An information encoding system based on bidirectional mode-locked fiber laser

Abstract

The present application relates to a kind of information coding system based on bidirectional mode-locked fiber laser.The system includes pulse signal transmitting module, time delay scale adjusting module and signal processing system;The pulse signal transmitting module is used to generate basic mode-locked signal, including clockwise and counterclockwise two-way mode-locked signal;The time delay scale adjusting module is used to modulate the two-way basic mode-locked pulse output by pulse signal transmitting module, and the relative delay of clockwise pulse signal and counterclockwise pulse signal in time domain is controllably adjusted;The signal processing system receives the output signal modulated by time delay scale adjusting module, and is encoded after being processed by system.The present application inserts graphene oxide / polyvinyl alcohol film as saturable absorber into bidirectional laser for the first time to realize mode-locking, with the characteristics of low cost and convenient manufacturing process;The present application adopts all-fiber structure, without external signal modulation, with the characteristics of simple process steps and easy operation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photoelectric information coding, and particularly relates to an information coding system and method of a bidirectional mode-locked fiber laser based on a graphene oxide saturable absorber. BACKGROUND

[0002] The fiber laser has high efficiency, good heat dissipation, compact structure, high stability, and high beam quality, and has extremely important applications in scientific research and industrial application. As a high-quality and stable ultrafast pulse light source, with the aid of passive mode-locking technology, the nonlinear absorption characteristics of the saturable absorber are used to adjust the loss in the resonant cavity, and the mode-locked fiber laser can easily realize the output of femtosecond-level (10 -15 second) ultrafast pulse laser, and thus has many potential applications in the field of optical communication.

[0003] The bidirectional mode-locked fiber laser has the advantages of high stability, compact structure, and high stability, and in recent years, many scholars at home and abroad have made breakthroughs in the research on the multi-soliton state of the bidirectional mode-locked fiber laser. However, there is little research on the application of the bidirectional mode-locked fiber laser in the field of optical communication. In addition, the current research generally uses carbon nanotubes as the saturable absorption device of the bidirectional mode-locked fiber laser. However, compared with other mode-locking materials, the carbon nanotubes have a higher cost, and the process is complex, which increases the equipment manufacturing cost and limits its wide application. SUMMARY

[0004] In view of the above improvement needs of the prior art, the application provides an information transmission and coding system based on a bidirectional mode-locked fiber laser. The application first uses a graphene oxide film as a saturable absorber in a bidirectional laser, which has ultrafast carrier relaxation and large optical nonlinearity, has the potential of ultrafast photons, can be produced on a large scale in industry by an improved Hummers method, and has a lower preparation cost. The application does not need the modulation intervention of an external signal, reduces the system design cost, and is more convenient to operate.

[0005] To achieve the above object, the application provides the following scheme:

[0006] An information coding system based on a bidirectional mode-locked fiber laser, comprising: a pulse signal transmitting module, a time delay scale adjusting module, and a signal processing system.

[0007] The pulse signal transmitting module is used to generate a basic mode-locked signal, including clockwise and counterclockwise bidirectional mode-locked signals.

[0008] The time delay scale adjusting module is used to modulate the bidirectional basic mode-locked pulses output by the pulse signal transmitting module, and controllably adjusts the relative delay of the clockwise pulse signal and the counterclockwise pulse signal in the time domain.

[0009] The signal processing system receives the output signal modulated by the time delay scale adjustment module, and encodes after system processing;

[0010] Preferably, the pulse signal emitting module comprises a laser diode pump source, a wavelength division multiplexer, a gain optical fiber, a polarization controller, a 2×2 optical coupler, and a saturable absorber.

[0011] Preferably, the time delay scale adjustment module comprises a clockwise light path unit and an anticlockwise modulation light path unit, the anticlockwise modulation light path unit comprises a first polarization independent isolator, and the clockwise modulation light path unit comprises a second polarization independent isolator, a first optical coupler, a first time delay modulator, a second time delay modulator, and a second optical coupler.

[0012] Preferably, the signal processing system comprises a photodetector, an oscilloscope, and a computer data encoding system.

