CN112350746B - Channel weakening detection system and method for power line carrier communication system - Google Patents
Channel weakening detection system and method for power line carrier communication system Download PDFInfo
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- 238000004891 communication Methods 0.000 title claims abstract description 34
- 238000001514 detection method Methods 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 title claims description 3
- 230000003313 weakening effect Effects 0.000 title abstract description 6
- 230000005540 biological transmission Effects 0.000 claims abstract description 49
- 238000012360 testing method Methods 0.000 claims abstract description 17
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- 238000012545 processing Methods 0.000 claims abstract description 4
- 239000003990 capacitor Substances 0.000 claims description 151
- 239000013078 crystal Substances 0.000 claims description 18
- 230000002457 bidirectional effect Effects 0.000 claims description 12
- 238000005562 fading Methods 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 9
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/02—Details
- H04B3/46—Monitoring; Testing
- H04B3/48—Testing attenuation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B3/00—Line transmission systems
- H04B3/54—Systems for transmission via power distribution lines
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2697—Multicarrier modulation systems in combination with other modulation techniques
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
- H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
Abstract
The invention discloses a channel attenuation detection system and a detection method thereof for a power line carrier communication system, belonging to the field of power line carrier communication systems; a channel attenuation detection system and a detection method thereof for a power line carrier communication system comprise: the device comprises a carrier transceiving unit, a system unit, a communication unit, a serial-parallel conversion unit, a signal processing unit and a low-pass filtering unit; when the power line carrier communication is performed and the channel is weakened, the system can perform channel test so as to know the weakening condition, the channel characteristic frequency characteristic at the moment is calculated and converted into the signal characteristic, and the channel weakening degree is calculated through the corresponding set of the frequency response value and the frequency; thereby frequency and amplitude modulating subsequent transmitted signals; and the carrier modulation module is used for carrying out orthogonal frequency division multiplexing transmission, and the transmission carrier signal is transmitted and modulated and then transmitted out through a wireless channel, so that the interference of noise on the signal can be effectively reduced.
Description
Technical Field
The invention discloses a channel attenuation detection system and a channel attenuation detection method for a power line carrier communication system, and belongs to the field of power line carrier communication systems.
Background
With the development of digital communication technology, the power line carrier communication technology is increasingly widely applied to building automation, automatic meter reading, intelligent control, internet of things, micro-grids and the like, and the effective transmission of high-quality communication signals by utilizing the existing power line architecture has great economic benefits and social benefits, and is a potential important means for realizing mutual circulation of energy and information of the energy internet in the future.
The power line carrier communication system in the prior art receives signals after the form of multi-line superposition is finished, meanwhile, line loss and transmission line delay can occur to the signals, so that a signal channel for power line transmission line attenuation is generated, noise interference which cannot be eliminated can be generated due to different environments when a power line works, harmonic noise can be generated due to the fact that the working frequency and the noise frequency of power equipment are synchronous, and great interference exists in channel transmission of carrier signals.
Disclosure of Invention
The purpose of the invention is as follows: a channel attenuation detection system and a detection method thereof for a power line carrier communication system are provided to solve the above problems.
The technical scheme is as follows: a channel fading detection system for a power line carrier communication system, comprising:
a carrier transceiver unit for transmitting and receiving a carrier signal on a power line through at least one transmitter and receiver;
the system unit is used for converting the transmission signal into a carrier signal and simultaneously carrying out frequency adjustment and amplitude control on the transmission signal;
a serial-parallel conversion unit for converting serial transmission and parallel transmission of the transmission carrier signal and the reception carrier signal;
the communication unit is used for generating a plurality of transmission channels and transmitting carrier signals with external communication equipment or the next power line;
the signal processing unit is used for modulating and demodulating subsequent transmitting signals and receiving signals when the carrier signal communication channel is weakened;
and a low-pass filtering unit for performing frequency response value in channel fading through a low-pass filter.
