A monitoring device and method for a wired communication system
By designing a monitoring device that includes electronic cutters, electronic switches and trigger switches, the problem of difficult monitoring of the physical layer security and confidential communication system in the Wyner sense is solved, seamless monitoring is achieved and communication is maintained, and communication is normal, with excellent hidden effect.
Patent Information
- Application Number
- CN202210663410.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-06-13
- Publication Date
- 2025-04-25
- Estimated Expiration
- 2042-06-13
AI Technical Summary
The prior art is difficult to effectively monitor confidential communication systems with the physical layer security in the Wyner sense, especially without affecting the normality of communication.
A monitoring device including an electronic cutter, an electronic switch and a trigger switch is designed. By connecting these elements in parallel, the telephone bus is cut and reorganized to form a telephone line 1, a telephone line 2 and a telephone line 3, so as to access the telephone line without being perceived, and achieve seamless monitoring of the monitored communication node.
The device can eliminate interference from high-power synchronous noise signals without affecting normal communication, acquire target information, and have excellent hidden effects, making monitoring difficult to detect.
Smart Images
Figure CN114844986B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of same-frequency self-interference communication monitoring in communication technology, and specifically relates to a monitoring device and method for a wired communication system. Background Art
[0002] In the current communication field, when important information is transmitted, in order to improve security, a strong power co-frequency self-interference signal is released in the communication line to drown out the target signal for confidential communication. This communication system can ensure that when multiple groups of users talk at the same time, each target signal frequency band can be drowned out by a high-power co-frequency noise signal, thereby achieving confidential communication with physical layer security in the sense of Wyner. This confidential communication method is different from the common upper-layer encrypted communication method. The upper-layer encrypted communication can be cracked by powerful computing equipment to intercept the target information, while the confidential communication with physical layer security in the sense of Wyner directly uses physical methods to allow high-power noise signals to drown out the co-frequency target signal to achieve the purpose of confidential communication. Therefore, how to monitor this communication system is a relatively large problem.
[0003] Therefore, there is an urgent need for a wired communication system monitoring device and method to solve the problem that criminals use the secure communication system to transmit illegal information. Summary of the invention
[0004] The object of the present invention is to provide a monitoring device and method for a wired communication system.
[0005] The technical solution for realizing the purpose of the present invention is: a monitoring device for a wired communication system, comprising a cutting and connecting part, the cutting and connecting part is connected to a communication maintaining part, and the communication maintaining part is connected to a signal demodulation part.
[0006] Furthermore, the disconnection and connection part includes an electronic disconnector, an electronic switch and a trigger switch. The number of the electronic disconnectors is 2. Two of the electronic disconnectors are installed at both ends of the monitored communication node on the telephone bus. The electronic switches include electronic switch 1, electronic switch 2 and electronic switch 3. Electronic switch 1, electronic switch 2 and electronic switch 3 are all installed on the telephone bus, wherein the electronic switch 1 is installed between one electronic disconnector and its adjacent communication node, and the electronic switch 3 is installed between another electronic disconnector and its adjacent communication node. The electronic switch 2 is arranged on the telephone bus between the two electronic disconnectors, and the electronic switch 1, electronic switch 2 and electronic switch 3 and the two electronic disconnectors are connected in parallel.
[0007] The parallel circuit of the two electronic disconnectors, electronic switch 1, electronic switch 2 and electronic switch 3 controls the closing of the main circuit through the trigger switch, so as to achieve the purpose of triggering the electronic switch 1, electronic switch 2, electronic switch 3 and the two electronic disconnectors at the same time, thereby ensuring that the disconnection and disconnection of the monitored communication node occur simultaneously, so that the monitoring device is connected to the telephone line without being perceived.
[0008] Furthermore, the two electronic disconnectors transform the telephone bus into telephone line 1, telephone line 2 and telephone line 3. There is only one communication node on telephone line 2, namely the monitored communication node. The electronic switch 1 is connected to telephone line 1, the electronic switch 2 is connected to telephone line 2, and the electronic switch 3 is connected to telephone line 3.
