High-frequency impulse noise is most harmful to digital signal processing systems. In order to improve the anti-interference performance of the system, the following measures can be taken in the digital signal processing system: 1. Increase the anti-interference ability of the bus. A bus structure in the form of a three-state gate is used, and a pull-up resistor is connected to the bus so that the bus is at a stable high level in an instant to avoid the bus from appearing in a floating state. The bus must be buffered. 2. Use software to eliminate interference. There are two common methods: 3. Improve the anti-interference ability of the system control signal. There are usually control lines such as RESET and STB in the system. When the transmission distance between the CPU and its control device is far and the impedance of the control line is high, it is susceptible to pulse noise interference. A 20PF capacitor can be connected in parallel to the input of the controlled device, and a 0.01UF capacitor can be connected in parallel to the control signal line such as RESET. Add a level of buffer to the control line, so that the impedance of the control line becomes low, and it also suppresses interference. 4. Resist the crosstalk of digital signals. This series-mode interference is caused by adjacent signal lines in the process of transmitting signals, and most of them occur on flat cables, bundled wires, or parallel wires on printed boards. The strength of series mode interference is related to the coupling impedance between two adjacent signal lines and the impedance of the signal itself. Flat cables are widely used in digital AV products as connecting wires. If improperly used, crosstalk is likely to occur, affecting the normal operation of the device. There is distributed capacitance between the conductors of the flat cable, and the distributed capacitance between adjacent conductors of 10 cm is about 3PF. When the frequency is 100MHZ, the impedance of the 1PF capacitor is 1.6 kiloohms, while the coupling impedance of the 10CM transmission line is only 0.5 kiloohms. Since the distributed capacitance of the flat cable conductor is proportional to its length, the cross-mode interference is particularly serious when the lead is long. Take the VCD machine as an example, the signal is a square wave signal from several hundred kilohertz to several megahertz and a clock signal of 10-20MHz, and contains dozens of times higher harmonics, and the signal spectrum is up to several hundred megahertz High-frequency components easily crosstalk with each other through the distributed capacitance between the conductors of the flat cable. To this end, the following measures can be taken in digital audio and video products:
Why the Glass wall curtain led display can lead the fashion of outdoor media?
The LED Glass curtain display appeared as an sudden emergence on the outdoor media market.
With the advantages of encapsulation technology, high brightness, wide viewing angle, adjustable screen area and easy installation, The transparent led glass display has gradually replaced the traditional billboards, light boxed, etc., And become the high-profile new force for outdoor advertising media. At the same time, a small pitch is applicable to the glass wall led screen and led glass screen for window. There`re various types of led display products suitable for glass wall and glass window, such as Transparent led display and led strip curtain screen. As if, indoor and outdoor led curtain wall display has become a leading industry for led display market
Led Glass Display,Led Display For Glass Window,Outdoor Transparent Led Display,Glass Wall Led Screen Shenzhen Priva Tech Co., Ltd. , https://www.privaled.com
1) Use the monitoring timer to detect whether the system is disturbed. Once the system is disturbed, an interrupt is generated immediately and the system is re-initialized and then restarted to eliminate the impact of interference;
2) The use of software fault-tolerance technology is to recognize that the existence of faults and errors is an objective fact and take corresponding measures to eliminate or resist its impact.
1) Try to shorten the length of the signal line;
2) When transmitting multiple levels of signals, try to divide the level signals with similar front and back edge times into a group for transmission.
3) Arranging a large area of ​​ground area on the back of the double-sided printed board can absorb and shield the high-frequency pulse noise generated by the device.