Adaptive video twisted-pair receiver

Abstract

The invention relates to an adaptive video twisted-pair receiver. A video twisted-pair signal is input from a twisted-pair interface J1 and resistors R3 and R4 are twisted-pair matched resistors. Pins 2 and 3 for inputting a level-2 lightning protection circuit differential signal into a video amplification chip IC3 are suppression diodes V1, V2, V3 and V4 and resistors R1 and R2, and pins 6 and 7 are used for inputting a +5V power supply and a -5V power supply. Capacitors C2 and C3 are power supply decoupling resistors. Resistors R5, R9, R12 and R6 and capacitors C12, C13 and C14 are 300-meter fixed-gain amplification circuits. A single-ended signal is output by a pin 8 of the video amplification chip IC3 and is input to a pin 14 of an adaptive equalizer IC2 through a capacitor C5. The MAX7474 adaptive equalizer IC2 is used for restoring loss of a composite video signal in twisted-pair cable transmission. The adaptive video twisted-pair receiver has the characteristics of long transmission distance and high transmission quality. The brightness, colour and real-time property of the original image are kept. The anti-jamming capability is strong. Common mode interference can be effectively inhibited, so that different signals cannot interfere with one another. Due to the adoption of a level-3 lightning protection circuit, lightning damage can be effectively avoided.

Description

technical field [0001] The invention relates to an adaptive video twisted pair receiver used in a security protection / video monitoring system. Background technique [0002] In the entire security / video surveillance system, the transmission of video images is a very important link. The media used to transmit image signals mainly include coaxial cables, optical fibers and twisted pairs. Due to the characteristics of the coaxial cable itself, when the video signal is transmitted in the coaxial cable, the attenuation it receives is related to the transmission distance and the frequency of the signal itself. When the video signal is transmitted in the coaxial cable, not only the overall amplitude of the signal is attenuated, but also the attenuation of each frequency component is very different, especially the attenuation of the color part is the largest, so the coaxial cable is only suitable for the video transmission distance of about 300 meters. Optical fiber is used to solv...

AI Technical Summary

Problems solved by technology

Due to the high price of the overall optical fiber transmission system, special equipment is required for laying and connecting optical fibers, and it is difficult to install and debug, it is difficult to find faults, and it is difficult to repair damage. For short-distance video transmission within 2000 meters, optical fiber is not a very good solution. choose

Images