Image transmission circuit of SD card to network port and wireless camera thereof
Patent Information
- Application Number
- CN202522270928.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-27
- Publication Date
- 2026-10-09
- Estimated Expiration
- 2035-10-27
AI Technical Summary
[0004]针对上述技术问题，本实用新型实施例提供了一种SD卡转网口的图像传输电路及其无线摄像头，以解决现有无线网络无线摄像头无线传输时因干扰影响图像质量的问题
[0017]本实用新型实施例提供的技术方案中，SD卡转网口的图像传输电路，设置在无线摄像头的壳体内，所述图像传输电路包括SD卡插接件、主控模块和转换模块；所述主控模块连接SD卡插接件和转换模块，SD卡插接件10内插有SD卡，转换模块通过网线连接控制端；所述SD卡插接件将SD卡内存储的无线摄像头的图像数据传输给主控模块，主控模块将所述图像数据实时打包并传输给转换模块，所述转换模块将打包后的图像数据转换为网络信号后通过网线上传给控制端。选择有线网络替代现有无线网络进行数据传输，能避免无线网络的干扰；SD卡具备较大的存储空间；通过SD卡转网口图像传输，结合无线摄像头和有线网络，即可解决现有无线网络无线摄像头无线传输时因干扰影响图像质量的问题。
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Figure CN224843895U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic technology, and in particular to an SD card to Ethernet port image transmission circuit and its wireless camera. Background Technology
[0002] With the increasing prevalence of wireless surveillance cameras, more and more wireless cameras are being widely used in security monitoring, home monitoring, smart homes, and other fields. However, due to the susceptibility of wireless networks to environmental interference and signal instability, image data transmission from wireless cameras is often delayed or packet loss occurs frequently. Especially in high-interference environments, interference during transmission can cause image delays and loss, often compromising the image transmission quality of wireless cameras, thus affecting monitoring effectiveness and causing problems for surveillance applications.
[0003] Therefore, existing technologies still need to be improved and enhanced. Utility Model Content
[0004] To address the aforementioned technical problems, this utility model provides an SD card to Ethernet port image transmission circuit and its wireless camera, thereby solving the problem of image quality being affected by interference during wireless transmission of existing wireless network cameras.
[0005] This utility model embodiment provides an SD card to Ethernet port image transmission circuit, which is installed inside the housing of a wireless camera. The image transmission circuit includes an SD card connector, a main control module, and a conversion module. The main control module connects the SD card connector and the conversion module. An SD card is inserted into the SD card connector 10, and the conversion module is connected to the control terminal via an Ethernet cable.
[0006] The SD card connector transmits the image data from the wireless camera stored on the SD card to the main control module. The main control module packages the image data in real time and transmits it to the conversion module. The conversion module converts the packaged image data into a network signal and then transmits it to the control terminal via a network cable.
[0007] Optionally, in the SD card to Ethernet image transmission circuit, the SD card connector is disposed in the SD card slot of the wireless camera, and the ribbon cable interface at one end of the FFC cable on the SD card connector is electrically connected to the main control module.
[0008] Optionally, in the SD card to Ethernet image transmission circuit, the main control module includes a main control chip. The MTMS, MTDI, MTCK, MTDO, GPIO2, and GPIO4 pins of the main control chip are connected one-to-one with pins 11, 7, 8, 9, 13, and 14 of the ribbon cable interface. The GPIO25, GPIO26, GPIO27, GPIO0, GPIO5, GPIO18, GPIO23, GPIO19, GPIO22, and GPIO21 pins of the main control chip are all connected to the conversion module.
[0009] Optionally, in the SD card to Ethernet image transmission circuit, the main control module further includes a first resistor, a first capacitor, and a button interface;
[0010] One end of the first resistor is connected to one end of the first capacitor, the CHIP_PU pin of the main control chip, and pins 1 and 2 of the button interface; the other end of the first resistor is connected to the power supply terminal; the other end of the first capacitor, pins 3 and 4 of the button interface are all grounded.
