal generation unit that modulates a carrier signal with the mixed signal to generate a modulated signal, and a transmission unit that transmits the modulated signal.

The mixed signal generation unit generates the first mixed signal and the second mixed signal including signals having one or more frequencies in different combinations for each value of the first coded data and the value of the second coded data. You may.

The mixed signal generation unit may generate the second mixed signal including a signal having one or more second frequencies different from the one or more first frequencies among a plurality of predetermined frequencies. The mixed signal generation unit may generate the mixed signal in which the first mixed signal and the second mixed signal are adjacent to each other.

The mixed signal generation unit continuously includes a plurality of signals composed of signals having the same combination of frequencies before the first mixed signal and the second mixed signal corresponding to one sampled value. May generate the mixed signal by arranging.

The coding unit generates a plurality of first sub-encoded data as the first coded data based on the sampling value of the sound signal, and inverts each of the plurality of first sub-encoded data. A plurality of second sub-encoded data as the second encoded data are generated, and the mixed signal generation unit includes the one or more first frequencies assigned to each of the plurality of first sub-encoded data, and the said. The mixed signal may be time-divided and multiplexed with the one or more second frequency signals assigned to each of the plurality of second sub-encoded data.

The sound signal receiving device of the second aspect of the present invention receives the modulated signal transmitted from the sound signal transmitting device. The sound signal receiving device has a demodulator that demolishes the modulated signal to generate a demolished signal, and a first coded data corresponding to the first coded data and the second coded data based on the frequency included in the demodulated signal. A decoding unit that generates the decoded data and the second decoded data, a determination unit that determines whether or not at least one of the first decoded data and the second decoded data has an error, and the first. When the determination unit determines that there is an error in at least one of the 1-decrypted data and the 2nd-decrypted data, the sampling value corresponding to the 1st-decrypted data and the 2nd-decrypted data is determined. It has an interpolation unit that replaces with an interpolation value generated based on another sampling value.

In the determination unit, for example, when the first decoded data and the second decoded data are not in an inverted relationship with each other, an error is found in at least one of the first decoded data and the second decoded data. Judge that there is.

The sound signal transmission system of the third aspect of the present invention includes a sound signal transmitting device for transmitting a sound signal and a sound signal receiving device for receiving the sound signal transmitted by the sound signal transmitting device. The sound signal transmission device includes a first coded data based on a sampled value of a sound signal, a coding unit that generates a second coded data obtained by inverting the first coded data, and the first coded data. A mixed signal including a first mixed signal including one or more assigned first frequency signals and a second mixed signal including one or more second frequency signals assigned to the second coded data. It has a mixed signal generation unit to generate, a modulated signal generation unit that modulates a carrier signal with the mixed signal to generate a modulated signal, and a transmission unit that transmits the modulated signal. The sound signal receiving device decodes the first coded data and the second coded data based on the demodulator that demolishes the modulated signal to generate the demodulated signal and the frequency included in the demodulated signal. A decoding unit that generates the first decoded data and the second decoded data, a determination unit that determines whether or not at least one of the first decoded data and the second decoded data has an error, and a determination unit. When the determination unit determines that there is an error in at least one of the first decoded data and the second decoded data, the sampling value corresponding to the first decoded data and the second decoded data. With an interpolation unit that replaces with an interpolation value generated based on another sampling value.

According to the present invention, it is possible to reduce the influence of data errors that occur during the transmission of sound signals.

It is a figure for demonstrating the outline of a sound signal transmission system. It is a figure which shows the structure of the sound signal transmission device. It is a figure for demonstrating operation of a coding part. It is a figure for demonstrating the coded data generated by a coding part. It is a figure which shows typically the structure of the frequency synthesizer and the mixed signal generation part. It is a figure for demonstrating the operation of the frequency synthesizer and the mixed signal generation part. It is a figure which shows the structure of the sound signal receiving apparatus. It is a figure which shows the operation of the decoding part schematically. It is a figure which shows the example of the sound signal generated by interpolating the value of the sampling data in which an error occurred by the interpolation part.

[Overview of sound signal transmission system S]
FIG. 1 is a diagram for explaining an outline of the sound signal transmission system S. The sound signal transmission system S is a system for transmitting a sound signal from the sound signal transmitting device 1 for transmitting the sound signal to the sound signal receiving device 2 for receiving the sound signal.

