Signal processing method and device

Abstract

The invention provides a signal processing method and device. The signal processing method provided by the invention comprises the following steps: receiving a first optical signal, wherein the first optical signal comprises optical signals of multiple frequencies; performing phase modulation processing on the first optical signal to obtain a second optical signal, the phase difference between the optical signal of the first frequency and the optical signal of the second frequency in the second optical signal being a first preset phase value, the absolute value of the difference between the first frequency and the third frequency in the second optical signal is the same as the absolute value of the difference between the second frequency and the fourth frequency in the second optical signal; and sending the second optical signal to a photoelectric detector PD. According to the signal processing method provided by the invention, the influence of the interference microwave signal demodulated by the stray light signal can be reduced.

Description

Signal processing method and device Technical Field

[0001] The present application relates to the field of communication technology, and more specifically, to a signal processing method and device. Background Art

[0002] Due to the advantages of optical fiber such as low loss and long signal transmission distance, in current optical wireless communication technology, the transmitter first modulates the original microwave signal onto an optical signal to obtain a modulated optical signal, and then transmits the modulated optical signal to the receiver via optical fiber. After that, when the receiver receives the modulated optical signal, it uses a photoelectric detector (PD) to convert the modulated optical signal into optical and electrical signals to demodulate the original microwave signal.

[0003] However, in the above-mentioned optical wireless communication technology, when the modulated optical signal is transmitted to the PD through a transmission medium such as an optical fiber, it is usually inevitably affected by nonlinear effects, introducing stray optical signals (which can be considered as some interfering optical signals). As a result, when the receiving end uses the PD to demodulate the modulated optical signal, the demodulated microwave signal includes not only the original microwave signal, but also some interfering microwave signals demodulated due to the stray optical signal. These interfering microwave signals will affect the communication quality.

[0004] Therefore, how to reduce the impact of interfering microwave signals demodulated from stray optical signals has become a technical problem that needs to be solved urgently.

[0005] Summary of the Invention

[0006] The present application provides a signal processing method and device, which can reduce the impact of interfering microwave signals demodulated from stray optical signals.

[0007] In a first aspect, the present application provides a signal processing method, which is applied to a signal processing device, including: receiving a first optical signal, the first optical signal including optical signals of multiple frequencies; performing phase modulation processing on the first optical signal to obtain a second optical signal, the phase difference between the optical signal of the first frequency and the optical signal of the second frequency in the second optical signal is a first preset phase value, the absolute value of the difference between the first frequency and the third frequency in the second optical signal is the same as the absolute value of the difference between the second frequency and the fourth frequency in the second optical signal; and sending the second optical signal to a photodetector PD.

[0008] Since the signal processing device only performs phase modulation processing on the first optical signal, in this embodiment, the frequencies included in the second optical signal obtained after the signal processing device performs phase modulation processing are the same as the multiple frequencies included in the first optical signal.

[0009] In this embodiment, after obtaining a first optical signal, to reduce interference caused by an optical signal of a certain frequency (also referred to as the first frequency) input into the PD, the phase difference between an optical signal of the first frequency and an optical signal of the second frequency in the first optical signal is adjusted to a first preset phase value. Alternatively, the phase difference between an optical signal of the second frequency and an optical signal of the first frequency in the first optical signal is adjusted to the first preset phase value. The first and second frequencies satisfy a condition where the absolute value of the difference between the first frequency and a third frequency among the multiple frequencies is the same as the absolute value of the difference between the second frequency and a fourth frequency among the multiple frequencies.

[0010] It should be understood that, after passing through the PD, the optical signal of the first frequency and the optical signal of the third frequency will form a first electrical signal having a frequency equal to the absolute value of the difference between the first frequency and the third frequency, while the optical signal of the second frequency and the optical signal of the fourth frequency will form a second electrical signal having a frequency equal to the absolute value of the difference between the second frequency and the fourth frequency after passing through the PD. Since the absolute value of the difference between the first frequency and the third frequency is the same as the absolute value of the difference between the second frequency and the fourth frequency among the multiple frequencies (in this embodiment, the frequency having a frequency equal to the absolute value of the difference between the first frequency and the third frequency or the absolute value of the difference between the second frequency and the fourth frequency is referred to as the target frequency), the first electrical signal will be superimposed on the second electrical signal. However, since in this embodiment, the phase difference between the optical signal of the second frequency and the optical signal of the first frequency is adjusted to the first preset phase value, the amplitude (or intensity) of the final target frequency electrical signal will be reduced after the first electrical signal is superimposed on the second electrical signal, thereby reducing the impact of the interfering microwave signal demodulated by the optical signal of the first frequency or the optical signal of the second frequency.

[0011] In combination with the first aspect, in a possible implementation, the first optical signal includes a modulated optical signal obtained by modulating the first microwave signal using an optical carrier signal, wherein the first frequency and the second frequency are different from frequencies included in the modulated optical signal.

[0012] It should be understood that after the first microwave signal is modulated using an optical carrier signal to obtain a modulated optical signal, the modulated optical signal may introduce some optical signals of frequencies other than the frequency included in the modulated optical signal during transmission. These optical signals of frequencies other than the frequency included in the modulated optical signal can be considered as signals that interfere with the modulated optical signal. Therefore, in this embodiment, frequencies other than the frequency included in the modulated optical signal can be used as the first frequency and the second frequency in this application. By adjusting the phase difference between the first frequency and the second frequency to a first preset phase value, the impact of interfering microwave signals demodulated from optical signals of frequencies other than the frequency included in the modulated optical signal can be reduced.

[0013] With reference to the first aspect, in a possible implementation, a portion of the multiple frequencies are distributed within a target frequency band, where the target frequency band is a frequency band where the modulated optical signal is located.

[0014] With reference to the first aspect, in a possible implementation, the first frequency is located within a target frequency band, and the second frequency is located outside the target frequency band.