[0011] Optionally, in the SD card to Ethernet image transmission circuit, the main control module further includes an antenna, a first inductor, a second inductor, a second capacitor, and a third capacitor;
[0012] The antenna's third pin is connected to one end of the first inductor and one end of the second inductor. The antenna's first and second pins are grounded. The other end of the first inductor is connected to one end of the third capacitor and the LNA_IN pin of the main control chip. The other end of the second inductor is grounded through the second capacitor, and the other end of the third capacitor is grounded.
[0013] Optionally, in the SD card to Ethernet image transmission circuit, the conversion module includes a PHY chip, a network interface, and a filtering circuit; the TRXN0, TRXP0, TRXN1, and TRXP1 pins of the PHY chip are all connected to the input of the filtering circuit; the RESET_N, TX_EN, TXD1, TXD0, TXC, RXD1, RXD0, CRS / CRS_DV, MDC, and MDIO pins of the PHY chip are connected one-to-one with the GPIO5, GPIO21, GPIO22, GPIO19, GPIO0, GPIO26, GPIO25, GPIO27, GPIO23, and GPIO18 pins of the main control chip; the output of the filtering circuit is connected to the network interface.
[0014] Optionally, in the SD card to Ethernet image transmission circuit, the filtering circuit includes a first filter, a second filter, a third filter, a fourth filter, a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh capacitor; pin 4 of the first filter is connected to pin TRXN1 of the PHY chip through the fourth capacitor, pin 1 of the first filter is connected to pin TRXP1 of the PHY chip through the fifth capacitor, pin 3 of the first filter is connected to pin 3 of the second filter and pin TX+ of the network interface, pin 2 of the first filter is connected to pin 1 of the second filter and pin TX- of the network interface, pins 2 and 4 of the second filter are both grounded, pin 4 of the third filter is connected to pin TRXN0 of the PHY chip through the sixth capacitor, pin 1 of the third filter is connected to pin TRXP0 of the PHY chip through the seventh capacitor, pin 3 of the third filter is connected to pin 3 of the fourth filter and pin RX+ of the network interface, pin 2 of the third filter is connected to pin 1 of the fourth filter and pin RX- of the network interface, pins 2 and 4 of the fourth filter are both grounded.
[0015] A second aspect of this utility model provides a wireless camera, including a housing, within which a circuit board is disposed, wherein the circuit board integrates the aforementioned SD card to Ethernet image transmission circuit; the image transmission circuit is connected to a control terminal via a network cable;
[0016] The image transmission circuit acquires image data from the wireless camera in real time from the SD card, converts the image data into a network signal, and then uploads it to the control terminal via a wired network cable.
[0017] In the technical solution provided by this utility model embodiment, an SD card to Ethernet image transmission circuit is installed inside the housing of a wireless camera. The image transmission circuit includes an SD card connector, a main control module, and a conversion module. The main control module connects the SD card connector and the conversion module. An SD card is inserted into the SD card connector 10, and the conversion module is connected to a control terminal via an Ethernet cable. The SD card connector transmits the image data from the wireless camera stored on the SD card to the main control module. The main control module packages the image data in real time and transmits it to the conversion module. The conversion module converts the packaged image data into a network signal and then transmits it to the control terminal via the Ethernet cable. Choosing a wired network instead of the existing wireless network for data transmission avoids interference from the wireless network. The SD card has a large storage capacity. By using an SD card to Ethernet port for image transmission, combined with a wireless camera and a wired network, the problem of image quality being affected by interference during wireless transmission by a wireless camera in existing wireless networks can be solved. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the image transmission circuit for converting an SD card to a network port in an embodiment of this utility model.
[0019] Figure 2 This is a circuit diagram of the SD card connector in an embodiment of this utility model.
[0020] Figure 3 This is a partial circuit diagram of the main control module in an embodiment of this utility model.
[0021] Figure 4 This is another part of the circuit diagram of the main control module in this embodiment of the present invention.
[0022] Figure 5 This is a partial circuit diagram of the conversion module in an embodiment of this utility model.
[0023] Figure 6 This is another part of the circuit diagram of the conversion module in this embodiment of the present invention. Detailed Implementation
[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments of the present utility model obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.
