A PIS system light signal transmitting card based on serial communication

Abstract

The utility model belongs to the field of electronic information technology discloses a PIS system light signal emission card based on serial communication, including power supply circuit, core control circuit, serial communication circuit, SDI signal reception and distribution circuit, SDI ring export circuit and SDI electric light conversion circuit. Its work time, receive external DC12V power supply, provide 3.3V working voltage for each module through power supply circuit;SDI signal reception and distribution circuit receive 1 way SDI electric signal and distribute into two ways, one way is by BNC interface ring export after SDI ring export circuit processing, another way is driven two optical module output 2 way light signal after SDI electric light conversion circuit processing;Core control circuit carries out handshaking communication with external play controller through serial communication circuit. The utility model simple structure, small, low in power consumption, adopts serial communication and improves equipment compatibility, is easy to maintain, effectively reduces equipment scrap rate and operation and maintenance cost.

Description

Technical Field

[0001] This utility model belongs to the field of electronic information technology, specifically relating to a PIS system optical signal transmitting card based on serial communication. Background Technology

[0002] Passenger Information System (PIS) is an indispensable component of modern subway operations. It disseminates train operation information and public media information to passengers through display terminals installed in stations and trains. Within the PIS system, the playback controller is the core device; its internal optical signal transmitter card is responsible for converting video electrical signals into optical signals for long-distance, high-quality transmission.

[0003] The existing optical signal transmission cards have many shortcomings:

[0004] 1. Limited communication and power supply methods: The PCI interface is commonly used for data handshaking and power supply to the playback controller motherboard. This requires the motherboard to have a PCI slot, which limits the selection of motherboards and lacks flexibility.

[0005] 2. Complex structure and large size: Typically, an FPGA chip is used in conjunction with multiple DDR memory chips for signal encoding and buffering, resulting in a complex circuit board design, a large number of components, and a large circuit board area. This also necessitates the use of a large 3U or 4U chassis for the entire playback controller, occupying valuable rack space.

[0006] 3. High power consumption and poor reliability: Due to the large number of components and the complexity of chip performance, the overall power consumption of the card is high and the heat generation is large. This not only increases the burden on the heat dissipation system, but also accelerates the aging of electronic components, resulting in a relatively high failure rate.

[0007] 4. Difficult maintenance and high scrap rate: For deployed equipment, the original equipment manufacturer often does not provide circuit diagrams and technical support for core components (such as optical signal transmitter cards). Once a failure occurs, maintenance personnel lack the necessary information, making it difficult to perform chip-level repairs, resulting in the scrapping of the entire playback controller and causing huge economic losses and resource waste. Utility Model Content

[0008] The present invention aims to at least partially solve the aforementioned technical problems. Therefore, the objective of this invention is to provide a PIS system optical signal transmitting card based on serial communication.

[0009] The technical solution adopted in this utility model is as follows:

[0010] A PIS system optical signal transmitting card based on serial communication includes: a power supply circuit, a core control circuit, a serial communication circuit, an SDI signal receiving and distribution circuit, an SDI loop-out circuit, and an SDI electro-optic conversion circuit.

[0011] The power supply circuit is used to receive external DC power and convert it into a preset system operating voltage to power other circuit modules of the optical signal transmitting card.

[0012] The SDI signal receiving and distribution circuit has an input terminal for receiving one SDI electrical signal and distributing the SDI electrical signal into a first SDI signal and a second SDI signal.

[0013] The SDI loop-out circuit is connected to the SDI signal receiving and distribution circuit. It is used to receive the first SDI signal, process it, and output it as an SDI loop-out signal for local monitoring or connection to other devices.

[0014] The SDI electro-optic conversion circuit is connected to the SDI signal receiving and distribution circuit, and is used to receive the second SDI signal and convert it into at least one optical signal output for long-distance transmission.

[0015] The core control circuit uses a microcontroller as the main control unit, which is connected to the SDI signal receiving and distribution circuit, the SDI loop-out circuit, and the SDI electro-optic conversion circuit, respectively, for initializing and controlling the operating status of each circuit chip.

[0016] The serial communication circuit is connected to the core control circuit and is used to realize level conversion and serial communication between the core control circuit and the external playback controller, complete the handshake protocol, and ensure the normal operation of the playback control software.

[0017] As a further optimization of this utility model:

[0018] The power supply circuit receives external power through a DC12V input interface and uses a step-down circuit based on the TPS54331DR chip to stably convert the DC12V voltage to DC3.3V to power all chips in the card.

[0019] The core control circuit uses an STC12LE5A60S2 microcontroller, which manages the initialization and operating status of peripheral chips through a preset chip program.

[0020] The serial communication circuit uses the MAX3221ECPWR chip to achieve bidirectional conversion between the TTL level used by the microcontroller and the RS232 level used by the industrial control computer's serial port.