Preferably, the system unit comprises: the device comprises a carrier module, an amplitude modulation module and a frequency modulation module;
wherein the carrier module comprises: the circuit comprises a single chip microcomputer U2, an integrated circuit U1, a resistor R1, a capacitor C11, a polar capacitor C10, a capacitor C3, a resistor R3, a capacitor C9, a crystal oscillator tube X1, a capacitor C4, a capacitor C5, a crystal oscillator tube X2, a capacitor C6, a capacitor C7, a capacitor C8 and a resistor R2;
pin No. 10 of the integrated circuit U1 is connected to one end of the resistor R1 and one end of the capacitor C11, voltage is input to the other end of the resistor R1, the other end of the capacitor C11 is grounded, pin No. 7 and pin No. 5 of the integrated circuit U1 are connected to one end of the capacitor C3 and one end of the polar capacitor C10, voltage is input to the other end of the polar capacitor C10 and the other end of the capacitor C3 are connected to ground, pin No. 6 of the integrated circuit U1 is connected to one end of the capacitor C9 and one end of the resistor R3, the other end of the capacitor C9 is grounded, voltage is input to the other end of the resistor R3, pin No. 19 of the integrated circuit U1 is connected to one end of the capacitor C4 and pin No. 1 of the crystal tube X1, pin No. 21 of the integrated circuit U1 is connected to pin No. 2 of the crystal tube X1 and one end of the capacitor C5, the other end of the capacitor C4 is connected with the other end of the capacitor C5 and grounded, pin No. 13 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C6 and pin No. 1 of the crystal oscillator tube X2, pin No. 14 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C7, pin No. 2 of the crystal oscillator tube X2 and pin No. 3 of the singlechip U2, pin No. 11 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C8 and one end of the resistor R2, voltage is input into the other end of the resistor R2, pin No. 15 of the integrated circuit U1 is simultaneously connected with the other end of the capacitor C7 and the other end of the capacitor C8, the other end of the capacitor C7 is connected with the other end of the capacitor C6 and grounded, pin No. 2 of the integrated circuit U1 is connected with pin No. 5 of the singlechip U2, and pin No. 4 of the integrated circuit U1 is connected with pin No. 584 of the singlechip U5734, no. 3 pin of integrated circuit U1 with No. 1 pin of singlechip U2 is connected, No. 23 pin of integrated circuit U1 with No. 3 pin of singlechip U2 is connected, No. 1 pin of integrated circuit U1 with No. 7 pin of singlechip U2 is connected, No. 16 pin of integrated circuit U1 is connected with No. 8 pin of singlechip U2, No. 24 pin of integrated circuit U1 with No. 9 pin of singlechip U2 is connected, No. 20 pin of integrated circuit U1 with No. 11 pin of singlechip U2 is connected, No. 12 pin to No. 19 pin of singlechip U2 are exported.
Preferably, the amplitude modulation module includes: the circuit comprises a resistor R10, a diode D4, a diode D5, a triode Q3, a triode Q6, a triode Q5, a triode Q4, a voltage regulator tube D6, a resistor R11, a capacitor C1, a capacitor C2, a resistor R12 and a voltage regulator tube D7;
a signal is input at one end of the resistor R10, the other end of the resistor R10 is connected to the anode of the diode D4, the cathode of the diode D5, the emitter of the transistor Q3 and the emitter of the transistor Q6 at the same time, the anode of the diode D5 is grounded, the base of the transistor Q3 is connected to the collector of the transistor Q5, the base of the transistor Q6 and the collector of the transistor Q4 at the same time, the collector of the transistor Q3 is connected to the cathode of the diode D4, the cathode of the regulator D6 and the emitter of the transistor Q5 at the same time, the emitter of the transistor Q4 is connected to the collector of the transistor Q6 and the anode of the regulator D7 at the same time, the base of the transistor Q5 is connected to one end of the resistor R11 and the anode of the regulator D6 at the same time, the base of the transistor Q4 is connected to one end of the resistor R12 and the cathode of the regulator D7 at the same time, the other end of the resistor R11 is connected with one end of the capacitor C1, the other end of the resistor R12 is connected with one end of the capacitor C2, and the other end of the capacitor C1 is connected with the other end of the capacitor C2 and is input into the carrier module.
Preferably, the frequency modulation module comprises: the circuit comprises a transformer TR1, a bidirectional diode D1, a resistor R8, a capacitor 15, an inductor L1, a resistor R9, a diode D2, a diode D3, a capacitor C16, a resistor R4, a transistor Q1, a capacitor C12, a polar capacitor C14, a capacitor 13, a resistor R5, a resistor R6, a resistor R7, a triode Q2 and a frequency modulator U3;
a voltage is input to an input end of the transformer TR1, an output end of the transformer TR1 is connected to the bidirectional diode D1, one end of the bidirectional diode D1 is connected to one end of the resistor R8, one end of the capacitor C15 is connected to the other end of the resistor R8 and one end of the inductor L1, the other end of the capacitor C15 is connected to the other end of the bidirectional diode D1 and the other end of the inductor L1 and grounded, one end of the resistor R9 is connected to one end of the inductor L1 and an anode of the diode D2, the other end of the resistor R9 is connected to the other end of the inductor L1 and a cathode of the diode D2, a cathode of the diode D3 is connected to an anode of the diode D2 and one end of the capacitor C16, an anode of the diode D3 is connected to a cathode of the diode D2, and the other end of the capacitor C16 is connected to a frequency modulation pin 16 of the U3, a pin 1 of the frequency modulator U3 is connected to a carrier module, a pin 3 of the frequency modulator U3 is connected to one end of the resistor R4 and a source of the transistor Q1, a pin 5 of the frequency modulator U3 is connected to one end of the capacitor C12 and a drain of the transistor Q1, a pin 4 of the frequency modulator U3 is connected to a gate of the transistor Q1, the other end of the resistor R4 and one end of the polar capacitor C14, the other end of the polar capacitor C14 is grounded, one end of the resistor R5 is connected to one end of the resistor R7 and one end of the polar capacitor C14, a base of the triode Q2 is connected to the other end of the capacitor C12 and one end of the resistor R6, the other end of the resistor R7 is grounded, a collector of the triode Q2 is connected to the other end of the resistor R5, the other end of the resistor R6 and one end of the capacitor C13, the emitter of the transistor Q2 is grounded, and the other end of the capacitor C13 outputs a signal.