[0025] It is readily understood that relational terms such as "first" and "second" are used merely to distinguish one entity, operation, or direction from another, without requiring or implying any actual relationship or order between these entities, operations, or directions. The directional terms such as "up," "down," "left," "right," "front," "back," "front," "back," "top," and "bottom," mentioned or possibly used in this specification, are defined relative to the constructions shown in the accompanying drawings. They are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be construed as restrictive. In the following description, various parameters and components are described for embodiments of different constructions. These specific parameters and components are merely examples and do not limit the embodiments of this application.
[0026] Please also refer to Figures 1 to 6 This utility model provides a wireless camera, including a housing. A circuit board is disposed within the housing, and the circuit board integrates an SD card to Ethernet image transmission circuit. The image transmission circuit is connected to a control terminal (such as a PC) via an Ethernet cable. The image transmission circuit acquires image data from the wireless camera in real time from the SD card, converts the image data into a network signal, and then uploads it to the control terminal via a wired network.
[0027] To address the issue of image data transmission delays and losses caused by environmental electromagnetic interference in wireless cameras, a wired network transmission method is used to avoid wireless network interference. SD cards, a common storage medium in wireless cameras, offer ample storage space for image data. By using an SD card-to-Ethernet adapter for image transmission, combined with the wireless camera and wired network, the problem of image delays and losses caused by interference is solved. Transmitting data via wired network, instead of wireless network, fundamentally resolves the issue of unstable image transmission in complex wireless environments. The wired network ensures the stability, real-time nature, and timeliness of image information transmission.
[0028] In this embodiment, the image transmission circuit includes an SD card connector 10, a main control module 20, and a conversion module 30. The main control module 20 connects the SD card connector 10 and the conversion module 30. The SD card connector 10 contains an SD card, and the conversion module 30 is connected to the control terminal via a network cable. The SD card connector 10 transmits image data from the wireless camera to the main control module 20. The main control module 20 packages the image data in real time and transmits it to the conversion module 30. The conversion module 30 converts the packaged image data into a network signal and then transmits it to the control terminal via the network cable.
[0029] The SD card connector 10 is located in the SD card slot of the wireless camera. It is used to insert an SD card and is electrically connected to the main control chip (MCU) in the main control module 20 via an FFC (Flexible Flat Cable) ribbon cable on the SD card connector 10. The circuit connecting the ribbon cable interface J1 at one end of the FFC ribbon cable to the main control module 20 is as follows. Figure 2 As shown, the four data pins (pins 7, 8, 13, and 14), the control pin (pin 9), and the clock pin (pin 11) of the ribbon cable interface J1 are all connected to the main control module 20; the power pin (pin 10) is connected to the power supply terminal (providing VDD3V3 voltage).
[0030] The SD card connector 10 allows the wireless camera to write image data to the SD card for storage in real time, and simultaneously transmits image data to the main control chip for further processing and transmission via an FFC cable. The SD_D0 to D3 signals are used to transmit image data, the SD_CMD signal is used to send commands and receive responses, and the SD_CLK signal is used to input the clock signal. The FFC cable adopts the SDIO (Secure Digital Input / Output) four-wire protocol, a highly efficient serial data transmission protocol that enables high-speed data read and write operations, ensuring rapid data transmission between the wireless camera and the main control chip. The four-wire protocol improves signal transmission stability and anti-interference capabilities, making it suitable for high-quality image transmission requirements.
[0031] In practical implementation, the four data pins, control pin, clock pin, and power pin can each be connected to the main control module 20 via a 0Ω resistor; the 0Ω resistor on the clock pin can also be grounded via a filter capacitor. To avoid misreading or writing caused by pulse signals, the 0Ω resistors on the four data pins and control pin can each be connected in series with a 10KΩ pull-up resistor to the power supply terminal.
[0032] like Figure 3 and Figure 4 As shown, the main control module 20 includes a main control chip U1, preferably of model ESP32-D0WDQ6-V3. The MTMS, MTDI, MTCK, MTDO, GPIO2, and GPIO4 pins of the main control chip U1 are connected one-to-one with pins 11, 7, 8, 9, 13, and 14 of the ribbon cable interface J1. The GPIO25, GPIO26, GPIO27, GPIO0, GPIO5, GPIO18, GPIO23, GPIO19, GPIO22, and GPIO21 pins of the main control chip U1 are all connected to the conversion module 30.
