CN115459855A - Digital pulse shaping method based on linear superposition and optical fiber communication system - Google Patents
Digital pulse shaping method based on linear superposition and optical fiber communication system Download PDFInfo
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- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
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- H04B10/66—Non-coherent receivers, e.g. using direct detection
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Abstract
The invention provides a digital pulse shaping method based on linear superposition and an optical fiber communication system, wherein the optical fiber communication system comprises a pulse shaping digital filter; the digital pulse shaping method based on linear superposition comprises the following steps: carrying out linear superposition processing on N different pulse shaping digital filter models to obtain a superposed pulse shaping digital filter model, wherein N is a positive integer greater than 1; according to the superposed pulse shaping digital filter model, carrying out parameter adjustment on the pulse shaping digital filter; and the pulse shaping digital filter after the digital signal to be transmitted is subjected to parameter adjustment generates a shaped digital signal. According to the invention, the N pulse shaping digital filter models are linearly superposed, so that the parameter adjustment of the pulse shaping digital filter can be realized, the adjustment freedom degree is large, the compatibility is strong, and the flexible and flexible adjustment can be realized, thereby improving the transmission performance and reducing the cost and the complexity.
Description
Technical Field
The invention relates to the technical field of optical fiber communication, in particular to a digital pulse shaping method based on linear superposition and an optical fiber communication system.
Background
In a direct alignment detection (IM/DD) fiber communication system, especially in a C-band (1530-1565 nm), since chromatic dispersion is large, after transmission through a fiber at a certain distance, chromatic dispersion and square rate detection cause frequency selective fading (fading) of a signal, power of different frequency components of the signal is attenuated to different degrees and even completely submerged by noise, and strong intersymbol interference (ISI) is introduced from the time domain, which greatly limits communication performance, capacity and transmission distance of an actual IM/DD system. Especially for low-cost high-speed (> 100 Gb/s) data center optical interconnection (> 2km, inter-DCI) transmission systems.
On the other hand, pulse shaping (pulse shaping) is very critical in the communication field, and can reduce the influence of intersymbol interference (ISI) due to limitations such as bandwidth in actual transmission. The effective bandwidth required for different pulse shaping is different and has different frequency distributions. Common simple pulse shaping techniques include raised cosine-shaped nonreturn-to-zero pulse shaping (RC-NRZ pulse shaping, abbreviated as RC) and rectangular nonreturn-to-zero pulse shaping (Rect-NRZ pulse shaping, abbreviated as Rect) and rectangular return-to-zero pulse shaping (Rect-RZ pulse shaping, abbreviated as RZ).
The Rect and RZ frequencies are distributed fixedly, any parameter adjustment does not exist, the transmission performance is difficult to further improve in a long-distance large-capacity system, and certain limitation is realized; while RC can achieve a certain degree of freedom in adjustment through a roll-off factor (RoF), it is also difficult to further improve transmission performance in a long-distance, high-capacity system. There are of course other sophisticated pulse shaping techniques that can change their frequency distribution, but are more complex to implement. That is, the existing pulse shaping technology has certain limitations for the optical fiber channel with actual bandwidth limitation and chromatic dispersion.
Therefore, the prior art has defects and needs to be improved and developed.
Disclosure of Invention
The present invention provides a digital pulse shaping method and an optical fiber communication system based on linear superposition, aiming at solving the problem that the transmission performance cannot be further improved in a long-distance large-capacity system by simple parameter adjustment in the prior art.
The technical scheme adopted by the invention for solving the technical problem is as follows:
a digital pulse shaping method based on linear superposition is applied to an optical fiber communication system, and is characterized in that the optical fiber communication system comprises: a pulse shaping digital filter;
the digital pulse shaping method based on linear superposition comprises the following steps:
carrying out linear superposition processing on N different pulse shaping digital filter models to obtain a superposed pulse shaping digital filter model, wherein N is a positive integer greater than 1;
according to the superposed pulse shaping digital filter model, carrying out parameter adjustment on the pulse shaping digital filter;
and the pulse shaping digital filter after the digital signal to be transmitted is subjected to parameter adjustment generates a shaped digital signal.
