Noise suppression circuit and image acquisition equipment

Abstract

The invention discloses a noise suppression circuit and image acquisition equipment, the noise suppression circuit comprises a power supply noise sampling circuit, a noise conversion circuit and a noise elimination circuit, the power supply noise sampling circuit is connected with an interface and a power supply circuit, and is used for extracting electric power from the interface and providing the electric power for the power supply circuit, sampling current of the power supply circuit and eliminating noise; obtaining a current interference signal; the noise conversion circuit is connected with the power supply noise sampling circuit and is used for converting the current interference signal into a voltage interference signal; the noise elimination circuit is connected with the interface and the noise conversion circuit, and is used for carrying out noise reduction processing on the uplink signal received by the interface based on the voltage interference signal. Through the above mode, the problem that the current fluctuation signal and the low-frequency uplink signal cannot be eliminated when the frequency bands are overlapped can be solved, so that the probability of error codes in uplink data demodulation is reduced, and the communication reliability and the communication efficiency are improved.

Description

Technical Field

[0001] The present application relates to the field of signal processing technology, and in particular to a noise suppression circuit and an image acquisition device. Background Art

[0002] In the industrial field, most image acquisition devices need to be powered by coaxial cables and perform high-speed data transmission to achieve high-bandwidth image transmission. Taking industrial camera equipment as an example, the power of industrial camera equipment will change continuously during operation. The power consumption of industrial camera equipment during data transmission after taking an image will be greater than the power consumption during exposure. This will cause current fluctuations on the coaxial cable. These current fluctuation signals appear as low-frequency interference signals in the frequency domain, which overlap with the frequency band of the uplink signal received by the image acquisition device, thereby interfering with the demodulation of normal data, increasing the bit error rate, and affecting the normal communication of the image acquisition device. Summary of the invention

[0003] The present application proposes a noise suppression circuit and an image acquisition device to solve the above-mentioned problems.

[0004] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a noise suppression circuit, which is used for an image acquisition device, and the image acquisition device includes an interface, a noise suppression circuit and a power supply circuit. The interface is an interface that uses the same medium to transmit data signals and power supply signals. The noise suppression circuit includes a power supply noise sampling circuit, a noise conversion circuit and a noise elimination circuit. The power supply noise sampling circuit is connected to the interface and the power supply circuit, and is used to extract power from the interface and provide it to the power supply circuit, and sample the current of the power supply circuit to obtain a current interference signal; the noise conversion circuit is connected to the power supply noise sampling circuit, and is used to convert the current interference signal into a voltage interference signal; the noise elimination circuit is respectively connected to the interface and the noise conversion circuit, and is used to perform noise reduction processing on the uplink signal received by the interface based on the voltage interference signal.

[0005] Among them, the power supply noise sampling circuit includes a power extraction circuit and a noise sampling sub-circuit, the power extraction circuit is connected to the interface and the noise sampling sub-circuit, and the noise sampling sub-circuit is connected to the power supply circuit; the power extraction circuit is used to extract power from the cable connected to the interface and provide it to the power supply circuit, and the noise sampling sub-circuit is used to sample the current of the power supply circuit to obtain a current interference signal.

[0006] The noise sampling subcircuit includes a first resistor, a second resistor, a first operational amplifier and a transistor, wherein the first end of the first resistor is connected to the power extraction circuit, and the second end of the first resistor is connected to the power supply circuit; the first end of the second resistor is connected to the first end of the first resistor; the first input end of the first operational amplifier is connected to the second end of the second resistor, and the second input end of the first operational amplifier is connected to the second end of the first resistor; the first path end of the transistor is connected to the second end of the second resistor, the control end of the transistor is connected to the output end of the first operational amplifier, and the second path end of the transistor is used to output a current interference signal; the current of the power supply circuit generates a voltage drop on the first resistor and forms a current interference signal after being amplified by the first operational amplifier, and the current interference signal is sent to the noise conversion circuit through the second path end of the transistor.