[0033] In this embodiment, the main control chip U1 serves as the core controller of the entire system. It reads image data from the SD card via the SD card connector 10 and performs corresponding processing (communication is transmitted via SD_D0~D3 signals, SD_CMD signal, and SD_CLK signal). The main control chip U1 transmits the real-time wireless camera data stream (i.e., image data) to the RMII (Reduced Media Independent Interface) protocol according to data processing requirements to ensure that the image data can be transmitted stably and efficiently in sequence through the wired network. The packaged image data is then transmitted to the PHY chip (physical layer chip) U2 in the conversion module 30 (the communication signals include RMII_TX_EN1, RMII_TXD11, RMII_TXD01, RMII_CLK1, RMII_RXD11, RMII_RXD01, RMII_CRS_DV, MDCK1, MDIO1, and PHY_REST1 signals). This allows image data to be transmitted from a wireless camera to a PC via a wired network in real time with low latency for display or storage.
[0034] Preferably, such as Figure 4 As shown, GPIO pins 25, 26, 27, 5, 18, 23, 19, 22, and 21 of the main control chip U1 can be connected to the conversion module 30 via a 0Ω resistor; GPIO pin 0 of the main control chip U1 is connected to the conversion module 30 via a 33Ω resistor; the signal names on each pin change accordingly after the resistors are connected (specifically as shown in the diagram). Figure 4 (As shown). These resistors serve to protect against short circuits and prevent interference, ensuring the accuracy and stability of signal transmission between the resistors and the conversion module 30.
[0035] The main control chip U1 can also be externally reset via a button interface. Therefore, the main control module 20 further includes a first resistor R1, a first capacitor C1, and a button interface J2. One end of the first resistor R1 is connected to one end of the first capacitor C1, the CHIP_PU pin of the main control chip U1, and pins 1 and 2 of the button interface J2. The other end of the first resistor R1 is connected to the power supply. The other end of the first capacitor C1, and pins 3 and 4 of the button interface J2 are all grounded. Upon power-up, R1 charges C1, generating an EN signal that changes from low to high for reset. Pressing the button on the button interface J2 lowers the EN signal, releasing the charge stored in C1. Recharging again resets the capacitor.
[0036] In practical implementation, the main control chip U1 can also receive wireless signals by connecting an antenna. The main control module 20 further includes an antenna ANT (preferably ANT3X3-HT1_15_P3), a first inductor L1, a second inductor L2, a second capacitor C2, and a third capacitor C3. Pin 3 of the antenna ANT is connected to one end of the first inductor L1 and one end of the second inductor L2. Pins 1 and 2 of the antenna ANT are grounded. The other end of the first inductor L1 is connected to one end of the third capacitor C3 and the LNA_IN pin of the main control chip. The other end of the second inductor L2 is grounded through the second capacitor C2, and the other end of the third capacitor C3 is grounded. L1, L2, C2, and C3 form an impedance matching circuit at the chip level. The weak signal input to the LNA_IN pin (the input of the low-noise amplifier inside U1) is amplified, and the external transmission noise is reduced by the low-noise amplifier inside U1.
[0037] The clock signals (XTAL_N and XTAL_P signals) of the main control chip U1 are implemented by a circuit consisting of a crystal oscillator Y and two capacitors and a resistor, which is existing technology. Each pin of the main control chip U1 connected to the power supply (including the VDDA, VDD3P3_RTC, VDD_SDIO, and VDD3P3_CPU pins) can be grounded through a filter capacitor to increase power supply stability.
[0038] like Figure 5 and Figure 6 As shown, the conversion module 30 includes a PHY chip U2, a network interface J3 (i.e., an RJ45 interface), and a filter circuit 31. The TRXN0, TRXP0, TRXN1, and TRXP1 pins of the PHY chip U2 are all connected to the input of the filter circuit 31. The RESET_N, TX_EN, TXD1, TXD0, TXC, RXD1, RXD0, CRS / CRS_DV, MDC, and MDIO pins of the PHY chip U2 are connected one-to-one with the GPIO5, GPIO21, GPIO22, GPIO19, GPIO0, GPIO26, GPIO25, GPIO27, GPIO23, and GPIO18 pins of the main control chip U1. The output of the filter circuit 31 is connected to the network interface J3.
