WO2020147192A1 - Cable signal coupling system and method - Google Patents

Abstract

Disclosed in the present invention are a cable signal coupling system and method. The system comprises: a direct-current power transmission system circuit, a signal modulation coupling circuit, and a signal demodulation circuit; wherein the signal modulation coupling circuit is used for performing processing and modulating on a system baseband signal, generating a high-frequency carrier signal, and loading the high-frequency carrier signal to a direct-current power transmission wire of the direct-current power transmission system circuit so as to transmit the high-frequency carrier signal to the signal demodulation circuit by means of the direct-current power transmission wire; and the signal demodulation circuit is used for performing frequency division filtering on the high-frequency carrier signal transmitted by the direct-current power transmission wire to obtain a filtering signal, performing reduction processing on the filtering signal to obtain a reduced baseband signal, and outputting the reduced baseband signal. According to the present invention, the high-frequency carrier signal is directly transmitted by adopting the direct-current power transmission wire, so that the costs of repeatedly constructing a signal transmission channel are saved, and the construction costs of a communication channel are reduced.

Description

Cable signal coupling system and method Technical field

The invention relates to the technical field of electric energy transmission, in particular to a cable signal coupling system and method.

Background technique

With the advancement of high-power high-voltage DC power electronic transmission technology, high-power and high-efficiency high-voltage DC transmission systems have greatly promoted the development of the field of power transmission. Among them, the high-voltage direct current transmission system is applied to the power supply of subsea system equipment, which greatly promotes the development of its subsea resource detection and research.

At present, in the long-distance high-voltage direct current transmission system, the length of the copper wire cable is hundreds of kilometers, especially the optical fiber copper wire that needs to construct the optical fiber channel, and the cost is extremely expensive. Specifically, the existing long-distance HVDC power transmission system usually uses optical communication equipment to transmit signals through optical fiber composite copper cables. The transmission signal has a large amount of signal data, strong anti-interference and long transmission distance, but a separate communication transmission circuit is required. , The communication channel construction cost is high.

Summary of the invention

In view of this, the present invention provides a cable signal coupling system and method to solve the problem of high transmission cost of long-distance submarine direct current transmission lines in the prior art.

In the first aspect, an embodiment of the present invention provides a cable signal coupling system, including: a direct current transmission system circuit, a signal modulation coupling circuit, and a signal demodulation circuit;

The signal modulation coupling circuit is used to process and modulate the system baseband signal to generate a high-frequency carrier signal, and load the high-frequency carrier signal to the DC transmission wire of the DC transmission system circuit to pass the DC transmission The wire is transmitted to the signal demodulation circuit;

The signal demodulation circuit is used to perform frequency division filtering on the high-frequency carrier signal transmitted by the direct current transmission wire to obtain a filtered signal, and perform restoration processing on the filtered signal to obtain a restored baseband signal, and output The restored baseband signal.

Optionally, the DC transmission system circuit includes: a shore-based power supply, an underwater DC power supply, and a DC transmission wire; one end of the DC transmission wire is connected to the shore-based power supply and the signal modulation coupling circuit, and the DC transmission The other end of the wire is connected to the underwater DC power supply and the signal mediation circuit; the DC transmission wire is used to transmit the high voltage DC power provided by the shore-based power supply to the underwater DC power supply; the underwater DC power supply, It is used to perform voltage reduction processing on the high-voltage direct current to generate low-voltage direct current, wherein the voltage of the high-voltage direct current is higher than the voltage of the low-voltage direct current.

Optionally, the signal modulation coupling circuit includes a signal modulation driving circuit, a carrier generating circuit, and a resonance coupling circuit; one end of the carrier generating circuit is connected to the signal modulation driving circuit, and the other end of the carrier generating circuit is connected to the Resonant coupling circuit; the signal modulation drive circuit is used to modulate the received system baseband signal to generate a pulse width modulation signal, and output a drive signal to the carrier generation circuit according to the pulse width modulation signal; the carrier generation circuit , Used to generate a carrier signal according to the drive signal and transmit the carrier signal to the resonant coupling circuit; the resonant coupling circuit is used to amplify the power of the carrier signal to generate a high frequency carrier signal, and The high-frequency carrier signal is loaded onto the direct current transmission wire.

Optionally, the carrier generating circuit includes a transistor unit, the control terminal of the transistor unit is connected to the signal modulation drive circuit, and the output terminal of the transistor unit is connected to the resonance coupling circuit; the resonance coupling circuit includes isolation Transformer, the resonant coupling circuit is connected to the direct current transmission wire through the isolation transformer.

Optionally, the signal demodulation circuit includes: a signal dc blocking circuit, a signal frequency selective filter circuit, and a signal restoration circuit; one end of the signal dc blocking circuit is connected to the DC transmission wire, and the other of the signal dc blocking circuit One end is connected to the signal frequency selective filter circuit, which is used to transmit the high frequency carrier signal transmitted by the direct current transmission wire to the signal frequency selective filter circuit; the signal frequency selective filter circuit is used to The carrier signal is frequency-divided and filtered to produce a filtered signal, and the filtered signal is output to the signal restoration circuit; the signal restoration circuit is used to restore the filtered signal to obtain the restored baseband signal, and Output the restored baseband signal.

Optionally, the signal frequency selective filter circuit includes: a resonant filter circuit unit and a precision rectifier circuit unit; the resonant filter circuit unit is connected to the signal dc blocking circuit and is used to filter out the high-frequency carrier signal Line clutter, generate a filtered signal, and output the filtered signal to the precision rectifier circuit unit; the precision rectifier circuit unit is used to rectify the filtered signal and output the rectified filtered signal to the The signal restoration circuit.

Optionally, the resonance filter circuit unit includes a resonance filter capacitor, a resonance filter inductor, and a resonance adjustment resistor; one end of the resonance adjustment resistor is connected to the resonance filter capacitor, and the other end of the resonance adjustment resistor is connected to the resonance filter Inductance; the first output terminal of the signal blocking circuit is connected to a resonant filter capacitor, and the second output terminal of the signal blocking circuit is connected to the resonant filter inductor.

Optionally, the signal DC blocking circuit includes a DC blocking capacitor and an isolation transformer; the primary side of the isolation transformer is connected to the DC transmission wire through the DC blocking capacitor, and the secondary side of the isolation transformer is connected to the resonant filter circuit. Unit connection.

Optionally, the signal frequency selective filter circuit further includes: a conditioning filter circuit unit; the input end of the conditioning filter circuit unit is connected to the signal DC blocking circuit through the resonance filter circuit unit, and the conditioning filter circuit The output terminal of the unit is connected with the precision rectifier circuit unit.

