Vehicle-mounted AHL analog high-definition noise reduction matching interface circuit

Abstract

The utility model discloses a vehicle-mounted AHL analog high-definition noise reduction matching interface circuit in the technical field of automobile intelligent cabins, and provides a vehicle-mounted AHL analog high-definition noise reduction matching interface circuit, which comprises a TX interface circuit, an input end of the TX interface circuit is connected with an Encoder chip, an output end of the TX interface circuit is connected with an RX interface circuit, and the RX interface circuit is connected with a power supply. And the RX interface circuit is connected with the Decoder chip. Through cooperation of the TX interface circuit and the RX interface circuit, noise reduction processing of video signals sent by the Encoder chip is achieved, high-definition analog video signals are input to the Decoder chip, and noise resistance, reliability and EMC performance of an AHL video transmission scheme are improved.

Description

Technical Field

[0001] The utility model relates to a vehicle-mounted AHL analog high-definition noise reduction matching interface circuit in the technical field of automobile intelligent cockpit. Background Art

[0002] Automotive Hi-Definition Link (AHL) technology is a new video transmission technology designed for automotive camera systems. It can transmit high-definition video on the same cables and connections as standard-definition CVBS systems, and has low cost, low power consumption, simplified system design, strong anti-noise capabilities, and meets the automotive requirements for reliability and EMC. The AHL transmission link sends compressed video data from the Camera to the Encoder, which is integrated into an AHL signal through the TX interface circuit, and then received by the RX interface circuit through a 100 ohm (characteristic impedance) transmission line, and then decoded into a Bt656 signal by the Decoder and given to the Video Processor for processing and application. Because the AHL transmission solution is mainly aimed at the 10M~30M passenger car video transmission environment, the TX (output) interface and the input (RX) interface both need to match the noise reduction protection processing to cope with the complex electromagnetic environment of the car. The prior art discloses a vehicle-mounted analog video signal anti-interference system with a publication number of CN206350063U and a publication date of 2017.07.21, which improves the anti-interference ability of the analog video signal. However, the above existing technologies cannot be applied to AHL to achieve good noise reduction effects. Utility Model Content

[0003] The purpose of the utility model is to provide a vehicle-mounted AHL analog high-definition noise reduction matching interface circuit to improve the noise resistance, reliability and EMC performance of the AHL video transmission solution.

[0004] To achieve the above-mentioned purpose, the utility model provides a vehicle-mounted AHL analog high-definition noise reduction matching interface circuit, including a TX interface circuit, the input end of the TX interface circuit is connected to the Encoder chip, the output end of the TX interface circuit is connected to the RX interface circuit through a transmission line with a characteristic impedance of 100 ohms, and the RX interface circuit is connected to the Decoder chip.

[0005] Compared with the prior art, the beneficial effect of the utility model is that the noise reduction processing of the video signal emitted by the Encoder chip is realized through the cooperation of the TX interface circuit and the RX interface circuit, and the high-definition analog video signal is input to the Decoder chip, thereby improving the noise resistance, reliability and EMC performance of the AHL video transmission solution.

[0006] As a further improvement of the utility model, the TX interface circuit includes a TX noise reduction matching circuit, which is connected to the TX protection circuit; the TX noise reduction matching circuit includes a common mode inductor L3, and the 1st foot of the common mode inductor L3 is connected to the CAM1_AFE+ foot of the Encoder chip via the capacitor C1, and the 4th foot of the common mode inductor L3 is connected to the CAM1_AFE- foot of the Encoder chip via the capacitor C2, and the 2nd foot of the common mode inductor L3 is respectively connected to the 1st foot of the common mode inductor L4 and the 2nd foot of the socket J3, and the 3rd foot of the common mode inductor L3 is respectively It is connected to pin 3 of the common-mode inductor L4 and pin 3 of the socket J3, pin 1 of the socket J3 is connected to the 12V power supply and grounded via capacitor C9, pins 4, 5, 6, 7 and 8 of the socket J3 are connected and grounded; pin 2 of the common-mode inductor L4 is connected to one end of the capacitor C7, the other end of the capacitor C7 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R3 and grounded via resistor R6, the other end of the resistor R3 is connected to pin 4 of the common-mode inductor L4 via capacitor C8, and the REXT pin of the Decoder chip is grounded via resistor R4.