[0015] In this implementation, by adjusting the phase difference between an optical signal corresponding to a first frequency within the frequency band where the modulated optical signal is located (i.e., the target frequency band) and an optical signal corresponding to a second frequency outside the frequency band where the modulated optical signal is located to a first preset phase value, the influence of the interfering microwave signal demodulated from the optical signal corresponding to the first frequency within the target frequency band can be reduced by the optical signal corresponding to the second frequency outside the target frequency band.

[0016] With reference to the first aspect, in a possible implementation manner, the third frequency and the fourth frequency are located within the target frequency band, the first frequency is located outside the target frequency band, and the second frequency is located outside the target frequency band.

[0017] In this implementation, by adjusting the phase difference between the optical signal corresponding to the first frequency and the optical signal corresponding to the second frequency, both of which are outside the frequency band where the modulated optical signal is located (i.e., the target frequency band), to a first preset phase value, the optical signal corresponding to the second frequency outside the target frequency band can be used to reduce the impact of the interfering microwave signal demodulated from the optical signal corresponding to the first frequency outside the target frequency band.

[0018] With reference to the first aspect, in a possible implementation, the third frequency and the fourth frequency are the same frequency.

[0019] Exemplarily, the same frequency is the frequency of the optical carrier signal.

[0020] With reference to the first aspect, in a possible implementation, the first preset phase value is 180 degrees.

[0021] In combination with the first aspect, in a possible implementation, the method further includes: receiving first feedback information, the first feedback information indicating a second microwave signal demodulated by the PD based on the second optical signal at a first preset phase value; and adjusting the first preset phase value based on the second microwave signal.

[0022] In this implementation, the signal processing device can receive the first feedback information and determine whether the first preset phase value needs to be adjusted based on the second microwave signal indicated by the first feedback information, so that the signal processing device can better phase-modulate the first optical signal to further reduce the influence of the interfering microwave signal generated by demodulation of the optical signal of the first frequency and the optical signal of the second frequency.

[0023] In a second aspect, the present application provides a signal processing device, including: a transceiver module for receiving a first optical signal, the first optical signal including optical signals of multiple frequencies; a processing module for performing phase modulation processing on the first optical signal to obtain a second optical signal, the phase difference between the optical signal of the first frequency and the optical signal of the second frequency in the second optical signal is a first preset phase value, and the absolute value of the difference between the first frequency and the third frequency in the second optical signal is the same as the absolute value of the difference between the second frequency and the fourth frequency in the second optical signal; the transceiver module is also used to send the second optical signal to the photodetector PD.

[0024] In combination with the second aspect, in a possible implementation, the first optical signal includes a modulated optical signal obtained by modulating the first microwave signal using an optical carrier signal, wherein the first frequency and the second frequency are different from the frequencies included in the modulated optical signal.

[0025] In combination with the second aspect, in a possible implementation manner, a portion of the multiple frequencies are distributed within a target frequency band, where the target frequency band is a frequency band where the modulated optical signal is located.

[0026] With reference to the second aspect, in a possible implementation manner, the first frequency is located within the target frequency band, and the second frequency is located outside the target frequency band.

[0027] With reference to the second aspect, in a possible implementation, the first frequency is outside the target frequency band, and the second frequency is outside the target frequency band.

[0028] With reference to the second aspect, in a possible implementation, the third frequency and the fourth frequency are the same frequency.

[0029] Exemplarily, the same frequency is the frequency of the optical carrier signal.

[0030] In combination with the second aspect, in a possible implementation, the first preset phase value is 180 degrees.

[0031] In combination with the second aspect, in one possible implementation, the transceiver module is also used to: receive first feedback information, the first feedback information indicating a second microwave signal demodulated by the PD based on the second optical signal at a first preset phase value; the processing module is also used to adjust the first preset phase value based on the second microwave signal.

[0032] In a third aspect, the present application provides a signal processing device comprising: a memory and a processor; the memory is used to store program instructions; the processor is used to call the program instructions in the memory to execute the method described in the first aspect or any possible implementation thereof.

[0033] In a fourth aspect, the present application provides a communication system, comprising a signal processing device as described in the second aspect or the third aspect or any possible implementation thereof.

[0034] In a fifth aspect, the present application provides a computer-readable medium, which stores a program code for computer execution, wherein the program code includes instructions for executing the method as described in the first aspect or any possible implementation thereof.

[0035] In a sixth aspect, the present application provides a computer program product, which includes a computer program code. When the computer program code is run on a computer, the computer implements the method described in the first aspect or any possible implementation thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG1 is a schematic diagram of an application scenario provided by this application;

[0037] FIG2 is a schematic diagram of a structure for reducing the influence of interfering microwave signals demodulated from stray optical signals in the prior art;

[0038] FIG3 is a flow chart of a signal processing method provided by an embodiment of the present application;

[0039] FIG4 is a structural diagram of a first optical signal provided by an embodiment of the present application;

[0040] FIG5 is a structural schematic diagram of a phase modulation process provided by one embodiment of the present application;

[0041] FIG6 is a schematic diagram of a spectrum of a first optical signal obtained by introducing a stray optical signal into a modulated optical signal according to an embodiment of the present application;

[0042] FIG7 is a structural schematic diagram of a phase modulation process provided by one embodiment of the present application;

[0043] FIG8 is a structural schematic diagram of a phase modulation process provided by one embodiment of the present application;

[0044] FIG9 is a structural diagram of a signal processing system according to an embodiment of the present application;

[0045] FIG10 is a structural diagram of a signal processing device provided in one embodiment of the present application;

[0046] FIG11 is a structural diagram of a signal processing device provided in another embodiment of the present application. DETAILED DESCRIPTION

[0047] Microwave photonics technology modulates microwave signals onto optical signals, performing signal generation, processing, and transmission in the optical domain. As a result, it has been widely used in fields such as radio over fiber (ROF) communications, array radar, and cable television.