Although the microphone unit is illustrated as the sound signal transmitting device 1 in FIG. 1, the sound signal transmitting device 1 is another electronic device having a function of outputting a sound signal, such as an audio player, a computer, or a smartphone. There may be. Further, although the speaker is illustrated as the sound signal receiving device 2 in FIG. 1, the sound signal receiving device 2 is another electronic device having a function of inputting a sound signal, such as a hard disk, a computer, or a smartphone. There may be.

It is possible to transmit a sound signal between the sound signal transmitting device 1 and the sound signal receiving device 2 by using an arbitrary transmission means such as infrared rays, radio waves, or cables, but in the present embodiment, infrared rays are used. An example of a sound signal transmission system S for transmitting a sound signal from a sound signal transmitting device 1 to a sound signal receiving device 2 using IR is illustrated.

The sound signal transmission device 1 converts the sampled data obtained by sampling the input analog sound signal at predetermined time intervals into digital data. The sound signal transmission device 1 encodes digital data and generates a mixed signal including an oscillation signal having a frequency corresponding to the encoded data. The sound signal transmitting device 1 generates a modulated signal by modulating the carrier signal with the generated mixed signal, and transmits the generated modulated signal to the sound signal receiving device 2.

When the sound signal receiving device 2 receives the modulated signal from the sound signal transmitting device 1, the sound signal receiving device 2 decodes the mixed signal contained in the modulated signal by analyzing the frequency pattern included in the signal after demodulating the modulated signal. do. The sound signal receiving device 2 determines whether or not an error has occurred in the decoded data. When the sound signal receiving device 2 detects that an error has occurred in the decoded data, the sound signal receiving device 2 does not use the data in which the error has occurred, but interpolates based on the value of other normal sampling data.

Although the details will be described later, the sound signal transmission system S includes a first coded data obtained by encoding the sampling data and a second coded data obtained by inverting each bit value of the first coded data. It is characterized by transmitting. By doing so, it is possible to increase the probability that the sound signal receiving device 2 can detect that a data error has occurred during transmission.

As described above, the sound signal receiving device 2 does not reproduce the sound of the sampling data in which an error occurs during transmission as it is, but interpolates it based on the values of other sampling data, so that the sound is larger than the values of the sampling data before and after. Makes it difficult to reproduce sampling data with different incorrect values. Therefore, even if a data error occurs during the transmission of the sound signal, it becomes difficult to hear the noise in the sound output by the sound signal receiving device 2, and the influence of the data error can be reduced.
Hereinafter, the configurations of the sound signal transmitting device 1 and the sound signal receiving device 2 will be described in detail.

[Configuration of sound signal transmitter 1]
FIG. 2 is a diagram showing a configuration of a sound signal transmitting device 1.
The sound signal transmission device 1 includes a sound signal input unit 11, a coding unit 12, a frequency synthesizer 13, a mixed signal generation unit 14, a carrier signal generation unit 15, a modulation signal generation unit 16, and a transmission unit 17. , Have.

The sound signal input unit 11 is a microphone that receives an input of a sound signal. The sound signal input unit 11 inputs the input signal after amplifying and / or filtering the input sound signal to the coding unit 12.

The coding unit 12 samples the sound signal input from the sound signal input unit 11 at predetermined time intervals, and converts the sampled sound signal value into digital data to generate coded data. The coding unit 12 generates, for example, 16-bit coded data corresponding to the value of the sampled signal. The coding unit 12 inputs the generated coded data to the mixed signal generation unit 14.

FIG. 3 is a diagram for explaining the operation of the coding unit 12. FIG. 3A shows that the sound signal is sampled at the sampling times T1, T2, T3, T4, and T5. FIG. 3B shows sampling data corresponding to the value of the sound signal sampled at each sampling time.

Subsequently, the coding unit 12 generates a first coded data based on the sampling value of the sound signal and a second coded data obtained by inverting the first coded data based on one sampling data. The first coded data is, for example, the sampling data itself shown in FIG. 3 (b), and the second coded data is the first coded data in which the bit value 0 in the first coded data is inverted to 1. This is the data generated by inverting the bit value 1 to 0.