[0007] In this way, the common-mode and differential impedances of the common-mode inductor within the working range increase with the increase of frequency, so a special design method is adopted for L3 / L4 to reduce the impedance of the common-mode signal and increase the electrical impedance of the differential signal. AHL uses a current source output driver, so the common-mode inductor will increase the impedance of the parallel resistor, thereby generating a larger voltage signal to the cable, improving the signal transmission immunity, and reducing the common-mode noise, but does not affect the signal level.

[0008] As a further improvement of the present invention, the TX protection circuit includes an electrostatic protection tube TVS1, one end of the electrostatic protection tube TVS1 is connected to pin 1 of the common mode inductor L4, the other end of the electrostatic protection tube TVS1 is connected to one end of the electrostatic protection tube TVS2 and grounded, and the other end of the electrostatic protection tube TVS2 is connected to pin 3 of the common mode inductor L4.

[0009] In this way, electrostatic protection can be achieved through the electrostatic protection tube, which can suppress the effects of instantaneous overvoltage and surge pulse voltage, and avoid electromagnetic interference (EMI) that may be generated by equipment such as the ignition system, generator, and rectifier during operation.

[0010] As a further improvement of the present utility model, the RX interface circuit includes a socket J2, pins 1-8 of the socket J2 are respectively connected to pins 1-8 of the socket J3, pin 1 of the socket J2 is connected to the 12V power supply and grounded via capacitor C18, pins 4, 5, 6, 7 and 8 of the socket J2 are connected and grounded, the socket J2 is connected to the RX DC isolation protection circuit, and the RX DC isolation protection circuit is connected to the RX noise reduction matching circuit via the RX voltage divider interface circuit.

[0011] In this way, the RX interface circuit and the TX interface circuit are connected through the connection of the socket J2 and the socket J3, and the analog video signal is further processed by the RX DC isolation protection circuit, the RX voltage divider interface circuit and the RX noise reduction matching circuit, and then output to the Decoder chip.

[0012] As a further improvement of the present utility model, the RX DC blocking protection circuit includes an electrostatic protection tube TVS3, one end of which is respectively connected to pin 2 of the socket J2 and one end of the capacitor C3, the other end of which is respectively connected to one end of the electrostatic protection tube TVS4 and grounded, and the other end of which is respectively connected to pin 3 of the socket J2 and one end of the capacitor C6.

[0013] This isolates the DC current, thus preventing the DC current from the wiring harness from entering the interface and causing circuit damage.

[0014] As a further improvement of the present utility model, the RX voltage divider interface circuit includes a resistor R10, one end of the resistor R10 is connected to the other end of the capacitor C3, the other end of the resistor R10 is connected to one end of the resistor R12, the other end of the resistor R12 is connected to one end of the resistor R13 and grounded, the other end of the resistor R13 is connected to the other end of the resistor R11, and one end of the resistor R11 is connected to the other end of the capacitor C6.

[0015] Because the received signal level specifications may deviate from the standard, and different decoder chips have different requirements for input levels, adjust the resistance values ​​of R10, R11, R12, and R13DE according to the actual situation to meet the input level requirements of the matching receiving chip interface.

[0016] As a further improvement of the utility model, the RX noise reduction matching circuit includes a common-mode inductor L2, and pin 1 of the common-mode inductor L2 is respectively connected to the other end of the resistor 10 and pin 1 of the common-mode inductor L1, pin 2 of the common-mode inductor L2 is connected to one end of the capacitor C10, and the other end of the capacitor C10 is connected to one end of the resistor R5, and one end of the resistor R5 is connected to one end of the resistor R16 and grounded through the resistor R17, and the other end of the resistor R16 is connected to pin 4 of the common-mode inductor L2 through the capacitor C11, and pin 3 of the common-mode inductor L2 is respectively connected to the other end of the resistor R11 and pin 4 of the common-mode inductor L1, and pin 2 of the common-mode inductor L1 is connected to the RR_CAM1_AFE+ pin of the Decoder chip through the capacitor C5, and pin 3 of the common-mode inductor L1 is connected to the RR_CAM1_AFE- pin of the Decoder chip through the capacitor C12.