[0048] For example, Figure 1 is a schematic diagram of an application scenario provided by this application. As shown in Figure 1, in a ROF communication scenario, due to the advantages of optical fiber such as low loss, long transmission distance, larger transmission capacity, and lower cost, the transmitting end 101 first uses an optical modulator to modulate the microwave signal to obtain a modulated optical signal (i.e., the microwave signal is converted into an optical signal after modulation), and then transmits the modulated optical signal to the receiving end 102 via optical fiber. Afterwards, when the receiving end 102 receives the modulated optical signal, it uses a photoelectric detector (PD) to perform photoelectric conversion on the modulated optical signal to demodulate the microwave signal and obtain the transmitted information.

[0049] However, in the above-mentioned ROF communication scenario, when the modulated optical signal is transmitted to the PD through a transmission medium such as an optical fiber, it is usually inevitably affected by nonlinear effects, thereby introducing stray optical signals of other frequencies. These stray optical signals can be considered as some interference signals, such as second-order intermodulation stray optical signals and third-order intermodulation signals, etc. Some of these stray optical signals are odd-order stray optical signals, and some are even-order stray optical signals. They may be distributed within the frequency band or outside the frequency band. Usually, stray optical signals outside the frequency band can be removed by filtering, etc., while the stray optical signals within the frequency band are the most difficult to eliminate. As a result, when the modulated optical signal is demodulated using the PD, the demodulated microwave signal also includes some interfering microwave signals demodulated by the stray optical signals of other frequencies. These interfering microwave signals will affect the communication quality. Therefore, how to reduce the impact of the interfering microwave signals demodulated by the stray optical signals has become a technical problem that needs to be solved urgently.

[0050] It should be noted that the embodiments of the present application do not limit the number of frequency components included in the microwave signal. For example, the microwave signal may be a microwave signal including only one frequency component, also referred to as a single-frequency microwave signal in the present application; or, the microwave signal may be a microwave signal including multiple frequency components, also referred to as a multi-frequency microwave signal in the present application.

[0051] It should be understood that, whether it is a single-frequency microwave signal or a multi-frequency microwave signal, the modulated optical signal obtained through optical modulation will include the optical carrier frequency used during modulation, that is, the modulated optical signal obtained through modulation is a signal including multiple frequency components.

[0052] Currently, one implementation method for reducing the impact of interfering microwave signals demodulated from stray optical signals is shown in FIG2 : an original microwave signal (e.g., a microwave signal including frequencies f1 and f2) is passed through a 180-degree hybrid coupler. The 180-degree hybrid coupler is used to output two microwave signals based on the original microwave signal. Specifically, the first microwave signal is the original microwave signal, and the second microwave signal is a microwave signal with a phase difference of 180 degrees with the original microwave signal. The first microwave signal is then modulated using a laser 1 (LD1 in FIG2 ) to obtain a first modulated optical signal, and the second microwave signal is modulated using a laser 2 (LD2 in FIG2 ) to obtain a second modulated optical signal. The two modulated optical signals are transmitted to a balanced photodetector (BPD) via an optical fiber. Finally, the BPD demodulates the first modulated optical signal to obtain a first microwave signal and the second modulated optical signal to obtain a second microwave signal, and performs a subtraction between the first and second microwave signals to output a demodulated target microwave signal.

[0053] It can be understood that in the process of transmitting the first modulated optical signal and the second modulated optical signal to the balanced photodetector through the optical fiber, stray optical signals may be introduced into the first modulated optical signal and the second modulated optical signal. It is assumed that the first modulated optical signal after the introduction of stray optical signals is called the first distorted modulated optical signal, and the second modulated optical signal after the introduction of stray optical signals is called the second distorted modulated optical signal. In this implementation, since the phases of the first microwave signal and the second microwave signal differ by 180 degrees, the phases of the odd-order stray light signals included in the first distorted modulated optical signal and the odd-order stray light signals included in the second distorted modulated optical signal are in opposite phases, while the phases of the even-order stray light signals included in the first distorted modulated optical signal and the even-order stray light signals included in the second distorted modulated optical signal are in phase. Therefore, after the first distorted modulated optical signal and the second distorted modulated optical signal are input into the BPD, the interfering microwave signals caused by the anti-phase stray light signals in the first distorted modulated optical signal and the second distorted modulated optical signal are added together, while the interfering microwave signals caused by the in-phase stray light signals in the first distorted modulated optical signal and the second distorted modulated optical signal cancel each other out, thereby eliminating the even-order stray light signals.

[0054] Among them, when reducing the interfering microwave signal demodulated by the stray optical signal, as shown in Figure 2, a variable optical attenuator (VOA) can be used to adjust the amplitude of the first optical signal, and a variable optical delay line (VODL) can be used to adjust the phase of the second optical signal, so that the even-order stray optical signals in the demodulated first microwave signal and the second microwave signal can be better offset.

[0055] It can be seen that this method of eliminating stray light signals can only cancel out even-numbered stray light signals, but cannot cancel out odd-numbered stray light signals. In addition, this method requires two modulators and two photodetectors, which is relatively costly.

[0056] In view of this, an embodiment of the present application proposes a signal processing method to reduce the impact of interfering microwave signals demodulated from stray optical signals.

[0057] Figure 3 is a schematic diagram illustrating a signal processing method according to one embodiment of the present application. As shown in Figure 3 , the method includes steps S301, S302, and S303. The method can be performed by a signal processing device. The signal processing device can be a chip for processing the signal processing method described herein and can be located within the receiving end 102 shown in Figure 1 and before the PD included in the receiving end 102.