Optionally, the signal modulation drive circuit includes: a digital signal modulation circuit unit and a signal drive circuit unit; the input end of the signal drive circuit unit is connected to the digital signal modulation circuit unit, and the output end of the signal drive circuit unit Connect the carrier generating circuit.

In the second aspect, an embodiment of the present invention also provides a cable signal coupling method, which is applied to a cable signal coupling system. The system includes a DC transmission system circuit, a signal modulation coupling circuit, and a signal demodulation circuit. The method includes: The signal modulation and coupling circuit processes and modulates the baseband signal of the system to generate a high-frequency carrier signal, and loads the high-frequency carrier signal to the DC transmission wire of the DC transmission system circuit; the signal demodulation circuit controls the DC The high-frequency carrier signal transmitted by the power transmission wire is frequency-divided and filtered to obtain a filtered signal, and the filtered signal is restored to obtain a restored baseband signal, and the restored baseband signal is output.

Optionally, the signal modulation and coupling circuit processes and modulates the baseband signal of the system to generate a high-frequency carrier signal, and load the high-frequency carrier signal onto the DC transmission wire of the DC transmission system circuit, including: signal modulation The drive circuit modulates the received system baseband signal to generate a pulse width modulation signal, and outputs a drive signal to the carrier generation circuit according to the pulse width modulation signal; the carrier generation circuit generates a carrier signal according to the drive signal and combines The carrier signal is transmitted to the resonant coupling circuit; through the resonant coupling circuit, the carrier signal is power-amplified to generate a high-frequency carrier signal, and the high-frequency carrier signal is loaded onto the direct current transmission wire.

Optionally, the signal demodulation circuit performs frequency division filtering on the high-frequency carrier signal transmitted by the direct current transmission wire to obtain a filtered signal, and performs restoration processing on the filtered signal to obtain a restored baseband signal, including : Transmit the high-frequency carrier signal transmitted by the DC transmission wire to the signal frequency selective filter circuit through a signal direct current transmission circuit; the signal frequency selective filter circuit performs frequency division filtering on the high frequency carrier signal to produce Filtering a signal, and outputting the filtered signal to the signal restoration circuit; and performing restoration processing on the filtered signal through the signal restoration circuit to obtain a restored baseband signal.

Optionally, the signal frequency selective filtering circuit performs frequency division filtering on the high-frequency carrier signal to produce a filtered signal, and outputting the filtered signal to the signal restoration circuit includes: filtering out all the signals through a resonance filtering circuit. The line clutter in the high-frequency carrier signal generates a filtered signal, and the filtered signal is output to the precision rectifier circuit unit; through the precision rectifier circuit unit, the filtered signal is rectified, and the rectified The filtered signal is output to the signal restoration circuit.

The present invention processes and modulates the baseband signal of the system through the signal modulation coupling circuit, and loads the generated high-frequency carrier signal to the DC transmission wire of the DC transmission system circuit, so that the DC transmission wire is used to directly transmit the high-frequency carrier signal without a separate construction The communication loop eliminates the cost of repetitive construction of signal transmission channels, reduces the construction cost of communication channels, and solves the problem of high transmission cost of existing long-distance submarine direct current transmission lines.

BRIEF DESCRIPTION

Figure 1 is a structural block diagram of a cable signal coupling system according to an embodiment of the present invention;

Figure 2 is a structural block diagram of a cable signal coupling system suitable for long-distance submarine direct current transmission in an example of the present invention;

Figure 3 is a schematic diagram of the structure of a DC transmission system circuit in an example of the present invention;

Fig. 4 is a schematic structural diagram of a signal modulation coupling circuit in an example of the present invention;

5 is a schematic diagram of the signal modulation coupling circuit in an example of the present invention generating 4 PWM signals;

Fig. 6 is a schematic diagram of process waveforms generated when a signal modulation coupling circuit of an example of the present invention performs modulation and coupling;

Fig. 7 is an example diagram of a single-channel decoding circuit of a signal demodulation circuit in an example of the present invention;

Fig. 8 is a waveform diagram of a decoding circuit of a cable signal coupling system in an example of the present invention;

Fig. 9 is a flow chart of steps of a cable signal coupling method in an embodiment of the present invention.

detailed description

The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, in order to facilitate description, the drawings only show parts but not all structures related to the present invention.

With the development of intelligent power transmission, the reliability and real-time performance of shore-based power and underwater power signal transmission in DC power transmission systems are very important. Therefore, the construction of a cable signal coupling system and method suitable for long-distance submarine direct current transmission has high academic and engineering value.

At present, there are two main ways of signal transmission in the submarine cable transmission system: one is to use optical communication equipment to transmit signals through optical fiber composite copper cables. The transmission signal has a large amount of data, strong anti-interference and long transmission distance, but separate communication is required. The transmission loop and communication protocol are complex, and the real-time communication is poor; the other is to use the power line carrier method for transmission, but the current carrier communication is mostly used in short-distance, low-voltage transmission lines. Specifically, with the development of power line carrier communication, power line carrier communication is widely used in low-voltage DC transmission grids. At present, power line carrier generation mostly adopts the form of triode amplifier, which has the disadvantages of low carrier generation efficiency, high power consumption and short transmission distance. In addition, the strong signal interference and the difficulty of carrier communication in HVDC transmission lines have also become difficulties that restrict the mature application of carrier communication.

In order to solve the problems of high transmission cost, complex implementation and poor real-time performance in the prior art, the present invention provides a new cable signal coupling system and method, which combines carrier communication technology and transmits directly through DC transmission wires signal.

Referring to Fig. 1, a structural block diagram of a cable signal coupling system according to an embodiment of the present invention is shown. The cable signal coupling system may be suitable for the occasion of direct current transmission submarine cable signal mutual transmission, and specifically may include: a direct current transmission system circuit 110, a signal modulation coupling circuit 120 and a signal demodulation circuit 130. Wherein, the output terminal of the signal modulation coupling circuit 120 is connected to the DC transmission wire of the DC transmission system circuit 110, and is used to process and modulate the system baseband signal to generate a high-frequency carrier signal, and load the high-frequency carrier signal to the The direct current transmission wire of the direct current transmission system circuit 110 is transmitted to the signal demodulation circuit through the direct current transmission wire. The signal demodulation circuit 130 is used to perform frequency division filtering on the high-frequency carrier signal transmitted by the direct current transmission wire to obtain a filtered signal, and restore the filtered signal to obtain the restored baseband signal, and output the The restored baseband signal.

In summary, the cable signal coupling system in the embodiment of the present invention processes and modulates the system baseband signal through the signal modulation coupling circuit 120, and loads the generated high-frequency carrier signal to the DC transmission wire of the DC transmission system circuit 110 to use The DC transmission wire directly transmits high-frequency carrier signals without the need to construct a communication loop separately, thereby reducing the construction cost of communication channels, and solving the problem of high transmission cost of existing long-distance submarine DC transmission lines.