[0017] In this way, the impedance of the parallel resistor will be increased through the common mode inductor, thereby generating a larger voltage signal to the cable and improving the signal transmission immunity. Therefore, the common mode noise can be reduced by the coordination of inductors L1 and L2 without affecting the signal level. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the hardware block diagram of the utility model.

[0019] Figure 2 This is the schematic diagram of the TX interface of the AHL transmission link of the utility model.

[0020] Figure 3 This is the schematic diagram of the RX interface of the AHL transmission link of the utility model.

[0021] Figure 4 This is the AHL transmission link waveform and color burst signal diagram of the utility model. DETAILED DESCRIPTION

[0022] The utility model is further described below in conjunction with the accompanying drawings:

[0023] like Figure 1-3 The vehicle-mounted AHL analog high-definition noise reduction matching interface circuit shown includes a TX interface circuit, the input end of the TX interface circuit is connected to the Encoder chip, the output end of the TX interface circuit is connected to the RX interface circuit through a transmission line with a characteristic impedance of 100 ohms, and the RX interface circuit is connected to the Decoder chip.

[0024] The TX interface circuit includes a TX noise reduction matching circuit, which is connected to the TX protection circuit; the TX noise reduction matching circuit includes a common-mode inductor L3, pin 1 of the common-mode inductor L3 is connected to the CAM1_AFE+ pin of the Encoder chip via a capacitor C1, pin 4 of the common-mode inductor L3 is connected to the CAM1_AFE- pin of the Encoder chip via a capacitor C2, pin 2 of the common-mode inductor L3 is respectively connected to pin 1 of the common-mode inductor L4 and pin 2 of the socket J3, and pin 3 of the common-mode inductor L3 is respectively connected to pin 1 of the common-mode inductor L4 and pin 2 of the socket J3. Pin 3 of the common-mode inductor L4 is connected to pin 3 of the socket J3, pin 1 of the socket J3 is connected to the 12V power supply and grounded via capacitor C9, pins 4, 5, 6, 7 and 8 of the socket J3 are connected and grounded; pin 2 of the common-mode inductor L4 is connected to one end of the capacitor C7, the other end of the capacitor C7 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R3 and grounded via resistor R6, the other end of the resistor R3 is connected to pin 4 of the common-mode inductor L4 via capacitor C8, and the REXT pin of the Decoder chip is grounded via resistor R4.

[0025] The TX protection circuit includes an electrostatic protection tube TVS1, one end of which is connected to pin 1 of the common mode inductor L4, the other end of which is connected to one end of the electrostatic protection tube TVS2 and grounded, and the other end of which is connected to pin 3 of the common mode inductor L4. The RX interface circuit includes a socket J2, pins 1-8 of which are respectively connected to pins 1-8 of the socket J3, pin 1 of the socket J2 is connected to a 12V power supply and grounded via capacitor C18, pins 4, 5, 6, 7 and 8 of the socket J2 are connected and grounded, and the socket J2 is connected to the RX DC isolation protection circuit, which is connected to the RX noise reduction matching circuit via the RX voltage divider interface circuit.

[0026] The RX DC isolation protection circuit includes an electrostatic protection tube TVS3, one end of which is connected to pin 2 of the socket J2 and one end of the capacitor C3, the other end of which is connected to one end of the electrostatic protection tube TVS4 and grounded, and the other end of which is connected to pin 3 of the socket J2 and one end of the capacitor C6. The RX voltage divider interface circuit includes a resistor R10, one end of which is connected to the other end of the capacitor C3, the other end of which is connected to one end of the resistor R12, the other end of which is connected to one end of the resistor R13 and grounded, the other end of which is connected to the other end of the resistor R11, and one end of which is connected to the other end of the capacitor C6.

[0027] The RX noise reduction matching circuit includes a common-mode inductor L2, wherein pin 1 of the common-mode inductor L2 is respectively connected to the other end of the resistor 10 and pin 1 of the common-mode inductor L1, pin 2 of the common-mode inductor L2 is connected to one end of the capacitor C10, the other end of the capacitor C10 is connected to one end of the resistor R5, one end of the resistor R5 is connected to one end of the resistor R16 and is grounded via the resistor R17, the other end of the resistor R16 is connected to pin 4 of the common-mode inductor L2 via the capacitor C11, pin 3 of the common-mode inductor L2 is respectively connected to the other end of the resistor R11 and pin 4 of the common-mode inductor L1, pin 2 of the common-mode inductor L1 is connected to the RR_CAM1_AFE+ pin of the decoder chip via the capacitor C5, and pin 3 of the common-mode inductor L1 is connected to the RR_CAM1_AFE- pin of the decoder chip via the capacitor C12.