[0009] Furthermore, the communication maintenance part includes a 2\4-line conversion circuit and an adder, the 2\4-line conversion circuit includes a 2\4-line conversion circuit 1, a 2\4-line conversion circuit 2 and a 2\4-line conversion circuit 3, the adder includes adder 1, adder 2 and adder 3, the 2\4-line conversion circuit is connected to the telephone line port of the electronic switch, and the output port of the adder is connected to the signal application port of the 2\4-line conversion circuit.
[0010] The electronic switch 1 in the cutting and connecting part is connected to the telephone line port of the 2\4-wire conversion circuit 1, and the output port of the adder 1 is connected to the signal application port of the 2\4-wire conversion circuit 1; the electronic switch 2 in the cutting and connecting part is connected to the telephone line port of the 2\4-wire conversion circuit 2, and the output port of the adder 2 is connected to the signal application port of the 2\4-wire conversion circuit 2; the electronic switch 3 in the cutting and connecting part is connected to the telephone line port of the 2\4-wire conversion circuit 3, and the output port of the adder 3 is connected to the signal application port of the 2\4-wire conversion circuit 3.
[0011] Furthermore, the ports of the 2\4-wire conversion circuit include a telephone line port, a signal application port and a signal receiving port. The telephone line port of the 2\4-wire conversion circuit is connected to the telephone bus through an electronic switch for sending and receiving signals; the 2\4-wire conversion circuit sends the received signal to the telephone bus through its own signal application port and then sends it to the telephone bus through its own telephone line port; the signal receiving port of the 2\4-wire conversion circuit outputs the signal received by the telephone line port of the 2\4-wire conversion circuit from the telephone bus.
[0012] Furthermore, the signal receiving ports of the 2\4-wire conversion circuit 1 and the 2\4-wire conversion circuit 2 are connected to the input port of the adder 3 as the input of the adder 3 and as the input of the signal applying port of the 2\4-wire conversion circuit 3; the signal receiving ports of the 2\4-wire conversion circuit 2 and the 2\4-wire conversion circuit 3 are connected to the input port of the adder 1 as the input of the adder 1 and as the input of the signal applying port of the 2\4-wire conversion circuit 1; the signal receiving ports of the 2\4-wire conversion circuits 1 and 3 are connected to the input port of the adder 2 as the input of the adder 2 and as the input of the signal applying port of the 2\4-wire conversion circuit 2.
[0013] Furthermore, the signal demodulation part includes a carrier frequency detector, an adjustable bandpass filter, a down converter and a demodulator, the carrier frequency detector input port is connected to the signal receiving port of the 2\4 line conversion circuit 2, the carrier frequency detector output port is connected to the adjustable bandpass filter input port, the adjustable bandpass filter output port is connected to the down converter input port, and the down converter output port is connected to the demodulator input port.
[0014] A monitoring method for a wired communication system comprises the following steps:
[0015] S1: There are n communication nodes on the telephone bus. An electronic disconnector is placed on the telephone bus between communication node (p-1) and communication node p, and another electronic disconnector is placed on the telephone bus between communication node p and communication node (p+1);
[0016] S2: electronic switch 1 is connected to the telephone bus between the communication node (p-1) and the electronic disconnector near the communication node (p-1); electronic switch 2 is connected to the telephone bus between the two electronic disconnectors; electronic switch 3 is connected to the telephone bus between the communication node (p+1) and the electronic disconnector near the communication node (p+1);
[0017] S3: Activate the trigger button in the disconnection and connection part, and trigger the two electronic disconnectors, electronic switch 1, electronic switch 2 and electronic switch 3 to operate at the same time, and cut the telephone bus into telephone line 1, telephone line 2 and telephone line 3, wherein electronic switch 1 is connected to telephone line 1; electronic switch 2 is connected to telephone line 2; electronic switch 3 is connected to telephone line 3, and only communication node p is connected to telephone line 2;
[0018] S4: The telephone line port of the 2\4-line conversion circuit 1 receives the information signal and high-power noise signal sent by the communication node 1 to the communication node (p-1) from the telephone line 1. The information signal and the high-power noise signal are S i and N iThe information signal and high-power noise signal sent by the i-th communication node are then transmitted to the input ports of adder 2 and adder 3 through the signal receiving port of 2\4-wire conversion circuit 1, transmitted to the signal applying ports of 2\4-wire conversion circuits 2 and 3, and finally transmitted to telephone line 2 and telephone line 3 through the telephone line ports of 2\4-wire conversion circuits 2 and 3;
