Noise removing apparatus, noise removing method, and noise removing program

Abstract

To provide a noise removing apparatus, a noise removing method, and a noise removing program capable of suppressing generation of beat noise in a signal received via an adjacent communication cable.SOLUTION: A noise removing apparatus includes: a beat waveform generation condition determination unit that determines whether a beat waveform generation condition, which is a condition for beat waveform generation by first and second signals, is satisfied based on frequencies of the first and second signals received via adjacent communication cables; a correction unit that corrects the frequency of at least one of the first and second signals when the beat waveform generation condition determination unit determines that the beat waveform generation condition is satisfied; and a transmission unit that transmits at least the signal of which the frequency has been corrected by the correction unit.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a noise removal device, a noise removal method, and a noise removal program for removing noise from a signal received via an adjacent communication cable. [Background technology]

[0002] Various techniques have been proposed for removing noise from a received signal. As an example of such a technique, Patent Document 1 discloses a noise detection device that determines whether or not noise is superimposed on a received signal based on the difference between the characteristics of noise caused by the switching operation of a switching amplifier that amplifies an amplitude-adjusted audio signal and the characteristics of the received signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-125586 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the noise detection device disclosed in Patent Document 1 determines the presence or absence of noise caused by the switching operation of a switching amplifier that amplifies an amplitude-adjusted audio signal, it cannot detect beat noise that occurs when multiple signals are received simultaneously via adjacent communication cables.As a result, the noise detection device disclosed in Patent Document 1 has the problem of being unable to suppress the occurrence of beat noise in signals received via adjacent communication cables.

[0005] In view of the above-mentioned problems, an object of the present disclosure is to provide a noise removal device, a noise removal method, and a noise removal program that can suppress the occurrence of beat noise in signals received via adjacent communication cables. [Means for solving the problem]

[0006] The noise removal device according to the present disclosure comprises: a beat waveform generation condition determination unit that determines whether a beat waveform generation condition, which is a condition for generating a beat waveform due to the first signal and the second signal, is satisfied based on the frequencies of the first signal and the second signal received via the adjacent communication cable; a correction unit that corrects the frequency of at least one of the first signal and the second signal when the beat waveform generation condition determination unit determines that the beat waveform generation condition is satisfied; The radio communication system includes at least a transmitter that transmits a signal whose frequency has been corrected by the corrector.

[0007] The noise removal method according to the present disclosure includes: determining whether a beat waveform generation condition, which is a condition for generating a beat waveform due to the first signal and the second signal, is satisfied based on the frequencies of the first signal and the second signal received via the adjacent communication cable; If it is determined that the beat waveform generation condition is satisfied, the frequency of at least one of the first signal and the second signal is corrected; At a minimum, a frequency corrected signal is transmitted.

[0008] The noise removal program according to the present disclosure is for a computer to: determining whether a beat waveform generation condition, which is a condition for generating a beat waveform due to the first signal and the second signal, is satisfied based on the frequencies of the first signal and the second signal received via the adjacent communication cable; If it is determined that the beat waveform generation condition is satisfied, the frequency of at least one of the first signal and the second signal is corrected; At the very least, a frequency corrected signal is transmitted. [Effects of the Invention]

[0009] The present disclosure makes it possible to provide a communication device, method, and program capable of suppressing the occurrence of beat noise in signals received via adjacent communication cables. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of a hardware configuration of a noise removal device according to the present disclosure. [Figure 2] 1 is a block diagram showing functions of a noise removal device according to the present disclosure. [Figure 3] 10 is a flowchart illustrating an example of processing executed by a noise removal device according to the present disclosure. [Figure 4] 10 is a flowchart illustrating another example of processing executed by the noise removal device according to the present disclosure. [Figure 5] FIG. 1 is a diagram illustrating main components of a noise removal device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, exemplary embodiments will be described with reference to the drawings. FIG. 1 is a diagram showing the hardware configuration of a noise removal device 1 according to the present disclosure. The noise removal device 1 is a device that removes noise from a signal received from a detection device and transmits the signal. The noise removal device 1 is connected to a detection device installed in a remote location via multiple communication cables such as submarine cables. A specific example of a detection device is a sensor that performs seabed observation.

