CN109857021B - Active shielding system and method for resisting interference of M-bus - Google Patents
Active shielding system and method for resisting interference of M-bus Download PDFInfo
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Abstract
The invention discloses an active shielding system and method for resisting interference of an M-bus. A signal detection circuit is arranged in the transmission circuit; the receiving circuit comprises a current signal amplifying module, an adder module, a shielding switch, a wave trough detector and a voltage comparator; the output end of the voltage comparator is used for outputting the demodulated reply signal; the signal detection circuit is connected with the shielding switch. The invention takes out the switch signal from the M-bus sending circuit, controls the shielding switch, and simultaneously adopts the wave trough detector with the characteristics of slow rising and fast falling to output the reference value, so that the uprush current signal is not enough to interfere with the wave trough detector with slow rising and fast falling, and the undershoot signal is actively shielded through the shielding switch, thereby keeping the stability of the reference value.
Description
Technical Field
The invention relates to an anti-interference shielding method for a high-power M-bus and an anti-interference shielding system for the high-power M-bus.
Background
Most of water meters, heat meters and gas meters of residential users adopt M-bus communication, but at present, high floors in cities are more, and high-power and high-stability M-bus master meter reading equipment is needed for construction convenience and cost control so as to realize the purpose that a single bus reads the M-bus meter of the whole unit building.
An ideal M-bus slave is a purely constant current load, and there is no current ripple and no interference on the bus when the M-bus master sends a voltage signal. However, in reality, M-BUS slave devices inevitably have equivalent parallel capacitors and equivalent parallel resistors, when M-BUS master devices have more slave devices, the BUS equivalent parallel capacitors and resistors generate larger current interference when the M-BUS master devices send voltage signals, so that a receiving demodulation circuit is disordered, the interference cannot be timely recovered when the slave devices reply current signals, and the M-BUS master devices cannot accurately analyze the current signals, so that communication failure is caused.
The solution in the prior art is mainly that the slave device replies with a delay, and the reference value of the voltage signal demodulated by the receiving circuit is stable, but the reference value affects the normal operation of communication and can not meet the use requirement.
Therefore, the interference caused by the voltage signal seriously affects the carrying quantity and the communication quality of the slave equipment of the single M-bus, and the construction and the popularization of the automatic centralized meter reading of the M-bus metering equipment such as water, heat, gas and the like in a high-density cell are hindered.
Disclosure of Invention
The invention provides an anti-interference active shielding system and method for an M-bus, which aims to: the current interference generated after the M-bus master device sends the voltage signal is prevented from influencing the current signal returned by the slave device.
The technical scheme of the invention is as follows:
an active shielding method for resisting interference of an M-bus comprises the following steps: detecting a voltage signal transmitted by a master device in a transmitting circuit of the M-bus through a signal detection circuit; a wave trough detector is used for outputting a demodulation signal reference value in a receiving circuit of the M-bus, and the signal transmission of the wave trough detector is controlled through a shielding switch;
when the main equipment sends a high-voltage signal, the shielding switch is conducted, the wave trough detector works normally, and a demodulation signal reference value is output;
when the master equipment sends a low-voltage signal, the signal detection circuit sends a shielding signal to the shielding switch, and the shielding switch shields the input signal of the wave trough detector, so that the current undershoot signal cannot interfere with the wave trough detector.
The invention also provides an anti-interference active shielding system for the M-bus, wherein the M-bus is used for communication between the master equipment and the slave equipment, the master equipment sends a voltage signal to the slave equipment through the sending circuit, the slave equipment sends a reply current signal to the master equipment through the receiving circuit, and the sending circuit is provided with a signal detection circuit; the receiving circuit comprises a current signal amplifying module, an adder module, a shielding switch, a wave trough detector and a voltage comparator; the slave device is connected with the input end of the current signal amplification module, the output end of the current signal amplification module is connected with the positive end of the voltage comparator sequentially through the adder module, the shielding switch and the wave trough detector, the output end of the current signal amplification module is also directly connected with the negative end of the voltage comparator, and the output end of the voltage comparator is used for outputting a demodulated reply signal;
the signal detection circuit is connected with the shielding switch, the signal detection circuit is used for sending a shielding signal to the shielding switch when the main equipment sends a low-level voltage signal, and the shielding switch is used for shielding the signal sent to the wave trough detector by the adder module after receiving the shielding signal so as to stabilize the reference signal output by the wave trough detector.