In one implementation, the fiber optic communication system includes: a weight distribution unit and a superposition unit which are connected with each other; the linear superposition processing is performed on the N different pulse shaping digital filter models to obtain a superposed pulse shaping digital filter model, and the method comprises the following steps:
determining N different pulse shaping digital filter models and the weight coefficient of each pulse shaping digital filter model in advance according to the actual channel requirement;
generating a pulse shaping digital filter model with a corresponding weight value by the weight distribution unit according to the respective weight coefficient of each pulse shaping digital filter model;
and all the pulse shaping digital filter models with the corresponding weights pass through the superposition unit, and the tap values of the corresponding positions of all the pulse shaping digital filter models are added to obtain the superposed pulse shaping digital filter model.
In one implementation, the weight assignment unit is a multiplier, an amplifier, or an attenuator; the superposition unit is an adder or a beam combiner.
In one implementation, the pulse-shaping digital filter model is a raised cosine non-return-to-zero pulse-shaping digital filter model, a rectangular non-return-to-zero pulse-shaping digital filter model, or a rectangular return-to-zero pulse-shaping digital filter model.
In one implementation, the fiber optic communication system further comprises: a digital signal generator connected to the pulse shaping digital filter; the pulse shaping digital filter after the digital signal to be transmitted is superposed generates a shaped digital signal, and the pulse shaping digital filter comprises:
when the digital signal generator generates a digital signal to be transmitted, the signal to be transmitted passes through the pulse shaping digital filter to generate a shaped digital signal.
In one implementation, the fiber optic communication system further comprises: the pulse shaping digital filter, the digital-to-analog converter and the intensity modulator are connected in sequence; after the pulse shaping digital filter after the digital signal to be transmitted is subjected to parameter adjustment generates a shaped digital signal, the method further comprises the following steps:
inputting the shaped digital signal into the digital-to-analog converter to obtain an analog electric signal;
and the intensity modulator modulates the analog electric signal to a single-frequency optical carrier output by the laser to generate an optical signal.
In one implementation, the fiber optic communication system further comprises: the optical fiber, and an optical amplifier, an optical attenuator, a photoelectric detector, an oscilloscope and an off-line digital signal processing module which are connected in sequence; the intensity modulator modulates the analog electrical signal onto a single-frequency optical carrier output by the laser, and after generating an optical signal, the intensity modulator further comprises:
transmitting the optical signal through an optical fiber;
the transmitted optical signals are sequentially amplified by the optical amplifier, attenuated by the optical attenuator and subjected to photoelectric conversion by the photoelectric detector to obtain received electrical signals;
sampling the received electric signal by the oscilloscope to obtain a received digital signal;
and inputting the received digital signal into the offline digital signal processing module for offline digital signal processing.
The present invention also provides an optical fiber communication system, wherein the optical fiber communication system comprises: the digital pulse shaping device comprises a weight distribution unit, a superposition unit and a pulse shaping digital filter which are sequentially connected;
the weight distribution unit is used for receiving the corresponding pulse shaping digital filter model in the N different pulse shaping digital filter models and generating a pulse shaping digital filter model with a corresponding weight according to a preset weight coefficient;
the superposition unit is used for adding tap values of corresponding positions of the pulse shaping digital filter models with corresponding weights to obtain superposed pulse shaping digital filter models;
and the pulse shaping digital filter is used for carrying out parameter adjustment according to the superposed pulse shaping digital filter model and shaping the digital signal to be transmitted.
In one implementation, the fiber optic communication system further comprises: the pulse shaping digital filter is connected with the digital signal generator, and the pulse shaping digital filter, the digital-to-analog converter and the intensity modulator are sequentially connected; the optical fiber communication system also comprises an optical fiber, and an optical amplifier, an optical attenuator, a photoelectric detector, an oscilloscope and an off-line digital signal processing module which are connected in sequence;
the digital signal generator is used for generating a digital signal to be transmitted;
the digital-to-analog converter is used for converting the shaped digital signal into an analog electric signal;
the intensity modulator is used for modulating the analog electric signal to a single-frequency optical carrier output by the laser to generate an optical signal;
the optical fiber is used for transmitting the optical signal;
the optical amplifier is used for amplifying the optical signal after transmission;
the optical attenuator is used for attenuating the amplified optical signal;
the photoelectric detector is used for performing photoelectric conversion on the attenuated optical signal to obtain a receiving electrical signal;
the oscilloscope is used for sampling the received electric signal to obtain a received digital signal;
the off-line digital signal processing module is used for off-line digital signal processing of the received digital signal.