[0012] The noise removal device 1 includes a calculation device 10, receiving units 11 and 21, storage devices 12 and 22, and transmitting units 13 and 23. The calculation device 10 is a device that performs overall control of the processing executed by the noise removal device 1. Specific examples of the calculation device 10 include processors such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit). Alternatively, the calculation device 10 may be an integrated circuit such as an FPGA (Field-Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0013] The receiving units 11 and 21 are interfaces that receive signals transmitted from an external device, such as a detection device, via adjacent, separate communication cables. The receiving units 11 and 21 are each connected to a separate communication cable. The receiving units 11 and 21 can simultaneously receive signals via adjacent communication cables. If the frequencies of two signals received substantially simultaneously are close to each other, or if the frequencies of the multiples of these signals are close to each other, beat noise due to crosstalk may occur. Hereinafter, of the two signals received by the receiving units 11 and 21 of the noise removal device 1, the signal with the higher frequency will be referred to as the first signal, and the signal with the lower frequency will be referred to as the second signal.

[0014] The storage devices 12 and 22 are storage devices that store signals received by the receiving units 11 and 21. The transmitting units 13 and 23 are interfaces that transmit signals to devices located downstream of the noise removal device 1 via cables.

[0015] 3 is a block diagram showing an example of a noise removal program 100 executed by the arithmetic device 10. The noise removal program 100 includes a beat waveform generation condition determination unit 101, a correction unit 102, and a signal storage unit 103.

[0016] The beat waveform generation condition determination unit 101 is a program that determines whether or not two signals satisfy the conditions for generating a beat waveform. FIG. 3 is a diagram showing an example of processing executed by the beat waveform generation condition determination unit 101.

[0017] In step S1, the beat waveform generation condition decision section 101 reduces the frequencies of the first signal and the second signal based on Equations 1 and 2.

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[0018] In step S2, the beat waveform generation condition decision unit 101 determines the frequency F of the first signal. i,1 The corresponding threshold f th,1 The frequency F of the first signal is determined to be greater than i,1 is the threshold f th,1 If it is determined that the frequency F of the first signal is equal to or less than the predetermined frequency F (NO), in other words, i,1 and the frequency of the second signal F i,2 If the ratio is not an integer ratio, the beat waveform generation condition decision unit 101 determines in step S5 that the beat waveform generation condition is not satisfied.

[0019] The frequency of the first signal, F i,1 is the threshold f th,1If it is determined that the frequency F of the second signal is greater than 1 (YES), then in step S3, the beat waveform generation condition determination unit 101 determines whether the frequency F of the second signal is greater than 1 (YES). i,2 The corresponding threshold f th,2 The frequency of the second signal is determined to be greater than F. i,2 is the threshold f th,2 If it is determined that the value is greater than (YES), the process returns to step S1.

[0020] On the other hand, the frequency of the second signal F i,2 is the threshold f th,2 If it is determined that the frequency F of the first signal is equal to or less than the predetermined frequency F (NO), the beat waveform generation condition determination unit 101 determines in step S4 that the beat waveform generation condition is satisfied. i,1 and the frequency of the second signal F i,2 The ratio of this to is an integer ratio.

[0021] When the ratio of the frequency f1 of the received first signal to the frequency f2 of the second signal is α:β, the α-th harmonic of the first signal and the β-th harmonic of the second signal will generate beats, resulting in the generation of unintended noise waveforms. In general, low-order harmonics (when the values ​​of α and β are small) tend to be more affected by beats, while high-order harmonics (when the values ​​of α and β are large) tend to be less affected by beats. Therefore, it is possible to determine in advance the ratio conditions at which significant effects occur, such as ignoring beats when the first signal and the second signal are high-order harmonics of 100th order or higher. For example, to ignore beats between harmonics of 100th order or higher, the threshold f th,1 can be set to 1 / 100 (f1 / 100) of the frequency f1 of the first signal received by the receiver 11. Note that the 100th order is an example, and the threshold value f can be set to any value depending on the conditions under which a significant effect occurs. th,1 can be set.

[0022] The ratio between the frequency f1 of the received first signal and the frequency f2 of the received second signal is likely to deviate slightly from a strict integer ratio. th,2 is the threshold f th,1 A positive value that is sufficiently small compared to, say, a threshold f th,11 / 100 of (f th,1 / 100), i.e., 1 / 1000 (f1 / 1000) of the frequency f1 of the received first signal. th,2 does not necessarily depend on the threshold f th,1 It is not necessary to set the threshold value f th,1 : threshold f th,2 The ratio of these thresholds does not have to be an integer ratio. Note that these thresholds are independent numerical values.