As a further improvement of the system: the valley detector comprises an operational amplifier D11B, a resistor R100, a resistor R101, a resistor R92, a diode V34 and a capacitor C60;
the positive end of the operational amplifier D11B is used for being connected with the output end of the adder module through a shielding switch, the negative end of the operational amplifier D11B is connected with the positive electrode of a diode V34 through a resistor R100, the negative electrode of the diode V34 is connected with the output end of the operational amplifier D11B, and the positive electrode of the diode V34 is further connected with an equipotential end through a resistor R101 and a capacitor C60 in sequence; the junction between the resistor R101 and the capacitor C60 is connected to the MBUS low level signal MBUS _ LV through a resistor R92.
As a further improvement of the system: the shielding switch comprises a diode V25, a resistor R83, a resistor R85, a diode V27, a triode V30 and a resistor R90;
the positive electrode of the diode V25 is connected with a signal detection circuit to receive a shielding signal, the shielding signal is a low-level signal, the negative electrode of the diode V25 is connected with an equipotential end through a resistor R83 and a resistor R85 in sequence, a connection point between the resistor R83 and the resistor R85 is connected with the positive electrode of the diode V27 and also connected with the base of the triode V30, the negative electrode of the diode V27 is connected with the emitter of the triode V30, the emitter of the triode V30 is also connected with an MBUS low-level signal MBUS _ LV, the collector of the triode V30 is used for being connected with the positive end of the operational amplifier D11B, and the collector of the triode V30 is also connected with the output end of the adder module through the resistor R90.
As a further improvement of the system: the signal detection circuit comprises an optical coupler E8, a totem-pole circuit, a PMOS tube D10A, a diode V16 and a diode V18;
the input end of the optical coupler E8 is used for being connected with the input end of a transmitting circuit, the output end of the optical coupler E8 is used for controlling the on-off of a PMOS tube D10A through a totem-pole circuit, one end of the PMOS tube is connected with a MBUS high-level signal MBUS _ HV, the other end of the PMOS tube is used as the output end of a signal detection circuit to transmit a shielding signal, the other end of the PMOS tube is also connected with the anode of a diode V16, the anode of the diode V18 is connected with a MBUS low-level signal MBUS _ LV, the cathode of the diode V18 is connected with the cathode of a diode V16, and the cathode of the diode V16 is used for being connected with the output end of the transmitting.
As a further improvement of the system: and the receiving circuit is also provided with a protection circuit.
Compared with the prior art, the invention has the following positive effects: (1) the invention takes out a switching signal from an M-bus sending circuit, controls a shielding switch, and simultaneously adopts a wave trough detector with slow rising and fast falling characteristics to output a reference value, when M-bus master equipment sends a voltage signal and passes through capacitive and resistive loads, large current fluctuation can be generated on a bus, an uprush current signal is not enough to interfere with the slow rising and fast falling wave trough detector, and an undershoot signal is actively shielded through the shielding switch, so that the stability of the reference value is kept; (2) the invention does not need time delay waiting and can be suitable for M-bus meters with various parameters; (3) when the slave device replies '0' or the sending circuit sends high level to cause current rush, the diode V34 of the wave trough detector is switched off, the capacitor C60 is charged slowly, the output voltage of the wave trough detector is kept stable, and therefore the problem that the current rush interferes with the demodulation reference value is solved.
Drawings
Fig. 1 is a schematic view of the overall structure of the system.
Fig. 2 is a schematic diagram of a transmit circuit.
Fig. 3 is a schematic diagram of a receiving circuit.
FIG. 4 is a partial schematic view of a shield switch and valley detector section.
FIG. 5 is a waveform diagram of the voltage across the sampling resistor in the embodiment.
FIG. 6 is a developed graph of voltage waveforms across the sampling resistor in the example.
Fig. 7 is a waveform diagram of an output of the current signal amplifying module in the embodiment.
FIG. 8 is a waveform diagram of the output of the adder module in an embodiment.
FIG. 9 is a waveform diagram of an output of a valley detector in the embodiment.
Fig. 10 is a comparison diagram of communication messages in the embodiment.