The present invention also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program executable for implementing the steps of the digital pulse shaping method based on linear superposition as described above.
The invention provides a digital pulse shaping method based on linear superposition and an optical fiber communication system, wherein the optical fiber communication system comprises a pulse shaping digital filter; the digital pulse shaping method based on linear superposition comprises the following steps: carrying out linear superposition processing on N different pulse shaping digital filter models to obtain a superposed pulse shaping digital filter model, wherein N is a positive integer greater than 1; according to the superposed pulse shaping digital filter model, carrying out parameter adjustment on the pulse shaping digital filter; and the pulse shaping digital filter after the digital signal to be transmitted is subjected to parameter adjustment generates a shaped digital signal. According to the invention, the parameters of the pulse shaping digital filter can be adjusted by linearly superposing the N pulse shaping digital filter models, the adjustment freedom degree is large, the compatibility is strong, and the flexibility is realized, so that the transmission performance is improved, and the cost and the complexity are reduced.
Drawings
Fig. 1 is a flow chart of a preferred embodiment of the digital pulse shaping method based on linear superposition according to the present invention.
Fig. 2 is a detailed flowchart of step S100 in the preferred embodiment of the digital pulse shaping method based on linear superposition according to the present invention.
Fig. 3 is a schematic block diagram of an embodiment of the digital pulse shaping method based on linear superposition according to the present invention.
Fig. 4 is a functional schematic diagram of a preferred embodiment of a fiber optic communication system of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Referring to fig. 1, fig. 1 is a flow chart of a digital pulse shaping method based on linear superposition according to the present invention. As shown in fig. 1, a digital pulse shaping method based on linear superposition according to an embodiment of the present invention includes the following steps:
and S100, carrying out linear superposition processing on N different pulse shaping digital filter models to obtain a superposed pulse shaping digital filter model, wherein N is a positive integer greater than 1.
In particular, the digital pulse shaping method based on linear superposition is applied to an optical fiber communication system, and is especially used for a direct alignment detection m-PAM optical fiber communication system. The optical fiber communication system includes: a pulse shaping digital filter. Because the common simple pulse shaping technologies comprise raised cosine non-return-to-zero pulse shaping (RC), rectangular non-return-to-zero pulse shaping (Rect) and rectangular return-to-zero pulse shaping (RZ), the invention can use the models of the simple pulse shaping technologies as the basis, that is, the pulse shaping digital filter model can be a raised cosine non-return-to-zero pulse shaping digital filter model, a rectangular non-return-to-zero pulse shaping digital filter model or a rectangular return-to-zero pulse shaping digital filter model. Two or more than two of the models of the simple pulse shaping technology are linearly superposed to obtain pulse shaping digital filter models with different average powers, and then the parameters of the pulse shaping digital filter are adjusted according to the superposed pulse shaping digital filter models.
In one implementation, the fiber optic communication system includes: a weight assignment unit and a superposition unit connected to each other. As shown in fig. 2, the step S100 specifically includes:
step S110, determining N different pulse shaping digital filter models and weight coefficients of each pulse shaping digital filter model in advance according to actual channel requirements;
step S120, generating pulse shaping digital filter models with corresponding weights by the weight distribution unit according to respective weight coefficients of the pulse shaping digital filter models;
and step S130, adding the tap values of the corresponding positions of all the pulse shaping digital filter models with the corresponding weights through the superposition unit to obtain the superposed pulse shaping digital filter model.
The invention relates to a novel digital pulse shaping technology which is based on N simple pulse shaping technologies and carries out linear superposition by different weights. Because different actual channels have different requirements on the average power of the filter, the specific selection of different N pulse shaping digital filter models and the corresponding weights thereof are determined according to the actual channel requirements. Specifically, in the digital domain, each path of pulse shaping digital filter model utilizes a corresponding weight distribution unit to distribute weights.