As an example of the present invention, as shown in FIG. 2, a cable signal coupling system suitable for long-distance submarine direct current transmission may include: a long-distance direct current transmission circuit as a direct current transmission system circuit 110, a signal modulation coupling circuit 120, and a signal demodulation Circuit 130. Long-distance DC transmission circuits can convert three-phase AC power into high-voltage DC power through shore-based power supplies, and can be transmitted to subsea equipment through DC transmission wires. Among them, the long-distance DC transmission circuit may use copper wires as the DC transmission wires, that is, the DC transmission wires in the DC transmission system circuit 110 may be DC transmission copper wires.

Specifically, the long-distance DC transmission circuit can be connected to the DC transmission copper wire to generate high-voltage direct current to the DC transmission copper wire, and the voltage can be adjusted at the underwater power terminal connected to the terminal to supply power to the load. The signal modulation coupling circuit 120 can be connected to the shore-based power terminal in the long-distance DC transmission circuit, and is used to process and modulate the system baseband signal to generate a high-frequency signal with a composite frequency, and can use the high-frequency signal as a high-frequency carrier signal , Loaded into the DC transmission copper wire, so that the high-frequency carrier signal can be transmitted to the signal demodulation circuit 130 through the DC transmission copper wire for restoration processing.

The signal demodulation circuit 130 performs frequency-division filtering on the high-frequency carrier signal of the DC transmission copper wire, and restores it to a baseband signal by the signal processing circuit, that is, obtains and outputs the restored baseband signal. For example, the signal demodulation circuit 130 can restore the signal through the signal blocking and isolation circuit, multi-signal frequency selection and multi-channel band-pass active filter circuit and level comparison circuit to obtain the restored baseband signal, and restore the The baseband signal is output to the signal receiving terminal to realize carrier communication.

It can be seen that the cable signal coupling system in this example uses the coupled carrier method to build a coupling channel in the high-voltage line of the long-distance DC transmission circuit, eliminating the cost of repetitive construction of signal transmission channels, thereby reducing the transmission cost of long-distance submarine DC transmission lines .

Furthermore, the DC power transmission system circuit 110 in the embodiment of the present invention may include: a shore-based power supply 111, an underwater DC power supply 112, and a DC power transmission wire 113. One end of the DC transmission wire 113 is connected to the shore-based power supply 111 and the signal modulation coupling circuit 120, and the other end of the DC transmission wire 113 is connected to the underwater DC power supply 112 and the signal modulation circuit 130. In a specific implementation, the DC power transmission wire 113 is used to transmit the high-voltage DC power provided by the shore-based power source 111 to the underwater DC power source 112. The underwater DC power supply 112 is used to perform voltage reduction processing on the high-voltage DC power to generate low-voltage DC power, wherein the voltage of the high-voltage DC power is higher than the voltage of the low-voltage DC power.

In a specific implementation, the DC transmission system circuit 110 can convert three-phase AC power into high-voltage DC power for use by subsea equipment through a shore-based power supply. Specifically, the shore-based power terminal 111 can adopt an AC-DC module method to raise the three-phase mains power to the high-voltage bus voltage, that is, provide high-voltage direct current to the copper wire of long-distance direct current transmission; the underwater power terminal 112 can transmit power through long-distance direct current The current loop constructed by the copper wire and the seawater loop powers the subsea equipment. Specifically, the DC-DC module can be used to step down the high-voltage direct current transmitted by the high-voltage bus, such as reducing the teeth to 600V (600V). Equipment.

For example, as shown in Figure 3, the shore-based power supply terminal 111 can be used as a shore-based power supply circuit, which can convert the connected three-phase alternating current (Alternating Curren, AC) into direct current (Direct Current) through one or more AC-DC power modules. Current, DC), and can boost the voltage of the direct current to the high-voltage bus voltage to generate high-voltage direct current, which is transmitted to the underwater power circuit through the cable power supply circuit connected to it. Among them, the long-distance DC transmission copper wire connected to the shore-based power supply terminal can be used as a high-voltage bus in the cable power supply circuit, and the sea water between the shore-based power supply terminal and the underwater power supply terminal can be used as another high-voltage bus in the cable power supply circuit. The bus, thus forming a sea water circuit. In addition, the underwater power terminal 112 as an underwater power circuit can adjust the voltage of the high-voltage direct current through one or more DC-DC power modules, so as to supply power to the load based on the adjusted voltage. The load may include underwater equipment, such as subsea equipment, which is not limited in the embodiment of the present invention.

It can be seen that the cable signal coupling system in the embodiment of the present invention is suitable for the use of the DC system, and can be applied to any high-voltage long-distance line signal carrier transmission. For example, the cable signal coupling system in the embodiment of the present invention may use digital frequency shift keying to transmit signals. Specifically, the signal modulation coupling circuit in the cable signal coupling system can adopt the inductance-inductance-capacitance (LLC) series resonance method for carrier modulation, and can be combined with the LLC resonance topology with high efficiency, large transmission energy, high reliability and coupling sine Good features: With good coupling sine, the generated high-frequency carrier signal is directly loaded on the DC transmission line 113 for transmission, which meets the long-distance, high-voltage and high-reliability transmission requirements, and overcomes the existing carrier communication only The shortcomings used in short-distance, low-voltage transmission lines have expanded the application range of power line carrier communication.

In an optional embodiment of the present invention, the aforementioned signal modulation coupling circuit 120 may include a signal modulation driving circuit 121, a carrier generating circuit 122, and a resonance coupling circuit 123. As shown in FIG. 2, one end of the carrier generating circuit 122 is connected to the signal modulation drive circuit 121, and the other end of the carrier generating circuit 122 is connected to the resonance coupling circuit 123. The signal modulation driving circuit 121 is used to modulate the received system baseband signal to generate a pulse width modulation signal, and output a driving signal to the carrier generating circuit 122 according to the pulse width modulation signal. The carrier generating circuit 122 is configured to generate a carrier signal according to the driving signal, and transmit the carrier signal to the resonance coupling circuit 123. The resonant coupling circuit 113 can be used to amplify the power of the carrier signal, generate a high-frequency carrier signal, and load the high-frequency carrier signal onto the direct current transmission wire. It can be seen that, in the embodiment of the present invention, a carrier signal with a complex frequency can be generated by the carrier generating circuit 122, and a carrier signal with a high frequency (ie, a high frequency carrier signal) can be coupled to the DC transmission wire for transmission through the resonance coupling circuit 123, which is easy to implement It solves the difficulty of carrier communication caused by the use of triode amplifier in the existing power line carrier generation, and has good anti-noise and anti-attenuation performance, and overcomes the strong signal interference and the difficulty of carrier communication in the high-voltage direct current transmission line in the prior art The resulting difficulties in carrier communication applications have expanded the scope of carrier communication applications.

