当从射频到ADC系统设计时，噪声性能在各元件间并不是完全一样的。本文探讨了不同器件之间的转换，射频设计者可使用这些信息来设计自己的系统拓扑结构，并选择器件以优化灵敏度。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……