[0028] In the utility model, since CCH is very sensitive to noise, common-mode inductors L3 and L4 are used to reduce common-mode noise: common-mode inductors are devices that have higher impedance to common-mode signals and lower impedance to differential signals. Since the common-mode and differential impedances of the inductor device within the working range increase with increasing frequency, the combination of L3 / L4 reduces the impedance of the common-mode signal and increases the electrical impedance of the differential signal. AHL uses a current source output driver, so the common-mode inductor will increase the impedance of the parallel resistor, thereby generating a larger voltage signal to the cable and improving the signal transmission anti-interference performance. In summary, the combination of L3 and L4 can reduce common-mode noise without affecting the signal level.

[0029] After repeated calculations, tests and debugging, the conventional 100 ohm (characteristic impedance) wiring harness is matched: L3 uses the model DLW32MH201XK2L; L4 uses the model SRF2012-300YA; C7 and C8 use 4.7uF capacitors; R1 and R3 use 42.2Ω1% resistors; R6 uses 41.2Ω1% resistors; to achieve the best effect. The internal DC blocking capacitors take into account the AHL frequency characteristics, and C1 and C2 use 100nF.

[0030] TX drive current setting: AHL uses a current source output driver, set R4=4.7K, according to the internal calculation of the TX chip, the output drive current Imax=16mA

[0031] TX protection circuit: The vehicle-mounted electromagnetic environment is complex, and there are a variety of electrical equipment and systems, such as the ignition system, generator, rectifier, etc. These devices may generate electromagnetic interference (EMI) when working, so a protection circuit is necessary. The electrostatic protection tube is set to achieve electrostatic protection and suppress instantaneous overvoltage and surge pulse voltage.

[0032] The TX interface receives 12V power from the host and sets the power filter capacitor C9 to 100nF.

[0033] The principle of the RX protection circuit is the same as that of the TX protection circuit. The internal DC blocking capacitors C5 and C12 of RX are 100nF. The external DC blocking capacitors of RX need to prevent the DC power of the wiring harness from entering the interface and causing damage to the circuit. This capacitor plays a role in stabilizing the voltage at the interface and can absorb fluctuating voltage to stabilize the circuit voltage. Nf-level capacitors have a small capacitance and a limited amount of charge absorbed, which leads to large fluctuations in the circuit voltage and affects the stability of the circuit. uF-level capacitors can store more charge and provide better stability. Therefore, Nf-level capacitors are selected. The capacitance value needs to take into account the high-frequency characteristics of the capacitor, which causes the distortion and loss of the video transmission waveform. C3 and C6 use 4.7uF capacitors. The design highlights are as follows:

[0034] Currently there are four types of AHL signals: 720P@25fps, 720P@30fps, 1080P@25fps, 1080P@30fps, among which the lowest transmission frequency (720P@25fps) is:

[0035] H total=1980 (1280+700); V total=750 (1720+730);

[0036] CLK=1980*750*25=37.125MHz; maximum transmission frequency (1080P@30fps);

[0037] H total=2200 (1920+280); V total=1125 (1080+45)

[0038] CLK=2200*1125*30=74.25MHz

[0039] Z = 1 / (2πfC); where: Z is the impedance of the capacitor (ohms); f is the frequency (Hz); C is the capacitance value (farads)

[0040] At 20.0 MHz, the impedance of a 4.7uF capacitor is: 0.17 ohms

[0041] At 30.0 MHz, the impedance of a 4.7uF capacitor is: 0.11 ohms

[0042] At 40.0 MHz, the impedance of a 4.7uF capacitor is: 0.08 ohms

[0043] At 50.0 MHz, the impedance of a 4.7uF capacitor is: 0.11 ohms

[0044] At 100.0 MHz, the impedance of a 4.7uF capacitor is: 0.06 ohms

[0045] At 150.0 MHz, the impedance of a 4.7uF capacitor is: 0.04 ohms

[0046] As the frequency increases, the impedance of the capacitor gradually decreases;

[0047] From the above data, it can be seen that the effect of the DC blocking capacitor on the 100-ohm characteristic impedance transmission line is negligible; in the actual video test, the test video display effect, before and after adding the capacitor, is consistent with the theoretical calculation.