[0007] Among them, the noise conversion circuit includes a third resistor, an impedance element and a first capacitor. The first end of the third resistor is connected to the power supply noise sampling circuit to receive the current interference signal; the first end of the impedance element is connected to the second end of the third resistor, and the second end of the impedance element is grounded; the first end of the first capacitor is connected to the second end of the third resistor, and the second end of the first capacitor is used to output the voltage interference signal; the third resistor is used to adjust the amplitude of the voltage interference signal, and the impedance element is used to simulate the impedance characteristics of the interface; the first capacitor is used to isolate the DC component in the voltage interference signal.

[0008] Among them, the impedance element includes a fourth resistor and a second capacitor, the first end of the fourth resistor is connected to the second end of the third resistor, and the second end of the fourth resistor is grounded; the first end of the second capacitor is connected to the first end of the third resistor, and the second end of the second capacitor is grounded; the fourth resistor is used to simulate the resistance of the interface; the second capacitor is used to filter out noise greater than a preset frequency in the current interference signal.

[0009] Among them, the noise elimination circuit includes a variable resistor and a subtraction circuit, the first end of the variable resistor is connected to the noise conversion circuit, and the variable resistor is used to adjust the gain of the voltage interference signal; the first input end of the subtraction circuit is connected to the second end of the variable resistor; the second input end of the subtraction circuit is connected to the interface; the subtraction circuit is used to perform noise reduction processing on the uplink signal based on the voltage interference signal to obtain the uplink signal after noise reduction.

[0010] Among them, the subtraction circuit includes a fifth resistor, a sixth resistor, a seventh resistor and a second operational amplifier, the first end of the fifth resistor is grounded, the second end of the fifth resistor is connected to the first input end of the second operational amplifier, and the connection node between the second end of the fifth resistor and the first input end of the second operational amplifier serves as the first input end of the subtraction circuit; the first end of the sixth resistor serves as the second input end of the subtraction circuit, the second end of the sixth resistor and the first end of the seventh resistor are connected to the second input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the second end of the seventh resistor.

[0011] The power extraction circuit includes an inductor and a third capacitor, the first end of the inductor is connected to the interface, and the second end of the inductor is connected to the first end of the power supply noise sampling circuit; the first end of the third capacitor is grounded, and the second end of the third capacitor is connected to the second end of the inductor and the first end of the power supply noise sampling circuit.

[0012] Among them, the noise suppression circuit also includes a DC isolation circuit, a signal filtering circuit and a signal shaping circuit. The DC isolation circuit is connected to the interface and is used to isolate the DC component of the power supply circuit; the signal filtering circuit is connected to the DC isolation circuit and the noise elimination circuit and is used to filter out external interference of the uplink signal; the signal shaping circuit is connected to the output end of the noise elimination circuit and is used to binarize the uplink signal after noise reduction to generate a corresponding digital signal.

[0013] Among them, the DC isolation circuit includes a fourth capacitor and an eighth resistor, the first end of the fourth capacitor is connected to the interface, and the second end of the fourth capacitor is connected to the signal filtering circuit; the first end of the eighth resistor is grounded, and the second end of the eighth resistor is connected to the second end of the fourth capacitor and the signal filtering circuit.

[0014] In order to solve the above-mentioned technical problems, another technical solution adopted in the present application is: to provide an image acquisition device, which includes the noise suppression circuit, interface, power supply circuit and signal demodulation circuit of any one of the above-mentioned items, wherein the interface is connected to the power supply noise sampling circuit and the noise elimination circuit, the power supply noise sampling circuit is connected to the power supply circuit, and the noise elimination circuit is connected to the signal demodulation circuit; wherein the signal demodulation circuit is used to demodulate the uplink signal after noise reduction processing.

[0015] The beneficial effects of the present application are as follows: Different from the prior art, the noise suppression circuit of the present application includes a power supply noise sampling circuit, a noise conversion circuit and a noise elimination circuit. The power supply noise sampling circuit is connected to the interface and the power supply circuit, and is used to extract power from the interface and provide it to the power supply circuit, and to sample the current of the power supply circuit to obtain a current interference signal; the noise conversion circuit is connected to the power supply noise sampling circuit, and is used to convert the current interference signal into a voltage interference signal; the noise elimination circuit is respectively connected to the interface and the noise conversion circuit, and is used to perform noise reduction processing on the uplink signal received by the interface based on the voltage interference signal. Through the above-mentioned method, the present application can use the power supply noise sampling circuit to detect the current interference signal generated by the current fluctuation in the power supply circuit in real time, and convert the current interference signal into a voltage interference signal, and finally use the voltage interference signal to perform noise reduction on the uplink signal received by the interface, which can solve the problem that the current fluctuation signal and the low-frequency uplink signal cannot be eliminated when the frequency band overlaps, thereby reducing the probability of bit errors in uplink data demodulation and improving the reliability and efficiency of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a structural schematic diagram of the first embodiment of the noise suppression circuit of the present application;