[0019] S5: The telephone line port of the 2\4-line conversion circuit 2 receives the information signal and high-power noise signal sent by the communication node p from the telephone line 2. The information signal and the high-power noise signal are S p and N p , the information signal and the high-power noise signal are then transmitted to the input ports of adder 1 and adder 3 through the signal receiving port of 2\4-wire conversion circuit 2, transmitted to the signal applying ports of 2\4-wire conversion circuits 1 and 3, and finally transmitted to telephone line 1 and telephone line 3 through the telephone line ports of 2\4-wire conversion circuits 1 and 3;
[0020] S6: The telephone line port of the 2\4-line conversion circuit 3 receives the information signal and high-power noise signal sent by the communication node (p+1) to the communication node n on the telephone bus 3. The information signal and the high-power noise signal are The information signal and the high-power noise signal are then transmitted to the input ports of adder 1 and adder 2 through the signal receiving port of 2\4-wire conversion circuit 3, transmitted to the signal applying ports of 2\4-wire conversion circuit 1 and 2, and finally transmitted to telephone line 1 and telephone line 2 through the telephone line ports of 2\4-wire conversion circuit 1 and 2;
[0021] S7: The carrier frequency detector in the monitoring demodulation part receives the information signal and high-power noise signal sent by the communication node p (i.e., the monitored communication node) through the signal receiving end of the 2\4-wire conversion circuit 2. According to the principle of realizing secure communication by the same-frequency self-interference communication system, the information signal and the high-power noise signal sent by the communication node p use different carrier frequencies, the carrier frequency used by the information signal is f1, and the carrier frequency used by the high-power noise signal is f2. The carrier detector detects the frequencies f1 and f2 of the two carrier signals, and then uses two bandpass filters with center frequencies of f1 and f2 to perform bandpass filtering, down-conversion, demodulation and other operations on the information signal and the high-power noise signal sent by the communication node p, respectively. Assume that the demodulated high-power noise signal and information signal are Noise(t) and Sound(t), respectively. Finally, a two-choice extraction operation is performed through a dip switch to obtain a voice signal.
[0022] Compared with the prior art, the present invention has the following significant advantages:
[0023] The present invention utilizes a device and method for simultaneously connecting three 2\4-wire circuits and simultaneously cutting off the main line of the telephone line to realize seamless monitoring technology for the communication system, which can eliminate the interference of high-power same-frequency noise signals in the communication system and obtain target information; it can monitor any telephone connected to the main line and ensure that the telephone communicates normally with other telephones without affecting the normal communication of all telephones on the main line, so that the monitoring device is not easy to be detected and has an excellent hiding effect. When the law enforcement agency uses the device to monitor criminals, it will not be detected by the criminals and can further obtain relevant evidence.
[0024] The present invention is further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 The present invention is a schematic structural diagram of a monitoring device and method for a wired communication system.
[0026] Figure 2 It is a schematic diagram of triggering the cutting and connecting parts of the present invention.
[0027] Figure 3 It is a schematic diagram of the 2\4-wire conversion circuit port of the present invention.
[0028] Figure 4 It is a schematic diagram of the architecture of the wired communication system to be monitored according to the present invention.
[0029] Figure 5 The present invention is a schematic diagram of a device access structure of a monitoring device and method for a wired communication system. DETAILED DESCRIPTION
[0030] In order to more clearly describe the ideas, technical solutions and advantages of the present invention, the specific implementation methods are illustrated by examples and drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0031] Example
[0032] like Figure 1-5 As shown, a monitoring device for a wired communication system includes a cutting and connecting part, the cutting and connecting part is connected to a communication maintaining part, and the communication maintaining part is connected to a signal demodulation part.