As shown in FIG. 3B, the coding unit 12 in the present embodiment divides one first coded data into a plurality of first sub-coded data according to the bit position. Specifically, the data at the bit positions 0 to 3 constitutes the 4-bit first sub-encoded data D0, and the data at the bit positions 4 to 7 constitutes the 4-bit first sub-encoded data D1. The data at positions 8 to 11 constitutes the 4-bit first sub-encoded data D2, and the data at bit positions 12 to 15 constitutes the 4-bit first sub-encoded data D3. The coding unit 12 generates the second sub-encoded data in which each bit value of the first sub-encoded data is inverted.

FIG. 4 is a diagram for explaining the coded data generated by the coding unit 12. FIG. 4 shows the coded data based on the sampling data at the sampling time T2 in FIG. The coded data is composed of synchronization data, a plurality of first sub-coded data as the first coded data, and a plurality of second sub-coded data as the second coded data. The coding unit 12 inverts the value of each bit with respect to the first sub-encoded data D0 in which the values of the bit positions 0 to 3 are (0, 0, 0, 1), respectively, so that the bit positions 0 to 0 to The second sub-encoded data D0'in which the value of 3 is (1, 1, 1, 0) is generated, respectively. The coding unit 12 also generates the second sub-encoded data D1', D2', D3'for the first sub-encoded data D1, D2, D3.

The coding unit 12 arranges the first sub-encoded data and the second sub-encoded data so as to be adjacent to each other. In the example shown in FIG. 4, the coding unit 12 generates coded data arranged in the order of D0, D0', D1, D1', D2, D2', D3, D3', following the synchronization data. do. The synchronization data includes, for example, a plurality of data having the same value consecutively. In the example shown in FIG. 4, the synchronization data is composed of three consecutive (1, 1, 0, 0) and one (0, 0, 1, 1).

Subsequently, other components of the sound signal transmitting device 1 will be described.
The frequency synthesizer 13 generates oscillation signals of a plurality of frequencies. The frequency synthesizer 13 generates oscillation signals having a number corresponding to the number of a plurality of data patterns assumed as the first sub-encoded data and the second sub-encoded data. The frequency synthesizer 13 generates, for example, an oscillation signal having a frequency corresponding to the number of bits of the first sub-encoded data and the second sub-encoded data. The frequency synthesizer 13 inputs the generated oscillation signal to the mixed signal generation unit 14.

The mixed signal generation unit 14 generates a mixed signal including an oscillation signal having one or more frequencies input from the frequency synthesizer 13 based on the coded data input from the coding unit 12. The mixed signal generation unit 14 inputs the generated mixed signal to the modulation signal generation unit 16.

The mixed signal generation unit 14 includes a first mixed signal including one or more first frequency signals assigned to the first coded data or the first sub-encoded data, and the second coded data or the second sub-encoded. A second mixed signal containing one or more second frequency signals assigned to the data and a mixed signal containing the second mixed signal are generated. Specifically, the mixing signal generation unit 14 has one or more frequencies of different combinations for each value of the first coded data or the first sub-coded data and the value of the second coded data or the second sub-coded data. A first mixed signal and a second mixed signal including the signal of are generated.

FIG. 5 is a diagram schematically showing the configuration of the frequency synthesizer 13 and the mixed signal generation unit 14. FIG. 6 is a diagram for explaining the operation of the frequency synthesizer 13 and the mixed signal generation unit 14. As shown in FIG. 5, the mixing signal generation unit 14 has each of the bit data d0 to d3 based on the values of the plurality of bit data d0 to d3 included in the sub-encoded data input from the coding unit 12. Determines whether to include the oscillation signal of the frequency corresponding to. When the value of the bit data of the first sub-encoded data and the second sub-encoded data (hereinafter, may be referred to as a bit value) is 1, the mixing signal generation unit 14 has a frequency corresponding to the position of the bit. When the bit values of the first sub-encoded data and the second sub-encoded data are 0, the mixed signal including the oscillation signal and not including the oscillation signal of the frequency corresponding to the position of the bit is generated.

Specifically, the mixing signal generation unit 14 mixes a plurality of bit data d0 to d3 by mixing an oscillation signal having a frequency corresponding to the bit data having a predetermined bit value (for example, 1) in the mixer 141. Generate a signal. More specifically, when the bit value of the bit data d0 is 1, the mixing signal generation unit 14 includes an oscillation signal having a frequency f0 corresponding to the bit data d0 in the mixing signal. When the bit value of the bit data d1 is 1, the mixed signal generation unit 14 includes the oscillation signal of the frequency f1 corresponding to the bit data d1 in the mixed signal. When the bit value of the bit data d2 is 1, the mixed signal generation unit 14 includes the oscillation signal of the frequency f2 corresponding to the bit data d2 in the mixed signal. When the bit value of the bit data d3 is 1, the mixed signal generation unit 14 includes the oscillation signal of the frequency f3 corresponding to the bit data d3 in the mixed signal.