Preferably, the model of the singlechip U2 is AT89C2051, and the model of the integrated circuit U1 is PL 2000A; the model of the frequency modulator U3 is MC 3361.
A detection method for a channel attenuation detection system of a power line carrier communication system is disclosed, when the power line carrier communication is performed and channel attenuation occurs, the system can perform channel test, so that the attenuation condition can be known, and the specific steps are as follows:
step 1, firstly, judging the type of attenuation, and judging and calculating the attenuation caused by the frequency, the transmission distance, the voltage and the phase of a signal;
T＝exp[-a(f)*L]
wherein T represents time decay;
-a (f) represents the frequency attenuation caused by aging of the material;
l represents a transmission distance;
T＝exp(-k*fx*L)
wherein k and x represent material basic constants;
f represents the signal frequency;
thus, the attenuation of the carrier signal of the line is increased along with the increase of the distance L and the frequency f;
wherein B represents phase decay;
v1 represents the emission voltage;
v2 represents the received voltage;
step 17, setting a phase initial value;
step 18, calculating the time channel characteristic frequency characteristic of the signal at the moment;
step 20, filtering through a low-pass filter to obtain a frequency response value;
step 21, calculating the channel attenuation degree through the frequency response value and the frequency corresponding set;
step 22, channel attenuation improvement is carried out;
step 23, when carrier emission output is carried out, a higher emission frequency is set through the frequency modulation module, and meanwhile, the output voltage is stable;
and step 25, sampling multiple channels to transmit with each other, thereby reducing transmission blockage and interference.
Preferably, in general, the input impedance to the power line is related to the frequency f of the signal, and when the frequency becomes lower, the impedance increases, and since the type of network in which the load is connected to the power supply and the impedance changes at different frequencies are different, the time of connection and disconnection of the load is not fixed, and the change in line impedance becomes more unpredictable in practical situations.
Preferably, in normal operation, there are some noise interferences that cannot be eliminated, and in general, the noise is random noise, but the degree of change is not severe, and is generally formed by aggregation of a plurality of low-power noise sources; but there are some harmonic noises with different amplitudes, which are mainly caused by the synchronization of the operating frequency of the power equipment and the noise frequency, and the duration is short, and the period of the harmonic noises is that or the power spectral density of the harmonic noises which repeats back and forth decreases with the increase of the frequency; in the face of generated harmonic noise and random noise, orthogonal frequency division multiplexing transmission is carried out through a carrier modulation module, and a transmission carrier signal is subjected to transmission modulation and then is sent out through a wireless channel; at the receiving end, a group of orthogonal signals are respectively subjected to correlation operation with the transmitted signals to realize demodulation, and then the original signals are recovered and subjected to carrier signal demodulation at the received signals, so that the interference of noise to the signals can be effectively reduced.
Has the advantages that: when the power line carrier communication is performed and the channel is weakened, the system can perform channel test so as to know the weakening condition, the channel characteristic frequency characteristic at the moment is calculated and converted into the signal characteristic, and the channel weakening degree is calculated through the corresponding set of the frequency response value and the frequency; thereby frequency and amplitude modulating subsequent transmitted signals; the carrier modulation module is used for carrying out orthogonal frequency division multiplexing transmission, and a transmission carrier signal is subjected to transmission modulation and then is sent out through a wireless channel; at the receiving end, a group of orthogonal signals are respectively subjected to correlation operation with the transmitted signals to realize demodulation, and then the original signals are recovered and subjected to carrier signal demodulation at the received signals, so that the interference of noise to the signals can be effectively reduced.
Drawings
FIG. 1 is a flow chart of the operation of the present invention.
Fig. 2 is a circuit diagram of a system unit of the present invention.
Fig. 3 is a circuit diagram of a carrier module of the present invention.
Fig. 4 is a circuit diagram of an amplitude modulation module of the present invention.
Fig. 5 is a circuit diagram of a fm module of the present invention.