[0023] The correction unit 102 is a program that corrects at least one of the frequencies of two signals received by the receiving units 11 and 21 of the noise removal device 1. For example, the correction unit 102 can correct one of the frequencies of the two signals by adding or subtracting a predetermined frequency to or from it.

[0024] The signal storage unit 103 is a program that stores the signal whose frequency has been corrected by the correction unit 102 in the storage devices 12 and 22 .

[0025] The arithmetic device 10 can output the execution results of the above-described processes via the transmission units 13 and 23.

[0026] 4 is a flowchart showing an example of processing executed by the noise removal device according to the present disclosure. The following description will be given taking the noise removal device 1 as an example.

[0027] In step S11, the beat waveform generation condition determination unit 101 of the noise removal device 1 determines whether or not the beat waveform generation condition is satisfied based on the frequencies of the two signals received by the receiving units 11 and 21 of the noise removal device 1. If it is determined that the beat waveform generation condition is not satisfied (NO), the process branches to step S14. In step S14, the transmitting units 13 and 23 each transmit a signal.

[0028] On the other hand, if it is determined in step S11 that the beat waveform generation condition is met (YES), the process branches to step S12. In step S12, the correction unit 102 corrects the frequency of at least one of the two signals received by the receiving units 11 and 21, respectively.

[0029] In step S13, the signal storage unit 103 stores the two signals in the storage devices 12 and 22. At this time, if correction has been applied to both of the two signals, the signal storage unit 103 stores the two corrected signals in the storage devices 12 and 22. If correction has been applied to only one of the signals, the signal storage unit 103 stores the corrected signal and the uncorrected signal in the storage devices 12 and 22.

[0030] After step S13 is completed, the process returns to step S11. In step S11, the beat waveform generation condition determination unit 101 determines whether the beat waveform generation condition is satisfied using the frequency-corrected signals. More specifically, if the frequencies of both the first signal and the second signal have been corrected, the beat waveform generation condition determination unit 101 determines whether the beat waveform generation condition is satisfied based on the corrected frequencies of the first signal and the second signal. If the frequency of the first signal has been corrected but the frequency of the second signal has not, the beat waveform generation condition determination unit 101 determines whether the beat waveform generation condition is satisfied based on the corrected frequency of the first signal and the uncorrected frequency of the second signal. If the frequency of the first signal has not been corrected but the frequency of the second signal has been corrected, the beat waveform generation condition determination unit 101 determines whether the beat waveform generation condition is satisfied based on the uncorrected frequency of the first signal and the corrected frequency of the second signal.

[0031] After the signal is stored in step S13, if it is determined in step S11 that the beat waveform generation condition is not satisfied, the transmitters 13 and 23 transmit the latest signals stored in the storage devices 12 and 22 in step S14. Specifically, if the frequencies of both the first signal and the second signal have been corrected, the transmitters 13 and 23 transmit the frequency-corrected first signal and the frequency-corrected second signal, respectively. If the frequency of one of the first signal and the second signal has been corrected, the transmitters 13 and 23 transmit the frequency-corrected signal and the frequency-uncorrected signal. More specifically, if the frequency of the first signal has been corrected, the transmitter 13 transmits the frequency-corrected first signal, and the transmitter 23 transmits the frequency-uncorrected second signal. On the other hand, if the frequency of the second signal has been corrected, the transmitter 13 transmits the frequency-corrected first signal, and the transmitter 23 transmits the frequency-corrected second signal.

[0032] 5 is a diagram showing the main components of the noise removal device 1 according to the present disclosure. The noise removal device 1 includes a beat waveform generation condition determination unit 101, a correction unit 102, and transmission units 13 and 23.

[0033] The beat waveform generation condition determination unit 101 determines whether a beat waveform generation condition, which is a condition for generating a beat waveform from the first signal and the second signal, is satisfied based on the frequencies of the first signal and the second signal received via adjacent communication cables. If the beat waveform generation condition determination unit determines that the beat waveform generation condition is satisfied, the correction unit 102 corrects the frequency of at least one of the first signal and the second signal. The transmission units 13 and 23 transmit at least the signal whose frequency has been corrected by the correction unit 102.