[0013] The laser diode pump source is connected with a first port of the wavelength division multiplexer; a third port of the wavelength division multiplexer is connected with the gain optical fiber; the gain optical fiber is connected with the polarization controller; the polarization controller is connected with a first port of the 2×2 optical coupler; a second port of the 2×2 optical coupler is connected with the saturable absorber; and the saturable absorber is connected with a second port of the wavelength division multiplexer.

[0014] Preferably, the gain optical fiber is a low-doped erbium-doped optical fiber.

[0015] The polarization controller is used to adjust the optical fiber birefringence effect and the intracavity beam polarization state, so that the intracavity dispersion and nonlinear effects are balanced to generate an initial mode-locked pulse signal.

[0016] The anticlockwise modulation light path unit is sequentially connected with a third port of the 2×2 optical coupler, the first polarization independent isolator, and a first port of a third optical coupler.

[0017] A fourth port of the 2×2 optical coupler is connected with a second polarization independent isolator of the clockwise modulation light path unit; the second polarization independent isolator is connected with a first port of the first optical coupler; a second port of the first optical coupler is connected with the first time delay modulator; a third port of the first optical coupler is connected with the second time delay modulator; the first time delay modulator is connected with a first port of the second optical coupler; the second time delay modulator is connected with a second port of the second optical coupler; and a third port of the second optical coupler is connected with a second port of the third optical coupler.

[0018] The first time delay modulator and the second time delay modulator are both length-adjustable single-mode optical fibers.

[0019] The first time delay modulator and the second time delay modulator are used for modulating the relative delay of the clockwise pulse signal and the counterclockwise pulse signal in the time domain.

[0020] The third port of the third optical coupler in the time delay scale adjustment module is connected with the photodetector; the oscilloscope is connected with the photodetector; and the computer terminal data coding system is connected with the oscilloscope.

[0021] The photodetector is used for converting the received optical signal into an electrical signal and outputting the electrical signal to the oscilloscope.

[0022] The oscilloscope is used for recording the relative time delay position of the bidirectional mode-locked pulse signal, and converting the electrical signal into a data format and transmitting the data format to the computer terminal data coding system.

[0023] The computer terminal data coding system is used for receiving the data file transmitted by the oscilloscope, and converting the corresponding signal data into coded characters after system processing.

[0024] Compared with the prior art, the above technical scheme conceived by the present application can achieve the following beneficial effects:

[0025] 1. The information coding system based on the bidirectional mode-locked fiber laser provided by the present application is composed of a pulse signal transmitting module, a time delay scale adjustment module and a signal processing system, the pulse signal transmitting module generates a basic mode-locked signal, including one counterclockwise bidirectional mode-locked signal and two clockwise bidirectional mode-locked signals, the time delay scale adjustment module modulates the bidirectional basic mode-locked pulse output by the pulse signal transmitting module, controllably adjusts the relative delay of the clockwise pulse signal and the counterclockwise pulse signal in the time domain, generates one main pulse and two distinguishable sub-pulses, and finally the signal processing system receives the output information modulated by the time delay scale adjustment module and converted into a data format, and encodes the information after system processing.

[0026] 2. The pulse signal transmitting module of the present application is composed of an all-fiber laser, the entire laser resonant cavity is formed as a whole by means of optical fiber fusion, without any external device, and has the characteristics of good beam quality, anti-electromagnetic interference, simple and compact structure, high coupling efficiency of pump light, good stability, low cost and high realizability.

[0027] 3. The saturable absorber of the passively mode-locked bidirectional laser in the pulse signal transmitting module adopts a graphene oxide film, the material preparation is simpler, and the implementation cost is lower.

[0028] 4. Bidirectional transmission, flexible and versatile, the bidirectional mode-locked fiber laser as a multifunctional multiplexing laser has many potential applications in the field of fiber communication. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a complete structure schematic diagram of an information coding system based on a bidirectional mode-locked fiber laser in a preferred embodiment of the present application.

[0030] Figure 2 is a principle diagram of an information coding method based on a bidirectional mode-locked fiber laser in a preferred embodiment of the present application.

[0031] Figure 3 is an information coding rule schematic diagram based on a bidirectional mode-locked fiber laser in a preferred embodiment of the present application.

