从射频元件开始至ADC的全系统设计时，噪声特性在各部件之间并不是始终一样的。本文就不同术语之间的转换进行分析。射频工作者可以使用这些信息来设计他们系统的拓扑结构和元件选择以提高灵敏度。Signal Chain Noise Analysis for RF-to-Digital Receivers Design Note 439 Cheng-Wei Pei Introduction equal to an NF of approximately 14dB), so here we use NF. Designers of signal receiver systems often need to per- When working in a xed-impedance (50Ω) environment, form cascaded chain analysis of system performance using NF simplies the analysis of an RF signal chain. from the antenna all the way to the ADC. Noise is a criti- However, if the assumptions of constant impedance and cal parameter in the chain analysis because it limits the proper source/load termination are not valid, then NF ov……