[0017] Figure 2 is a structural schematic diagram of a second embodiment of the noise suppression circuit of the present application;

[0018] Figure 3 is a schematic structural diagram of a third embodiment of the noise suppression circuit of the present application;

[0019] Figure 4 is a structural schematic diagram of a fourth embodiment of the noise suppression circuit of the present application;

[0020] Figure 5 It is a schematic diagram of the waveforms of various signals in the noise suppression circuit of the present application;

[0021] Figure 6 It is a structural schematic diagram of an embodiment of the image acquisition device of the present application. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0023] In the industrial field, most image acquisition devices need to be powered by coaxial cables and perform high-speed data transmission to achieve high-bandwidth image transmission. Taking industrial camera equipment as an example, the power of industrial camera equipment will change continuously during operation. The power consumption of industrial camera equipment during data transmission after taking an image will be greater than the power consumption during exposure. This will cause current fluctuations on the coaxial cable. These current fluctuation signals appear as low-frequency interference signals in the frequency domain, which overlap with the frequency band of the uplink signal received by the image acquisition device, thereby interfering with the demodulation of normal data, increasing the bit error rate, and affecting the normal communication of the image acquisition device.

[0024] Taking industrial camera equipment as an example, when the industrial camera equipment adopts the CXP (CoaXPress) standard protocol, the industrial camera equipment adopting the CXP standard protocol can be called a CXP camera equipment. Among them, CXP is a high-speed data transmission standard, which is widely used in industrial fields such as machine vision, medical imaging and life sciences. In the CXP standard protocol, the high-speed data sent by the CXP camera equipment to the host (usually a frame grabber or controller) is called a downlink signal, which mainly includes video data and control data, while the low-speed signal sent by the host to the CXP camera equipment is called an uplink signal, which is mainly a control command. The downlink signal is transmitted at a higher frequency, and the uplink signal is transmitted at a lower frequency. They occupy different frequency bands and share the same transmission medium through frequency division multiplexing. At the receiving end, a filter with matching frequency is used to separate the two signals to achieve demodulation. In addition, in this embodiment, the industrial camera device also adopts Power over CoaXPress (PoCXP) technology. PoCXP is a technology that provides power to devices (such as industrial camera devices) through coaxial cables with CXP standard protocol. PoCXP technology allows power to be transmitted through the same coaxial cable while transmitting data. To achieve this, power is injected into the coaxial cable on the host side. This is usually achieved through a power injector to ensure that power and data signals coexist in the cable without interfering with each other. At the receiving end (such as industrial camera equipment), a power extractor extracts power from the cable and provides it to the industrial camera equipment after conversion. At this time, as mentioned above, the power of the industrial camera equipment will continue to change during operation. When the power consumption of the industrial camera equipment during transmission after taking the image is greater than the power consumption during exposure, this will generate current fluctuations on the coaxial cable. These current fluctuation signals appear as low-frequency interference signals in the frequency domain, which overlap with the frequency band of the uplink signal, thereby interfering with normal data demodulation, increasing the bit error rate, and affecting the normal communication of the industrial camera.

[0025] In order to solve the above problems, the present application first proposes a noise suppression circuit. Figure 1 , Figure 1 1 is a schematic diagram of the structure of the first embodiment of the noise suppression circuit of the present application. In this embodiment, the noise suppression circuit 100 is used in an image acquisition device, and the image acquisition device includes an interface, a noise suppression circuit 100 and a power supply circuit. The interface is an interface that uses the same medium to transmit data signals and power supply signals. The noise suppression circuit 100 includes a power supply noise sampling circuit 10, a noise conversion circuit 20 and a noise elimination circuit 30.