[0034] By adopting this configuration, when two signals are received simultaneously via adjacent communication cables and beat noise is likely to occur in these two signals, the noise elimination device 1 corrects the frequency of at least one of the signals.The noise elimination device 1 then transmits the signal with the corrected frequency.This makes it possible for a transmission device downstream of the noise elimination device 1 to suppress beat noise in the transmitted signal.

[0035] Furthermore, the beat waveform generation condition determination unit 101 determines whether or not the beat waveform generation condition is satisfied based on the frequency of the signal corrected by the correction unit 102. If it is determined that the beat waveform generation condition is not satisfied based on the frequency of the signal corrected by the correction unit 102, the transmission units 13 and 23 transmit the signal whose frequency has been corrected by the correction unit 102. This allows the transmission device downstream of the noise removal device 1 to effectively suppress the occurrence of beat noise in the transmitted signal.

[0036] In the above examples, the program includes instructions (or software code) that, when loaded into a computer, cause the computer to perform one or more functions described in the embodiments. The program may be stored on a non-transitory computer-readable medium or a tangible storage medium. By way of example and not limitation, computer-readable medium or tangible storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD) or other memory technology, CD-ROM, digital versatile disk (DVD), Blu-ray® disk or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage device. The program may also be transmitted on a transitory computer-readable medium or communication medium. By way of example and not limitation, transitory computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagated signals.

[0037] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate.

[0038] Each drawing is merely an example for describing one or more embodiments. Each drawing may relate not only to one particular embodiment, but also to one or more other embodiments. As will be understood by those skilled in the art, various features or steps described with reference to any one drawing can be combined with features or steps shown in one or more other drawings to create, for example, an embodiment not explicitly shown or described. Not all features or steps shown in any one drawing are necessary to describe an exemplary embodiment, and some features or steps may be omitted. The order of steps described in any drawing may be changed as appropriate.

[0039] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) a beat waveform generation condition determination unit that determines, based on the frequencies of a first signal and a second signal received via adjacent communication cables, whether a beat waveform generation condition, which is a condition under which a beat waveform is generated by the first signal and the second signal, is satisfied; a correction unit that corrects the frequency of at least one of the first signal and the second signal when the beat waveform generation condition determination unit determines that the beat waveform generation condition is satisfied; and a transmitter that transmits at least a signal whose frequency has been corrected by the corrector; A noise removal device comprising: (Appendix 2) the beat waveform generation condition determination unit determines whether the beat waveform generation condition is satisfied based on the frequency of the signal corrected by the correction unit; 2. The noise removal device according to claim 1, wherein the transmitting unit transmits a signal whose frequency has been corrected by the correcting unit when it is determined that the beat waveform generation condition is not satisfied based on the frequency of the signal corrected by the correcting unit. (Appendix 3) Among the received signals, one having a higher frequency is designated as the first signal, and one having a lower frequency is designated as the second signal; The beat waveform generation condition determination unit is configured to determine whether or not a beat waveform generation condition is satisfied by the following equation:

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[0040] Some or all of the elements described in Supplementary Notes 4 to 6 that are dependent on Supplementary Note 1 may also be dependent on Supplementary Note 9 in the same dependent relationship as Supplementary Note 4 to 6. Some or all of the elements described in Supplementary Notes 2 to 6 that are dependent on Supplementary Note 1 may also be dependent on Supplementary Note 10 in the same dependent relationship as Supplementary Note 2 to 6. Some or all of the elements described in any Supplementary Note may be applied to various hardware, software, recording means for recording software, systems, and methods. [Explanation of symbols]

[0041] 1. Noise reduction device 10 Arithmetic unit 11 Receiving unit 12 Storage device 13 Transmitter 21 Receiving unit 22 Storage device 23 Transmitter 100 Noise Removal Program 101 Beat waveform generation condition determination section 102 Correction unit 103 Signal storage section

Claims

1. a beat waveform generation condition determination unit that determines, based on the frequencies of a first signal and a second signal received via adjacent communication cables, whether a beat waveform generation condition, which is a condition for generating a beat waveform due to the first signal and the second signal, is satisfied; a correction unit that corrects the frequency of at least one of the first signal and the second signal when the beat waveform generation condition determination unit determines that the beat waveform generation condition is satisfied; and a transmitter that transmits at least a signal whose frequency has been corrected by the corrector; A noise removal device comprising:

2. the beat waveform generation condition determination unit determines whether the beat waveform generation condition is satisfied based on the frequency of the signal corrected by the correction unit; 2. The noise removal device according to claim 1, wherein the transmitting unit transmits the signal whose frequency has been corrected by the correcting unit when it is determined that the beat waveform generation condition is not satisfied based on the frequency of the signal corrected by the correcting unit.