Detailed Description
In this embodiment, as shown in fig. 1, a channel fading detection system for a power line carrier communication system includes: the device comprises a carrier transceiving unit, a system unit, a communication unit, a serial-parallel conversion unit, a signal processing unit and a low-pass filtering unit; the system unit includes: the device comprises a carrier module, an amplitude modulation module and a frequency modulation module.
In a further embodiment, the carrier module comprises: the circuit comprises a single chip microcomputer U2, an integrated circuit U1, a resistor R1, a capacitor C11, a polar capacitor C10, a capacitor C3, a resistor R3, a capacitor C9, a crystal oscillator tube X1, a capacitor C4, a capacitor C5, a crystal oscillator tube X2, a capacitor C6, a capacitor C7, a capacitor C8 and a resistor R2.
In a further embodiment, pin No. 10 of the integrated circuit U1 is connected to one end of the resistor R1 and one end of the capacitor C11, the other end of the resistor R1 inputs a voltage, the other end of the capacitor C11 is grounded, pin No. 7 and pin No. 5 of the integrated circuit U1 are connected to one end of the capacitor C3 and one end of the polar capacitor C10 and input a voltage, the other end of the polar capacitor C10 and the other end of the capacitor C3 are connected to ground, pin No. 6 of the integrated circuit U1 is connected to one end of the capacitor C9 and one end of the resistor R3, the other end of the capacitor C9 is grounded, the other end of the resistor R3 inputs a voltage, pin No. 19 of the integrated circuit U1 is connected to one end of the capacitor C4 and pin No. 1 of the crystal tube X1, pin No. 21 of the integrated circuit U1 is connected to one end of the crystal tube X1 and one end of the capacitor C5, the other end of the capacitor C4 is connected with the other end of the capacitor C5 and grounded, pin No. 13 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C6 and pin No. 1 of the crystal oscillator tube X2, pin No. 14 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C7, pin No. 2 of the crystal oscillator tube X2 and pin No. 3 of the singlechip U2, pin No. 11 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C8 and one end of the resistor R2, voltage is input into the other end of the resistor R2, pin No. 15 of the integrated circuit U1 is simultaneously connected with the other end of the capacitor C7 and the other end of the capacitor C8, the other end of the capacitor C7 is connected with the other end of the capacitor C6 and grounded, pin No. 2 of the integrated circuit U1 is connected with pin No. 5 of the singlechip U2, and pin No. 4 of the integrated circuit U1 is connected with pin No. 584 of the singlechip U5734, no. 3 pin of integrated circuit U1 with No. 1 pin of singlechip U2 is connected, No. 23 pin of integrated circuit U1 with No. 3 pin of singlechip U2 is connected, No. 1 pin of integrated circuit U1 with No. 7 pin of singlechip U2 is connected, No. 16 pin of integrated circuit U1 is connected with No. 8 pin of singlechip U2, No. 24 pin of integrated circuit U1 with No. 9 pin of singlechip U2 is connected, No. 20 pin of integrated circuit U1 with No. 11 pin of singlechip U2 is connected, No. 12 pin to No. 19 pin of singlechip U2 are exported.
In a further embodiment, the amplitude modulation module comprises: the circuit comprises a resistor R10, a diode D4, a diode D5, a triode Q3, a triode Q6, a triode Q5, a triode Q4, a voltage regulator tube D6, a resistor R11, a capacitor C1, a capacitor C2, a resistor R12 and a voltage regulator tube D7.
In a further embodiment, a signal is input to one end of the resistor R10, the other end of the resistor R10 is connected to the positive electrode of the diode D4, the negative electrode of the diode D5, the emitter of the transistor Q3 and the emitter of the transistor Q6 at the same time, the positive electrode of the diode D5 is grounded, the base of the transistor Q3 is connected to the collector of the transistor Q5, the base of the transistor Q6 and the collector of the transistor Q4 at the same time, the collector of the transistor Q3 is connected to the negative electrode of the diode D4, the negative electrode of the regulator D6 and the emitter of the transistor Q5 at the same time, the emitter of the transistor Q4 is connected to the collector of the transistor Q6 and the positive electrode of the regulator D7 at the same time, the base of the transistor Q5 is connected to one end of the resistor R11 and the positive electrode of the regulator D6 at the same time, the base of the transistor Q4 is connected to one end of the resistor R12 and the negative electrode of the regulator D7 at the same time, the other end of the resistor R11 is connected with one end of the capacitor C1, the other end of the resistor R12 is connected with one end of the capacitor C2, and the other end of the capacitor C1 is connected with the other end of the capacitor C2 and is input into the carrier module.
In a further embodiment, the frequency modulation module comprises: the circuit comprises a transformer TR1, a bidirectional diode D1, a resistor R8, a capacitor 15, an inductor L1, a resistor R9, a diode D2, a diode D3, a capacitor C16, a resistor R4, a transistor Q1, a capacitor C12, a polar capacitor C14, a capacitor 13, a resistor R5, a resistor R6, a resistor R7, a triode Q2 and a frequency modulator U3.