Detailed Description
The technical scheme of the invention is explained in detail in the following with the accompanying drawings:
as shown in fig. 1, an active barrier system for an M-bus that is immune to interference for communication between a master device that sends a voltage signal to a slave device via a sending circuit and a slave device that sends a reply current signal to the master device via a receiving circuit.
The transmission circuit is provided with a signal detection circuit 1.
As shown in fig. 2, the signal detection circuit 1 includes an optical coupler E8, a totem-pole circuit, a PMOS transistor D10A, a diode V16, a diode V18, and the like.
The input end of the optical coupler E8 is used for being connected with the input end of a transmitting circuit, the output end of the optical coupler E8 is used for controlling the on-off of a PMOS tube D10A through a totem-pole circuit, one end of the PMOS tube is connected with a MBUS high-level signal MBUS _ HV, the other end of the PMOS tube is used as the output end of a signal detection circuit 1 to transmit a shielding signal, the other end of the PMOS tube is also connected with the anode of a diode V16, the anode of the diode V18 is connected with a MBUS low-level signal MBUS _ LV, the cathode of the diode V18 is connected with the cathode of a diode V16, and the cathode of the diode V16 is used for being connected with the output end of the transmitting.
The serial port of the single chip microcomputer drives an optical coupler E8 through a resistor R55, an output signal of the optical coupler E8 controls a totem-pole circuit composed of triodes V15 and V17 through resistors R54 and R57, then a PMOS tube D10A is controlled through a resistor R53, the PMOS tube D10A, diodes V16 and V18 achieve high-low level transmission together, and meanwhile a shielding signal P _ MOS _ OUT _1 is taken OUT between the D10A and the V16.
When the MBUSI _ TX is at a high level, the optocoupler E8 outputs a low level, and a totem-pole circuit consisting of the triodes V15 and V17 is controlled to output a low level through the resistors R54 and R57 to drive the PMOS tube D10A to be switched on, at the moment, the diode V16 is switched on, the diode V18 is switched off, and the MBUS bus outputs a High Voltage (HV) to the slave device; on the contrary, when the MBUSI _ TX is at a low level, the optocoupler E8 outputs a high level, and controls the totem-pole circuit composed of the triodes V15 and V17 to output a high level through the resistors R54 and R57 to drive the PMOS transistor D10A to turn off, at this time, the diode V16 is turned off, the diode V18 is turned on, the MBUS bus outputs a Low Voltage (LV), and at this time, the P _ MOS _ OUT _1 sends a low level shielding signal.
As shown in fig. 1, the receiving circuit includes a current signal amplifying module 2, an adder module 3, a shielding switch 4, a valley detector 5, and a voltage comparator 6. The slave device is connected with the input end of the current signal amplification module 2, the output end of the current signal amplification module 2 is connected with the positive end of the voltage comparator 6 sequentially through the adder module 3, the shielding switch 4 and the wave trough detector 5, the output end of the current signal amplification module 2 is also directly connected with the negative end of the voltage comparator 6, and the output end of the voltage comparator 6 is used for outputting a demodulated reply signal.
The wave trough detector 5 is responsible for transmitting a demodulation reference value to the voltage comparator 6, and the voltage comparator 6 compares the reference value with the signal obtained by current sampling and amplification and outputs the demodulated signal.
The signal detection circuit 1 is connected with the shielding switch 4, the signal detection circuit 1 is used for sending a shielding signal to the shielding switch 4 when the main equipment sends a low-level voltage signal, and the shielding switch 4 is used for shielding the signal sent to the wave trough detector 5 by the adder module 3 after receiving the shielding signal so as to stabilize the reference signal output by the wave trough detector 5.
And the receiving circuit is also provided with a protection circuit.
The specific structure of the receiving circuit is shown in fig. 3:
the M-bus1N direct connection M-bus slave devices receive current signals, which are converted into voltage signals through TVS V22 (responsible for electrostatic protection), D10B sampling resistors R86 and R87 in sequence. The voltage signal is output to the demodulation circuit and the protection circuit through resistors R82 and R84, respectively.