[0033] The disconnection and connection part includes an electronic disconnector, an electronic switch and a trigger switch. The number of the electronic disconnectors is 2. Two of the electronic disconnectors are installed at both ends of the monitored communication node on the telephone bus. The electronic switches include electronic switch 1, electronic switch 2 and electronic switch 3. Electronic switch 1, electronic switch 2 and electronic switch 3 are all installed on the telephone bus. Electronic switch 1 is installed between one electronic disconnector and its adjacent communication node, and electronic switch 3 is installed between another electronic disconnector and its adjacent communication node. Electronic switch 2 is arranged on the telephone bus between the two electronic disconnectors. Electronic switch 1, electronic switch 2 and electronic switch 3 are connected in parallel with the two electronic disconnectors.
[0034] The parallel circuit of the two electronic disconnectors, electronic switch 1, electronic switch 2 and electronic switch 3 controls the closing of the main circuit through the trigger switch, so as to achieve the purpose of triggering the electronic switch 1, electronic switch 2, electronic switch 3 and the two electronic disconnectors at the same time, thereby ensuring that the disconnection and disconnection of the monitored communication node occur simultaneously, so that the monitoring device is connected to the telephone line without being perceived.
[0035] The two electronic disconnectors convert the telephone bus into telephone line 1, telephone line 2 and telephone line 3. There is only one communication node on telephone line 2, namely the monitored communication node. The electronic switch 1 is connected to telephone line 1, the electronic switch 2 is connected to telephone line 2, and the electronic switch 3 is connected to telephone line 3.
[0036] The communication maintenance part includes a 2\4-line conversion circuit and an adder, the 2\4-line conversion circuit includes a 2\4-line conversion circuit 1, a 2\4-line conversion circuit 2 and a 2\4-line conversion circuit 3, the adder includes adder 1, adder 2 and adder 3, the 2\4-line conversion circuit is connected to the telephone line port of the electronic switch, and the output port of the adder is connected to the signal application port of the 2\4-line conversion circuit.
[0037] The electronic switch 1 in the cutting and connecting part is connected to the telephone line port of the 2\4-wire conversion circuit 1, and the output port of the adder 1 is connected to the signal application port of the 2\4-wire conversion circuit 1; the electronic switch 2 in the cutting and connecting part is connected to the telephone line port of the 2\4-wire conversion circuit 2, and the output port of the adder 2 is connected to the signal application port of the 2\4-wire conversion circuit 2; the electronic switch 3 in the cutting and connecting part is connected to the telephone line port of the 2\4-wire conversion circuit 3, and the output port of the adder 3 is connected to the signal application port of the 2\4-wire conversion circuit 3.
[0038] The ports of the 2\4-wire conversion circuit include a telephone line port, a signal application port and a signal receiving port. The telephone line port of the 2\4-wire conversion circuit is connected to the telephone bus through an electronic switch for sending and receiving signals; the 2\4-wire conversion circuit sends the received signal to the telephone bus through its own signal application port and then sends it to the telephone bus through its own telephone line port; the signal receiving port of the 2\4-wire conversion circuit outputs the signal received by the telephone line port of the 2\4-wire conversion circuit from the telephone bus.
[0039] The signal receiving ports of the 2\4-wire conversion circuit 1 and the 2\4-wire conversion circuit 2 are connected to the input port of the adder 3 as the input of the adder 3 and as the input of the signal applying port of the 2\4-wire conversion circuit 3; the signal receiving ports of the 2\4-wire conversion circuit 2 and the 2\4-wire conversion circuit 3 are connected to the input port of the adder 1 as the input of the adder 1 and as the input of the signal applying port of the 2\4-wire conversion circuit 1; the signal receiving ports of the 2\4-wire conversion circuits 1 and 3 are connected to the input port of the adder 2 as the input of the adder 2 and as the input of the signal applying port of the 2\4-wire conversion circuit 2.