As shown in FIG. 6, for example, when the values of the first sub-encoded data and the second sub-encoded data are 0, the mixed signal generation unit 14 generates a mixed signal that does not include an oscillation signal. When the values of the first sub-encoded data and the second sub-encoded data are 1, the mixed signal generation unit 14 generates a mixed signal composed of an oscillation signal having a frequency f0. When the values of the first sub-encoded data and the second sub-encoded data are 7, the mixing signal generation unit 14 generates a mixed signal including an oscillation signal having a frequency f0, an oscillation signal having a frequency f1, and an oscillation signal having a frequency f2. Generate. In this way, the mixing signal generation unit 14 has one or more first frequencies assigned to each of the plurality of first sub-encoded data, and one or more first frequencies assigned to each of the plurality of second sub-encoded data. Generates a two-frequency signal and a time-division-multiplexed mixed signal.

Since the second sub-encoded data is data obtained by inverting the first sub-encoded data, the first frequency and the second frequency have different frequencies from each other. That is, the mixing signal generation unit 14 is one or more first ones included in the first mixed signal generated based on the first sub-encoded data among a plurality of predetermined frequencies based on the second sub-encoded data. A second mixed signal containing one or more second frequency signals different from the frequency is generated.

Further, as shown in FIG. 4, the mixed signal generation unit 14 generates a mixed signal in which the first mixed signal and the second mixed signal are adjacent to each other on the time axis. Although the details will be described later, by adjoining the first mixed signal and the second mixed signal in this way, the probability that an error generated during transmission is detected can be improved.

The mixed signal generation unit 14 arranges a synchronous signal continuously including a plurality of signals composed of signals having the same combination of frequencies in front of the first mixed signal and the second mixed signal corresponding to one sampling value. As a result, a mixed signal to be transmitted is generated. Specifically, the mixed signal generation unit 14 has a synchronization signal corresponding to one sampling data, an oscillation signal corresponding to a plurality of first sub-encoded data, and an oscillation signal corresponding to a plurality of second sub-encoded data. Generates a mixed signal that changes over a predetermined period of time less than or equal to the sampling interval. When the sampling frequency is 8 kHz and the sampling interval is 125 microseconds, the mixing signal generation unit 14 generates a mixed signal whose frequency changes sequentially within 125 microseconds.

The mixing signal generation unit 14 causes interference between each oscillation signal included in the mixing signal, and interference between each oscillation signal included in the mixing signal and the carrier signal generated by the carrier signal generation unit 15 described later. Generates a mixed signal that includes an oscillation signal with a frequency that does not. In the case of the example shown in FIGS. 5 and 6, the respective frequencies of the oscillation signals of frequencies f0, f1, f2, and f3 are such frequencies or the frequencies of the harmonics of these oscillation signals are the frequencies of the other oscillation signals. It is determined so as not to match the frequency of the harmonics of other oscillation signals, and the frequency of the carrier signal and the frequency of the harmonics of the carrier signal. Further, the respective frequencies of the oscillation signals of the frequencies f0, f1, f2, and f3 are such frequencies or the frequencies of the harmonics of these oscillation signals are the frequencies of a part of the oscillation signals of the frequencies f0, f1, f2, and f3. It is determined not to match the frequency generated when mixing.

The mixing signal generation unit 14 gradually increases the amplitude of the oscillation signal corresponding to each of the plurality of first sub-encoded data and the plurality of second sub-encoded data based on a predetermined window function, and maximizes the amplitude. After reaching the amplitude value, the amplitude may be gradually reduced. By doing so, the mixed signal generation unit 14 can prevent the mixed signal from containing unnecessary high frequency components.

The carrier signal generation unit 15 is an oscillator that generates a carrier signal. The carrier signal is, for example, an oscillation signal having a frequency in the range of 2 MHz or more and 3 MHz or less, which is used as the frequency of the carrier signal for infrared communication. The carrier signal generation unit 15 inputs the generated carrier signal to the modulation signal generation unit 16.