In one embodiment, the weight assignment unit is a multiplier, an amplifier, or an attenuator. That is, in the digital domain, N different pulse-shaping digital filter models are multiplied by the corresponding weight coefficients via a multiplier or amplifier, or attenuated by an attenuator, thus generating N pulse-shaping digital filter models of different weights (different average powers). The superposition unit is an adder or a beam combiner. And the N pulse shaping digital filter models with different weights are linearly superposed through an adder or a beam combiner to realize the required superposed novel pulse shaping digital filter model.
Specifically, the linear superposition is an addition implementation, for example, if two pulse shaping digital filter models are linearly superposed, corresponding expressions of the two pulse shaping digital filter models are f (n) and g (n), the linear superposition is a × f (n) + b × g (n), and a and b are corresponding weight coefficients.
The step S100 is followed by: and S200, adjusting parameters of the pulse shaping digital filter according to the superposed pulse shaping digital filter model.
According to the invention, the parameters of the pulse shaping digital filter can be adjusted by linearly superposing the N pulse shaping digital filter models, so that the communication transmission capacity and the transmission distance of the direct alignment direct detection transmission system are improved, or the transmission performance of the whole system is improved, the cost and the complexity are reduced, and the characteristics of large adjustment freedom, strong compatibility and flexible pass are realized.
The step S200 is followed by: and step S300, the digital signal to be transmitted is subjected to parameter adjustment by the pulse shaping digital filter, and a shaped digital signal is generated.
In one implementation, the fiber optic communication system further comprises: a digital signal generator coupled to the pulse shaping digital filter. The step S300 specifically includes: when the digital signal generator generates a digital signal to be transmitted, the signal to be transmitted passes through the pulse shaping digital filter to generate a shaped digital signal.
Specifically, the digital signal generator is an m-PAM digital signal generator, and the m-PAM digital signal to be transmitted generates a required shaped m-PAM digital signal through a novel pulse shaping digital filter, so as to be used for subsequent digital-to-analog conversion and electro-optical modulation, and for transmission of an actual optical fiber system.
In one embodiment, the fiber optic communication system further comprises: the pulse shaping digital filter, the digital-to-analog converter and the intensity modulator are connected in sequence. The step S300 is followed by: inputting the shaped digital signal into the digital-to-analog converter to obtain an analog electric signal; and the intensity modulator modulates the analog electric signal to a single-frequency optical carrier output by the laser to generate an optical signal. That is, before the optical fiber transmission, a signal to be transmitted is processed into an optical signal. Specifically, the pulse-shaped signal is a 60-Gbaud PAM-4 digital signal. And the 60-Gbaud PAM-4 digital signal is converted into a 60-Gbaud PAM-4 analog electrical signal through a digital-to-analog converter. The intensity modulator modulates the PAM-4 analog electric signal to a single-frequency optical carrier (1550.12 nm) output by the laser, and the single-frequency optical carrier is linearly mapped to the intensity of the optical carrier.
In one implementation, the fiber optic communication system further comprises: the optical fiber, and the optical amplifier, the optical attenuator, the photoelectric detector, the oscilloscope and the off-line digital signal processing module which are connected in sequence. The intensity modulator modulates the analog electrical signal onto a single-frequency optical carrier output by the laser, and after generating an optical signal, the intensity modulator further includes: transmitting the optical signal through an optical fiber; the transmitted optical signals are sequentially amplified by the optical amplifier, attenuated by the optical attenuator and subjected to photoelectric conversion by the photoelectric detector to obtain received electrical signals; sampling the received electric signal by the oscilloscope to obtain a received digital signal; and inputting the received digital signal into the offline digital signal processing module for offline digital signal processing.
Specifically, the optical signal is sent to an optical fiber for transmission, and the optical fiber may be a 100 km standard single mode optical fiber. Different parameters of the single-mode optical fiber, such as dispersion value and loss, affect the overall performance, i.e. the larger the dispersion value or the larger the loss, the performance will be deteriorated. The transmitted optical signal is amplified by an optical amplifier and attenuated by an optical attenuator to change the optical power of the subsequent detection; carrying out photoelectric conversion by a photoelectric detector to obtain a received electric signal, and carrying out sampling by an oscilloscope to obtain a received digital signal; and finally, sending the received digital signals to an offline Digital Signal Processing (DSP) module for offline digital signal processing. Thus, the complete transmission process of the digital signal to be transmitted is realized.
