从双频信号模型出发,分析了包络通道带宽和相位包络间信号延时差对交调失真的共同影响,得出了一个更符合测试结果的通用简化模型.该简化模型克服了Raab模型只能处理零延时差和无穷包络通道带宽这两个特例的局限性;采用本文模型得出的交调失真等高线图还可以帮助设计者快速准确地选择电路参数.最后,基于GSM/EDGE射频信号,用一个935MHz的射频功放示范了本文提出的设计方法.
Based on an architecture model of a two-tone signal, we analyze the effects of the finite envelope modulator band-width and differential delay between envelope signal and RF phase signal on the intermodulation distortion (IMD), and derive a general simplified model that is much closer to laboratory measurements. This model overcomes the limitation of Raab'ss model, which can only solve two specific instances: zero differential delay and infinite bandwidth of the envelope path. A contour map derived from the general model can help designers choose circuit parameters quickly and accurately. Finally, an envelope elimination and restoration RF power amplifier (EER RF PA) operating at 935MHz with a GSM/EDGE signal source is applied to demonstrate how to use the analysis method presented here.