Optionally, the signal modulation drive circuit in the embodiment of the present invention may include: a digital signal modulation circuit unit and a signal drive circuit unit; the input end of the signal drive circuit unit is connected to the digital signal modulation circuit unit, and the signal drive The output terminal of the circuit unit is connected to the carrier generating circuit. Among them, the digital signal modulation circuit unit can be specifically used to modulate the received system baseband signal to generate a pulse width modulation signal, and can output the pulse width modulation signal to the signal drive circuit unit, so that the signal drive circuit unit can be based on The pulse width modulation signal outputs a drive signal. The signal driving circuit unit is used for outputting a driving signal to the carrier generating circuit according to the pulse width modulation signal output by the digital signal modulation circuit unit.

For example, in combination with the above examples, the signal modulation coupling circuit 120 can be used as the signal modulation and coupling part of a cable signal coupling system suitable for long-distance submarine direct current transmission. The signal modulation driving circuit 121 in the signal modulation coupling circuit 120 can include digital signal modulation. The circuit unit 410 and the signal driving circuit unit 420, and the carrier generating circuit 122 and the resonance coupling circuit 123 in the signal modulation coupling circuit 120 can be integrated in the same circuit unit. As shown in FIG. 4, the carrier generating circuit 122 and the resonance coupling The circuit 123 may be integrated in the carrier generation and isolation circuit unit 430 of the signal modulation coupling circuit 120.

In this example, the signal modulation coupling circuit 120 can use LLC full-bridge topology to generate carrier signals of different frequencies and couple them to the DC transmission copper wires, and can modulate the baseband signal into the high-frequency carrier through the frequency shift keying modulation mode. Specifically, the Microcontroller Unit (MCU) in the digital signal modulation circuit unit 410 can be used to modulate the system baseband signal into a pulse width modulation (PWM) signal that is complementary to the four circuits and the lower tube, as shown in Figure 4. The PWM1, PWM2, PWM3, and PWM4 shown in the signal drive circuit unit 420 can then be transmitted to the control terminal of the transistor unit in the carrier generation and isolation circuit unit 430 through the chip in the signal drive circuit unit 420, so that the carrier generation and isolation circuit unit 430 generates High-frequency carrier signal, and the generated high-frequency carrier signal is loaded into the DC transmission wire for transmission. Wherein, the transistor unit in the carrier generation and isolation circuit unit 430 may include one or more transistors, for example, the transistor may be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), or other transistors. Type of transistor, this example does not limit this.

Furthermore, the carrier generating circuit 122 in the embodiment of the present invention includes a transistor unit, the control terminal of the transistor unit is connected to the signal modulation driving circuit 121, and the output terminal of the transistor unit is connected to the resonance coupling circuit 123. The resonant coupling circuit 123 may include an isolation transformer Tp, and the resonant coupling circuit 123 is connected to the direct current transmission wire 113 through the isolation transformer Tp. Specifically, in the embodiment of the present invention, the transistor unit in the carrier generating circuit 122 can be used to form an LLC full-bridge topology, and then the LLC full-bridge topology can be used to generate carrier signals of different frequencies to be coupled to the DC transmission wire 113, and can be frequency shifted. The control modulation mode modulates the baseband signal into a high-frequency carrier to realize signal transmission by means of power line carrier.

For example, in combination with the above example, the signal drive circuit unit 420 can use a low-cost drive circuit composed of the chip R2113, so that the pulse width modulation signal output by the digital signal modulation circuit unit 410 can be processed through the chip IR2113 to generate and transmit to the carrier generation and isolation The driving signal of the circuit unit 430. The driving signal may be used to drive one or more transistors of the carrier generating and isolating circuit unit 430, and may specifically include a driving signal transmitted to one or more transistors, for example, may include: transmitting to the carrier generating and isolating circuit unit 430 The driving signal G1 of the control terminal of the first field effect transistor Q1, the driving signal G2 transmitted to the control terminal of the second field effect transistor Q2 in the carrier generation and isolation circuit unit 430, and the third field effect transmission to the carrier generation and isolation circuit unit 430 The drive signal G3 of the control terminal of the tube Q3 is transmitted to the drive signal G4 of the control terminal of the fourth field effect transistor Q4 in the carrier generation and isolation circuit unit 430.

Among them, the inductance Lp, the capacitance Cp and the isolation transformer Tp in the carrier generation and isolation circuit unit 430 can form a classic LLC resonance circuit. The frequency of the high-frequency carrier signal loaded by the carrier generation and isolation circuit unit 430 to the DC transmission line can be determined by the inductance Lp, the capacitance Cp and the isolation transformer Tp, for example, it can be determined according to the following system formula:

It should be noted that Lm in the system formula can be the excitation inductance of the isolation transformer Tp, Lr can be the equivalent leakage inductance of the transformer primary, f1 can be the carrier frequency of the high-level signal, and f2 can be the carrier frequency of the low-level signal. fm can be the emergency signal carrier frequency. For example, the frequency of f1 can be 250kHz, the frequency of f2 can be 1MHz, the frequency of fm can be 500kHz, and so on.

In the specific implementation, the system baseband signal can be selected by the digital logic circuit in the digital signal modulation circuit unit 410 to select the carrier signal frequency to be transmitted, that is, the MCU controller in the digital signal modulation circuit unit 410 can be based on the above system formula to receive The received system baseband signal is modulated to generate 4 PWM signals, and the driving signals corresponding to these 4 PWM signals are transmitted to the control terminal of each transistor in the carrier generation and isolation circuit unit 430 through the signal driving circuit unit, that is, to The control terminals of the first field effect tube Q1, the second field effect tube Q2, the third field effect tube Q2, and the fourth field effect tube Q4 to trigger the carrier generation and isolation circuit unit 430 to generate the corresponding high-frequency carrier signal, and load it To the DC transmission wire for transmission.