In the demodulation circuit, firstly, the signal is amplified by the current signal amplification module 2:
V+＝V-
in the formula:
IIN: bus current value
VIN: voltage across sampling resistor
VOUT: operational amplifier D11A output voltage
V+: operational amplifier D11A positive input pin voltage
V-: negative input pin voltage of operational amplifier D11A
Setting:
R86＝R87＝10Ω
R82＝R95＝1kΩ
R78＝R96＝100kΩ
R82＝R91＝8.2kΩ
MBUS_LV＝18V
substituting the formula to obtain:
VOUT＝8.2VIN+1.476(V)
VOUT＝41IIN+1.476(V)
VOUTnamely, the output voltage value of the current signal amplification module 2, one path of the voltage value sequentially passes through the adder module 3 and the valley detector 5 to form a reference value, and the other path of the voltage value directly enters the voltage comparator 6D12A to be compared with the reference value to obtain a demodulation signal.
Referring to fig. 3, the adder module 3 adopted in the present invention is simple and reliable, and comprises two resistors R76 and R89 and a PNP transistor V28. The principle is as follows:
setting:
R76＝30kΩ
R89＝680Ω
VBE 0.5V (voltage drop between triodes BE)
MBUS_HV＝30V
VCThe voltage is output by the collector of the transistor V28.
Substituting the formula to obtain:
VC＝VOUT+261(mV)。
as shown in fig. 3 and 4, the valley detector 5 includes an operational amplifier D11B, a resistor R100, a resistor R101, a resistor R92, a diode V34, and a capacitor C60;
the positive end of the operational amplifier D11B is used for being connected with the output end of the adder module 3 through a shielding switch 4, the negative end of the operational amplifier is connected with the anode of a diode V34 through a resistor R100, the cathode of the diode V34 is connected with the output end of the operational amplifier D11B, and the anode of the diode V34 is further connected with an equipotential end through a resistor R101 and a capacitor C60 in sequence; the junction between the resistor R101 and the capacitor C60 is connected to the MBUS low level signal MBUS _ LV through a resistor R92.
When the M-bus master port voltage signal transmitting unit transmits a High (HV) Low (LV) voltage signal, the bus may have large current fluctuation due to the existence of the equivalent parallel resistor and the equivalent parallel capacitor, which causes the output voltage of the adder module 3 to fluctuate.
When the voltage at the positive input end (pin 5) of the D11B is higher than that at the negative input end (pin 6), the output end (pin 7) outputs high level, the diode V34 is turned off, the capacitor C60 can only be slowly charged through the resistor R92 (with a very large resistance of 2M), and the RC time constant is much longer than the duration of the signal from the slave device to return "0". Therefore, when the slave device replies to the "0" signal or the sending circuit sends a high level, which causes the current to rush (the duration is shorter than the duration of replying the "0" signal), the output voltage of the valley detector 5 can be automatically maintained stable, thus solving the problem of interference caused by the bus current rush to the reference value of the demodulation signal at the moment of powering on the M-bus.
When the voltage of the positive input end (pin 5) of the D11B is lower than that of the negative input end (pin 6), that is, when the current is charged, if the voltage of the positive input end is not shielded, the output end (pin 7) outputs a low level, the diode V34 is turned on, the capacitor C60 is rapidly discharged through the resistor R101 (the resistance value is smaller than 100 Ω), and the current cannot be recovered for a long time.
In order to solve the above problem, active shielding is performed according to the shielding signal and the shielding switch 4:
as shown in fig. 3 and 4, the shielding switch 4 includes a diode V25, a resistor R83, a resistor R85, a diode V27, a transistor V30, and a resistor R90.
The positive electrode of the diode V25 is connected to the signal detection circuit 1 to receive a shielding signal, the shielding signal is a low level signal, the negative electrode of the diode V25 is connected to an equipotential end through a resistor R83 and a resistor R85 in sequence, a connection point between the resistor R83 and the resistor R85 is connected to the positive electrode of the diode V27 and also connected to the base of the transistor V30, the negative electrode of the diode V27 is connected to the emitter of the transistor V30, the emitter of the transistor V30 is also connected to the MBUS low level signal MBUS _ LV, the collector of the transistor V30 is connected to the positive electrode of the operational amplifier D11B, and the collector of the transistor V30 is connected to the output terminal of the adder module 3 through the resistor R90.