[0039] In this embodiment, the PHY chip U2 converts the digital signal sent by the main control chip U1 into an analog network signal that meets the requirements of network transmission. This signal is then coupled to the network interface J3 via a transformer within the filter circuit 31, allowing the network signal to be transmitted to the wired network (network cable). The PHY chip supports the RMII protocol, enabling efficient data transmission and reception, ensuring a smooth data flow from the wireless camera to the wired network, and protecting the signal from wireless interference.
[0040] The filtering circuit 31 includes a first filter LC1, a second filter LC2, a third filter LC3, a fourth filter LC4, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, and a seventh capacitor C7. Pin 4 of the first filter LC1 is connected to pin TRXN1 of the PHY chip U2 via capacitor C4; pin 1 of the first filter LC1 is connected to pin TRXP1 of the PHY chip U2 via capacitor C5; pin 3 of the first filter LC1 is connected to pin 3 of the second filter LC2 and pin TX+ of the network interface J3; and pin 2 of the first filter LC1 is connected to pin 2 of the second filter LC2. The first pin of the third filter LC3 is connected to the TX- pin of the network interface J3. The second and fourth pins of the second filter LC2 are both grounded. The fourth pin of the third filter LC3 is connected to the TRXN0 pin of the PHY chip U2 through the sixth capacitor C6. The first pin of the third filter LC3 is connected to the TRXP0 pin of the PHY chip U2 through the seventh capacitor C7. The third pin of the third filter LC3 is connected to the third pin of the fourth filter LC4 and the RX+ pin of the network interface J3. The second pin of the third filter LC3 is connected to the first pin of the fourth filter LC4 and the RX- pin of the network interface J3. The second and fourth pins of the fourth filter LC4 are both grounded.
[0041] The first filter LC1 and the third filter LC3 are preferably WCM2012F2SF-801-N common-mode filters, used to reduce common-mode interference and improve signal quality. The second filter LC2 and the fourth filter LC4 are preferably DCM321620F2SF-600T02 two-channel surface-mount common-mode filters, used to reduce electromagnetic interference. In specific implementations, a TVS diode (transient voltage suppressor) can be connected between pins 1 and 4 of the first filter LC1 and between pins 1 and 4 of the third filter LC3 for overvoltage and electrostatic discharge protection.
[0042] The network interface is an RJ45 interface, which connects to the PC via a network cable; the signal can then be transmitted from the PHY chip U2 to the PC via the wired network. The use of a wired network effectively avoids the impact of wireless network interference on image transmission, ensuring data stability. This wired network is preferably a Local Area Network (LAN), but other forms of wired internet can also be used. Data signals are transmitted faster and with lower latency in wired networks, making them suitable for real-time transmission of large amounts of data such as images and videos.
[0043] In practical implementation, the main control module 20 and conversion module 30 in the image transmission circuit can be separated into an independent module or device, while the SD card connector 10 is still located in the SD card slot of the wireless camera. This module or device is connected via an FFC cable. This expands the application range of the image transmission circuit.
[0044] In summary, the SD card to Ethernet image transmission circuit and its wireless camera provided by this invention combine a wireless camera with the SD card to Ethernet image transmission circuit, using a wired network to replace existing wireless transmission. This results in more stable and faster signal transmission, avoids wireless network interference, and ensures the stability, reliability, and real-time performance of data transmission. Using an RJ45 interface to transmit data to the wired network ensures stable image data transmission, unaffected by wireless signal fluctuations.
[0045] The SD card and the main control chip use efficient SDIO four-wire communication, providing high-speed data transmission. Its simple hardware implementation reduces system complexity and ensures efficient data exchange between the SD card and the main control chip. It can be applied to various wireless cameras and transmission devices, exhibiting strong versatility.
[0046] The main control chip and the PHY chip communicate using the RMII protocol. Through simplified hardware connections, high-speed and stable data transmission is achieved. Data can be seamlessly transmitted between the MCU and the PHY, ensuring the real-time performance and stability of image data, effectively reducing latency, and guaranteeing efficient data transmission.