[0058] It should be noted that this embodiment does not limit the specific form of receiving end 102. For example, receiving end 102 may be a base station that performs optoelectronic conversion on modulated optical signals to demodulate microwave signals. In this case, the signal processing device in this embodiment may be located in the base station and before the PD included in the base station.

[0059] S301: Receive a first optical signal, where the first optical signal includes optical signals of multiple frequencies.

[0060] It is understandable that a signal can usually be decomposed into signals of different frequencies, or in other words, a signal can usually be composed of the superposition of multiple signals of different frequencies, or in other words, signals of different frequencies can be synthesized into one signal.

[0061] In this embodiment, the first optical signal including optical signals of multiple frequencies can be understood as: the first optical signal is formed by superimposing optical signals of multiple frequencies, or the optical signals of multiple frequencies can be combined into the first optical signal.

[0062] It should be noted that the embodiments of the present application do not limit how to obtain optical signals of multiple frequencies included in the first optical signal. For example, an optical spectrum diagram of the first optical signal can be obtained by a spectrometer, and the optical spectrum diagram of the first optical signal can be analyzed to obtain optical signals of multiple frequencies included in the first optical signal.

[0063] As described in the relevant parts of the previous application, optical signals are usually inevitably affected by nonlinear effects during transmission. Therefore, in this embodiment, the first optical signal received by the signal processor may usually be a nonlinearly distorted optical signal, that is, in addition to including some target optical signals corresponding to desired frequencies, the first optical signal may also include some other optical signals corresponding to unwanted frequencies. Among them, the optical signals corresponding to these unwanted frequencies are also referred to as interfering optical signals or stray optical signals in this application. Specifically, these stray optical signals can be odd-numbered stray optical signals or even-numbered stray optical signals.

[0064] For example, FIG4 is a structural diagram of a first optical signal provided by an embodiment of the present application. As shown in FIG4 , the first optical signal includes: an optical signal with a frequency of f1, an optical signal with a frequency of f2; in addition, it also includes optical signals with a frequency of 2f1-f2 and a frequency of 2f2-f1, and an optical signal with a frequency of f2-f1 and a frequency of f1+f2. Among them, the optical signal with a frequency of f1 and the optical signal with a frequency of f2 are the desired target optical signals, the optical signals with a frequency of f2-f1 and a frequency of f1+f2 are second-order intermodulation optical signals generated based on the frequency f1 and the frequency f2, and the optical signals with a frequency of 2f1-f2 and a frequency of 2f2-f1 are third-order intermodulation optical signals generated based on the frequency f1 and the frequency f2. That is, in addition to the target optical signal, the first optical signal of this example also includes a second-order intermodulation optical signal and a third-order intermodulation optical signal, and the second-order intermodulation optical signal and the third-order intermodulation optical signal are stray optical signals.

[0065] S302: Perform phase modulation processing on the first optical signal to obtain a second optical signal, wherein the phase difference between the optical signal of the first frequency and the optical signal of the second frequency in the second optical signal is a first preset phase value, and the absolute value of the difference between the first frequency and the third frequency in the second optical signal is the same as the absolute value of the difference between the second frequency and the fourth frequency in the second optical signal.

[0066] As described in S301, since the first optical signal includes not only the target optical signal corresponding to the desired frequency, it may also include some stray optical signals corresponding to other unwanted frequencies. These stray optical signals may be either odd-order stray optical signals or even-order stray optical signals.

[0067] It is understood that if the first optical signal includes stray light signals, after the first optical signal passes through a photoelectric detector (PD), the microwave signal output by the PD may also contain interfering microwave signals demodulated from the stray light signals, potentially affecting signal transmission. Therefore, in this embodiment, phase modulation processing is performed on the first optical signal before it is input to the PD.

[0068] Specifically, in this embodiment, after obtaining the first optical signal, if it is to reduce the interference caused by the stray optical signal of a certain frequency (also called the first frequency) being input into the PD, the phase difference between the optical signal of the first frequency and the optical signal of the second frequency in the first optical signal is adjusted to a first preset phase value, or in other words, the phase difference between the optical signal of the second frequency and the optical signal of the first frequency in the first optical signal is adjusted to the first preset phase value.

[0069] The first frequency and the second frequency satisfy the condition that an absolute value of a difference between the first frequency and a third frequency among the multiple frequencies is the same as an absolute value of a difference between the second frequency and a fourth frequency among the multiple frequencies.

[0070] It should be noted that the embodiment of the present application does not limit the specific value of the first preset phase value. Preferably, the first preset phase value is 180 degrees.

[0071] For example, for the first optical signal in FIG4 , if it is desired to reduce the interference signal caused by the optical signal with a frequency of 2f2-f1 after passing through the PD, since the absolute value of the frequency difference between 2f2-f1 and frequency f2 (|f2-f1|) is exactly the same as the absolute value of the frequency difference between 2f1-f2 and frequency f1 (|f2-f1|), the phase difference between the optical signal with a frequency of 2f1-f2 and the optical signal with a frequency of 2f2-f1 can be set to 180 degrees, thereby obtaining the second optical signal shown in FIG5 . For another example, if it is desired to reduce the interference signal caused by the optical signal with a frequency of f1+f2 after passing through the PD, since the absolute value of the frequency difference between f1+f2 and frequency f2 (f1) is exactly the same as the absolute value of the frequency difference between f2-f1 and frequency f2 (f1), the phase difference between the optical signal with a frequency of f1+f2 and the optical signal with a frequency of f2-f1 can be set to 180 degrees.

[0072] It should be noted that Figure 4 is only an example of the first optical signal, and the first optical signal may also include more frequency information, which is not limited in this application.

[0073] In this embodiment, after phase modulation processing is performed on the first optical signal, a second optical signal is obtained. It should be understood that in the second optical signal obtained in this embodiment, the frequency included in the second optical signal is the same as the frequency included in the first optical signal, but the difference is that the phase difference between the optical signal of the first frequency and the optical signal of the second frequency in the second optical signal is a first preset phase value.