For example, the signal modulation coupling circuit in the embodiment of the present invention can use a switched inductor-inductor-capacitor (LLC) series resonant converter to modulate the baseband signal into high frequency sine waves of different frequency bands; and can pass through a high frequency and high voltage isolation transformer Load the carrier signal into the long-distance submarine cable. Specifically, as shown in Figure 5, when the system baseband signal includes low level "0", high level "1", and emergency signal "EM" corresponding to three different state frequency signals, the baseband signal can pass The digital logic circuit in the MCU controller selects the frequency of the carrier signal that needs to be sent, and then divides it into 4 PWM signals through the PWM generation circuit and transmits them to the control terminals of Q1-Q4, so as to form the corresponding inverter bridge formed by Q1-Q4 Inverter carrier, that is, when the low level "0", high level "1", and emergency signal "EM" correspond to three different state frequency signals, they can be modulated by high frequency carrier to form respective characteristics. The carrier passes through the inverter bridges Q1-Q4 to form respective square wave outputs. As shown in Figure 6, the carrier frequency of low level "0" can be f2, the carrier frequency of high level "1" can be f1, and the emergency signal "EM" The carrier frequency of "can be fm. The inverter carrier output from the inverter bridge Q1-Q4 is transformed into a sine wave after carrier generation and LLC resonance in the isolation circuit unit 430. The waveform of the sine wave is as shown in the primary waveform of the transformer in Figure 6, and can be The sine wave is coupled to the high-voltage DC bus through the isolation transformer Tp to perform signal transmission through the high-voltage DC bus. It should be noted that the signal transmitted by the high-voltage DC bus is used as a high-frequency carrier signal, and its signal waveform is the high-voltage DC bus waveform shown in FIG. 6.

It can be seen that the cable signal coupling system in this embodiment can use LLC mode for carrier modulation, and combines the characteristics of LLC resonance topology with high efficiency, large transmission energy, high reliability, and good coupling sine, which can meet the requirements of long-distance submarine DC transmission In the occasion, the application needs of long distance, high voltage and high reliability.

In addition, the cable signal coupling system in the embodiment of the present invention can be decoded by a method of multi-carrier frequency independent loop filtering and processing, which eliminates the difficulty of filtering design and improves the reliability of system decoding.

In a specific implementation, the signal mediation circuit 130 may in turn include a signal blocking and transformer isolation circuit, a multi-series LC frequency selection network, a multi-band second-order active band-pass frequency selection filter, a voltage comparator, and a digital signal processing circuit, and The carrier signal can be detected by multi-resonance and frequency selection, and the signal can be restored by the level comparison circuit.

In an optional implementation manner, the aforementioned signal demodulation circuit 130 may include: a signal DC blocking circuit 131, a signal frequency selective filtering circuit 132, and a signal restoration circuit 133. One end of the signal blocking circuit 131 is connected to the direct current transmission wire, and the other end of the signal blocking circuit 131 is connected to the signal frequency selective filter circuit 132 for transmitting the high frequency carrier wave transmitted by the direct current transmission wire. The signal is transmitted to the signal frequency selective filtering circuit 132. The signal frequency selective filtering circuit 132 is configured to perform frequency division filtering on the high-frequency carrier signal to produce a filtered signal, and output the filtered signal to the signal restoration circuit 133. The signal restoration circuit 133 is configured to perform restoration processing on the filtered signal to obtain a restored baseband signal, and output the restored baseband signal.

Specifically, the high-voltage DC bus voltage carrying the carrier signal can be restored to a high-frequency carrier signal through the DC blocking capacitor Cdc and the isolation transformer Ts in the signal DC blocking circuit 131, as shown in Figure 2, and then can be frequency-selected by the signal The series resonance circuit in the filter circuit 132 filters out the line noise in the high-frequency carrier signal to output the filtered signal obtained after filtering to the signal restoration circuit 133, and then the signal restoration circuit 133 can select the frequency of the signal by the filter circuit The filtered signal output by 132 is restored to output the restored baseband signal to realize the decoding function of the cable signal coupling system.

In this embodiment, optionally, the above-mentioned signal frequency selective filter circuit 132 may include: a resonance filter circuit unit and a precision rectifier circuit unit. Wherein, the resonant filter circuit unit may be connected to the signal dc blocking circuit for filtering out line noise in the high-frequency carrier signal, generating a filtered signal, and outputting the filtered signal to the precision rectifier circuit unit. The precision rectifier circuit unit is used to rectify the filtered signal, and can output the rectified filtered signal to the signal restoration circuit.

In a specific implementation, the resonance filter circuit unit may include a resonance filter capacitor Cs1, a resonance filter inductor Ls1, and a resonance adjustment resistor R1. One end of the resonance adjusting resistor R1 is connected to the resonance filter capacitor Cs1, the other end of the resonance adjusting resistor R1 is connected to the resonance filter inductor Ls1; the first output end of the signal blocking circuit 131 is connected to the resonance filter capacitor Cs1 , And the second output terminal of the signal DC blocking circuit 131 is connected to the resonant filter inductor Ls1. Among them, the resonance adjustment resistor R1 can be used for the resonant circuit quality factor value Q, that is, during the debugging process, the resonance adjustment resistor R1 can be adjusted to adjust the resonant circuit Q value in the resonant filter circuit unit to adjust the system filter sensitivity.

Further, the signal DC blocking circuit 131 may include a DC blocking capacitor Cdc and an isolation transformer Ts. The primary side of the isolation transformer Ts is connected to the DC transmission wire through the DC blocking capacitor Cdc, and the secondary side of the isolation transformer Ts is connected to the resonant filter circuit unit. In a specific implementation, the primary side of the isolation transformer Ts can be connected to the DC transmission wire through the DC blocking capacitor Cdc, and the secondary side of the isolation transformer Ts can be connected to the signal frequency selective filter circuit 132 through the resonance filter circuit unit. For example, as shown in Figure 2, one end of the DC blocking capacitor Cdc can be connected to the primary side of the isolation transformer Ts, and the other end of the DC blocking capacitor Cdc can be connected to the b terminal of the underwater DC power supply; as shown in Figure 7 One end of the DC blocking capacitor Cdc can be connected to the primary side of the isolation transformer Ts, and the other end of the DC blocking capacitor Cdc can be connected to the a terminal of the underwater DC power supply and the other end of the DC transmission wire.

As an example of the present invention, a channel decoding circuit in the signal demodulation circuit 130 may include a signal DC blocking circuit 131, a signal frequency selection filter circuit 132, and a signal restoration circuit 133 connected in sequence. As shown in Figure 7, the DC blocking capacitor Cdc and the isolation transformer Ts in the signal DC blocking circuit 131 can be integrated in the same circuit unit with the resonant filter capacitor Cs1, the resonant filter inductor Ls1 and the resonant adjusting resistor R1 in the resonant filter circuit unit. As shown in FIG. 7, a resonant filter capacitor Cs1, a resonant filter inductor Ls1, a resonant filter capacitor Cs1, a resonant filter inductor Ls1, and a resonant adjusting resistor R1 can constitute a DC blocking and resonant filter circuit unit 710.