[0021] The SDI signal receiving and distribution circuit uses the GS2993 chip to perform equalization, automatic gain control and clock data recovery on one input SDI signal, and then distributes and outputs two high-quality SDI differential signals.

[0022] The SDI loop-out circuit uses the GS2988 chip as a driver to drive and impedance match one SDI differential signal from the SDI signal receiving and distribution circuit, so as to drive the 75Ω coaxial cable and loop out through the BNC interface.

[0023] The SDI electro-optic conversion circuit uses the GS2989 chip to redistribute another SDI differential signal from the SDI signal receiving and distribution circuit into two SDI differential signals. Each signal drives an optical module, thereby realizing the final conversion of one SDI input into two optical signal outputs.

[0024] The beneficial effects of this utility model are as follows:

[0025] This invention utilizes an external 12V power supply and serial communication, eliminating reliance on the motherboard's PCI slot and allowing for flexible compatibility with any playback controller motherboard equipped with a serial port. Employing a highly integrated dedicated chip and modular design, the circuit structure is simple, the number of components is significantly reduced, the circuit board area is smaller, and rack space is saved. Attached Figure Description

[0026] Figure 1 This is a system structure block diagram of this utility model.

[0027] Figure 2 This is the circuit diagram of the core control circuit in this utility model.

[0028] Figure 3 This is the circuit diagram of the power supply circuit in this utility model.

[0029] Figure 4 This is the circuit diagram of the serial communication circuit in this utility model.

[0030] Figure 5 This is a circuit diagram of the SDI signal receiving and distribution circuit in this utility model.

[0031] Figure 6 This is the circuit diagram of the SDI loop-out circuit in this utility model.

[0032] Figure 7 This is a circuit diagram of the SDI electro-optic conversion circuit in this utility model. Detailed Implementation

[0033] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0034] It should be understood that, and also noted, in the embodiments, the functions / actions may appear in a different order than those shown in the figures. For example, depending on the functions / actions involved, they may actually be performed substantially concurrently, or sometimes the two figures shown consecutively may be performed in reverse order.

[0035] like Figure 1 As shown, the optical signal transmitting card of this utility model adopts a modular design and is mainly composed of six modules: power supply circuit, core control circuit, serial communication circuit, SDI signal receiving and distribution circuit, SDI loop-out circuit, and SDI electro-optical conversion circuit.

[0036] The overall workflow of the card is as follows: An external DC 12V power supply is converted to DC 3.3V through a power supply circuit to power all modules. One external SDI electrical signal is input to the SDI signal receiving and distribution circuit. This circuit processes the signal and splits it into two paths: one signal is sent to the SDI loop-out circuit, processed, and output through the BNC interface for local monitoring; the other signal is sent to the SDI electro-optical conversion circuit, processed, and drives two optical modules to output two optical signals. The core control circuit is responsible for managing and controlling the initialization and operation of each functional circuit chip. Simultaneously, the core control circuit communicates with an external industrial computer (playback controller) via a serial communication circuit to ensure that the PIS system playback software can start and run normally.

[0037] Power supply circuit (reference) Figure 3 The circuit accepts a wide range of DC voltages from 7V to 28V (typically DC 12V) via interface J3. The core of the circuit is the TPS54331DR buck converter chip U8, which efficiently converts the input voltage to a stable DC 3.3V voltage. After passing through a filter circuit, it provides a clean power supply to all chips and modules on the card that require 3.3V.

[0038] Core control circuit (refer to) Figure 2 This circuit uses the STC12LE5A60S2-35I-LQFP44 microcontroller U7 as the main control chip. A 22.1184MHz crystal oscillator Y2 provides a precise operating clock for the microcontroller. A REST reset circuit ensures reliable startup of the microcontroller. The I / O pins of the microcontroller U7 are connected to the SDI signal receiving and distribution circuit (…). Figure 5 U2 in the middle), SDI loop-out circuit ( Figure 6 U1 in the middle), SDI electro-optical conversion circuit ( Figure 7 It is connected to the control pins of chips such as U4 in the system, and is responsible for configuring and initializing these chips after the system is powered on, and can perform status control according to the instructions of the host computer.

[0039] Serial communication circuit (reference) Figure 4 The core of this circuit is the MAX3221ECPWR level converter chip U9. The serial port pins (TXD, RXD) of the microcontroller U7 output TTL levels, while the industrial control computer's serial port (usually RS232 standard) uses RS232 levels; therefore, they cannot communicate directly. Chip U9 is responsible for bidirectional level conversion between the two. The converted signal is connected to the industrial control computer through interface J5 to achieve handshake communication. LEDs H3 and H4 indicate the receive (RXD) and transmit (TXD) status of the serial port, respectively, facilitating debugging and status monitoring.