[0040] The communication maintenance part works as follows: First, Figure 5 In the embodiment, there are 5 communication nodes on telephone lines 1, 2, and 3, of which communication nodes 1 and 2 are on telephone line 1, communication node 3 is on telephone line 2, and communication nodes 4 and 5 are on telephone line 3.
[0041] The telephone line port of the 2\4-line conversion circuit 1 will receive the information signal and high-power noise signal sent by all communication nodes on telephone line 1 from telephone line 1. The total signal is S i and N i The information signal and high-power noise signal sent by the i-th communication node are then transmitted to the input ports of adders 2 and 3 through the signal receiving port of the 2\4-wire conversion circuit 1.
[0042] The telephone line port of the 2\4 line conversion circuit 2 will receive the information signal and high-power noise signal sent by all communication nodes on the telephone line 2. In fact, there is only one communication node p on the telephone line 2, that is, the monitored communication node. The signal received by the telephone line port of the 2\4 line conversion circuit 2 is the information signal and high-power noise signal sent by the communication node 3. S 3 and N 3 The information signal and high-power noise signal sent by the communication node 3 are then transmitted to the input ports of the adders 1 and 3 through the signal receiving port of the 2\4-wire conversion circuit 2.
[0043] The telephone line port of the 2\4-line conversion circuit 3 will receive the information signal and high-power noise signal sent by all communication nodes on the telephone line 3. The total signal is S i and N i The information signal and high-power noise signal sent by the i-th communication node are then transmitted to the input ports of adders 1 and 2 through the signal receiving port of the 2\4-wire conversion circuit 3.
[0044] Finally, the two input ports of adder 1 receive the signal S output by the signal receiving ports of 2\4 line conversion circuit 2 and 2\4 line conversion circuit 3. 3 、N 3 and It is then transmitted to the signal application port of the 2\4-wire conversion circuit 1, and finally transmitted to the telephone line 1 through the telephone line port of the 2\4-wire conversion circuit 1, completing the transmission of the signals on the telephone lines 2 and 3 to the telephone line 1.
[0045] The two input ports of adder 2 receive the signals output by the signal receiving ports of 2\4 line conversion circuit 1 and 2\4 line conversion circuit 3. and It is then transmitted to the signal application port of the 2\4-wire conversion circuit 2, and finally transmitted to the telephone line 2 through the telephone line port of the 2\4-wire conversion circuit 2, completing the transmission of the signals on the telephone lines 1 and 3 to the telephone line 2.
[0046] The two input ports of adder 3 receive the signals output by the signal receiving ports of 2\4 line conversion circuit 1 and 2\4 line conversion circuit 2. S 3 and N 3 , and then transmitted to the signal application port of the 2\4 line conversion circuit 3, and finally transmitted to the telephone line 3 through the telephone line port of the 2\4 line conversion circuit 3, completing the transmission of the signals on the telephone lines 1 and 2 to the telephone line 3.
[0047] At this point, the communication maintenance part ensures the mutual transmission of all signals between telephone lines 1, 2, and 3, thereby maintaining normal communication between all communication nodes on telephone lines 1, 2, and 3, so that when the monitoring device monitors the telephone line, it will not be discovered by criminals due to affecting the normal communication between the communication nodes, making the monitoring of this monitoring device very covert.
[0048] The signal demodulation part includes a carrier frequency detector, an adjustable bandpass filter, a down converter and a demodulator, wherein the carrier frequency detector input port is connected to the signal receiving port of the 2\4 line conversion circuit 2, the carrier frequency detector output port is connected to the adjustable bandpass filter input port, the adjustable bandpass filter output port is connected to the down converter input port, and the down converter output port is connected to the demodulator input port.