Optionally, the signal frequency selective filter circuit 132 in the embodiment of the present invention may further include a conditioning filter circuit unit. The input end of the conditioning filter circuit unit can be connected to the signal dc blocking circuit 131 through the resonance filter circuit unit, and the output end of the conditioning filter circuit unit can be connected to the precision rectifier circuit unit.

In specific implementation, as shown in Figure 7, the conditioning filter circuit unit 720 can be used as a circuit conditioning and active filter circuit in the cable signal coupling system, and can form a differential amplifier through the op amp A1 and its peripheral circuits to adjust the system's filtering The amplitude is used to filter out the differential interference caused by the system, so that the signal after the interference is removed to the precision rectification circuit unit 730 for precision rectification to form a carrier signal with high frequency ripple, which can then be The carrier signal of the frequency ripple is used as the filtered signal obtained after filtering and is transmitted to the signal restoration circuit 133 for restoration processing by the signal processing circuit in the signal restoration circuit 133.

Taking the signal frequency f1 as an example, the high-voltage DC bus voltage carrying the carrier signal can be restored to the carrier signal through the blocking capacitor Cdc and the isolation transformer Ts, and the line clutter is filtered by the series resonance circuit. The relationship between circuit parameters Cs1 and Ls1 is as formula

As shown, that is, the circuit parameters Cs1 and Ls1 can be as large as

determine.

In this example, the value of R1 in the DC blocking and resonant filter circuit unit 710 can be used to adjust the Q value of the resonant tank to adjust the filter sensitivity of the system during the debugging process. The operational amplifier A1 and its peripheral circuits can form a differential amplifier, which can be specifically used to adjust the filter amplitude of the system to filter out the differential interference caused by the system. The specific amplification factor A and circuit parameters of the differential amplifier can be shown in the following formula 1.

Formula 1:

Among them, A in formula 1 represents the amplification factor of the differential loop; R2 can be used to represent the value of the resistor R2 connected to the input end of the op amp A1; R3 can be used to represent the value of the resistor R3 connected to the input end of the op amp A1 Value; R4 can be used to represent the value of the resistor R4 connected to the operational amplifier A1; R5 can be used to represent the value of the resistor R5 connected to the operational amplifier A1.

The op amp A2 and its peripheral circuits can form a second-order active filter. The cut-off frequency fL of the low-pass part of the filter and the cut-off frequency fH of the high-pass part of the filter can be shown in Equation 2 below.

Formula 2:

Among them, C1 in formula 1 can represent the value of the first capacitor C1 connected to the input terminal of the operational amplifier A2; C2 can represent the value of the second capacitor C2 connected to the input terminal of the operational amplifier A2; R7 can be used to represent the first capacitor C2 The value of the resistor R7 connected to the two capacitors C2; R9 can be used to represent the value of the resistor R9 connected to the operational amplifier A2.

Circuit conditioning and the filter ratio amplification factor Auf and the passband amplification factor Aup of the active filter circuit can be as shown in formula 3.

Formula 3:

According to the analysis of formula 2 and formula 3, it can be seen that if fH is set at the carrier frequency-3dB gain, the carrier signal will not change significantly after the op amp. When the cut-off frequency of the high-pass part is designed to attenuate at 1.5dB, the gain can be effectively increased At the same time, the communication signal attenuation according to this design remains unchanged.

In a specific implementation, the dense rectifier circuit unit 730 in this example can be used as a precision rectifier circuit in a cable signal coupling system. As shown in Figure 7, the previous stage op amp A3 in the precision rectifier circuit can be used as a half-wave precision rectifier circuit. When the diode D1 is off, the next stage op amp A4 can be an inverting summing circuit. The precision rectifier circuit can realize the absolute value output of the result, and its input-output relationship can be shown in formula 4.

Formula 4:

Among them, Vrout in formula 4 can represent the output voltage value of the precision rectifier circuit; Vrin can represent the output voltage value of the precision rectifier circuit; R11 can be used to represent the value of the resistor R11 connected to the op amp A4; R12 can be used to represent The value of the resistor R12 connected to the operational amplifier A3; R15 can be used to represent the value of the resistor R15 connected to the operational amplifier A4; R17 can be used to represent the value of the resistor R17 connected to the operational amplifier A4.

After precise rectification, the cable signal coupling system can be restored by the signal restoration circuit 133, and the restored baseband signal can be sent to the signal processing circuit through the overvoltage comparator A5 in the signal restoration circuit 133. Of mutual communication.

For example, as shown in Figure 8, when the low level "0", the high level "1", and the emergency signal "EM" correspond to three different state frequency signals, the high voltage DC bus is used as a carrier signal The high-voltage DC bus waveform can be restored to the resonant filter waveform corresponding to the high-frequency carrier signal after the high-frequency transformer Ts, the DC blocking capacitor Cdc, and the band-pass filtering in the signal frequency selection filter circuit 132. After the resonant filter waveform passes through the precision rectification circuit, a carrier signal with high-frequency ripple can be formed, such as the signal corresponding to the precision rectification waveform shown in FIG. 8. Compared with the traditional amplitude detection method, the signal demodulation method in this example obtains greater signal energy and shorter signal delay. After the voltage comparator, it is basically restored to a baseband signal and sent to the signal processing circuit.

Further, the cable signal coupling system in this example can build an emergency channel by itself, so as to directly perform a switch-level emergency shutdown through the emergency channel in an emergency situation. Specifically, in the event of an emergency, the cable signal coupling system can directly perform emergency shutdown of the switch level, which increases the safety and stability of the system.

In summary, by providing a new cable signal coupling system, the embodiments of the present invention realize high-power long-distance two-way transmission of communication signals in high-voltage submarine cables, and the cable signal coupling system has high signal transmission power and strong anti-interference. The carrier generation efficiency is high and the signal delay time is short; and, by separately establishing the emergency control channel of the cable signal coupling system, the real-time response of the system is improved.

On the basis of the foregoing embodiment, the embodiment of the present invention also provides a cable signal coupling method to be applied to a cable signal coupling system. The cable signal coupling system may be the cable signal coupling system mentioned in any of the above embodiments, and may specifically include a DC transmission system circuit, a signal modulation coupling circuit, a signal demodulation circuit, and the like.

Referring to FIG. 9, there is shown a flow chart of the steps of a cable signal coupling method in an embodiment of the present invention. The cable signal coupling method can be applied to a cable signal coupling system, and specifically may include the following steps:

Step 910: The signal modulation coupling circuit processes and modulates the system baseband signal to generate a high-frequency carrier signal, and loads the high-frequency carrier signal to the DC transmission wire of the DC transmission system circuit.