[0032] Figure 4 is a final display schematic diagram of a computer terminal data coding system interface in a specific example.

[0033] In all the drawings, the same reference signs are used to represent the same elements or structures, wherein:

[0034] 1, pulse signal transmitting module; 2, laser diode pump source; 3, wavelength division multiplexer; 4, gain light; 5, polarization controller; 6, 2x2 optical coupler; 7, graphene oxide saturable absorber; 8, time delay scale adjustment module; 9, first polarization independent isolator; 10, second polarization independent isolator; 11, first optical coupler; 12, first time delay modulator; 13, second time delay modulator; 14, second optical coupler; 15, third optical coupler; 16, signal processing system; 17, photodetector; 18, oscilloscope; 19, computer terminal data coding system. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0036] The terms "first", "second", "third" and the like in the specification and claims of the present application are used to distinguish different objects, and are not used to describe a specific order.

[0037] The present application provides an information coding system based on a bidirectional mode-locked fiber laser, which uses graphene oxide film as a saturable absorber in a bidirectional laser for the first time, without the need for external signal modulation intervention, reducing the system design cost and making the operation more simple.

[0038] As Figure 1As shown is a kind of information coding system structure schematic diagram provided by the embodiment of the application, comprising: pulse signal output module 1, time delay scale adjustment module 8 and information processing system 16.

[0039] Pulse signal emission module 1 is used to generate basic mode-locked signal, including clockwise and counterclockwise bidirectional mode-locked signal.

[0040] Time delay scale adjustment module 8 is used to modulate the bidirectional basic mode-locked pulse output by pulse signal emission module, and the relative delay of clockwise pulse signal and counterclockwise pulse signal in time domain is controllably adjusted by using first time delay modulator 12 and second time delay modulator 13.

[0041] Signal processing system 16 receives the output signal modulated by time delay scale adjustment module 8, and encodes after system processing.

[0042] Among them, pulse signal emission module 1 includes: laser diode pump source 2, wavelength division multiplexer 3, gain optical fiber 4, polarization controller 5, 2×2 optical coupler 6 and graphene saturable absorber 7.

[0043] Time delay scale adjustment module 8 includes clockwise optical path unit and counterclockwise modulation optical path unit, the counterclockwise optical path unit includes: first polarization-independent isolator 9, the clockwise modulation optical path unit includes: second polarization-independent isolator 10, first optical coupler 11, first time delay modulator 12, second time delay modulator 13 and second optical coupler 14.

[0044] Signal processing system 16 includes: photodetector 17, oscilloscope 18 and computer data encoding system 19.

[0045] The laser diode pump source 2 is connected with the first port 3a of the wavelength division multiplexer 3;The third port 3c of the wavelength division multiplexer 3 is connected with the gain optical fiber 4;The gain optical fiber 4 is connected with the polarization controller 5;The polarization controller 5 is connected with the first port 6a of the 2×2 optical coupler 6, the second port 6b of the 2×2 optical coupler 6 is connected with the graphene saturable absorber 7;The graphene saturable absorber is connected with the second port 3b of the wavelength division multiplexer 3.

[0046] Gain optical fiber 4 adopts low-doped erbium-doped optical fiber, which is used to absorb pump light energy, and provides gain for laser pulse through stimulated radiation amplification effect.

[0047] Polarization controller 5 is used to adjust the optical fiber birefringence effect and the polarization state of intracavity light beam, so that the intracavity dispersion and nonlinear effect reach balance to generate initial mode-locked pulse signal.

[0048] The graphene oxide saturable absorber 7 is used to realize bidirectional mode-locked pulse operation.

[0049] The third port 6c of the 2*2 optical coupler 6 is connected with the counterclockwise optical path unit first polarization-independent isolator 9; the first polarization-independent isolator 9 is connected with the first port 15a of the third optical coupler 15.

[0050] The fourth port 6d of the 2*2 optical coupler 6 is connected with the clockwise modulation optical path unit second polarization-independent isolator 10; the second polarization-independent isolator 10 is connected with the first port 11a of the first optical coupler 11; the second port 11b of the first optical coupler 11 is connected with the first time delay modulator 12; the third port 11c of the first optical coupler 11 is connected with the second time delay modulator 13; the first time delay modulator 12 is connected with the first port 14a of the second optical coupler 14; the second time delay modulator 13 is connected with the second port 14b of the second optical coupler 14; the third port 14c of the second optical coupler 14 is connected with the second port 15b of the third optical coupler 15.