[0074] S303: Send a second optical signal to the photodetector PD.

[0075] In this embodiment, after the first optical signal is subjected to phase modulation processing to obtain the second optical signal, the second optical signal is sent to the PD instead of the first optical signal.

[0076] It should be understood that the optical signal of the first frequency and the optical signal of the third frequency will form a first electrical signal whose frequency is the absolute value of the difference between the first frequency and the third frequency after passing through the PD, while the optical signal of the second frequency and the optical signal of the fourth frequency will form a second electrical signal whose frequency is the absolute value of the difference between the second frequency and the fourth frequency after passing through the PD.

[0077] In this embodiment, since the absolute value of the difference between the first frequency and the third frequency is the same as the absolute value of the difference between the second frequency and the fourth frequency among the multiple frequencies (in this embodiment, the frequency whose frequency value is the absolute value of the difference between the first frequency and the third frequency or the absolute value of the difference between the second frequency and the fourth frequency is also referred to as the target frequency), the first electrical signal will be superimposed on the second electrical signal, but since the phase difference between the optical signal of the second frequency and the optical signal of the first frequency is adjusted to the first preset phase value in this embodiment, after the first electrical signal is superimposed on the second electrical signal, the amplitude (or intensity) of the final target frequency electrical signal will be reduced, thereby reducing the interference microwave signal demodulated by the optical signal of the first frequency or the optical signal of the second frequency.

[0078] Optionally, if the first preset phase value is 180 degrees, and the amplitudes of the optical signal of the first frequency and the second optical signal are exactly the same, then the first electrical signal formed by the optical signal of the first frequency and the optical signal of the third frequency after passing through the PD can completely cancel each other out after being superimposed with the second electrical signal formed by the optical signal of the second frequency and the optical signal of the fourth frequency after passing through the PD, thereby better reducing the amplitude of the interfering microwave signal demodulated by the optical signal of the first frequency or the optical signal of the second frequency.

[0079] It is noted that in the embodiment of the present application, sending the second optical signal to the PD may also be referred to as outputting the second optical signal to the PD. It is also noted that in the present application, more modules may be included between the signal processing device and the PD, which does not constitute a limitation of the present application.

[0080] In this embodiment, the signal processing device adjusts the phase difference between the first frequency optical signal and the second frequency optical signal that meet the conditions in the first optical signal to a first preset threshold, thereby reducing the influence of the interfering microwave signal demodulated by the first frequency optical signal and the second frequency optical signal after passing through the PD.

[0081] As an optional embodiment, the first optical signal in the present application includes a modulated optical signal obtained by modulating the first microwave signal using an optical carrier signal, wherein the first frequency and the second frequency are different from the frequencies included in the modulated optical signal.

[0082] It is understood that when the first optical signal includes a modulated optical signal obtained by modulating the first microwave signal using an optical carrier signal, generally, the optical signal corresponding to the frequency included in the modulated optical signal is the desired target optical signal, while the optical signal corresponding to the first frequency and the optical signal corresponding to the second frequency, which are different from the frequency included in the modulated optical signal, can be considered as unwanted optical signals that may cause interference. In other words, in this embodiment, the optical signals corresponding to frequencies other than the modulated optical signal in the first optical signal can be considered as the first frequency optical signal or the second frequency stray optical signal whose interference is to be reduced after passing through the PD in this embodiment of the present application.

[0083] It is also understood that during transmission, the modulated optical signal may introduce stray optical signals both within the frequency band of the modulated optical signal and outside the frequency band of the modulated optical signal. That is, in this embodiment, after the modulated optical signal is obtained by introducing stray optical signals to obtain a first optical signal, a portion of the multiple frequencies included in the first optical signal is within the frequency band of the modulated optical signal (also referred to as the target frequency band in this application), while the frequencies other than the portion are outside the target frequency band.

[0084] For example, FIG6 is a schematic diagram of the spectrum of a first optical signal obtained after introducing a stray optical signal into a modulated optical signal provided by an embodiment of the present application. As shown in FIG6 , the first optical signal includes frequencies f1, f2, f n-1 ,……f n The modulated optical signals obtained by modulating the first microwave signals by the optical carrier signal include frequencies such as F1, F2, ..., F in the figure. n-1 and F n And so on (the black thick solid line in the figure indicates that they are all within the target frequency band), wherein the optical signals of these frequencies can be considered as the desired target optical signals. In addition, as shown in FIG6 , there are also some optical signals of other frequencies, such as the frequencies F2-F1, 2F1-F2, 2F2-F1, F2+F1, F n -F n-1 , 2F n-1 -F n , 2F n -F n-1 、F n +F n-1 The optical signals corresponding to the same frequencies as F2-F1, 2F1-F2, 2F n -F n-1 、F n +F n-1The stray light signals are all outside the target frequency band, and the frequencies are 2F2-F1, F2+F1, F n -F n-1 , 2F n-1 -F n All stray light signals are within the target frequency band.

[0085] It should be noted that this embodiment does not limit how to obtain the spectrum diagram shown in Figure 6. For example, a spectrum monitoring module may be used to analyze the spectrum characteristics of the first optical signal to obtain the frequency distribution of the first optical signal.

[0086] Furthermore, in the present application, when the first frequency and the second frequency are different from the frequencies included in the modulated optical signal, the first frequency in this embodiment may be within the target frequency band, and the second frequency may be outside the target frequency band.