In a further embodiment, a voltage is input to an input terminal of the transformer TR1, an output terminal of the transformer TR1 is connected to the bidirectional diode D1, one terminal of the bidirectional diode D1 is connected to one terminal of the resistor R8, one terminal of the capacitor C15 is connected to both the other terminal of the resistor R8 and one terminal of the inductor L1, the other terminal of the capacitor C15 is connected to both the other terminal of the bidirectional diode D1 and the other terminal of the inductor L1 and grounded, one terminal of the resistor R9 is connected to both one terminal of the inductor L1 and an anode of the diode D2, the other terminal of the resistor R9 is connected to both the other terminal of the inductor L1 and a cathode of the diode D2, a cathode of the diode D3 is connected to both an anode of the diode D2 and one terminal of the capacitor C16, an anode of the diode D3 is connected to a cathode of the diode D2, the other end of the capacitor C16 is connected to the pin 16 of the frequency modulator U3, the pin 1 of the frequency modulator U3 is connected to the carrier module, the pin 3 of the frequency modulator U3 is connected to one end of the resistor R4 and the source of the transistor Q1, the pin 5 of the frequency modulator U3 is connected to one end of the capacitor C12 and the drain of the transistor Q1, the pin 4 of the frequency modulator U3 is connected to the gate of the transistor Q1, the other end of the resistor R4 and one end of the polar capacitor C14, the other end of the polar capacitor C14 is grounded, one end of the resistor R5 is connected to one end of the resistor R7 and one end of the polar capacitor C14, the base of the triode Q2 is connected to the other end of the capacitor C12 and one end of the resistor R6, the other end of the resistor R7 is grounded, and the collector of the triode Q2 is connected to the other end of the resistor R5, The other end of the resistor R6 is connected with one end of the capacitor C13, the emitter of the triode Q2 is grounded, and the other end of the capacitor C13 outputs a signal.
A detection method for a channel attenuation detection system of a power line carrier communication system is disclosed, when the power line carrier communication is performed and channel attenuation occurs, the system can perform channel test, so that the attenuation condition can be known, and the specific steps are as follows:
step 1, firstly, judging the type of attenuation, and judging and calculating the attenuation caused by the frequency, the transmission distance, the voltage and the phase of a signal;
T＝exp[-a(f)*L]
wherein T represents time decay;
-a (f) represents the frequency attenuation caused by aging of the material;
l represents a transmission distance;
T＝exp(-k*fx*L)
wherein k and x represent material basic constants;
f represents the signal frequency;
thus, the attenuation of the carrier signal of the line is increased along with the increase of the distance L and the frequency f;
wherein B represents phase decay;
v1 represents the emission voltage;
v2 represents the received voltage;
step 17, setting a phase initial value;
step 18, calculating the time channel characteristic frequency characteristic of the signal at the moment;
step 20, filtering through a low-pass filter to obtain a frequency response value;
step 21, calculating the channel attenuation degree through the frequency response value and the frequency corresponding set;
step 22, channel attenuation improvement is carried out;
step 23, when carrier emission output is carried out, a higher emission frequency is set through the frequency modulation module, and meanwhile, the output voltage is stable;
and step 25, adopting multi-channel mutual transmission, thereby reducing transmission blockage and interference.
In a further embodiment, the input impedance to the power line is generally related to the frequency f of the signal, and as the frequency becomes lower, the impedance increases, and as the type of network connecting the load to the power supply, and the impedance changes at different frequencies are different, the time of connecting and disconnecting the load is not fixed, and the change in line impedance becomes more unpredictable in practical situations.
In a further embodiment, in normal operation, there are also some noise interferences that cannot be eliminated, generally, the noise is random noise, but the degree of change is not severe, and generally, the noise interferences are aggregated by a plurality of low-power noise sources; but there are some harmonic noises with different amplitudes, which are mainly caused by the synchronization of the operating frequency of the power equipment and the noise frequency, and the duration is short, and the period of the harmonic noises is that or the power spectral density of the harmonic noises which repeats back and forth between the harmonic noises decreases along with the increase of the frequency; in the face of generated harmonic noise and random noise, orthogonal frequency division multiplexing transmission is carried out through a carrier modulation module, and a transmission carrier signal is subjected to transmission modulation and then is sent out through a wireless channel; at the receiving end, a group of orthogonal signals are respectively subjected to correlation operation with the transmitted signals to realize demodulation, and then the original signals are recovered and subjected to carrier signal demodulation at the received signals, so that the interference of noise to the signals can be effectively reduced.