[0051] The first time delay modulator 12 and the second time delay modulator 13 are both length-adjustable single-mode optical fibers, which are used to modulate the relative delay of the clockwise pulse signal and the counterclockwise pulse signal in the time domain; by modulating the length of the single-mode optical fiber, the corresponding time delay modulation of the mode-locked pulse in the time domain can be realized.

[0052] The photodetector 17 is connected with the third port 15c of the third optical coupler 15 in the time delay scale adjustment module 8; the oscilloscope 18 is connected with the photodetector 17; the computer terminal data coding system 19 is connected with the oscilloscope 18.

[0053] The photodetector 17 is used to convert the received optical signal into an electrical signal output to the oscilloscope 18.

[0054] The oscilloscope 18 is used to record the relative time delay position of the bidirectional mode-locked pulse signal, and convert the tested electrical signal into a data format and transmit it to the computer terminal data coding system 19.

[0055] The computer terminal data coding system 19 is used to receive the data file transmitted by the oscilloscope, and convert the corresponding signal data into coded characters after system processing.

[0056] As Figure 2 The information coding method based on the bidirectional mode-locked fiber laser provided by the application is shown in the schematic diagram, which comprises:

[0057] 20, the first time delay modulator 12 and the second time delay modulator 13 are used to generate the modulated bidirectional mode-locked soliton pulse with controllable relative time delay in the time domain.

[0058] 20Specifically includes: change access clockwise modulation optical path unit of first time delay modulator 12 and second time delay modulator 13, so that the mode-locked pulse generated by the clockwise modulation optical path unit and the mode-locked pulse generated by the counterclockwise optical path unit have a relative, controllable time delay in the time domain.

[0059] 21, pulse sequence scale diagram.

[0060] 21Specifically includes: the relative time delay generated by the mode-locked pulse generated by the clockwise modulation optical path unit and the mode-locked pulse generated by the counterclockwise optical path unit in the time domain is converted from an optical signal to an electrical signal by a photodetector 17, and output to an oscilloscope 18 to display a corresponding distinguishable pulse sequence scale.

[0061] As Figure 3 The information encoding rule based on the bidirectional mode-locked fiber laser provided by the present application is shown in the schematic diagram, which includes:

[0062] 22, an example of scale conversion to characters.

[0063] 22Specifically includes: the two grid sub-scales shown in the pulse sequence scale diagram (21) are "1-6" (left 1), "2-6" (left 2), "3-6" (left 3), "4-6" (left 4), "5-6" (left 5), "1-6" (right 1), "1-7" (right 2), "1-8" (right 3), "1-9" (right 4) and "1-10" (right 5). Corresponding characters are "B", "G", "L", "Q", "V", "B", "C", "D", "E" and "F" respectively. In this way, the information encoding rule based on the bidirectional mode-locked fiber laser can obtain 25 kinds of sub-scale arrangement combinations.

[0064] 23, a complete information encoding rule, the computer data encoding system 19 automatically uses the signal data processed by the information encoding rule to convert the scale code to text information display.

[0065] 23Specifically includes: oscilloscope 18 reads the pulse signal, according to the pulse intensity amplitude of the pulse signal is distinguished as a main pulse and two side pulse, and the pulse signal is processed as a data file transmission to the computer data encoding system 19, computer data encoding system 19 is automatically according to the pulse intensity amplitude of the pulse signal is distinguished as a main pulse (CW) and two side pulse (CCW1, CCW2) signal, and carries out normalization processing, the signal greater than or equal to the first threshold (0.9) is converted into corresponding main scale, the signal greater than or equal to the second threshold (0.2) is converted into two side scale, the normalized signal is drawn into pulse sequence diagram and displayed on the interface, according to information coding rule to determine the text information, and the pulse sequence diagram is displayed on the interface together. According to the information coding rule 23, the scale coding of only main pulse CW is character "A"; CCW1 pulse is fixed at side scale 1 position, and CCW2 pulse is located at side scale "6" to side scale "10" respectively, and the scale coding is character "B", "C", "D", "E", "F"; CCW1 pulse is fixed at side scale 2 position, and CCW2 pulse is located at side scale "6" to side scale "10" respectively, and the scale coding is character "G", "H", "I", "J", "K"; CCW1 pulse is fixed at side scale 3 position, and CCW2 pulse is located at side scale "6" to side scale "10" respectively, and the scale coding is character "L", "M", "N", "O", "P"; CCW1 pulse is fixed at side scale 4 position, and CCW2 pulse is located at side scale "6" to side scale "10" respectively, and the scale coding is character "Q", "R", "S", "T", "U"; CCW1 pulse is fixed at side scale 5 position, and CCW2 pulse is located at side scale "6" to side scale "10" respectively, and the scale coding is character "V", "W", "X", "Y", "Z".