[0047] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. An SD card to Ethernet port image transmission circuit, disposed within the housing of a wireless camera, characterized in that, The image transmission circuit includes an SD card connector, a main control module, and a conversion module; the main control module connects the SD card connector and the conversion module, the SD card connector contains an SD card, and the conversion module is connected to the control terminal via a network cable; The SD card connector transmits the image data from the wireless camera stored on the SD card to the main control module. The main control module packages the image data in real time and transmits it to the conversion module. The conversion module converts the packaged image data into a network signal and then transmits it to the control terminal via a network cable.
2. The SD card to Ethernet image transmission circuit according to claim 1, characterized in that, The SD card connector is installed in the SD card slot of the wireless camera, and the FFC cable connector on the SD card connector is electrically connected to the main control module.
3. The SD card to Ethernet image transmission circuit according to claim 2, characterized in that, The main control module includes a main control chip. The MTMS, MTDI, MTCK, MTDO, GPIO2, and GPIO4 pins of the main control chip are connected one-to-one with pins 11, 7, 8, 9, 13, and 14 of the ribbon cable interface. The GPIO25, GPIO26, GPIO27, GPIO0, GPIO5, GPIO18, GPIO23, GPIO19, GPIO22, and GPIO21 pins of the main control chip are all connected to the conversion module.
4. The SD card to Ethernet image transmission circuit according to claim 3, characterized in that, The main control module also includes a first resistor, a first capacitor, and a button interface; One end of the first resistor is connected to one end of the first capacitor, the CHIP_PU pin of the main control chip, and pins 1 and 2 of the button interface; the other end of the first resistor is connected to the power supply terminal; the other end of the first capacitor, pins 3 and 4 of the button interface are all grounded.
5. The SD card to Ethernet image transmission circuit according to claim 4, characterized in that, The main control module also includes an antenna, a first inductor, a second inductor, a second capacitor, and a third capacitor; The antenna's third pin is connected to one end of the first inductor and one end of the second inductor. The antenna's first and second pins are grounded. The other end of the first inductor is connected to one end of the third capacitor and the LNA_IN pin of the main control chip. The other end of the second inductor is grounded through the second capacitor, and the other end of the third capacitor is grounded.
6. The SD card to Ethernet image transmission circuit according to claim 3 or 5, characterized in that, The conversion module includes a PHY chip, a network interface, and a filtering circuit. The TRXN0, TRXP0, TRXN1, and TRXP1 pins of the PHY chip are all connected to the input of the filtering circuit. The RESET_N, TX_EN, TXD1, TXD0, TXC, RXD1, RXD0, CRS / CRS_DV, MDC, and MDIO pins of the PHY chip are connected one-to-one with the GPIO5, GPIO21, GPIO22, GPIO19, GPIO0, GPIO26, GPIO25, GPIO27, GPIO23, and GPIO18 pins of the main control chip. The output of the filtering circuit is connected to the network interface.
7. The SD card to Ethernet image transmission circuit according to claim 6, characterized in that, The filtering circuit includes a first filter, a second filter, a third filter, a fourth filter, a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh capacitor. The fourth pin of the first filter is connected to the TRXN1 pin of the PHY chip via the fourth capacitor; the first pin of the first filter is connected to the TRXP1 pin of the PHY chip via the fifth capacitor; the third pin of the first filter is connected to the third pin of the second filter and the TX+ pin of the network interface; the second pin of the first filter is connected to the first pin of the second filter and the TX- pin of the network interface; both the second and fourth pins of the second filter are grounded; the fourth pin of the third filter is connected to the TRXN0 pin of the PHY chip via the sixth capacitor; the first pin of the third filter is connected to the TRXP0 pin of the PHY chip via the seventh capacitor; the third pin of the third filter is connected to the third pin of the fourth filter and the RX+ pin of the network interface; the second pin of the third filter is connected to the first pin of the fourth filter and the RX- pin of the network interface; both the second and fourth pins of the fourth filter are grounded.
8. A wireless camera, comprising a housing, wherein a circuit board is disposed within the housing, characterized in that, The circuit board integrates an SD card to Ethernet port image transmission circuit as described in any one of claims 1-7; the image transmission circuit is connected to the control terminal via a network cable. The image transmission circuit acquires image data from the wireless camera in real time from the SD card, converts the image data into a network signal, and then uploads it to the control terminal via a wired network cable.