[0048] RX voltage divider circuit: Since the received signal level specifications may deviate from the standard, different decoders have different requirements for input levels. Therefore, a voltage divider circuit needs to be designed to match the interface requirements of the receiving chip. The resistance values ​​of R10, R11, R12, and R13 can be adjusted according to actual conditions.

[0049] RX noise reduction matching circuit: L1 uses model DLW32MH201XK2L; L2 uses model SRF2012-300YA; C10 and C11 use 4.7uF capacitors; R5 and R16 use 42.2Ω1% resistors; R17 uses 41.2Ω1% resistors; to achieve the best effect.

[0050] RX power output: output camera 12V power supply, set the power filter capacitor C18 = 100nF.

[0051] In actual use, the Encoder chip sends out an AHL analog video signal, which is isolated from the DC level by capacitors C1 and C2. The video signal then passes through inductors L3 and L4 to reduce common-mode noise, increasing the impedance of parallel resistors R1 and R3, thereby outputting a stronger voltage signal, providing signal transmission resistance and not affecting the signal level.

[0052] After the noise reduction processing of the TX interface circuit, the video signal is input from the socket J3 to the socket J2 through the wiring harness, and then enters the RX interface circuit. The video signal is processed by the isolated DC power of capacitors C3 and C6 to prevent the DC power of the wiring harness from entering the interface and causing circuit damage. After that, the video signal is divided by resistors R10, R11, R12, and R13 to obtain the voltage signal required by the Decoder chip. The signal is then reduced by inductors L1 and L2 to reduce common-mode noise, and the impedance of parallel resistors R1 and R3 is increased, thereby outputting a voltage signal with greater intensity. Finally, after the isolation DC level processing of external DC blocking capacitors C5 and C12, the final analog high-definition video signal after a series of noise reduction processing is output to the Decoder chip.

[0053] Take the color burst signal level threshold design as an example to explain it in detail. Figure 4 As shown:

[0054] Theoretical color burst signal design level 40±2 IRE (271.32~285.60~299.88mVp-p)

[0055] Where: 1IRE=7.14mV, 100% white level is defined as 100IRE

[0056] When the color burst signal is lower than the Decoder color kill detection threshold, the image will change from color to black and white. Based on the color burst threshold monitoring of multiple cameras on the market and the worst case statistics combined with the wiring harness specifications (some examples):

[0057] Camera module 1: 238.7mVp-p, circuit attenuation 4.1mVp-p, interface 242.8mVp-p;

[0058] Camera module 2: 209.5mVp-p, circuit attenuation 4.7mVp-p, interface 214.2mVp-p;

[0059] Based on the data, considering the reserved error margin, the detection threshold is set to -32% according to the chip specifications:

[0060] 40±2IRE=285.6±14.28 mVp-p; the lowest set threshold is: (285.6-14.28) mVp-p * (1-32%) = 184.5 mVp-p; meets the worst case in the statistical data.

[0061] This utility model is used for the vehicle-mounted AHL video transmission solution, which is composed of common common-mode inductors, resistors, capacitors, TVS tubes and other passive components. While maintaining low cost, it improves the noise resistance, reliability and EMC performance of the AHL video transmission solution, ensuring that the AHL video transmission solution achieves the following advantages:

[0062] It can realize high-definition display such as 720P@30fps and 1080P@30fps; it can control the signal compression and transparent transmission function to realize remote control diagnosis; it can reduce the cost of automotive cables and connectors by about 30%, making the wiring harness cost better; the quality performance is better: the image quality will not cause screen flickering due to signal disconnection; it can ensure 30M quality assurance under the condition of using control channel, making the increasingly complex automotive wiring more flexible and reliable.

[0063] The present utility model is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed herein, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present utility model.

Claims

1. A vehicle-mounted AHL analog high-definition noise reduction matching interface circuit, characterized in that: It includes a TX interface circuit, the input end of the TX interface circuit is connected to the Encoder chip, the output end of the TX interface circuit is connected to the RX interface circuit through a transmission line with a characteristic impedance of 100 ohms, and the RX interface circuit is connected to the Decoder chip.