[0026] like Figure 1As shown, the power supply noise sampling circuit 10 is connected to the interface and the power supply circuit, and is used to extract power from the interface and provide it to the power supply circuit, and sample the current of the power supply circuit to obtain a current interference signal; the noise conversion circuit 20 is connected to the power supply noise sampling circuit 10, and is used to convert the current interference signal into a voltage interference signal; the noise elimination circuit 30 is respectively connected to the interface and the noise conversion circuit 20, and is used to perform noise reduction processing on the uplink signal received by the interface based on the voltage interference signal.

[0027] In this embodiment, the image acquisition device can be the industrial camera device described above. In this embodiment, the interface is an interface that uses the same medium to transmit data signals and power supply signals, that is, the interface can be set to a CXP interface; at this time, the interface is connected to the host side via a coaxial cable, can receive the uplink signal from the host side and provide power for the industrial camera device.

[0028] In this embodiment, the power supply noise sampling circuit 10 includes a power extraction circuit 11 and a noise sampling subcircuit 12; the power extraction circuit 11 can extract power from the coaxial cable to the power supply circuit of the image acquisition device, and at the same time suppress the high-frequency noise from the power supply circuit from being transmitted back to the interface. The function of the noise sampling subcircuit 12 is to collect the current change from the power supply circuit; the function of the noise conversion circuit 20 is to realize the conversion from the current signal to the voltage signal, and convert the current interference signal into an equivalent voltage interference signal, which is the same as the voltage signal generated by the current interference signal on the coaxial cable and the matching impedance; the noise elimination circuit 30 is connected to the interface 210, and the function of the noise elimination circuit 30 is to eliminate the power supply noise in the received uplink signal based on the voltage interference signal to restore the original uplink signal. Among them, the specific circuit structures of the power supply noise sampling circuit 10, the noise conversion circuit 20 and the noise elimination circuit 30 are described below and will not be repeated here.

[0029] Different from the prior art, the noise suppression circuit 100 of the present application includes a power supply noise sampling circuit 10, a noise conversion circuit 20 and a noise elimination circuit 30. The power supply noise sampling circuit 10 is connected to the interface and the power supply circuit, and is used to extract power from the interface and provide it to the power supply circuit, and to sample the current of the power supply circuit to obtain a current interference signal; the noise conversion circuit 20 is connected to the power supply noise sampling circuit 10, and is used to convert the current interference signal into a voltage interference signal; the noise elimination circuit 30 is respectively connected to the interface and the noise conversion circuit 20, and is used to perform noise reduction processing on the uplink signal received by the interface based on the voltage interference signal. Through the above method, the present application can use the power supply noise sampling circuit 10 to detect the current interference signal generated by the current fluctuation in the power supply circuit in real time, and convert the current interference signal into a voltage interference signal, and finally use the voltage interference signal to perform noise reduction on the uplink signal received by the interface, which can solve the problem that the current fluctuation signal and the low-frequency uplink signal cannot be eliminated when the frequency band overlaps, thereby reducing the probability of bit errors in uplink data demodulation and improving the reliability and efficiency of communication.

[0030] In addition, compared with the solution of using a fixed frequency filter to separate interference noise in the prior art, in the present application, the power supply noise sampling circuit 10 is used to detect the interference noise generated by the power supply circuit in real time, and the interference noise is subtracted from the uplink signal with interference through the noise elimination circuit 30 to eliminate the interference. Compared with the prior art, the present application expands the passband of the filter and reduces the attenuation of the signal.

[0031] Optionally, see Figure 2 , Figure 2 Schematic diagram of the structure of the second embodiment of the noise suppression circuit of the present application. Figure 2 As shown, the power supply noise sampling circuit 10 of this embodiment includes a power extraction circuit 11 and a noise sampling sub-circuit 12. The power extraction circuit 11 is connected to the interface and the noise sampling sub-circuit 12, and the noise sampling sub-circuit 12 is connected to the power supply circuit; the power extraction circuit 11 is used to extract power from the cable connected to the interface and provide it to the power supply circuit, and the noise sampling sub-circuit 12 is used to sample the current of the power supply circuit to obtain a current interference signal.

