For the requirement of high gain and low noisefigure (NF) of the receiver RF destination, two LNAs most be cascaded, which is determined by each noise calculation of the two different LNAs.
接收射频前端的高增益和低噪声系数要求两级低噪放级联使用，通过计算低噪放的噪声估量确定了连接方式。
2
As the first stage of the system, its gain, noisefigure(NF) and linearity directly take effect on the whole circuit.