In the embodiment of the present invention, the signal modulation coupling circuit can be used as the signal modulation and coupling circuit of the cable signal coupling system, which can specifically include signal modulation and drive circuits, carrier generation circuits, LLC resonance and high voltage isolation circuits. The shore-based power information processing system can use the signal modulation coupling circuit in the cable signal coupling system to encode information into a baseband signal and transmit it to the modulation and drive circuit, and can realize the loading of the baseband signal by changing the signal frequency of the LLC resonant converter . It should be noted that the two resonance points of the LLC resonant converter can be f1 and f2 in sequence; among them, f1 can be the resonant frequency of the transformer magnetizing inductance, leakage inductance and resonant inductance and the same resonant capacitor; f2 can be the transformer leakage inductance The sum of the resonant inductance and the resonant capacitor's resonant frequency.

In a specific implementation, f1, f2, and the intermediate frequency fm can be selected in sequence as the high level, low level, and emergency signal frequency, and the baseband signal can be modulated by controlling the drive signal of the LLC resonant converter. Specifically, the two resonance points of the LLC resonance circuit can be used to achieve high-efficiency generation of high-frequency carrier waves, and the resonance point and high-voltage isolation circuit can be constructed through a high-frequency transformer.

In an optional embodiment of the present invention, the signal modulation coupling circuit includes a signal modulation driving circuit, a carrier generating circuit, and a resonance coupling circuit, and one end of the carrier generating circuit is connected to the signal modulation driving circuit, and The other end of the carrier generating circuit is connected to the resonance coupling circuit. The signal modulation coupling circuit processes and modulates the baseband signal of the system to generate a high-frequency carrier signal, and loads the high-frequency carrier signal to the DC transmission wire of the DC transmission system circuit, which may specifically include: a signal modulation drive circuit , Modulate the received system baseband signal to generate a pulse width modulation signal, and output a drive signal to the carrier generating circuit according to the pulse width modulation signal; the carrier generating circuit generates a carrier signal according to the drive signal, and combines the carrier The signal is transmitted to the resonant coupling circuit; through the resonant coupling circuit, the carrier signal is power-amplified to generate a high-frequency carrier signal, and the high-frequency carrier signal is loaded onto the direct current transmission wire.

Step 920: The signal demodulation circuit performs frequency division filtering on the high-frequency carrier signal transmitted by the DC transmission wire to obtain a filtered signal, and performs restoration processing on the filtered signal to obtain a restored baseband signal, and output the The restored baseband signal.

In the embodiment of the present invention, the signal demodulation circuit can effectively reduce the signal-to-noise ratio of the signal by constructing a multi-frequency selection signal network and a filter network, and can realize fast real-time data processing through a comparator and a digital holding and processing circuit. The emergency channel that can be constructed can quickly block the shore-based power supply and protect the transmission system.

In specific implementation, the signal demodulation circuit can be used as a signal decoding circuit, which can specifically include a signal blocking and isolation circuit, a multi-signal frequency selection and filtering circuit, and a level comparison circuit. The high-frequency carrier signal is filtered by a multi-signal frequency selection and filtering circuit, and then can be passed through a level comparison circuit and restored to a baseband signal by a digital signal processing circuit.

In an optional embodiment of the present invention, the signal demodulation circuit includes: a signal dc blocking circuit, a signal frequency selective filter circuit, and a signal restoration circuit; one end of the signal dc blocking circuit is connected to the DC transmission wire, so The other end of the signal DC blocking circuit is connected to the signal frequency selection filter circuit, and is used to transmit the high frequency carrier signal transmitted by the direct current transmission wire to the signal frequency selection filter circuit. Optionally, the signal demodulation circuit performs frequency division filtering on the high-frequency carrier signal transmitted by the direct current transmission wire to obtain a filtered signal, and performs restoration processing on the filtered signal to obtain a restored baseband signal, specifically It may include: transmitting the high-frequency carrier signal transmitted by the direct current transmission wire to the signal frequency selection filter circuit through a signal blocking circuit; the signal frequency selection filter circuit performs frequency division filtering on the high frequency carrier signal , Producing a filtered signal, and outputting the filtered signal to the signal restoration circuit; performing restoration processing on the filtered signal through the signal restoration circuit to obtain a restored baseband signal.

Further, the signal frequency selective filter circuit in the embodiment of the present invention may include: a resonant filter circuit unit and a precision rectifier circuit unit; the resonant filter circuit unit is connected to the signal dc blocking circuit for filtering out the high frequency The line clutter in the frequency carrier signal generates a filtered signal, and the filtered signal is output to the precision rectifier circuit unit. Optionally, the signal frequency selective filtering circuit performs frequency division filtering on the high-frequency carrier signal, produces a filtered signal, and outputs the filtered signal to the signal restoration circuit, which may specifically include: filtering through a resonance filtering circuit Remove line noise in the high-frequency carrier signal, generate a filtered signal, and output the filtered signal to the precision rectifier circuit unit; through the precision rectifier circuit unit, the filtered signal is rectified, and The rectified filtered signal is output to the signal restoration circuit.

In summary, the embodiment of the present invention adopts the method of separate loop filtering and processing at multi-carrier frequencies for decoding, which eliminates the difficulty of filtering design and improves the reliability of system decoding; and the system can be improved by separately establishing emergency control channels. Real-time response; and it is possible to construct a receiving system on shore and a transmitting system underwater for signal transmission, realizing two-way signal transmission.

It should be noted that for the method embodiments, for the sake of simple description, they are all expressed as a series of action combinations, but those skilled in the art should know that the embodiments of the present invention are not limited by the described sequence of actions, because According to the embodiments of the present invention, certain steps may be performed in other order or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

The embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments may refer to each other.

Those skilled in the art should understand that the embodiments of the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

The embodiments of the present invention are described with reference to the flowcharts and/or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each flow and/or block in the flowchart and/or block diagram and a combination of the flow and/or block in the flowchart and/or block diagram may be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine so that the instructions executed by the processor of the computer or other programmable data processing terminal device Means for generating the functions specified in a block or blocks of a flowchart or a flow and/or a block diagram.

These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing terminal equipment to work in a predictive manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device. The instruction device realizes the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.

These computer program instructions can also be loaded on a computer or other programmable data processing terminal equipment, so that a series of operation steps are executed on the computer or other programmable terminal equipment to generate computer-implemented processing, so that the computer or other programmable terminal equipment The instructions executed above provide steps for implementing functions specified in a flow or multiple flows in the flowchart and/or a block or multiple blocks in the block diagram.

Although the preferred embodiments of the embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

Finally, it should also be noted that in this article, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities Or there is any such actual relationship or order between operations. Moreover, the terms "include", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or terminal device that includes a series of elements includes not only those elements, but also those that are not explicitly listed The other elements listed may also include elements inherent to such processes, methods, articles, or terminal equipment. Without more restrictions, the element defined by the sentence "include one..." does not exclude that there are other identical elements in the process, method, article, or terminal device that includes the element.