3. Among the received signals, one having a higher frequency is designated as the first signal, and one having a lower frequency is designated as the second signal; The beat waveform generation condition determination unit is configured to determine whether or not a beat waveform is generated by the following equation (1): [Equation 1] Based on this, the frequency F of the first signal ｉ，１ and the frequency F of the second signal ｉ，２ and reducing the frequency F of the reduced first signal. ｉ，１ is the corresponding predetermined threshold f ｔｈ，１ and the frequency F of the second signal ｉ，２ is the corresponding predetermined threshold f ｔｈ，２ It is determined that the beat waveform generation condition is satisfied if: In the above formula 1, i is an integer representing the number of times the frequency of the first signal and the second signal is reduced, and F ｉ，１ represents the frequency of the first signal reduced i times, F ｉ，２ represents the frequency of the second signal reduced i times, F ０，２ represents the frequency of the second signal before it is reduced in frequency, and F ０，１ is the frequency f of the first signal before it is reduced in frequency. １ represents n ｉ is an integer that satisfies the condition of Equation 2. [Equation 2] The noise removal device according to claim 1 or 2.

4. 3. The noise removal device according to claim 1, wherein, when it is determined that the beat waveform generation condition is satisfied, the correction unit corrects the frequency of at least one of the first signal and the second signal by adding a predetermined frequency to the frequency of at least one of the first signal and the second signal or by subtracting a predetermined frequency from the frequency of the at least one of the first signal and the second signal.

5. 3. The noise removal device according to claim 1, wherein when the frequencies of both the first signal and the second signal are corrected by the correction unit, the transmission unit transmits the first signal and the second signal whose frequencies have been corrected.

6. when the frequency of the first signal is corrected by the correction unit, the transmission unit transmits the first signal whose frequency has been corrected and the second signal whose frequency has not been corrected; 6. The noise removal device according to claim 5, wherein, when the frequency of the second signal is corrected by the correction unit, the transmission unit transmits the first signal whose frequency is not corrected and the second signal whose frequency is corrected.

7. The computer determining whether a beat waveform generation condition, which is a condition for generating a beat waveform due to the first signal and the second signal, is satisfied based on frequencies of the first signal and the second signal received via the adjacent communication cable; If it is determined that the beat waveform generation condition is satisfied, correcting the frequency of at least one of the first signal and the second signal; At a minimum, transmit a frequency corrected signal Noise removal method.

8. The computer determining whether the beat waveform generation condition is satisfied based on the frequency of the corrected signal; 8. The noise removal method according to claim 7, further comprising transmitting a signal whose frequency has been corrected when it is determined that the beat waveform generation condition is not satisfied based on the frequency of the corrected signal.

9. Among the received signals, one having a higher frequency is designated as the first signal, and one having a lower frequency is designated as the second signal; The computer calculates Equation 1 [Equation 1] Based on this, the frequency F of the first signal ｉ，１ and the frequency F of the second signal ｉ，２ and reducing the frequency F of the reduced first signal. ｉ，１ and the frequency F of the second signal ｉ，２ and determining that the beat waveform generation condition is satisfied when both of the above are equal to or less than the corresponding predetermined threshold values; In the above formula 1, i is an integer representing the number of times the frequency of the first signal and the second signal is reduced, and F ｉ，１ represents the frequency of the first signal reduced i times, F ｉ，２ represents the frequency of the second signal reduced i times, F ０，２ represents the frequency of the second signal before it is reduced in frequency, and F ０，１ is the frequency f of the first signal before it is reduced in frequency. １ represents n ｉ is an integer that satisfies the condition of Equation 2. [Equation 2] The noise removal method according to claim 7 or 8.

10. For computers, determining whether a beat waveform generation condition, which is a condition for generating a beat waveform due to the first signal and the second signal, is satisfied based on the frequencies of the first signal and the second signal received via the adjacent communication cable; If it is determined that the beat waveform generation condition is satisfied, the frequency of at least one of the first signal and the second signal is corrected; At the very least, have the frequency corrected signal transmitted. Noise removal program.

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