The working principle is as follows: when the power line carrier communication is carried out, power supply voltage is transmitted or transformed through a transformer TR1, meanwhile, working voltage is output through an output value amplitude modulation module and a frequency modulation module of the transformer TR1, voltage signals are protected and input through a capacitor C1, a resistor R8 and an inductor L1, voltage stabilization input is carried out through a resistor R9, a diode D2 and a diode D3 carry out frequency stabilization and input into a frequency modulator U3, at the moment, a pin 1 of the frequency modulator U3 carries out frequency modulation, the frequency modulation is carried out through a frequency modulator U3, the multiple is adjusted through a triode Q2, and then an output value integrated circuit U1 is carried out through a collector electrode of the triode Q2;
meanwhile, working voltage is protected and input into an amplitude modulation module through a resistor R10, a diode D4 and a diode D5 are connected in parallel to carry out amplitude modulation work, meanwhile, a triode Q3, a triode Q4, a triode Q5 and a triode Q5 carry out amplification output, a voltage regulator tube D6 and a voltage regulator tube D7 carry out voltage, and an input value protection integrated circuit U1 is carried out through a resistor R11 and a resistor R12; the integrated circuit U1 inputs the carrier signals after frequency modulation and amplitude modulation into the singlechip U2, and simultaneously transmits the carrier signals in the output value transmitter through the singlechip U2;
when signal transmission is carried out, the serial-parallel conversion unit can select a communication mode, and the communication unit establishes a communication channel and carries out transmission.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.
Claims (8)
1. A detection method based on a channel fading detection system, characterized by:
a channel fading detection system for a power line carrier communication system, comprising:
a carrier transceiver unit for transmitting and receiving a carrier signal on a power line through at least one transmitter and receiver;
the system unit is used for converting the transmission signal into a carrier signal and simultaneously carrying out frequency adjustment and amplitude control on the transmission signal;
a serial-parallel conversion unit for converting serial transmission and parallel transmission of the transmission carrier signal and the reception carrier signal; the communication unit is used for generating a plurality of transmission channels and carrying out carrier signal transmission with external communication equipment or a power line;
the signal processing unit is used for modulating and demodulating subsequent transmitting signals and receiving signals when the carrier signal communication channel is weakened;
the low-pass filtering unit is used for filtering through a low-pass filter to obtain a frequency response value in channel attenuation;
when the power line carrier communication is performed and the channel is weak, the system can perform channel testing so as to know the weak condition, and the specific steps are as follows:
step 1, firstly, judging the type of attenuation, and judging and calculating the attenuation caused by the frequency, the transmission distance, the voltage and the phase of a signal;
step 11, before a signal is transmitted to a received signal, attenuation of the frequency and the transmission distance of the carrier signal to a channel during transmission is time attenuation, and the expression is as follows:
T＝exp[-a(f)*L]
wherein T represents time decay;
-a (f) represents the frequency attenuation caused by aging of the material;
l represents a transmission distance;
step 12, according to the formula of step 11, the frequency attenuation caused by aging of the material can be further converted into:
T＝exp(-k*fx*L)
wherein k and x represent material basic constants;
f represents the signal frequency;
thus, the attenuation of the carrier signal of the line is increased along with the increase of the distance L and the frequency f;
step 13, completing a time attenuation test according to the step 11 and the step 12, and simultaneously testing the phase attenuation of the signal;
step 14, because the complex switching of the network load electrical device has great randomness, so that the voltage emitted by the signal is not matched with the received voltage, the matching degree of the whole line from emission to reception of the signal cannot be ensured, and the algorithm for obtaining the phase attenuation and the voltage of the carrier signal is as follows:
wherein B represents phase decay;
v1 represents the emission voltage;
v2 represents the received voltage;
step 15, performing a fading test according to the step 14 and the step 12, thereby obtaining that the channel fading test needs to compare the frequency and the phase of the signal;
step 16, calculating a frequency corresponding set according to the frequency and the phase of the received carrier signal at the moment;
step 17, setting a phase initial value;
step 18, calculating the time channel characteristic frequency characteristic of the signal at the moment;
step 19, converting the time channel characteristic frequency characteristic into a signal characteristic through inverse Fourier transform;
step 20, filtering through a low-pass filter to obtain a frequency response value;
step 21, calculating the channel attenuation degree through the frequency response value and the frequency corresponding set;
step 22, channel attenuation improvement is carried out;
step 23, when carrier emission output is carried out, a higher emission frequency is set through the frequency modulation module, and meanwhile, the output voltage is stable;
step 24, carrying out amplitude modulation on the original signal for the transmitted carrier signal;
and step 25, adopting multi-channel mutual transmission, thereby reducing transmission blockage and interference.
2. The method of claim 1, wherein the input impedance of the power line is related to the frequency f of the signal, and when the frequency becomes lower, the impedance increases, and the change in line impedance is unpredictable because the type of network connecting the load to the power source and the change in impedance at different frequencies are different, and the time of connection and disconnection of the load is not fixed.