[0040] SDI signal receiving and distribution circuit (refer to) Figure 5 The external SDI signal is input through interface J2 and sent to the GS2993 chip U2. U2 is an SDI signal equalizer and distributor. It can perform equalization processing, automatic gain control, and clock data recovery on SDI signals that may attenuate or become distorted after long-distance transmission, ensuring signal quality. After processing, U2 outputs two independent SDI differential signals: one (93O2_N, 93O2_P) is sent to the SDI loop-out circuit, and the other (93O1_N, 93O1_P) is sent to the SDI electro-optic conversion circuit.

[0041] SDI loopout circuit (reference) Figure 6 ): From Figure 5 The SDI differential signals (93O2_N, 93O2_P) are sent to the GS2988 chip U1. U1 is a high-performance SDI cable driver that converts the input differential signal into a single-ended signal suitable for driving a 75Ω coaxial cable and performs impedance matching. The final signal is looped out through the BNC interface J1 and can be connected to local monitors and other devices.

[0042] SDI electro-optical conversion circuit (reference) Figure 7 ): From Figure 5The other SDI differential signal (93O1_N, 93O1_P) is sent to the GS2989 chip U4. Chip U4 functions as an SDI signal distribution driver; it receives this input signal and redistributes it into two independent SDI differential signal outputs (SFP1_P / N and SFP2_P / N). These two SDI differential signals are connected to two optical module bases U3 and U5 (Molex 744410010), respectively, driving the SFP optical modules inserted into the bases. Each SFP optical module converts the received electrical signal into an optical signal and outputs it through a fiber optic interface. This achieves the function of converting one SDI electrical signal input into two independent optical signal outputs.

[0043] This invention, through modular circuit design, uses dedicated integrated chips to replace the complex FPGA solution, and realizes serial communication instead of PCI interface. While significantly reducing product size, power consumption and cost, it improves the compatibility and maintainability of the equipment, perfectly solving the pain points of the existing technology.

[0044] This utility model is not limited to the above-mentioned optional embodiments. Anyone can derive other forms of products under the guidance of this utility model. However, regardless of any changes made in its shape or structure, any technical solution that falls within the scope of the claims of this utility model shall be protected by this utility model.

Claims

1. A PIS system optical signal transmitting card based on serial communication, characterized in that, include: The power supply circuit is used to receive external DC power and convert it into a preset system operating voltage; The SDI signal receiving and distribution circuit has an input terminal for receiving one SDI electrical signal and distributing the SDI electrical signal into a first SDI signal and a second SDI signal. The SDI loop-out circuit is connected to the SDI signal receiving and distribution circuit, and is used to receive the first SDI signal and process it as an SDI loop-out signal for output. The SDI electro-optic conversion circuit is connected to the SDI signal receiving and distribution circuit, and is used to receive the second SDI signal and convert it into at least one optical signal output. The core control circuit is connected to the SDI signal receiving and distribution circuit, the SDI loop-out circuit, and the SDI electro-optic conversion circuit, respectively, and is used to initialize and control each circuit. A serial communication circuit, connected to the core control circuit, is used to realize level conversion and serial communication between the core control circuit and the external playback controller.

2. The optical signal transmitting card for a PIS system based on serial communication according to claim 1, characterized in that, The power supply circuit includes a DC voltage converter chip for converting the input DC12V voltage into a DC3.3V voltage as the system operating voltage.

3. The optical signal transmitting card for a PIS system based on serial communication according to claim 1, characterized in that, The core control circuit includes a main control microcontroller, which manages the working status of the SDI signal receiving and distribution circuit, the SDI loop-out circuit, and the SDI electro-optic conversion circuit through a preset program, and handles data transmission and reception with the serial communication circuit.

4. The optical signal transmitting card for a PIS system based on serial communication according to claim 1, characterized in that, The serial communication circuit includes a level conversion chip, which is used to convert between the TTL level signal output by the core control circuit and the RS232 level signal required by the external playback controller.

5. The optical signal transmitting card for a PIS system based on serial communication according to claim 1, characterized in that, The SDI signal receiving and distribution circuit includes a signal equalization and distribution chip. After equalizing and gain-controlling the input SDI electrical signal, the chip outputs the first SDI signal and the second SDI signal. Both the first SDI signal and the second SDI signal are differential signals.

6. The optical signal transmitting card for a PIS system based on serial communication according to claim 1, characterized in that, The SDI loop-out circuit includes an SDI driver chip for receiving the first SDI signal, performing impedance matching and signal driving, and outputting the SDI loop-out signal through a BNC interface.

7. A PIS system optical signal transmitting card based on serial communication according to claim 1 or 5, characterized in that, The SDI electro-optic conversion circuit includes a signal distribution driver chip and at least one optical module; the signal distribution driver chip receives the second SDI signal and distributes it into at least two SDI differential signals, each of which drives an optical module to achieve synchronous output of the two optical signals.

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