[0032] In this embodiment, as described above, the power extraction circuit 11 is used to extract power from the cable connected to the interface and provide it to the power supply circuit. In this embodiment, when sampling the interference signal, the voltage noise at the input of the power supply circuit is not directly sampled, but the current noise is sampled, and then the sampled current interference signal is indirectly obtained by the noise conversion circuit 20 to obtain the voltage interference signal. The reasons for this design are: (1) The output of the power extraction circuit 11 presents low impedance to the power supply circuit, and the voltage signal generated by the changing current signal is relatively weak, which is not convenient for sampling. If sampling is performed from the interface side, due to the inclusion of the uplink signal, the effective uplink signal will be eliminated when the power supply noise is eliminated; (2) The voltage signal is generated after the current signal is phase-shifted by the power extraction circuit 11, and there is a delay, which cannot reflect the immediate changes of the interference noise.

[0033] Optionally, see Figure 3 , Figure 3 A schematic diagram of the circuit structure of the third embodiment of the noise suppression circuit of the present application. Figure 3 As shown, in this embodiment, the noise sampling subcircuit 12 includes a first resistor R1, a second resistor R2, a first operational amplifier OP1 and a transistor Q, wherein a first end of the first resistor R1 is connected to the power extraction circuit 11, and a second end of the first resistor R1 is connected to the power supply circuit 230; a first end of the second resistor R2 is connected to a first end of the first resistor R1; a first input end of the first operational amplifier OP1 is connected to a second end of the second resistor R2, and a second input end of the first operational amplifier OP1 is connected to a second end of the first resistor R1; a first path end of the transistor Q is connected to a second end of the second resistor R2, a control end of the transistor Q is connected to an output end of the first operational amplifier OP1, and a second path end of the transistor Q is used to output a current interference signal.

[0034] In this embodiment, the current of the power circuit generates a voltage drop on the first resistor R1 and is amplified by the first operational amplifier OP1 to form a current interference signal, which is sent to the noise conversion circuit 20 through the second path end of the transistor Q.

[0035] In this embodiment, the current of the power circuit generates a voltage drop on the first resistor R1 and is amplified by the first operational amplifier OP1 to form a current interference signal with a fixed ratio to the output current of the power circuit. In other embodiments, the noise sampling subcircuit 12 can also be other circuit structures, for example, it can be implemented by sampling the voltage drop on the resistor or by coupling current sensors, but the basic function that the noise sampling subcircuit 12 needs to meet is to sample the current signal from the input loop of the power circuit.

[0036] Alternatively, if Figure 3As shown, the noise conversion circuit 20 of this embodiment includes a third resistor R3, an impedance element 21 and a first capacitor C1. The first end of the third resistor R3 is connected to the power supply noise sampling circuit 10 to receive the current interference signal; the first end of the impedance element 21 is connected to the second end of the third resistor R3, and the second end of the impedance element 21 is grounded; the first end of the first capacitor C1 is connected to the second end of the third resistor R3, and the second end of the first capacitor C1 is used to output the voltage interference signal.

[0037] In this embodiment, the function of the noise conversion circuit 20 is to simulate the impedance characteristics of the interface part, converting the current interference signal in the form of current into the voltage interference signal in the form of voltage. In the noise conversion circuit 20, the third resistor R3 is used to adjust the amplitude of the voltage interference signal, and the impedance element 21 is used to simulate the impedance characteristics of the interface; the first capacitor C1 is used to isolate the DC component in the voltage interference signal. In other embodiments, the noise conversion circuit 20 can also be in other circuit forms, for example, the noise conversion circuit 20 can be composed of RLC devices in different forms, as long as the impedance characteristics of the analog interface part are met.

[0038] Alternatively, if Figure 3 As shown, the impedance element 21 of this embodiment includes a fourth resistor R4 and a second capacitor C2, the first end of the fourth resistor R4 is connected to the second end of the third resistor R3, and the second end of the fourth resistor R4 is grounded; the first end of the second capacitor C2 is connected to the first end of the third resistor R3, and the second end of the second capacitor C2 is grounded; the fourth resistor R4 is used to simulate the resistance of the interface; the second capacitor C2 is used to filter out noise greater than a preset frequency in the current interference signal.