[0066] As Figure 4 It is a schematic diagram of a specific embodiment.

[0067] As a specific embodiment, Figure 4 The pulse sequence of the English word spelling "LASER" of "laser" is shown. Figure 4 It is a computer data encoding system display interface, including: information display interface 23, first normalized pulse sequence diagram (24), second normalized pulse sequence diagram (25), third normalized pulse sequence diagram (26), fourth normalized pulse sequence diagram (27), fifth normalized pulse sequence diagram (28), sixth normalized pulse sequence diagram (29), first text information 30, second text information 31, third text information 32, fourth text information 33, fifth text information 34, sixth text information 35, start button 36 and total encoding output result 37.

[0068] Figure 4 The first normalized pulse sequence graph (24), the second normalized pulse sequence graph (25), the third normalized pulse sequence graph (26), the fourth normalized pulse sequence graph (27) and the fifth normalized pulse sequence graph (28) show that the pulse sequence is divided into one main peak and two sub-peaks according to the intensity peak value, when the normalized pulse intensity amplitude exceeds the first threshold value (0.9), it is determined as the main peak, and the corresponding coding scale is the main scale, when the normalized pulse intensity amplitude exceeds the second threshold value (0.2), it is determined as the sub-peak, and the corresponding coding scale is the sub-scale. The time delay of the sub-peak relative to the main peak shown in the normalized pulse sequence graph can be directly recognized by the computer terminal data coding system 19 as the corresponding scale, and the length of the time delay corresponds to the size of the scale, and the time delay reaches 5ns, the system determines that the scale is increased by one to the high bit. The computer terminal data coding system determines that the sub-scale corresponding to the time delay of the sub-peak relative to the main peak in the first normalized pulse sequence graph (24) is “3-6”, the second normalized pulse sequence graph (25) only has the main peak, the sub-scale corresponding to the time delay of the sub-peak relative to the main peak in the third normalized pulse sequence graph (26) is “4-8”, the sub-scale corresponding to the time delay of the sub-peak relative to the main peak in the fourth normalized pulse sequence graph (27) is “1-9”, and the sub-scale corresponding to the time delay of the sub-peak relative to the main peak in the fifth normalized pulse sequence graph (28) is “4-7”. The corresponding first text information 30 is “3-6:L”, the second text information 31 is “A”, the third text information 32 is “4-8:S”, the fourth text information 33 is “1-9:E”, and the fifth text information 34 is “4-7:R”. The total coding output result 37 is “LASER”.

[0069] Figure 4 The first normalized pulse sequence graph (24), the second normalized pulse sequence graph (25), the third normalized pulse sequence graph (26), the fourth normalized pulse sequence graph (27) and the fifth normalized pulse sequence graph (28) all show that in addition to one main peak and two sub-peaks, there are additional peaks, which are interference peaks that cannot be avoided by the mode-locked pulse, and the interference of the additional peaks can be directly excluded by the system function.