Because other complex digital filters for adjusting the frequency domain distribution of signals mostly need to perform complex operation in the frequency domain, the invention only needs N simple pulse shaping digital filter models to perform linear superposition, has the characteristics of simple realization, strong compatibility and flexible flexibility, and simultaneously has higher adjustment freedom degree; compared with a single simple pulse shaping digital filter, the implementation complexity of the invention is comparable, but a new degree of freedom of adjustment is added, i.e., the specific selection of different N pulse shaping digital filter models and their corresponding weights implement the new degree of freedom of adjustment. The invention can increase the communication transmission capacity and the transmission distance of a direct alignment detection (IM/DD) m-PAM transmission system, or improve the transmission performance of the whole system, in particular to a low-cost high-speed (> 100 Gb/s) data center optical interconnection (> 2km, inter-DCI) transmission system in a C waveband.
The following description will be given by way of a specific example.
The first embodiment is as follows:
as shown in fig. 3, two pulse shaping digital filter models RZ + RC are selected in advance according to actual channel requirements, and a weight coefficient corresponding to RZ is determined as a, and a weight coefficient corresponding to RC is determined as b.
The RZ model is expressed as f (n), and is multiplied by a through a multiplier 1 to obtain a f (n); the RC model is expressed as g (n), and b is multiplied by a multiplier 1 to obtain b x g (n); and a x f (n) and b x g (n) are processed by an adder 2 to obtain a linear superposition a x f (n) + b x g (n), and parameter adjustment is carried out on a pulse shaping digital filter 3 in the optical fiber communication system according to a x f (n) + b x g (n).
PAM-4 digital signals generated by the m-PAM digital signal generator 4 are converted into PAM-4 analog electric signals of 60-Gbaud through a digital-to-analog converter 5;
the intensity modulator 6 modulates the PAM-4 analog electrical signal onto a single-frequency optical carrier (1550.12 nm) output by the laser 7, and the single-frequency optical carrier is linearly mapped onto the intensity of the optical carrier to obtain an optical signal;
sending the optical signal into a standard single mode optical fiber 8 of 100 kilometers for transmission;
the transmitted optical signal is amplified by an optical amplifier 9, and is attenuated by an optical attenuator 10 to change the optical power detected subsequently;
performing photoelectric conversion through a photoelectric detector 11 to obtain a received electrical signal, and performing sampling through an oscilloscope 12 to obtain a received digital signal;
and finally, sending the received digital signals to an offline digital signal processing module 13 for offline digital signal processing.
In addition, two pulse shaping digital filter models of RZ + Rect can be selected for linear superposition.
The present invention also provides an optical fiber communication system, referring to fig. 4, the optical fiber communication system includes: a weight distribution unit 21, a superposition unit 22, and a pulse shaping digital filter 23 connected in this order;
the weight distribution unit 21 is configured to receive a corresponding pulse shaping digital filter model from among N different pulse shaping digital filter models, and generate a pulse shaping digital filter model corresponding to a weight according to a preset weight coefficient;
the superposition unit 22 is configured to add tap values at corresponding positions of each pulse shaping digital filter model with corresponding weights to obtain a superposed pulse shaping digital filter model;
the pulse shaping digital filter 23 is configured to perform parameter adjustment according to the superimposed pulse shaping digital filter model, and perform shaping processing on a digital signal to be transmitted.