The modulation signal generation unit 16 frequency-modulates the carrier signal input from the carrier signal generation unit 15 with the mixing signal input from the mixing signal generation unit 14 to generate a modulated signal. The modulation signal generation unit 16 inputs the generated modulation signal to the transmission unit 17.

The transmission unit 17 transmits the modulation signal input from the modulation signal generation unit 16. The transmission unit 17 has, for example, a light emitting diode that emits infrared light and an amplifier circuit for driving the light emitting diode. The transmission unit 17 amplifies the frequency modulation signal input from the modulation signal generation unit 16 by an amplifier circuit, and changes the blinking cycle of light emission and extinguishing of the light emitting diode by the amplified signal, thereby infrared including the frequency modulation signal. Generates light. The transmission unit 17 has a high frequency circuit and an antenna, and may transmit radio waves including a modulated signal.

[Structure of sound signal receiving device 2]
Subsequently, the configuration of the sound signal receiving device 2 for receiving the modulated signal transmitted from the sound signal transmitting device 1 will be described in detail with reference to FIG. 7. FIG. 7 is a diagram showing the configuration of the sound signal receiving device 2. The sound signal receiving device 2 includes a receiving unit 21, a carrier signal generation unit 22, a demodulation signal generation unit 23, a decoding unit 24, a determination unit 25, and an interpolation unit 26.

The receiving unit 21 receives the frequency modulation signal transmitted from the sound signal transmitting device 1. When the sound signal transmitting device 1 emits infrared light including a modulated signal, the receiving unit 21 has an optical sensor that receives the infrared light. The receiving unit 21 inputs a light receiving signal whose blinking cycle changes according to the frequency modulation signal included in the received light to the demodulation signal generation unit 23.

Similar to the carrier signal generation unit 15, the carrier signal generation unit 22 is an oscillator that generates a carrier signal having a frequency in the range of 2 MHz or more and 3 MHz or less, which is used as a carrier signal frequency for infrared communication, for example. The carrier signal generation unit 22 inputs the generated carrier signal to the demodulation signal generation unit 23.

The demodulated signal generation unit 23 demodulates the modulated signal included in the received light signal input from the receiving unit 21 to generate a demodulated signal. Specifically, the demodulation signal generation unit 23 generates a demodulation signal corresponding to a mixed signal by mixing the light receiving signal input from the reception unit 21 and the carrier signal input from the carrier signal generation unit 22. do. The demodulation signal generation unit 23 inputs the generated demodulation signal to the decoding unit 24.

The decoding unit 24 generates synchronization data, first decoded data, and second decoded data based on the frequency included in the demodulated signal. FIG. 8 is a diagram schematically showing the operation of the decoding unit 24. As shown in FIG. 8, the decoding unit 24 has a plurality of bandpass filters that selectively pass signals having a plurality of frequencies f0, f1, f2, and f3 that may be included in the mixed signal. It also has a plurality of comparators that compare the level of the signal that has passed through each bandpass filter with a predetermined threshold value.

When the demodulated signal contains a signal component having a frequency f0, the bandpass filter corresponding to the frequency f0 inputs the signal component to the comparator. The comparator corresponding to the frequency f0 determines that the signal component of the frequency f0 is included in the demodulated signal when the amplitude of the input signal component or the amount of energy within a predetermined time is equal to or more than the threshold value, and is input. When the amplitude of the signal component or the amount of energy within a predetermined time is less than the threshold value, it is determined that the signal component having the frequency f0 does not exist in the demodulated signal. Similarly, the comparator corresponding to the frequency fn (n is 1, 2, 3) determines whether or not the signal component of the frequency fn is included in the demodulated signal.

When each comparator determines that the signal component of the corresponding frequency is included in the demodulated signal, each comparator outputs 1 as the decoded data of the corresponding frequency. When each comparator determines that the signal component of the corresponding frequency does not exist in the demodulated signal, it outputs 0 as the decoded data of the corresponding frequency. Specifically, the decoding unit 24 is the synchronization data in which the values of the bit data d0, d1, d2, and d3 are set to 1 or 0, respectively, depending on the presence or absence of the signal components of the frequencies f0, f1, f2, and f3. Generate the decrypted data and the second decoded data.

As shown in FIG. 3, when the first encoded data includes four first sub-encoded data, the decoding unit 24 has four as the first decoded data and the second decoded data, respectively. The first sub-decoding data and the second sub-decoding data are sequentially generated. The decoding unit 24 inputs the generated synchronization data, the first decoding data, and the second decoding data to the determination unit 25.