3. The detection method according to claim 1, wherein in the case where noise interference cannot be eliminated, the noise is random noise, but the degree of variation is not severe, and is a collection of a plurality of low-power noise sources; the other noises are harmonic noises with different amplitudes, the noises are caused by the synchronous operation frequency of the power equipment and the noise frequency, the duration is short, and the power spectral density of the harmonic noises is reduced along with the increase of the frequency; in the face of generated harmonic noise and random noise, orthogonal frequency division multiplexing transmission is carried out through a carrier modulation module, transmission modulation is carried out on a transmission carrier signal, and the transmission carrier signal is transmitted out through a wireless channel after modulation; and a group of orthogonal signals and the sending signal are respectively subjected to correlation operation at a receiving end to realize demodulation, and the original signal is finally recovered, so that the interference of noise on the signal can be effectively reduced.
4. The detection method of claim 1, wherein the channel impairment detection system comprises: the device comprises a carrier module, an amplitude modulation module and a frequency modulation module;
wherein the carrier module comprises: the circuit comprises a single chip microcomputer U2, an integrated circuit U1, a resistor R1, a capacitor C11, a polar capacitor C10, a capacitor C3, a resistor R3, a capacitor C9, a crystal oscillator tube X1, a capacitor C4, a capacitor C5, a crystal oscillator tube X2, a capacitor C6, a capacitor C7, a capacitor C8 and a resistor R2;
pin No. 10 of the integrated circuit U1 is connected to one end of the resistor R1 and one end of the capacitor C11, voltage is input to the other end of the resistor R1, the other end of the capacitor C11 is grounded, pin No. 7 and pin No. 5 of the integrated circuit U1 are connected to one end of the capacitor C3 and one end of the polar capacitor C10, voltage is input to the other end of the polar capacitor C10 and the other end of the capacitor C3 are connected to ground, pin No. 6 of the integrated circuit U1 is connected to one end of the capacitor C9 and one end of the resistor R3, the other end of the capacitor C9 is grounded, voltage is input to the other end of the resistor R3, pin No. 19 of the integrated circuit U1 is connected to one end of the capacitor C4 and pin No. 1 of the crystal tube X1, pin No. 21 of the integrated circuit U1 is connected to pin No. 2 of the crystal tube X1 and one end of the capacitor C5, the other end of the capacitor C4 is connected with the other end of the capacitor C5 and grounded, pin No. 13 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C6 and pin No. 1 of the crystal oscillator tube X2, pin No. 14 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C7, pin No. 2 of the crystal oscillator tube X2 and pin No. 3 of the singlechip U2, pin No. 11 of the integrated circuit U1 is simultaneously connected with one end of the capacitor C8 and one end of the resistor R2, voltage is input into the other end of the resistor R2, pin No. 15 of the integrated circuit U1 is simultaneously connected with the other end of the capacitor C7 and the other end of the capacitor C8, the other end of the capacitor C7 is connected with the other end of the capacitor C6 and grounded, pin No. 2 of the integrated circuit U1 is connected with pin No. 5 of the singlechip U2, and pin No. 4 of the integrated circuit U1 is connected with pin No. 584 of the singlechip U5734, no. 3 pin of the integrated circuit U1 is connected with No. 1 pin of the single chip microcomputer U2, No. 23 pin of the integrated circuit U1 is connected with No. 3 pin of the single chip microcomputer U2, No. 1 pin of the integrated circuit U1 is connected with No. 7 pin of the single chip microcomputer U2, No. 16 pin of the integrated circuit U1 is connected with No. 8 pin of the single chip microcomputer U2, No. 24 pin of the integrated circuit U1 is connected with No. 9 pin of the single chip microcomputer U2, No. 20 pin of the integrated circuit U1 is connected with No. 11 pin of the single chip microcomputer U2 and is output by No. 12 to No. 19 pins of the single chip microcomputer U2.
5. The detection method according to claim 4, wherein the amplitude modulation module comprises: the circuit comprises a resistor R10, a diode D4, a diode D5, a triode Q3, a triode Q6, a triode Q5, a triode Q4, a voltage regulator tube D6, a resistor R11, a capacitor C1, a capacitor C2, a resistor R12 and a voltage regulator tube D7;
a signal is input at one end of the resistor R10, the other end of the resistor R10 is connected to the anode of the diode D4, the cathode of the diode D5, the emitter of the transistor Q3 and the emitter of the transistor Q6 at the same time, the anode of the diode D5 is grounded, the base of the transistor Q3 is connected to the collector of the transistor Q5, the base of the transistor Q6 and the collector of the transistor Q4 at the same time, the collector of the transistor Q3 is connected to the cathode of the diode D4, the cathode of the regulator D6 and the emitter of the transistor Q5 at the same time, the emitter of the transistor Q4 is connected to the collector of the transistor Q6 and the anode of the regulator D7 at the same time, the base of the transistor Q5 is connected to one end of the resistor R11 and the anode of the regulator D6 at the same time, the base of the transistor Q4 is connected to one end of the resistor R12 and the cathode of the regulator D7 at the same time, the other end of the resistor R11 is connected with one end of the capacitor C1, the other end of the resistor R12 is connected with one end of the capacitor C2, and the other end of the capacitor C1 is connected with the other end of the capacitor C2 and is input into the carrier module.