[0087] For example, for the first optical signal shown in FIG6 , the frequencies F2-F1, 2F1-F2, 2F2-F1, F2+F1, F n -F n-1 , 2F n-1 -F n , 2F n -F n-1 、F n +F n-1 The optical signals corresponding to the same frequency can be considered as stray optical signals, while the frequencies 2F2-F1, F2+F1, F n -F n-1 , 2F n-1 -F n Located within the target frequency band (both can be considered as the first frequency in this application). Since the absolute value of the frequency difference between the stray light signal with a frequency of 2F2-F1 and the target light signal with a frequency of F2 is equal to the absolute value of the frequency difference between the stray light signal with a frequency of 2F1-F2 and the target light signal with a frequency of F1, as shown in FIG7 , 2F2-F1 can be used as the second frequency in this application, and then the phase difference between the stray light signal with a frequency of 2F1-F2 and the stray light signal with a frequency of 2F2-F1 is set to a first preset threshold, for example, 180 degrees.

[0088] Similarly, as shown in Figure 7, since the absolute value of the frequency difference between the stray light signal with a frequency of F2+F1 and the target light signal with a frequency of F2 is equal to the absolute value of the frequency difference between the stray light signal with a frequency of F2-F1 and the target light signal with a frequency of F2, F2-F1 can be used as the second frequency in this application, and then the phase difference between the stray light signal with a frequency of F2+F1 and the stray light signal with a frequency of F2-F1 is set to a first preset threshold, for example, 180 degrees.

[0089] Similarly, as shown in Figure 7, since the frequency is F n -F n-1 The stray light signal with frequency F n The absolute value of the difference in frequency between the target optical signal and the frequency F n +F n-1 The stray light signal with frequency F n The absolute value of the frequency difference of the target optical signal can be calculated by n +F n-1 As the second frequency in this application, then the frequency F n -F n-1 The stray light signal with frequency F n +F n-1 The phase difference of the stray light signal is set to a first preset threshold, for example, 180 degrees.

[0090] Similarly, as shown in Figure 7, since the frequency is 2F n-1 -F n The stray light signal with frequency F n-1 The absolute value of the difference in frequency between the target optical signal and the frequency is equal to 2F n -F n-1 The stray light signal with frequency F n The absolute value of the frequency difference of the target optical signal can be calculated by n -F n-1 As the second frequency in this application, then the frequency is 2F n-1 -F n The stray light signal with a frequency of 2F n -F n-1 The phase difference of the stray light signal is set to a first preset threshold, for example, 180 degrees.

[0091] In a specific implementation, after determining the frequency distribution ranges of different frequency bands, the signal processing device can set the frequency range of phase control so that the optical signals of the frequency components outside the band are in phase with the optical signals of the frequency components within the band. That is, the phases of the optical signals of the frequency components outside the band and the frequency components within the band are 180 degrees different from each other, thereby obtaining the second optical signal shown in Figure 7. In this way, when the second optical signal is input to the PD, it can offset the influence of the interfering microwave signal caused by the stray optical signals within the band after passing through the PD, including second-order and third-order stray optical signals.

[0092] In this embodiment, when the target frequency band where the modulated optical signal in the first optical signal is located includes a stray optical signal of the first frequency, the phase value of the stray optical signal of the second frequency outside the target frequency band is adjusted to differ from the stray optical signal of the first frequency by a first preset threshold value, so as to reduce the influence of the stray optical signal of the first frequency and the stray optical signal of the second frequency on the interfering microwave signal after PD demodulation.

[0093] As an optional embodiment, when the first frequency and the second frequency are different from the frequencies included in the modulated optical signal, the first frequency in this embodiment may be within the target frequency band, and the second frequency may be outside the target frequency band.

[0094] For example, as shown in Figure 8, some frequencies in the first optical signal are located within the target frequency band (i.e., the frequencies included in the frequency band circled in the figure), while other frequencies are located outside the target frequency band (i.e., the frequencies included in the frequency band circled in the figure). It should be understood that the optical signals corresponding to the frequencies outside the frequency band are usually stray optical signals, and in some cases, for two frequencies both located outside the frequency band, it is possible that the absolute value of the difference between one of the frequencies and the third frequency of the first optical signal is equal to the absolute value of the difference between the other of the two frequencies and the fourth frequency in the first optical signal. Therefore, in this embodiment, the optical signals corresponding to the two frequencies both located outside the frequency band can be respectively used as the optical signal of the first frequency and the optical signal of the second frequency in this application, and then the optical signal of the first frequency and the optical signal of the second frequency are used.

[0095] Alternatively, in one possible scenario, if the optical signal of the first frequency and the optical signal of the second frequency to be reduced are both symmetrical to the same frequency, then in this application, the phase difference between the stray optical signal of the first frequency and the stray optical signal of the second frequency is also set to a first preset threshold, for example, 180 degrees. It will be understood that in this scenario, the third frequency and the fourth frequency in this application are the same frequency.

[0096] Optionally, in the present application, when the third frequency and the fourth frequency are the same frequency, the same frequency in the present application may also be the frequency of the optical carrier signal.

[0097] It should be understood that in this scenario, the stray light signal of the first frequency and the stray light signal of the second frequency may both be located within the target frequency band or may both be located outside the target frequency band, which is not limited in this embodiment of the present application.

[0098] For example, as shown in FIG8 , the optical carrier signals corresponding to the two frequencies outside the frequency band may be symmetrical based on the optical carrier signal, that is, the absolute values ​​of the differences between the two frequencies and the frequencies corresponding to the optical carrier signal are the same. Therefore, in the present application, the two frequencies can be set to have a phase difference of 180 degrees.

[0099] In a specific implementation, after determining the frequency distribution ranges of different frequency bands, the signal processing device can set the frequency range for phase control, and then ensure that the phase difference between the stray optical signal corresponding to the frequencies included in the first frequency range and the stray optical signal corresponding to the frequencies included in the second frequency range is 180 degrees. The frequencies included in the first frequency range and the frequencies included in the second frequency range are symmetrical based on the frequency corresponding to the optical carrier signal, and the frequencies included in the first frequency range and the second frequency range are both frequencies outside the target frequency band, thereby obtaining a second optical signal. In this way, when the second optical signal is input into the PD, it can offset the influence of the interfering microwave signal after the PD demodulates the out-of-band stray optical signal.