The determination unit 25 determines whether or not there is an error in the synchronization data. Further, the determination unit 25 determines whether or not at least one of the first decoded data and the second decoded data has an error. The determination unit 25 determines that at least one of the first decoded data and the second decoded data has an error when the first decoded data and the second decoded data are not in an inverted relationship with each other. Hereinafter, the details of the operation of the determination unit 25 will be described.

The determination unit 25 compares the first four data of the data input from the decoding unit 24 with a predetermined synchronization data pattern, and data of a predetermined ratio or more among the four data (for example, at least one data). If does not match the pattern of the synchronization data, it is determined that an error has occurred in the synchronization data. Then, the determination unit 25 determines that there is a high possibility that an error has occurred in the first decoded data and the second decoded data following the synchronization data. In this case, the determination unit 25 notifies the interpolation unit 26 that an error has occurred in the sampling data corresponding to the synchronization data.

When the first four data of the data input from the decoding unit 24 match the pattern of the synchronization data, the determination unit 25 causes an error in the first decoded data and the second decoded data. Determine if it is. The determination unit 25 determines that an error has occurred in either the first decoded data or the second decoded data when the first decoded data and the second decoded data are not in an inverted relationship with each other. do. When the first decoded data and the second decoded data include four first sub-decoded data and the second sub-decoded data, respectively, the determination unit 25 determines the corresponding first sub-decoded data. When and the second sub-decoded data are not in an inverted relationship with each other, it is determined that an error has occurred in either the first sub-decoded data or the second sub-decoded data.

For example, when the coded data shown in FIG. 4 is transmitted without error, the first sub-decoding data D0 becomes (0, 0, 0, 1) and the second sub-decoding data D0'is (1, 1). 1, 0). In this case, the determination unit 25 determines that no error has occurred in the first sub-decoding data D0 and the second sub-decoding data D0'. On the other hand, since the noise of the frequency f0 is superimposed on the transmission path, the first sub-decoding data D0 becomes (1, 0, 0, 1) and the second sub-decoding data D0'is (1, 1, 1). , 0), the first sub-decoding data D0 and the second sub-decoding data D0'are not in an inverted relationship. In this case, the determination unit 25 determines that an error has occurred in either the first sub-decoding data D0 or the second sub-decoding data D0'.

In the sound signal transmission system S of the present embodiment, the first coded data and the second coded data obtained by inverting the first coded data are continuously transmitted. By doing so, when the same noise is superimposed on the first coded data and the second coded data, the oscillation signal of the frequency corresponding to the noise among the first decoded data and the second decoded data is superimposed. It is considered that the value of one that does not contain is changed and the value of the other that contains the oscillation signal of the frequency does not change. As a result, the bit value of a part of the first decoded data and the bit value of a part of the second decoded data become the same value, and the inversion relationship is broken, so that the determination unit 25 can detect the occurrence of an error. ..

In this regard, when the same data is sent twice in succession, noise is superimposed and the same error occurs in the two data. Therefore, the two data have the same value, and the determination unit 25 causes an error. Cannot be detected. Therefore, in order to increase the probability that the occurrence of data error can be detected, the first coded data and the second coded data obtained by inverting the first coded data are continuously connected as in the sound signal transmission system S. It is preferable to transmit.

The interpolation unit 26 corresponds to the first decoded data and the second decoded data when the determination unit 25 determines that there is an error in at least one of the first decoded data and the second decoded data. Replace the sampling value with an interpolated value generated based on another sampling value. After interpolating the sampling data in which the error has occurred, the interpolation unit 26 converts the digital data composed of the plurality of sampling data into an analog signal and outputs it as a sound signal.

The interpolation unit 26 interpolates the sampling data in which an error occurs based on the values of a plurality of other sampling data, for example, by interpolation based on the Taylor approximation formula or interpolation by the Lagrange interpolation method. When an error is continuously detected in the sampling data by a predetermined number or more, the interpolation unit 26 may stop the data output by fading out or the like without interpolating the sampling data in which the error has occurred. By doing so, the sound signal receiving device 2 can prevent noise from being output.