After the shielding switch 4 is introduced, when the current undershoots, a P _ MOS _ OUT _1 signal taken OUT from the sending circuit is changed from a high level to a low level, a triode V30 in the shielding switch 4 is conducted, the input voltage of a positive input end (pin 5) of the D11B is raised to be higher than that of a negative input end (pin 6), the high level is output by an output end (pin 7) of the D11B, the diode V34 is turned off, the capacitor C60 can only be slowly charged through a resistor R92 (the resistance is very large, 2M), the voltage is kept basically unchanged, and therefore the reference value of the demodulation signal is guaranteed to be stable.
Suppose the amplitude of the return current signal of the M-bus slave device is 11-20mA, the current (supply current only) is 0.8mA when the M-bus is not communicating, and the amplitude of the return current signal of the slave device is 16 mA. That is, the current of '1' sent by the slave device is 0.8mA, the amplified output voltage is 1.5088V, the voltage is 1.7698V after passing through the adder module 3, and the voltage is 1.7698V after passing through the trough detector 5; when sending "0", the bus current is 16.8mA, the amplifier voltage is 2.1648V, and the output voltage of the valley detector 5 is still 1.7698V basically unchanged. The output signal of the valley detector 5 is output to the positive input port of the voltage comparator 6D12A, and the output voltage of the D11A is output to the negative input port of the voltage comparator 6D12A through the resistor R106. When the voltage of the negative input end is less than 1.7698V, the comparator D12A outputs a '1' signal to the singlechip through the optocoupler E10; when the voltage of the negative input end is greater than 1.7698V, the comparator D12A outputs a '0' signal to the single chip microcomputer through the optocoupler E10.
The protection circuit in the receiving circuit has four functions: overload protection, short-circuit protection, line abnormity warning and bus power switch. The protection circuit ensures the functional integrity of the high-power M-bus main circuit. Referring to fig. 3, after the bus current is converted into a voltage signal through the sampling resistors R86 and R87, the voltage signal is transmitted to the input pin of the voltage reference source V32 through the resistor R84. When overload or short circuit occurs, the voltage reference source V32 acts, the NMOS tube D10B is turned off by a locking circuit formed by the triodes V29, V31, the resistors R81, R80 and R94 until the single chip drives the optocoupler E12 through the resistor R111, the triode V33 is turned on to reset the locking circuit, then the triodes V33 and V24 are turned off, the NMOS tube D10B is turned on again, if the short circuit or overload event disappears, the circuit works normally, otherwise, the processes are repeated, and an alarm signal is generated through the D12B and related devices.
Practical limit test conditions in the test circuit are shown in fig. 6 to 10, and the test conditions are as follows: the quiescent current is 220mA, and comprises a capacitor of 0.33uF and a resistor of 500 omega which are connected in parallel, and the signal current is 16 mA. The result shows that the anti-interference capability effect is good.
Claims (6)
1. An active shielding method for resisting interference of an M-bus is characterized by comprising the following steps: detecting a voltage signal transmitted by a master device in a transmitting circuit of the M-bus through a signal detection circuit (1); a wave trough detector (5) is used for outputting a demodulation signal reference value in a receiving circuit of the M-bus, and the signal input of the wave trough detector (5) is controlled through a shielding switch (4); the receiving circuit belongs to a master device;
when the main equipment sends a high-voltage signal, the shielding switch (4) is switched on, the wave trough detector (5) works normally, and a demodulation signal reference value is output;
when the main equipment sends a low-voltage signal, the signal detection circuit (1) sends a shielding signal to the shielding switch (4), and the shielding switch (4) shields the input signal of the wave trough detector (5), so that the current undershoot signal cannot interfere with the wave trough detector (5).
2. An active shielding system for an M-bus for communication between a master device and a slave device, the master device sending a voltage signal to the slave device via a sending circuit, the slave device sending a reply current signal to the master device via a receiving circuit, the active shielding system being resistant to interference, the active shielding system comprising: the transmitting circuit is provided with a signal detection circuit (1); the receiving circuit comprises a current signal amplifying module (2), an adder module (3), a shielding switch (4), a wave trough detector (5) and a voltage comparator (6); the slave device is connected with the input end of the current signal amplification module (2), the output end of the current signal amplification module (2) is connected with the positive end of the voltage comparator (6) sequentially through the adder module (3), the shielding switch (4) and the wave trough detector (5), the output end of the current signal amplification module (2) is also directly connected with the negative end of the voltage comparator (6), and the output end of the voltage comparator (6) is used for outputting a demodulated reply signal;
the signal detection circuit (1) is connected with the shielding switch (4), the signal detection circuit (1) is used for sending a shielding signal to the shielding switch (4) when the main equipment sends a low-level voltage signal, and the shielding switch (4) is used for shielding the signal sent to the wave trough detector (5) by the adder module (3) after receiving the shielding signal so as to stabilize the reference signal output by the wave trough detector (5).