[0100] In this embodiment, when the target frequency band where the modulated optical signal in the first optical signal is located includes an optical signal of the first frequency, the phase value of the optical signal of the second frequency located outside the target frequency band is adjusted to differ from the optical signal of the first frequency by a first preset threshold value, so as to reduce the influence of the interfering microwave signal after PD demodulation of the stray optical signal of the first frequency and the stray optical signal of the second frequency.

[0101] As an optional embodiment, in the present application, the signal processing device can also receive first feedback information, wherein the first feedback information indicates a second microwave signal demodulated by the PD based on the second optical signal at a first preset phase value; and then the signal processing device adjusts the first preset phase value based on the second microwave signal.

[0102] For example, FIG9 is a schematic structural diagram of a signal processing system according to an embodiment of the present application. As shown in FIG9 , the signal processing system includes a modulated laser 901 , a signal processing device 902 , a photodetector 903 , and a data processing module 904 .

[0103] The modulated laser 901 is used to receive the first microwave signal, such as the one shown in FIG9 , which includes frequencies f1, f2, and f n-1 ,……f n The first microwave signal (which is an electrical signal) is modulated using an optical carrier signal to obtain an optical signal (also referred to as a modulated optical signal in this embodiment). Since the modulated optical signal may introduce stray optical signals during transmission, causing the modulated optical signal to be distorted, it can be understood that the distorted modulated optical signal is the first optical signal in this application. In other words, the optical signal ultimately input to the signal processing device 902 is not actually the original modulated optical signal, but the first optical signal after the stray optical signals are introduced.

[0104] The signal processing device 902 is configured to perform phase modulation processing on the received first optical signal to obtain a second optical signal, and send the second optical signal to the photodetector 903 .

[0105] The photodetector 903 is used to demodulate the second optical signal to obtain a second microwave signal. After the PD receives the second optical signal and demodulates the second microwave signal, it can transmit a portion of the second microwave signal through the antenna and input a portion of the second microwave signal into the data processing module 904. The data processing module 904 is used to analyze the interference signal in the target microwave signal and send first feedback information to the signal processing device. The first feedback information indicates the second microwave signal demodulated by the PD based on the second optical signal at the first preset phase value, so that the signal processing device adjusts the first preset phase value based on the second microwave signal.

[0106] In this embodiment, the data processing module 904 can provide first feedback information to the signal processing device 902, where the first feedback information is used to indicate the second microwave signal. Accordingly, after receiving the first feedback information, the signal processing device can determine whether the first preset phase value needs to be adjusted based on the second microwave signal indicated by the first feedback information. In one embodiment, when the signal processing device obtains the second microwave signal, it can analyze the similarity between the second microwave signal and the first microwave signal, and then adjust the first preset phase value based on the similarity. For example, if the similarity between the second microwave signal and the first microwave signal is very low, the first preset phase value can be adjusted, so that the signal processing device can better process the first optical signal, thereby further reducing interference caused by stray optical signals of the first frequency and stray optical signals of the second frequency.

[0107] The signal processing method according to the embodiment of the present application is described in detail above with reference to FIG. 3 to FIG. 9 . The signal processing device according to the embodiment of the present application will be described in detail below with reference to FIG. 10 to FIG. 11 .

[0108] FIG10 is a schematic structural diagram of a signal processing device according to an embodiment of the present application. Specifically, as shown in FIG10 , the device 1000 includes a transceiver module 1001 and a processing module 1002 .

[0109] Among them, the transceiver module 1001 is used to receive a first optical signal, which includes optical signals of multiple frequencies. The processing module 1002 is used to perform phase modulation processing on the first optical signal to obtain a second optical signal, wherein the phase difference between the optical signal of the first frequency and the optical signal of the second frequency in the second optical signal is a first preset phase value, and the absolute value of the difference between the first frequency and the third frequency in the second optical signal is the same as the absolute value of the difference between the second frequency and the fourth frequency in the second optical signal. The transceiver module is also used to send the second optical signal to the photodetector PD.

[0110] As an example, the processing module 1002 may be configured to execute the step of performing phase modulation processing on the first optical signal in the method described in Figure 3. For example, the receiving module 1002 is configured to execute S302.

[0111] In a possible implementation, the first optical signal includes a modulated optical signal obtained by modulating the first microwave signal using an optical carrier signal, wherein the first frequency and the second frequency are different from frequencies included in the modulated optical signal.

[0112] In a possible implementation, a portion of the multiple frequencies are distributed within a target frequency band, where the target frequency band is a frequency band where the modulated optical signal is located.

[0113] In a possible implementation, the first frequency is within a target frequency band, and the second frequency is outside the target frequency band.

[0114] In a possible implementation manner, the first frequency is outside the target frequency band, and the second frequency is outside the target frequency band.

[0115] In a possible implementation, the third frequency and the fourth frequency are the same frequency.

[0116] Exemplarily, the same frequency is the frequency of the optical carrier signal.

[0117] In a possible implementation, the first preset phase value is 180 degrees.

[0118] In one possible implementation, the transceiver module 1001 is further used to: receive first feedback information, where the first feedback information indicates a second microwave signal demodulated by the PD based on the second optical signal at a first preset phase value; and the processing module 1002 is further used to: adjust the first preset phase value based on the second microwave signal.

[0119] Figure 11 is a schematic structural diagram of a signal processing device provided in another embodiment of the present application. The device shown in Figure 11 can be used to execute the method described in any of the above embodiments.

[0120] As shown in Figure 11 , the apparatus 1100 of this embodiment includes a memory 1101, a processor 1102, a communication interface 1103, and a bus 1104. The memory 1101, the processor 1102, and the communication interface 1103 are connected to each other via the bus 1104.