FIG. 9 is a diagram showing an example of a sound signal generated by interpolating the value of sampling data in which an error has occurred by the interpolation unit 26. The solid line in FIG. 9 is the sampling data generated by the sound signal transmission device 1. That is, the solid line in FIG. 9 is sampling data in which no error has occurred. The broken line in FIG. 9 is the data obtained by interpolating using the Taylor quadratic approximation formula based on the three sampling data immediately before, assuming that each sampling data has an error. For example, the sampling data of the sampling time T5 is interpolated based on the sampling data of the sampling times T2, T3, and T4 in which no error occurs.

The alternate long and short dash line in FIG. 9 is data obtained by interpolating using the Lagrange secondary interpolation method based on the immediately preceding three sampling data, assuming that each sampling data has an error. Neither the data obtained by interpolating using the Taylor quadratic approximation formula nor the data obtained by interpolating using the Lagrangian quadratic interpolation method show a large deviation from the data shown by the solid line, and the data is incorrect. It is considered that the sound based on the noise that cannot be heard is reproduced.

[Effect of sound signal transmission system S]
As described above, in the sound signal transmission system S, the coding unit 12 of the sound signal transmission device 1 reverses the first coded data based on the sampling value of the sound signal and the second coded data. Generate coded data. Then, the mixing signal generation unit 14 has a first mixed signal including one or more first frequency signals assigned to the first coded data, and one or more second frequencies assigned to the second coded data. A second mixed signal including the signal and a mixed signal including the signal are generated, and the transmission unit 17 transmits the modulated signal generated by modulating the carrier signal with the mixed signal.

Then, does the determination unit 25 of the sound signal receiving device 2 have an inversion relationship between the first decoded data corresponding to the first encoded data and the second decoded data corresponding to the second encoded data? Based on whether or not, it is determined whether or not a data error has occurred. When the determination unit 25 determines that a data error has occurred, the interpolation unit 26 interpolates the sampling data in which the data error has occurred. With such a configuration, the sound signal receiving device 2 can detect that an error has occurred in the data with high accuracy and prevent the generation of noise.

Further, the coding unit 12 of the sound signal transmission device 1 obtains a plurality of 4-bit wide first sub-encoded data and a plurality of 4-bit wide second sub-encoded data based on one sampling data. Generate. By doing so, the sound signal transmission device 1 can reduce the types of frequencies used for the mixed signal as compared with the case of transmitting the first coded data and the second coded data having a width of 16 bits. .. As a result, the number of filters provided in the decoding unit 24 of the sound signal receiving device 2 can be reduced.

[Modification example]
In the above description, the coding unit 12 of the sound signal transmission device 1 divides one sampling data into a plurality of first sub-encoded data having a width of 4 bits and a plurality of second sub-codes having a width of 4 bits. Although an example of generating the coded data is shown, the coded data generated by the coding unit 12 is not limited to this. The coding unit 12 may use the sampling data itself as the first coding data and the inverted data of the sampling data as the second coding data without dividing the sampling data. Further, the coding unit 12 may generate the first sub-encoded data and the second sub-encoded data having a bit width other than the 4-bit width based on one sampling data.

Further, the sound signal transmission system S may use the first coded data and the second coded data, and may also use an error detection code or an error correction code. The sound signal transmission system S further increases the probability of detecting an error by using an error detection code or an error correction code together, and when the error can be corrected by the error correction code, the sound signal transmission system S is reproduced by the sound signal receiving device 2. It is possible to bring the sound closer to the original sound.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist. be. For example, the specific embodiment of the distribution / integration of the device is not limited to the above embodiment, and all or a part thereof may be functionally or physically distributed / integrated in any unit. Can be done. Also included in the embodiments of the present invention are new embodiments resulting from any combination of the plurality of embodiments. The effect of the new embodiment produced by the combination has the effect of the original embodiment together.

1 Sound signal transmitter 2 Sound signal receiver 11 Sound signal input unit 12 Coding unit 13 Frequency synthesizer 14 Mixed signal generation unit 15 Carrier signal generation unit 16 Modulation signal generation unit 17 Transmission unit 21 Reception unit 22 Carrier signal generation unit 23 Demodition Signal generation unit 24 Decoding unit 25 Judgment unit 26 Interpretation unit 141 Mixer

Claims (9)

