利用时域反射计测量传输延时

Propagation delay measurements using TDR

随着时钟速率的提高,利用高速示波器的有源探头测量延时的传统方法很难获得准确结果。这些探头成为高速信号通路的一部分,并造成被测信号的失真,引入误差。探头还必须直接置于器件引脚,以消除PCB(印制电路板)引线长度产生的延时误差,满足探头位置的这一要求是困难而复杂的过程。介绍了如何利用TDR(时域反射计)测量降低探头误差的方法,有助于提高传输延时测量精度。

As clock speeds increase, it is more difficult for traditional methods of measuring delays with active probes connected to high-speed oscilloscopes to obtain accurate results. These probes become a part of the high-speed signal path and distort the signal being measured, thus introducing errors. The probes must also be placed directly on device pins to remove delay errors caused by PCB （printed circuit board） run lengths, and that placement is a difficult and complex procedure. This article will demonstrate how to use TDR （time-domain reflectometery） measurements to minimize probing errors and improve the accuracy of propagation delay measurements.