The above provides a detailed introduction to the cable signal coupling system and method provided by the present invention. In this article, specific examples are used to illustrate the principles and implementation of the present invention. The description of the above embodiments is only used to help understand the present invention. At the same time, for those of ordinary skill in the art, according to the ideas of the present invention, there will be changes in the specific implementation and the scope of application. In summary, the content of this specification should not be understood as Restrictions on the invention.

Claims (10)

1. A cable signal coupling system, which is characterized by comprising: a DC transmission system circuit, a signal modulation coupling circuit and a signal demodulation circuit;

   The signal modulation coupling circuit is used to process and modulate the system baseband signal to generate a high-frequency carrier signal, and load the high-frequency carrier signal to the DC transmission wire of the DC transmission system circuit to pass the DC transmission The wire is transmitted to the signal demodulation circuit;

   The signal demodulation circuit is used to perform frequency division filtering on the high-frequency carrier signal transmitted by the direct current transmission wire to obtain a filtered signal, and perform restoration processing on the filtered signal to obtain a restored baseband signal, and output The restored baseband signal.
2. The system according to claim 1, wherein the DC transmission system circuit comprises: shore-based power supply, underwater DC power supply, and DC transmission wire;

   One end of the DC power transmission wire is connected to the shore-based power supply and the signal modulation coupling circuit, and the other end of the DC power transmission wire is connected to the underwater DC power supply and the signal modulation circuit;

   The direct current transmission wire is used to transmit the high voltage direct current provided by the shore-based power supply to the underwater direct current power supply;

   The underwater direct current power supply is used to perform voltage reduction processing on the high-voltage direct current to generate low-voltage direct current, wherein the voltage of the high-voltage direct current is higher than the voltage of the low-voltage direct current.
3. The system according to claim 1, wherein the signal modulation coupling circuit comprises a signal modulation driving circuit, a carrier generating circuit, and a resonance coupling circuit;

   One end of the carrier generating circuit is connected to the signal modulation drive circuit, and the other end of the carrier generating circuit is connected to the resonance coupling circuit;

   The signal modulation driving circuit is used to modulate the received system baseband signal to generate a pulse width modulation signal, and output a driving signal to the carrier generating circuit according to the pulse width modulation signal;

   The carrier generating circuit is used for generating a carrier signal according to the driving signal, and transmitting the carrier signal to the resonance coupling circuit;

   The resonant coupling circuit is used to amplify the power of the carrier signal, generate a high-frequency carrier signal, and load the high-frequency carrier signal to the direct current transmission wire.
4. The system according to claim 3, wherein:

   The carrier generating circuit includes a transistor unit, a control terminal of the transistor unit is connected to the signal modulation drive circuit, and an output terminal of the transistor unit is connected to the resonance coupling circuit;

   The resonant coupling circuit includes an isolation transformer, and the resonant coupling circuit is connected to the direct current transmission wire through the isolation transformer.
5. The system according to claim 1, wherein the signal demodulation circuit comprises: a signal dc blocking circuit, a signal frequency selective filtering circuit and a signal restoration circuit;

   One end of the signal blocking circuit is connected to the direct current transmission wire, and the other end of the signal blocking circuit is connected to the signal frequency selective filter circuit for transmitting the high frequency carrier signal transmitted by the direct current transmission wire to The signal frequency selective filtering circuit;

   The signal frequency selective filtering circuit is used to perform frequency division filtering on the high-frequency carrier signal to produce a filtered signal, and output the filtered signal to the signal restoration circuit;

   The signal restoration circuit is used to perform restoration processing on the filtered signal to obtain a restored baseband signal, and output the restored baseband signal.
6. The system according to claim 5, wherein the signal frequency selective filter circuit comprises: a resonance filter circuit unit and a precision rectifier circuit unit;

   The resonant filter circuit unit is connected to the signal dc blocking circuit, and is used to filter out line noise in the high-frequency carrier signal, generate a filtered signal, and output the filtered signal to the precision rectifier circuit unit;

   The precision rectifier circuit unit is used to rectify the filtered signal and output the rectified filtered signal to the signal restoration circuit.
7. A cable signal coupling method, characterized in that it is applied to a cable signal coupling system, the system includes a DC transmission system circuit, a signal modulation coupling circuit, and a signal demodulation circuit, and the method includes:

   The signal modulation coupling circuit processes and modulates the baseband signal of the system to generate a high-frequency carrier signal, and loads the high-frequency carrier signal to the DC transmission wire of the DC transmission system circuit;

   The signal demodulation circuit performs frequency division filtering on the high-frequency carrier signal transmitted by the direct current transmission wire to obtain a filtered signal, and restores the filtered signal to obtain a restored baseband signal, and outputs the restored After the baseband signal.
8. The method according to claim 7, wherein the signal modulation coupling circuit processes and modulates the system baseband signal to generate a high-frequency carrier signal, and loads the high-frequency carrier signal to the circuit of the DC transmission system. DC transmission wires, including:

   The signal modulation drive circuit modulates the received system baseband signal to generate a pulse width modulation signal, and outputs a drive signal to the carrier generating circuit according to the pulse width modulation signal;

   The carrier generating circuit generates a carrier signal according to the driving signal, and transmits the carrier signal to the resonance coupling circuit;

   Through the resonance coupling circuit, the carrier signal is power-amplified to generate a high-frequency carrier signal, and the high-frequency carrier signal is loaded on the direct current transmission wire.
9. 7. The method according to claim 7, wherein the signal demodulation circuit performs frequency division filtering on the high-frequency carrier signal transmitted by the direct current transmission line to obtain a filtered signal, and restores the filtered signal , Get the restored baseband signal, including:

   Transmitting the high frequency carrier signal transmitted by the direct current transmission wire to the signal frequency selective filtering circuit through a signal direct current blocking circuit;

   The signal frequency selective filtering circuit performs frequency division filtering on the high-frequency carrier signal to produce a filtered signal, and outputs the filtered signal to the signal restoration circuit;

   Through the signal restoration circuit, restoration processing is performed on the filtered signal to obtain a restored baseband signal.
10. The method according to claim 9, wherein the signal frequency selection filter circuit performs frequency division filtering on the high-frequency carrier signal to produce a filtered signal, and output the filtered signal to the signal restoration circuit, include:

    Filter the line clutter in the high-frequency carrier signal through a resonance filter circuit to generate a filtered signal, and output the filtered signal to the precision rectifier circuit unit;

    The precision rectification circuit unit rectifies the filter signal, and outputs the rectified filter signal to the signal restoration circuit.

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