In one implementation, the fiber optic communication system further comprises: a digital signal generator 24, a digital-to-analog converter 25, an intensity modulator 26 and a laser 27, wherein the digital signal generator is connected with the pulse shaping digital filter, and the pulse shaping digital filter, the digital-to-analog converter and the intensity modulator are connected in sequence; the optical fiber communication system also comprises an optical fiber 28, and an optical amplifier 29, an optical attenuator 30, a photoelectric detector 31, an oscilloscope 32 and an offline digital signal processing module 33 which are connected in sequence;
the digital signal generator 24 is used for generating a digital signal to be transmitted;
the digital-to-analog converter 25 is used for converting the shaped digital signal into an analog electrical signal;
the intensity modulator 26 is configured to modulate the analog electrical signal onto a single-frequency optical carrier output by the laser 27 to generate an optical signal;
the optical fiber 28 is used for transmitting the optical signal;
the optical amplifier 29 is configured to amplify the transmitted optical signal;
the optical attenuator 30 is configured to attenuate the amplified optical signal;
the photoelectric detector 31 is used for performing photoelectric conversion on the attenuated optical signal to obtain a received electrical signal;
the oscilloscope 32 is configured to sample the received electrical signal to obtain a received digital signal;
the offline digital signal processing module 33 is configured to perform offline digital signal processing on the received digital signal; as described in detail above.
The present invention also provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program executable for implementing the steps of the digital pulse shaping method based on linear superposition as described above.
In summary, the present invention discloses a digital pulse shaping method based on linear superposition and an optical fiber communication system, wherein the optical fiber communication system includes a pulse shaping digital filter; the digital pulse shaping method based on linear superposition comprises the following steps: carrying out linear superposition processing on N different pulse shaping digital filter models to obtain a superposed pulse shaping digital filter model, wherein N is a positive integer greater than 1; according to the superposed pulse shaping digital filter model, carrying out parameter adjustment on the pulse shaping digital filter; and the pulse shaping digital filter after the digital signal to be transmitted is subjected to parameter adjustment generates a shaped digital signal. According to the invention, the parameters of the pulse shaping digital filter can be adjusted by linearly superposing the N pulse shaping digital filter models, the adjustment freedom degree is large, the compatibility is strong, and the flexibility is realized, so that the transmission performance is improved, and the cost and the complexity are reduced.
It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.
Claims (10)
1. A digital pulse shaping method based on linear superposition is applied to an optical fiber communication system, and is characterized in that the optical fiber communication system comprises: a pulse shaping digital filter;
the digital pulse shaping method based on linear superposition comprises the following steps:
carrying out linear superposition processing on N different pulse shaping digital filter models to obtain a superposed pulse shaping digital filter model, wherein N is a positive integer greater than 1;
according to the superposed pulse shaping digital filter model, carrying out parameter adjustment on the pulse shaping digital filter;
and the pulse shaping digital filter after the digital signal to be transmitted is subjected to parameter adjustment generates a shaped digital signal.
2. The linear superposition-based digital pulse shaping method according to claim 1, wherein the optical fiber communication system comprises: a weight distribution unit and a superposition unit connected with each other; the linear superposition processing is performed on the N different pulse shaping digital filter models to obtain a superposed pulse shaping digital filter model, and the method comprises the following steps:
determining N different pulse shaping digital filter models and the weight coefficient of each pulse shaping digital filter model in advance according to the actual channel requirement;
generating pulse shaping digital filter models with corresponding weights by the weight distribution unit according to respective weight coefficients of the pulse shaping digital filter models;
and all the pulse shaping digital filter models with the corresponding weights pass through the superposition unit, and the tap values of the corresponding positions of all the pulse shaping digital filter models are added to obtain the superposed pulse shaping digital filter model.
3. The linear superposition based digital pulse shaping method according to claim 2, wherein the weight distribution unit is a multiplier, an amplifier or an attenuator; the superposition unit is an adder or a beam combiner.
4. The linear superposition based digital pulse shaping method according to claim 1, wherein the pulse shaping digital filter model is a raised cosine non-return-to-zero pulse shaping digital filter model, a rectangular non-return-to-zero pulse shaping digital filter model, or a rectangular return-to-zero pulse shaping digital filter model.
5. The linear superposition-based digital pulse shaping method according to claim 1, wherein the optical fiber communication system further comprises: a digital signal generator connected to the pulse shaping digital filter; the pulse shaping digital filter after the digital signal to be transmitted is superposed generates a shaped digital signal, and the pulse shaping digital filter comprises:
when the digital signal generator generates a digital signal to be transmitted, the signal to be transmitted passes through the pulse shaping digital filter to generate a shaped digital signal.