3. The active shielding system for M-bus immunity to interference of claim 2, wherein: the valley detector (5) comprises an operational amplifier D11B, a resistor R100, a resistor R101, a resistor R92, a diode V34 and a capacitor C60;
the positive end of the operational amplifier D11B is used for being connected with the output end of the adder module (3) through a shielding switch (4), the negative end of the operational amplifier is connected with the anode of a diode V34 through a resistor R100, the cathode of the diode V34 is connected with the output end of the operational amplifier D11B, and the anode of the diode V34 is further connected with an equipotential end through a resistor R101 and a capacitor C60 in sequence; the junction between the resistor R101 and the capacitor C60 is connected to the MBUS low level signal MBUS _ LV through a resistor R92.
4. The active shielding system for M-bus immunity to interference of claim 3, wherein: the shielding switch (4) comprises a diode V25, a resistor R83, a resistor R85, a diode V27, a triode V30 and a resistor R90;
the positive electrode of the diode V25 is connected with the signal detection circuit (1) to receive a shielding signal, the shielding signal is a low-level signal, the negative electrode of the diode V25 is connected with an equipotential end through a resistor R83 and a resistor R85 in sequence, a connection point between the resistor R83 and the resistor R85 is connected with the positive electrode of the diode V27 and also connected with the base electrode of the triode V30, the negative electrode of the diode V27 is connected with the emitter electrode of the triode V30, the emitter electrode of the triode V30 is also connected with an MBUS low-level signal MBUS _ LV, the collector electrode of the triode V30 is used for being connected with the positive end of the operational amplifier D11B, and the collector electrode of the triode V30 is also connected with the output end of the adder module (3) through the resistor R90.
5. The active shielding system for M-bus immunity to interference of claim 2, wherein: the signal detection circuit (1) comprises an optical coupler E8, a totem-pole circuit, a PMOS tube D10A, a diode V16 and a diode V18;
the input end of the optical coupler E8 is used for being connected with the input end of a transmitting circuit, the output end of the optical coupler E8 is used for controlling the on-off of a PMOS tube D10A through a totem-pole circuit, one end of the PMOS tube is connected with a MBUS high-level signal MBUS _ HV, the other end of the PMOS tube is used as the output end of a signal detection circuit (1) to transmit a shielding signal, the other end of the PMOS tube is further connected with the anode of a diode V16, the anode of the diode V18 is connected with a MBUS low-level signal MBUS _ LV, the cathode of the diode V18 is connected with the cathode of a diode V16, and the cathode of the diode V16 is used for being connected with the output end of the transmitting circuit.
6. An active screening system for M-bus interference rejection according to any one of claims 2 to 5, wherein: and the receiving circuit is also provided with a protection circuit.
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|---|---|---|---|---|
| KR100251560B1 (en) * | 1996-10-29 | 2000-04-15 | 윤종용 | Apparatus for rejecting the outer interference signal in cdma terminal equipmeut |
| US8269622B2 (en) * | 2009-03-17 | 2012-09-18 | Jetlun Corporation | Method and system for intelligent energy network management control system |
| CN102082612A (en) * | 2010-11-29 | 2011-06-01 | 北京汽车新能源汽车有限公司 | Controller area network (CAN) bus-based anti-electromagnetic interference method and device |
| CN202331085U (en) * | 2011-11-26 | 2012-07-11 | 重庆市智能水表有限责任公司 | M-BUS bus data demodulating circuit |
| CN106454692A (en) * | 2015-08-12 | 2017-02-22 | 卢迪 | Dual-mode wireless communication chip, dual-mode wireless communication equipment and dual-mode wireless communication method |
| CN106877892B (en) * | 2017-02-16 | 2019-08-06 | 海能达通信股份有限公司 | A kind of anti-interference reception circuit structure, method and apparatus |
-
2019
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