[0070] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0071] Those skilled in the art will easily understand that the above only describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An information encoding system based on a bidirectional mode-locked fiber laser, characterized in that, include: The system comprises a pulse signal transmission module (1), a time delay scale adjustment module (8), and a signal processing system (16), wherein... The pulse signal transmitting module (1) is connected to the time delay scale adjustment module (8); the time delay scale adjustment module (8) is connected to the signal processing system (16); The pulse signal transmitting module (1) is used to generate basic mode-locked signals, including clockwise and counterclockwise bidirectional mode-locked signals; The time delay scale adjustment module (8) is used to modulate the bidirectional basic mode-locked pulse output by the pulse signal transmission module (1) and make controllable adjustments to the relative delay of the clockwise pulse signal and the counterclockwise pulse signal in the time domain. The signal processing system (16) receives the output signal modulated by the time delay scale adjustment module (8), and encodes it after system processing; The pulse signal transmitting module (1) includes: a laser diode pump source (2), a wavelength division multiplexer (3), a gain fiber (4), a polarization controller (5), a 2×2 optical coupler (6), and a graphene oxide saturable absorber (7); The laser diode pump source (2) is connected to the wavelength division multiplexer (3); the wavelength division multiplexer (3) is connected to the gain fiber (4); the gain fiber (4) is connected to the polarization controller (5); the polarization controller (5) is connected to the first port 6a of the 2×2 optical coupler (6); the second port (6b) of the 2×2 optical coupler (6) is connected to the graphene oxide saturable absorber (7). The graphene oxide saturable absorber (7) is a graphene oxide / polyvinyl alcohol film with nonlinear saturable absorption properties, which can introduce a mode-locking mechanism for the laser. It has the characteristics of simple preparation process and low cost. The laser diode pump source (2) is connected to the first port (3a) of the wavelength division multiplexer (3). The third port (3c) of the wavelength division multiplexer (3) is connected to the gain fiber (4). The gain fiber (4) is connected to the polarization controller (5). The polarization controller (5) is connected to the first port (6a) of the 2×2 optical coupler (6). The second port (6b) of the 2×2 optical coupler (6) is connected to the graphene oxide saturable absorber (7). The graphene oxide saturable absorber (7) is connected to the second port (3b) of the wavelength division multiplexer (3). The time delay scale adjustment module (8) includes: a first polarization-independent isolator (9), a second polarization-independent isolator (10), a first optical coupler (11), a first time delay modulator (12), a second time delay modulator (13), a second optical coupler (14), and a third optical coupler (15); the first polarization-independent isolator (9) is connected to the third port (6c) of the 2x2 optical coupler (6) and the first port (15a) of the third optical coupler (15); the second polarization-independent isolator (10) is connected to the fourth port (6d) of the 2x2 optical coupler (6) and the first port (11a) of the first optical coupler (11); the second port (11b) of the first optical coupler (11) is connected to the first time delay modulator (12); The third port (11c) of the first optical coupler (11) is connected to the second time delay modulator (13); the first time delay modulator (12) is connected to the first port (14a) of the second optical coupler (14); the second time delay modulator (13) is connected to the second port (14b) of the second optical coupler (14); the third port (14c) of the second optical coupler (14) is connected to the second port (15b) of the third optical coupler (15); the first port (15a) and the second port (15b) of the third optical coupler (15) are used to connect the counterclockwise optical path unit and the clockwise modulation optical path unit of the time delay scale adjustment module (8), and output the modulated optical signal through the third port (15c) of the third optical coupler (15).

2. The information encoding system based on a bidirectional mode-locked fiber laser according to claim 1, characterized in that, Both the first time delay modulator (12) and the second time delay modulator (13) are length-adjustable single-mode optical fibers.

3. The information encoding system based on a bidirectional mode-locked fiber laser according to claim 1, characterized in that, The signal processing system (16) includes: a photodetector (17), an oscilloscope (18), and a computer-based data encoding system (19); The photodetector (17) and the third port (15c) of the third optical coupler (15) are respectively connected to the oscilloscope (18); the oscilloscope (18) is connected to the computer-side data encoding system (19); The photodetector (17) is used to convert the received vector pulse signal into an electrical signal and transmit it to the oscilloscope (18); The oscilloscope (18) is used to record the relative time delay position of the bidirectional mode-locked pulse signal and convert the electrical signal into a data format to be transmitted to the computer data encoding system (19). The computer-side data encoding system (19) is used to receive data files transmitted by the oscilloscope (18), and after system processing, converts the corresponding signal data into encoded text.

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