[0121] The memory 1101 may be a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 1101 may store a program. When the program stored in the memory 1101 is executed by the processor 1102, the processor 1102 is configured to perform the steps of the method shown in FIG. 3 to FIG. 8 .

[0122] The processor 1102 can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits to execute relevant programs to implement the methods shown in Figures 3 to 8 of the present application.

[0123] The processor 1102 may also be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the method of FIG. 3 to FIG. 8 of the embodiment of the present application may be completed by an integrated logic circuit of hardware in the processor 1102 or by instructions in the form of software.

[0124] The processor 1102 may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. The processor 1102 may implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or any conventional processor.

[0125] The steps of the method disclosed in conjunction with the embodiments of the present application can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules within the decoding processor. The software modules can be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in memory 1101. Processor 1102 reads information from memory 1101 and, in conjunction with its hardware, performs the functions required by the units included in the apparatus of the present application. For example, the steps / functions of the embodiments shown in Figures 3 to 8 can be executed.

[0126] The communication interface 1103 may use, but is not limited to, a transceiver or other transceiver device to implement communication between the apparatus 1100 and other devices or a communication network.

[0127] The bus 1104 may include a path for transmitting information between various components of the device 1100 (eg, the memory 1101 , the processor 1102 , and the communication interface 1103 ).

[0128] It should be understood that the device 1100 shown in the embodiment of the present application can be an electronic device, such as the aforementioned base station or a processing device in the base station, or it can also be a chip configured in the electronic device.

[0129] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0130] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0131] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0132] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0133] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0134] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0135] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0136] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0137] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0138] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory, a random access memory, a magnetic disk, or an optical disk.

[0139] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A signal processing method, characterized in that: Applications in signal processing devices, including: receiving a first optical signal, wherein the first optical signal includes optical signals of multiple frequencies; performing phase modulation processing on the first optical signal to obtain a second optical signal, wherein a phase difference between an optical signal of the first frequency and an optical signal of the second frequency in the second optical signal is a first preset phase value, and an absolute value of a difference between the first frequency and a third frequency in the second optical signal is the same as an absolute value of a difference between the second frequency and a fourth frequency in the second optical signal; The second optical signal is sent to the photodetector PD.

2. The method according to claim 1, characterized in that The first optical signal includes a modulated optical signal obtained by modulating a first microwave signal using an optical carrier signal, wherein the first frequency and the second frequency are different from frequencies included in the modulated optical signal.

3. The method according to claim 2, characterized in that A portion of the multiple frequencies is distributed within a target frequency band, and the target frequency band is a frequency band where the modulated optical signal is located.

4. The method according to claim 3, characterized in that The first frequency is within the target frequency band, and the second frequency is outside the target frequency band.

5. The method according to claim 3, characterized in that The first frequency is outside the target frequency band, and the second frequency is outside the target frequency band.

6. The method according to any one of claims 1 to 5, characterized in that The third frequency and the fourth frequency are the same frequency.

7. The method according to claim 6, characterized in that The same frequency is the frequency of the optical carrier signal.

8. The method according to any one of claims 1 to 7, characterized in that The first preset phase value is 180 degrees.

9. The method according to any one of claims 1 to 8, characterized in that The method further comprises: receiving first feedback information indicating a second microwave signal demodulated by the PD based on the second optical signal at the first preset phase value; The first preset phase value is adjusted based on the second microwave signal.

10. A signal processing device, characterized in that: include: a transceiver module, configured to receive a first optical signal, wherein the first optical signal includes optical signals of multiple frequencies; a processing module, configured to perform phase modulation processing on the first optical signal to obtain a second optical signal, wherein a phase difference between an optical signal of the first frequency and an optical signal of the second frequency in the second optical signal is a first preset phase value, and an absolute value of a difference between the first frequency and a third frequency in the second optical signal is the same as an absolute value of a difference between the second frequency and a fourth frequency in the second optical signal; The transceiver module is further configured to send the second optical signal to the photodetector PD.

11. The device according to claim 10, characterized in that The first optical signal includes a modulated optical signal obtained by modulating a first microwave signal using an optical carrier signal, wherein the first frequency and the second frequency are different from frequencies included in the modulated optical signal.

12. The device according to claim 11, characterized in that A portion of the multiple frequencies is distributed within a target frequency band, and the target frequency band is a frequency band where the modulated optical signal is located.

13. The device according to claim 12, characterized in that The first frequency is within the target frequency band, and the second frequency is outside the target frequency band.

14. The device according to claim 12, characterized in that The first frequency is outside the target frequency band, and the second frequency is outside the target frequency band.

15. The device according to any one of claims 10 to 14, characterized in that The third frequency and the fourth frequency are the same frequency.

16. The device according to claim 15, characterized in that The same frequency is the frequency of the optical carrier signal.

17. The device according to any one of claims 10 to 16, characterized in that The first preset phase value is 180 degrees.

18. The device according to any one of claims 10 to 17, characterized in that The transceiver module is also used for: receiving first feedback information indicating a second microwave signal demodulated by the PD based on the second optical signal at the first preset phase value; The processing module is further configured to adjust the first preset phase value based on the second microwave signal.

19. A signal processing device, characterized in that: include: memory and processor; The memory is used to store program instructions; The processor is configured to call the program instructions in the memory to execute the method according to any one of claims 1 to 9.

20. A communication system, characterized in that: A signal processing device comprising the signal processing device according to any one of claims 10 to 19.

21. A computer-readable medium, characterized in that The computer-readable medium stores a program code for computer execution, the program code including instructions for executing the method according to any one of claims 1 to 9.

22. A computer program product, comprising computer program code, characterized in that: When the computer program code is run on a computer, the computer is caused to implement the method according to any one of claims 1 to 9.

Images