2. The vehicle-mounted AHL analog high-definition noise reduction matching interface circuit according to claim 1, characterized in that: The TX interface circuit includes a TX noise reduction matching circuit, which is connected to the TX protection circuit; the TX noise reduction matching circuit includes a common mode inductor L3, wherein pin 1 of the common mode inductor L3 is connected to the CAM1_AFE+ pin of the encoder chip via the capacitor C1, and pin 4 of the common mode inductor L3 is connected to the CAM1_AFE- pin of the encoder chip via the capacitor C2, and pin 2 of the common mode inductor L3 is respectively connected to pin 1 of the common mode inductor L4 and pin 2 of the socket J3, and pin 3 of the common mode inductor L3 is respectively connected to pin 3 of the common mode inductor L4 and pin 3 of the socket J3, and pin 1 of the socket J3 is connected to a 12V power supply and grounded via the capacitor C9, and pins 4, 5, 6, 7 and 8 of the socket J3 are connected and grounded; Pin 2 of the common-mode inductor L4 is connected to one end of the capacitor C7, the other end of the capacitor C7 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the resistor R3 and is grounded via the resistor R6, the other end of the resistor R3 is connected to pin 4 of the common-mode inductor L4 via the capacitor C8, and the REXT pin of the decoder chip is grounded via the resistor R4.

3. The vehicle-mounted AHL analog high-definition noise reduction matching interface circuit according to claim 2, characterized in that: The TX protection circuit includes an electrostatic protection tube TVS1, one end of which is connected to pin 1 of the common mode inductor L4, the other end of which is connected to one end of the electrostatic protection tube TVS2 and grounded, and the other end of which is connected to pin 3 of the common mode inductor L4.

4. The vehicle-mounted AHL analog high-definition noise reduction matching interface circuit according to claim 3, characterized in that: The RX interface circuit includes a socket J2, pins 1-8 of the socket J2 are respectively connected to pins 1-8 of the socket J3, pin 1 of the socket J2 is connected to a 12V power supply and grounded via a capacitor C18, pins 4, 5, 6, 7 and 8 of the socket J2 are connected and grounded, the socket J2 is connected to the RX DC isolation protection circuit, and the RX DC isolation protection circuit is connected to the RX noise reduction matching circuit via the RX voltage divider interface circuit.

5. The vehicle-mounted AHL analog high-definition noise reduction matching interface circuit according to claim 4, characterized in that: The RX DC blocking protection circuit includes an electrostatic protection tube TVS3, one end of which is respectively connected to pin 2 of the socket J2 and one end of the capacitor C3, the other end of which is connected to one end of the electrostatic protection tube TVS4 and grounded, and the other end of which is respectively connected to pin 3 of the socket J2 and one end of the capacitor C6.

6. The vehicle-mounted AHL analog high-definition noise reduction matching interface circuit according to claim 5, characterized in that: The RX voltage divider interface circuit includes a resistor R10, one end of the resistor R10 is connected to the other end of the capacitor C3, the other end of the resistor R10 is connected to one end of the resistor R12, the other end of the resistor R12 is connected to one end of the resistor R13 and grounded, the other end of the resistor R13 is connected to the other end of the resistor R11, and one end of the resistor R11 is connected to the other end of the capacitor C6.

7. The vehicle-mounted AHL analog high-definition noise reduction matching interface circuit according to claim 6, characterized in that: The RX noise reduction matching circuit includes a common-mode inductor L2, wherein pin 1 of the common-mode inductor L2 is respectively connected to the other end of the resistor 10 and pin 1 of the common-mode inductor L1, pin 2 of the common-mode inductor L2 is connected to one end of the capacitor C10, the other end of the capacitor C10 is connected to one end of the resistor R5, one end of the resistor R5 is connected to one end of the resistor R16 and is grounded via the resistor R17, the other end of the resistor R16 is connected to pin 4 of the common-mode inductor L2 via the capacitor C11, pin 3 of the common-mode inductor L2 is respectively connected to the other end of the resistor R11 and pin 4 of the common-mode inductor L1, pin 2 of the common-mode inductor L1 is connected to the RR_CAM1_AFE+ pin of the decoder chip via the capacitor C5, and pin 3 of the common-mode inductor L1 is connected to the RR_CAM1_AFE- pin of the decoder chip via the capacitor C12.

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