[0049] like Figure 4 As shown in the figure, the confidentiality method of the wired communication system is as follows: there are numerous communication nodes on the telephone bus of the wired communication system, and any two can form a group, and multiple groups can communicate through the telephone bus at the same time. The two communication nodes in each group use each frequency band to send information signals to each other, and at the same time release high-power noise signals to the other party's frequency band. The two frequency bands are different, and the frequency bands used by all communication nodes on the telephone line are different. In this way, the frequency band of each target signal on the telephone bus can be drowned out by a high-power noise signal of the same frequency. At the same time, because each target signal is in a different frequency band, it will not interfere with each other, thereby realizing physical layer security and confidentiality communication in the sense of Wyner.
[0050] According to the working principle of the same-frequency self-interference communication system, the carrier frequency used by the high-power noise signal sent by the monitored communication node is different from the carrier frequency used by the information signal it sends. The carrier frequency used by the information signal of the monitored communication node is f1, and the carrier frequency of the high-power noise signal of the monitored communication node is f2. The signal demodulation part first uses a carrier detector to detect the frequencies f1 and f2 of the two carrier signals. Then the signal demodulation part uses two bandpass filters with center frequencies of f1 and f2 to perform bandpass filtering, down-conversion, demodulation, decoding and other operations on the information signal and the high-power noise signal respectively. Suppose the noise signal and information signal demodulated and decoded are Noise(t) and Sound(t) respectively. A DIP switch is used to perform an extraction operation of selecting one of the two, thereby obtaining a voice signal Sound(t) to achieve monitoring.
[0051] A monitoring method for a wired communication system comprises the following steps:
[0052] S1: There are 5 communication nodes on the telephone bus. The monitored communication node is communication node 3 on the telephone bus. An electronic disconnector is placed on the telephone bus between communication nodes 2 and 3, and another electronic disconnector is placed on the telephone bus between communication nodes 3 and 4.
[0053] S2: electronic switch 1 is connected to the telephone bus between communication node 2 and the electronic disconnector near communication node 2; electronic switch 2 is connected to the telephone bus between the two electronic disconnectors; electronic switch 3 is connected to the telephone bus between communication node 4 and the electronic disconnector near communication node 4;
[0054] S3: Activate the trigger button in the disconnection and connection part, and trigger the two electronic disconnectors, electronic switch 1, electronic switch 2 and electronic switch 3 to operate at the same time, and cut the telephone bus into telephone line 1, telephone line 2 and telephone line 3, wherein electronic switch 1 is connected to telephone line 1; electronic switch 2 is connected to telephone line 2; electronic switch 3 is connected to telephone line 3, and only communication node 3 is connected to telephone line 2;
[0055] S4: The telephone line port of the 2\4-line conversion circuit 1 receives the information signal and high-power noise signal sent by the communication nodes 1 and 2 from the telephone line 1. 1 、N 1 , S 2 、N 2 , and then transmitted to the input ports of adder 2 and adder 3 through the signal receiving port of 2\4 line conversion circuit 1, and then transmitted to the signal applying ports of 2\4 line conversion circuits 2 and 3, and finally transmitted to telephone line 2 and telephone line 3 through the telephone line ports of 2\4 line conversion circuits 2 and 3;
[0056] S5: The telephone line port of the 2\4-line conversion circuit 2 receives the information signal and the high-power noise signal sent by the communication node 3 from the telephone line 2. 3 、N 3 , the information signal and the high-power noise signal are then transmitted to the input ports of adder 1 and adder 3 through the signal receiving port of 2\4-wire conversion circuit 2, and then transmitted to the signal applying ports of 2\4-wire conversion circuits 1 and 3, and finally transmitted to telephone line 1 and telephone line 3 through the telephone line ports of 2\4-wire conversion circuits 1 and 3;
[0057] S6: The telephone line port of the 2\4-line conversion circuit 3 receives the information signal and high-power noise signal sent by the communication nodes 4 and 5 from the telephone bus 3. 4 、N 5 , the information signal and the high-power noise signal are then transmitted to the input ports of adder 1 and adder 2 through the signal receiving port of the 2\4-wire conversion circuit 3, and then transmitted to the signal applying ports of the 2\4-wire conversion circuits 1 and 2, and finally transmitted to telephone line 1 and telephone line 2 through the telephone line ports of the 2\4-wire conversion circuits 1 and 2;
[0058] S7: The telephone line port of the 2\4-line conversion circuit 2 will obtain the information signal and high-power noise signal sent by the communication node 3 through the telephone line 2. 3、N 3 , and transmitted to the carrier frequency detector in the signal demodulation part. According to the principle of the same-frequency self-interference communication system, the information signal and the high-power noise signal sent by the communication node 3 use different carrier frequencies. The carrier frequency of the information signal is f1, and the carrier frequency of the high-power noise signal is f2. The carrier frequency detector will detect the frequencies f1 and f2 of the two carrier signals, and then use two bandpass filters with center frequencies of f1 and f2 to perform bandpass filtering, down-conversion, demodulation and other operations on the information signal and the high-power noise signal respectively. Suppose the demodulated high-power noise signal and information signal are Noise(t) and Sound(t) respectively. Finally, a dip switch is used to perform an extraction operation of selecting one of the two, thereby obtaining a voice signal.