[0039] In this embodiment, the second capacitor C2 is mainly used to filter out the higher frequency noise in the detection noise signal, and this part of the noise can be removed by the signal filtering circuit 50 described later. In other embodiments, the impedance element 21 can also be in other circuit forms, which is not limited here, as long as it meets the above functions.

[0040] Alternatively, if Figure 3 As shown, the noise elimination circuit 30 of this embodiment includes a variable resistor Rv and a subtraction circuit 31, the first end of the variable resistor Rv is connected to the noise conversion circuit 20, and the variable resistor Rv is used to adjust the gain of the voltage interference signal; the first input end of the subtraction circuit 31 is connected to the second end of the variable resistor Rv; the second input end of the subtraction circuit 31 is connected to the interface 210; the subtraction circuit 31 is used to perform noise reduction processing on the uplink signal based on the voltage interference signal to obtain the uplink signal after noise reduction.

[0041] In this embodiment, the second input end of the subtraction circuit 31 in the noise elimination circuit 30 is the uplink signal with interference, and the first input end is the voltage interference signal output by the noise conversion circuit 20. In addition, in this embodiment, the amplitude of the voltage interference signal can be controlled by adjusting the resistance value of the variable resistor Rv to match the noise amplitude in the input uplink signal with interference, thereby eliminating the power supply noise to the greatest extent.

[0042] Alternatively, if Figure 3 As shown, the subtraction circuit 31 of this embodiment includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a second operational amplifier OP2, the first end of the fifth resistor R5 is grounded, the second end of the fifth resistor R5 is connected to the first input end of the second operational amplifier OP2, and the connection node between the second end of the fifth resistor R5 and the first input end of the second operational amplifier OP2 serves as the first input end of the subtraction circuit 31; the first end of the sixth resistor R6 serves as the second input end of the subtraction circuit 31, the second end of the sixth resistor R6 and the first end of the seventh resistor R7 are connected to the second input end of the second operational amplifier OP2, and the output end of the second operational amplifier OP2 is connected to the second end of the seventh resistor R7.

[0043] In other embodiments, the noise elimination circuit 30 may be in other circuit forms, which are not limited here. The noise elimination circuit 30 only needs to meet the basic functions of adjusting the gain of the voltage interference signal and realizing the subtraction between the uplink signal and the voltage interference signal.

[0044] Alternatively, if Figure 4 As shown, in this embodiment, the power extraction circuit 11 includes an inductor L1 and a third capacitor C3, a first end of the inductor L1 is connected to the interface, and a second end of the inductor L1 is connected to a first end of the power supply noise sampling circuit 10; a first end of the third capacitor C3 is grounded, and a second end of the third capacitor C3 is connected to the second end of the inductor L1 and the first end of the power supply noise sampling circuit 10.

[0045] In this embodiment, the power extraction circuit 11 is composed of an inductor L1 and a third capacitor C3 to form a low-pass filter, which mainly extracts power from the coaxial cable signal and suppresses the high-frequency noise from the power supply circuit from being transmitted back to the interface. In addition, in the application, the power supply noise can be actively detected and eliminated, and at this time, the power extraction circuit 11 is no longer required to have excessive attenuation. Therefore, in this embodiment, small-sized capacitors and inductors can be used in the power extraction circuit 11 of this embodiment, which is conducive to saving the internal device layout space of the image acquisition device.

[0046] Optionally, see Figure 4 , Figure 41 is a circuit structure diagram of the fourth embodiment of the noise suppression circuit of the present application. In this embodiment, the noise suppression circuit 100 also includes a DC isolation circuit 40, a signal filtering circuit 50 and a signal shaping circuit 60. The DC isolation circuit 40 is connected to the interface 210 to isolate the DC component of the power supply circuit; the signal filtering circuit 50 is connected to the DC isolation circuit 40 and the noise elimination circuit 30 to filter out external interference of the uplink signal; the signal shaping circuit 60 is connected to the output end of the noise elimination circuit 30 to binarize the uplink signal after noise reduction to generate a corresponding digital signal.