6. The linear superposition-based digital pulse shaping method according to claim 1, wherein the optical fiber communication system further comprises: the pulse shaping digital filter, the digital-to-analog converter and the intensity modulator are sequentially connected; after the pulse shaping digital filter after the digital signal to be transmitted is subjected to parameter adjustment generates a shaped digital signal, the method further comprises the following steps:
inputting the shaped digital signal into the digital-to-analog converter to obtain an analog electric signal;
and the intensity modulator modulates the analog electric signal to a single-frequency optical carrier output by the laser to generate an optical signal.
7. The linear superposition-based digital pulse shaping method according to claim 6, wherein the optical fiber communication system further comprises: the optical fiber, and an optical amplifier, an optical attenuator, a photoelectric detector, an oscilloscope and an off-line digital signal processing module which are connected in sequence; the intensity modulator modulates the analog electrical signal onto a single-frequency optical carrier output by the laser, and after generating an optical signal, the intensity modulator further includes:
transmitting the optical signal through an optical fiber;
the transmitted optical signals are sequentially amplified by the optical amplifier, attenuated by the optical attenuator and subjected to photoelectric conversion by the photoelectric detector to obtain received electrical signals;
sampling the received electric signal by the oscilloscope to obtain a received digital signal;
and inputting the received digital signal into the offline digital signal processing module for offline digital signal processing.
8. A fiber optic communication system, comprising: the digital pulse shaping device comprises a weight distribution unit, a superposition unit and a pulse shaping digital filter which are sequentially connected;
the weight distribution unit is used for receiving the corresponding pulse shaping digital filter model in the N different pulse shaping digital filter models and generating a pulse shaping digital filter model with a corresponding weight according to a preset weight coefficient;
the superposition unit is used for adding tap values of corresponding positions of the pulse shaping digital filter models with corresponding weights to obtain superposed pulse shaping digital filter models;
and the pulse shaping digital filter is used for carrying out parameter adjustment according to the superposed pulse shaping digital filter model and shaping the digital signal to be transmitted.
9. A fiber optic telecommunications system according to claim 8, further comprising: the digital signal generator is connected with the pulse shaping digital filter, and the pulse shaping digital filter, the digital-to-analog converter and the intensity modulator are sequentially connected; the optical fiber communication system also comprises an optical fiber, and an optical amplifier, an optical attenuator, a photoelectric detector, an oscilloscope and an off-line digital signal processing module which are connected in sequence;
the digital signal generator is used for generating a digital signal to be transmitted;
the digital-to-analog converter is used for converting the shaped digital signal into an analog electric signal;
the intensity modulator is used for modulating the analog electric signal to a single-frequency optical carrier output by the laser to generate an optical signal;
the optical fiber is used for transmitting the optical signal;
the optical amplifier is used for amplifying the optical signal after transmission;
the optical attenuator is used for attenuating the amplified optical signal;
the photoelectric detector is used for performing photoelectric conversion on the attenuated optical signal to obtain a received electrical signal;
the oscilloscope is used for sampling the received electric signal to obtain a received digital signal;
the off-line digital signal processing module is used for carrying out off-line digital signal processing on the received digital signal.
10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program which can be executed for implementing the steps of the linear superposition based digital pulse shaping method according to any one of claims 1 to 7.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6337606B1 (en) * | 1999-02-02 | 2002-01-08 | Sicom, Inc. | Digital communications modulator having a modulation processor which supports high data rates |
| US20030063683A1 (en) * | 2001-09-28 | 2003-04-03 | Macfarlane Shearer Daniel D. | Digital transmitter with constrained envelope and spectral regrowth over a plurality of carriers |
| CN111884727A (en) * | 2020-07-15 | 2020-11-03 | 杭州电子科技大学 | High-speed photon digital-to-analog conversion method and system based on digital mapping |
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2022
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6337606B1 (en) * | 1999-02-02 | 2002-01-08 | Sicom, Inc. | Digital communications modulator having a modulation processor which supports high data rates |
| US20030063683A1 (en) * | 2001-09-28 | 2003-04-03 | Macfarlane Shearer Daniel D. | Digital transmitter with constrained envelope and spectral regrowth over a plurality of carriers |
| CN111884727A (en) * | 2020-07-15 | 2020-11-03 | 杭州电子科技大学 | High-speed photon digital-to-analog conversion method and system based on digital mapping |
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