[0059] The invention uses a device and method for connecting three 2\4-wire circuits at the same time and cutting off the main telephone line at the same time to realize seamless monitoring technology for the wired communication system based on the same-frequency self-interference communication principle, which can eliminate the interference of high-power same-frequency noise signals in the communication system and obtain target information; it can monitor any telephone connected to the main line and ensure that the telephone communicates normally with other telephones without affecting the normal communication of all telephones on the main line, making the monitoring device difficult to be detected and having an excellent hiding effect, so that the law enforcement department will not be noticed by the criminals when monitoring them, and further obtain relevant evidence.
[0060] The above embodiments provide further detailed description of the objectives, technical solutions and advantages of the present invention. It should be understood that the above embodiments are only preferred implementation modes of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A monitoring device for a wired communication system, comprising a disconnection and connection part, characterized in that: The disconnection and connection part is connected to a communication maintenance part, and the communication maintenance part is connected to a signal demodulation part; The disconnection and connection part includes an electronic disconnector, an electronic switch and a trigger switch. The number of the electronic disconnectors is 2. Two of the electronic disconnectors are installed at both ends of the monitored communication node on the telephone bus. The electronic switches include electronic switch 1, electronic switch 2 and electronic switch 3. Electronic switch 1, electronic switch 2 and electronic switch 3 are all installed on the telephone bus. Electronic switch 1 is installed between one electronic disconnector and its adjacent communication node, and electronic switch 3 is installed between another electronic disconnector and its adjacent communication node. Electronic switch 2 is arranged on the telephone bus between the two electronic disconnectors. Electronic switch 1, electronic switch 2 and electronic switch 3 are connected in parallel with the two electronic disconnectors, and are triggered simultaneously by a trigger switch on the main line.
2. The monitoring device of the wired communication system according to claim 1, characterized in that: The two electronic disconnectors change the telephone bus into telephone line 1, telephone line 2 and telephone line 3. There is only one communication node on telephone line 2, namely the monitored communication node.
3. The monitoring device of a wired communication system according to claim 1, characterized in that: The communication maintenance part includes a 2\4-line conversion circuit and an adder, the 2\4-line conversion circuit includes a 2\4-line conversion circuit 1, a 2\4-line conversion circuit 2 and a 2\4-line conversion circuit 3, and the adder includes adder 1, adder 2 and adder 3; the 2\4-line conversion circuit is connected to the telephone line port of the electronic switch, and the output port of the adder is connected to the signal application port of the 2\4-line conversion circuit.
4. The monitoring device of the wired communication system according to claim 3, characterized in that: The ports of the 2\4-wire conversion circuit include a telephone line port, a signal applying port and a signal receiving port; the 2\4-wire conversion circuit sends the received signal through its own signal applying port to the telephone bus through its own telephone line port.
5. The monitoring device of the wired communication system according to claim 4, characterized in that: The signal receiving ports of the 2\4-wire conversion circuit 1 and the 2\4-wire conversion circuit 2 are connected to the input port of the adder 3; the signal receiving ports of the 2\4-wire conversion circuit 2 and the 2\4-wire conversion circuit 3 are connected to the input port of the adder 1; the signal receiving ports of the 2\4-wire conversion circuits 1 and 3 are connected to the input port of the adder 2.