[0047] Alternatively, if Figure 4 As shown, in this embodiment, the DC isolation circuit 40 includes a fourth capacitor C4 and an eighth resistor R8, the first end of the fourth capacitor C4 is connected to the interface 210, and the second end of the fourth capacitor C4 is connected to the signal filtering circuit 50; the first end of the eighth resistor R8 is grounded, and the second end of the eighth resistor R8 is connected to the second end of the fourth capacitor C4 and the signal filtering circuit 50.

[0048] In one application scenario, see Figure 5 , Figure 5 Schematic diagram of the waveforms of various signals in the noise suppression circuit of the present application. Figure 4 and Figure 5 As shown, the noise suppression circuit 100 of this embodiment can sample the noise from the input end of the power supply circuit through a power supply noise sampling circuit 10 to obtain Figure 5 After obtaining the current interference signal, the noise conversion circuit 20 can be used to convert the current interference signal into the current interference signal as shown in FIG. Figure 5 At this time, after obtaining the equivalent voltage interference signal, the noise elimination circuit 30 can be used to receive the equivalent voltage interference signal. Figure 5 The voltage interference signal is filtered out from the interfering uplink signal shown in FIG. Figure 5 The noise-reduced uplink signal is then sent to the signal shaping circuit 60 to obtain the noise-reduced uplink signal. Figure 5 The digital signal is shown.

[0049] Optionally, the present application further proposes an image acquisition device, see Figure 6 , Figure 6 Schematic diagram of the structure of an embodiment of the image acquisition device of the present application. Figure 6As shown, the image acquisition device 200 of this embodiment includes any one of the above-mentioned noise suppression circuits 100, interface 210, power supply circuit 230 and signal demodulation circuit 220, wherein the interface 210 is connected to the power supply noise sampling circuit 10 and the noise elimination circuit 30, the power supply noise sampling circuit 10 is connected to the power supply circuit 230, and the noise elimination circuit 30 is connected to the signal demodulation circuit 220; wherein the signal demodulation circuit 220 is used to demodulate the uplink signal after noise reduction processing.

[0050] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A noise suppression circuit, characterized in that: Used in an image acquisition device, the image acquisition device includes an interface, a noise suppression circuit and a power supply circuit, the interface is an interface that uses the same medium to transmit a data signal and a power supply signal, and the noise suppression circuit includes: a power supply noise sampling circuit, the power supply noise sampling circuit being connected to the interface and the power supply circuit, and being used for extracting power from the interface and providing it to the power supply circuit, and sampling the current of the power supply circuit to obtain a current interference signal; A noise conversion circuit, the noise conversion circuit is connected to the power supply noise sampling circuit and is used to convert the current interference signal into a voltage interference signal; The noise elimination circuit is respectively connected to the interface and the noise conversion circuit, and is used to perform noise reduction processing on the uplink signal received by the interface based on the voltage interference signal.

2. The noise suppression circuit according to claim 1, characterized in that: The power supply noise sampling circuit includes a power extraction circuit and a noise sampling sub-circuit, wherein the power extraction circuit is connected to the interface and the noise sampling sub-circuit, and the noise sampling sub-circuit is connected to the power supply circuit; the power extraction circuit is used to extract power from the cable connected to the interface and provide it to the power supply circuit, and the noise sampling sub-circuit is used to sample the current of the power supply circuit to obtain the current interference signal.

3. The noise suppression circuit according to claim 2, characterized in that: The noise sampling subcircuit comprises: a first resistor, wherein a first end of the first resistor is connected to the power extraction circuit, and a second end of the first resistor is connected to the power supply circuit; a second resistor, a first end of the second resistor being connected to a first end of the first resistor; a first operational amplifier, wherein a first input terminal of the first operational amplifier is connected to a second terminal of the second resistor, and a second input terminal of the first operational amplifier is connected to a second terminal of the first resistor; a transistor, wherein a first path end of the transistor is connected to the second end of the second resistor, a control end of the transistor is connected to the output end of the first operational amplifier, and a second path end of the transistor is used to output the current interference signal; The current of the power supply circuit generates a voltage drop on the first resistor and forms the current interference signal after being amplified by the first operational amplifier. The current interference signal is sent to the noise conversion circuit through the second path end of the transistor.

