异步点时钟实现复合视频模数双向转换

摘要

In the method of synchronous pixel clock conversion, pixel clock is generated by horizontal sync signal phase-locked frequency. With technical progress of high frequency clock and programmable chip, asynchronous pixel clock conversion method could reduce pixel clock vibration errors by increasing clock frequency greatly, simplify circuits designing with precision guarantee and make conversion of analog and digital signals flexible. In the paper, high frequency clock and programmable FPGA are used to implement composite video A/D bi-direction conversion based on asynchronous pixel clock. This method has been applied to a section of avionics products with good results.%同步点时钟转换方法由行同步信号倍频锁相产生点时钟.随着高额时钟和可编程芯片的技术发展,异步点时钟转换方法可以通过大幅度提高时钟频率来降低点时钟抖动误差,在保证精度前提下简化电路设计,使模拟和数字之间的转换更加灵活.本文基于高频时钟和可编程FPGA实现异步点时钟复合视频模数双向转换的方法已经应用于某款航空电子产品中,应用效果良好.