6. The monitoring device of the wired communication system according to claim 5, characterized in that: The signal demodulation part includes a carrier frequency detector, an adjustable bandpass filter, a down converter and a demodulator, wherein the carrier frequency detector input port is connected to the signal receiving port of the 2\4 line conversion circuit 2, the carrier frequency detector output port is connected to the adjustable bandpass filter input port, the adjustable bandpass filter output port is connected to the down converter input port, and the down converter output port is connected to the demodulator input port.
7. A wired communication system monitoring method, characterized in that: The specific steps include: S1: There are n communication nodes on the telephone bus. An electronic disconnector is placed on the telephone bus between communication node p-1 and communication node p, and another electronic disconnector is placed on the telephone bus between communication node p and communication node p+1. S2: Connect the electronic switch 1 to the telephone bus between the communication node p-1 and the electronic disconnector close to the communication node p-1; The electronic switch 2 is connected to the telephone bus between the two electronic disconnectors; The electronic switch 3 is connected to the telephone bus between the communication node p+1 and the electronic disconnector close to the communication node p+1; S3: Activate the trigger button in the disconnection and connection part, and simultaneously trigger the two electronic disconnectors, electronic switch 1, electronic switch 2 and electronic switch 3 to operate; S4: The telephone line port of the 2\4-wire conversion circuit 1 receives the information signal and the high-power noise signal sent by the communication node 1 to the communication node p-1 from the telephone line 1, and then transmits them to the input ports of the adder 2 and the adder 3 through the signal receiving port of the 2\4-wire conversion circuit 1, and transmits them to the signal applying ports of the 2\4-wire conversion circuits 2 and 3, and finally transmits them to the telephone line 2 and the telephone line 3 through the telephone line ports of the 2\4-wire conversion circuits 2 and 3; S5: The telephone line port of the 2\4-wire conversion circuit 2 receives the information signal and the high-power noise signal sent by the communication node p from the telephone line 2, and the information signal and the high-power noise signal are then transmitted to the input ports of the adder 1 and the adder 3 through the signal receiving port of the 2\4-wire conversion circuit 2, and transmitted to the signal applying ports of the 2\4-wire conversion circuits 1 and 3, and finally transmitted to the telephone line 1 and the telephone line 3 through the telephone line ports of the 2\4-wire conversion circuits 1 and 3; S6: The telephone line port of the 2\4-wire conversion circuit 3 receives the information signal and the high-power noise signal sent by the communication node p+1~communication node n from the telephone bus 3, and the information signal and the high-power noise signal are then transmitted to the input ports of the adder 1 and the adder 2 through the signal receiving port of the 2\4-wire conversion circuit 3, and transmitted to the signal applying ports of the 2\4-wire conversion circuits 1 and 2, and finally transmitted to the telephone line 1 and the telephone line 2 through the telephone line ports of the 2\4-wire conversion circuits 1 and 2; S7: The carrier frequency detector in the monitoring demodulation part receives the information signal and the high-power noise signal sent by the communication node p through the signal receiving end of the 2\4-wire conversion circuit 2. According to the principle of achieving safe communication by the same-frequency self-interference communication system, the information signal and the high-power noise signal sent by the communication node p use different carrier frequencies. The carrier frequency used by the information signal is f1, and the carrier frequency used by the high-power noise signal is f2. The carrier detector detects the frequencies f1 and f2 of the two carrier signals, and then uses two bandpass filters with center frequencies of f1 and f2 to perform bandpass filtering, down-conversion, and demodulation operations on the information signal and the high-power noise signal sent by the communication node p, respectively. It is assumed that the demodulated high-power noise signal and information signal are Noise(t) and Sound(t), respectively. Finally, a two-choice extraction operation is performed through a dip switch to obtain a voice signal.
Citation Information
Patent Citations
Method and apparatus for delivering secured telephony service in a hybrid coaxial cable network
CN1110495A