4. The noise suppression circuit according to claim 1, characterized in that: The noise conversion circuit comprises: a third resistor, a first end of the third resistor being connected to the power supply noise sampling circuit to receive the current interference signal; an impedance element, wherein a first end of the impedance element is connected to a second end of the third resistor, and a second end of the impedance element is grounded; a first capacitor, wherein a first end of the first capacitor is connected to a second end of the third resistor, and a second end of the first capacitor is used to output the voltage interference signal; The third resistor is used to adjust the amplitude of the voltage interference signal, the impedance element is used to simulate the impedance characteristics of the interface; and the first capacitor is used to isolate the DC component in the voltage interference signal.

5. The noise suppression circuit according to claim 4, characterized in that: The impedance element comprises: a fourth resistor, wherein a first end of the fourth resistor is connected to a second end of the third resistor, and a second end of the fourth resistor is grounded; a second capacitor, wherein a first end of the second capacitor is connected to a first end of the third resistor, and a second end of the second capacitor is grounded; The fourth resistor is used to simulate the resistance of the interface; the second capacitor is used to filter out noise greater than a preset frequency in the current interference signal.

6. The noise suppression circuit according to claim 1, characterized in that: The noise elimination circuit comprises: A variable resistor, a first end of which is connected to the noise conversion circuit, and the variable resistor is used to adjust the gain of the voltage interference signal; A subtraction circuit, wherein the first input end of the subtraction circuit is connected to the second end of the variable resistor; the second input end of the subtraction circuit is connected to the interface; the subtraction circuit is used to perform noise reduction processing on the uplink signal based on the voltage interference signal to obtain the uplink signal after noise reduction.

7. The noise suppression circuit according to claim 6, characterized in that: The subtraction circuit includes a fifth resistor, a sixth resistor, a seventh resistor and a second operational amplifier. Among them, the first end of the fifth resistor is grounded, the second end of the fifth resistor is connected to the first input end of the second operational amplifier, and the connection node between the second end of the fifth resistor and the first input end of the second operational amplifier serves as the first input end of the subtraction circuit; the first end of the sixth resistor serves as the second input end of the subtraction circuit, the second end of the sixth resistor and the first end of the seventh resistor are connected to the second input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the second end of the seventh resistor.

8. The noise suppression circuit according to claim 2, characterized in that: The power extraction circuit comprises: an inductor, wherein a first end of the inductor is connected to the interface, and a second end of the inductor is connected to a first end of the power supply noise sampling circuit; A third capacitor, wherein a first end of the third capacitor is grounded, and a second end of the third capacitor is connected to the second end of the inductor and the first end of the power supply noise sampling circuit.

9. The noise suppression circuit according to claim 1, characterized in that: The noise suppression circuit further includes: A DC isolation circuit, connected to the interface and used to isolate a DC component of the power supply circuit; A signal filtering circuit, the signal filtering circuit is connected to the DC isolation circuit and the noise elimination circuit, and is used to filter out external interference of the uplink signal; A signal shaping circuit is connected to the output end of the noise elimination circuit and is used to binarize the uplink signal after noise reduction to generate a corresponding digital signal.

10. The noise suppression circuit according to claim 9, characterized in that: The DC isolation circuit comprises: a fourth capacitor, wherein a first end of the fourth capacitor is connected to the interface, and a second end of the fourth capacitor is connected to the signal filtering circuit; An eighth resistor, wherein a first end of the eighth resistor is grounded, and a second end of the eighth resistor is connected to the second end of the fourth capacitor and the signal filtering circuit.

11. An image acquisition device, characterized in that: It comprises the noise suppression circuit, interface, power supply circuit and signal demodulation circuit as described in any one of claims 1 to 10, wherein the interface is connected to the power supply noise sampling circuit and the noise elimination circuit, the power supply noise sampling circuit is connected to the power supply circuit, and the noise elimination circuit is connected to the signal demodulation circuit; wherein the signal demodulation circuit is used to demodulate the uplink signal after noise reduction processing.

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