6. The detection method according to claim 4, wherein the frequency modulation module comprises: a transformer TR1, a bidirectional diode D1, a resistor R8, a capacitor C15, an inductor L1, a resistor R9, a diode D2, a diode D3, a capacitor C16, a resistor R4, a transistor Q1, a capacitor C12, a polar capacitor C14, a capacitor C13, a resistor R5, a resistor R6, a resistor R7, a triode Q2 and a frequency modulator U3;
a voltage is input to an input end of the transformer TR1, an output end of the transformer TR1 is connected to the bidirectional diode D1, one end of the bidirectional diode D1 is connected to one end of the resistor R8, one end of the capacitor C15 is connected to the other end of the resistor R8 and one end of the inductor L1, the other end of the capacitor C15 is connected to the other end of the bidirectional diode D1 and the other end of the inductor L1 and grounded, one end of the resistor R9 is connected to one end of the inductor L1 and an anode of the diode D2, the other end of the resistor R9 is connected to the other end of the inductor L1 and a cathode of the diode D2, a cathode of the diode D3 is connected to an anode of the diode D2 and one end of the capacitor C16, an anode of the diode D3 is connected to a cathode of the diode D2, and the other end of the capacitor C16 is connected to a frequency modulation pin 16 of the U3, a pin 1 of the frequency modulator U3 is connected to a carrier module, a pin 3 of the frequency modulator U3 is connected to one end of the resistor R4 and a source of the transistor Q1, a pin 5 of the frequency modulator U3 is connected to one end of the capacitor C12 and a drain of the transistor Q1, a pin 4 of the frequency modulator U3 is connected to a gate of the transistor Q1, the other end of the resistor R4 and one end of the polar capacitor C14, the other end of the polar capacitor C14 is grounded, one end of the resistor R5 is connected to one end of the resistor R7 and one end of the polar capacitor C14, a base of the triode Q2 is connected to the other end of the capacitor C12 and one end of the resistor R6, the other end of the resistor R7 is grounded, a collector of the triode Q2 is connected to the other end of the resistor R5, the other end of the resistor R6 and one end of the capacitor C13, the emitter of the transistor Q2 is grounded, and the other end of the capacitor C13 outputs a signal.
7. The detection method according to claim 4, wherein the model of the singlechip U2 is AT89C2051, and the model of the integrated circuit U1 is PL 2000A.
8. The detection method according to claim 6, wherein the model of the frequency modulator U3 is MC 3361.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1845566A (en) * | 2005-11-28 | 2006-10-11 | 华为技术有限公司 | Communication line transmission wastage testing method and apparatus |
| CN102006101A (en) * | 2010-12-27 | 2011-04-06 | 东莞市华业新科电子科技有限公司 | Power line carrier communication module |
| CN106789764A (en) * | 2016-11-18 | 2017-05-31 | 杭州电子科技大学 | The transform domain quadratic estimate method of the denoising of joint Weighted Threshold and balanced judgement |
| CN206302412U (en) * | 2016-11-05 | 2017-07-04 | 国网江苏省电力公司盐城供电公司 | A kind of medium voltage power line narrowband carrier fading channel test system |
| CN109495174A (en) * | 2018-12-28 | 2019-03-19 | 中国电子科技集团公司第三十四研究所 | A kind of airborne laser communication method based on OFDM modulation /demodulation |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1845566A (en) * | 2005-11-28 | 2006-10-11 | 华为技术有限公司 | Communication line transmission wastage testing method and apparatus |
| CN102006101A (en) * | 2010-12-27 | 2011-04-06 | 东莞市华业新科电子科技有限公司 | Power line carrier communication module |
| CN206302412U (en) * | 2016-11-05 | 2017-07-04 | 国网江苏省电力公司盐城供电公司 | A kind of medium voltage power line narrowband carrier fading channel test system |
| CN106789764A (en) * | 2016-11-18 | 2017-05-31 | 杭州电子科技大学 | The transform domain quadratic estimate method of the denoising of joint Weighted Threshold and balanced judgement |
| CN109495174A (en) * | 2018-12-28 | 2019-03-19 | 中国电子科技集团公司第三十四研究所 | A kind of airborne laser communication method based on OFDM modulation /demodulation |
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