A first coded data based on a sampled value of a sound signal, a coding unit that generates a second coded data obtained by inverting the first coded data, and a coding unit.
A first mixed signal containing one or more first frequency signals assigned to the first coded data and a second mixed signal containing one or more second frequency signals assigned to the second coded data. And, a mixed signal generator that generates a time-divided and multiplexed mixed signal,
A modulation signal generation unit that modulates a carrier signal with the mixed signal to generate a modulation signal,
A transmitter that transmits the modulated signal and
A sound signal transmitter having. The mixed signal generation unit generates the first mixed signal and the second mixed signal including signals having one or more frequencies in different combinations for each value of the first coded data and the value of the second coded data. do,
The sound signal transmitting device according to claim 1. The mixed signal generation unit generates the second mixed signal including a signal having one or more second frequencies different from the one or more first frequencies among a plurality of predetermined frequencies.
The sound signal transmitting device according to claim 1 or 2. The mixed signal generation unit generates the mixed signal in which the first mixed signal and the second mixed signal are adjacent to each other on the time axis .
The sound signal transmitting device according to any one of claims 1 to 3. The mixed signal generation unit continuously connects a plurality of signals composed of signals having the same combination of frequencies before the first mixed signal and the second mixed signal corresponding to one sampling value on the time axis. By arranging the synchronization signal including the above, the mixed signal is generated.
The sound signal transmitting device according to claim 4. The coding unit generates a plurality of first sub -encoded data as the first coded data based on the sampling value of the sound signal, and a plurality of inverted first sub-encoded data. The second sub-encoded data is generated as the second encoded data, and the second sub-encoded data is generated.
The mixed signal generation unit includes the one or more first frequency signals assigned to each of the plurality of first sub-encoded data and the one or more assigned to each of the plurality of second sub-encoded data. Generates the time-division-multiplexed mixed signal with the second frequency signal.
The sound signal transmitting device according to any one of claims 1 to 5. The first coded data based on the sampling value of the sound signal, the coding unit that generates the second coded data obtained by inverting the first coded data, and the first coded data among a plurality of predetermined frequencies. A first mixed signal containing one or more assigned first frequency signals and a second mixed signal containing one or more second frequency signals assigned to the second encoded data among the predetermined plurality of frequencies. A mixed signal generation unit that generates a mixed signal in which the signal is time-divided and multiplexed, a modulated signal generation unit that modulates a carrier signal with the mixed signal to generate a modulated signal, and a transmission unit that transmits the modulated signal. A sound signal receiving device that receives the modulated signal transmitted from the sound signal transmitting device having the above.
A demodulation unit that demodulates the modulated signal to generate a demodulated signal,
A decoding unit that generates the first-decoded data and the second-decoded data corresponding to the first-coded data and the second-coded data based on the frequency included in the demodulated signal.
A determination unit for determining whether or not at least one of the first decoded data and the second decoded data has an error, and a determination unit.
When the determination unit determines that there is an error in at least one of the first decoded data and the second decoded data, the sampling value corresponding to the first decoded data and the second decoded data. With an interpolator that replaces with an interpolated value generated based on other sampling values,
Sound signal receiver with. The determination unit determines that at least one of the first decoded data and the second decoded data is erroneous when the first decoded data and the second decoded data are not in an inverted relationship with each other. judge,
The sound signal receiving device according to claim 7. A sound signal transmission system including a sound signal transmitting device for transmitting a sound signal and a sound signal receiving device for receiving the sound signal transmitted by the sound signal transmitting device.
The sound signal transmitter is
A first coded data based on a sampled value of a sound signal, a coding unit that generates a second coded data obtained by inverting the first coded data, and a coding unit.
A first mixed signal containing one or more first frequency signals assigned to the first coded data and a second mixed signal containing one or more second frequency signals assigned to the second coded data. And, a mixed signal generator that generates a time-divided and multiplexed mixed signal,
A modulation signal generation unit that modulates a carrier signal with the mixed signal to generate a modulation signal,
A transmitter that transmits the modulated signal and
Have,
The sound signal receiving device is
A demodulation unit that demodulates the modulated signal to generate a demodulated signal,
A decoding unit that decodes the first coded data and the second coded data based on the frequency included in the demodulated signal to generate the first decoded data and the second decoded data.
A determination unit for determining whether or not at least one of the first decoded data and the second decoded data has an error, and a determination unit.
When the determination unit determines that there is an error in at least one of the first decoded data and the second decoded data, the sampling value corresponding to the first decoded data and the second decoded data. With an interpolator that replaces with an interpolated value generated based on other sampling values,
Sound signal transmission system with.

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