二、如下圖所示之電路,假設R1 = 90 kΩ、R2 = 50 kΩ、R3 = 50 kΩ、 R4 = 16 kΩ、 R5 = 16 kΩ、R6 = 5 kΩ、R7 = 6 kΩ、Cgs = 1 pF、 Cgd = 0.2 pF、C1 = 1 μF、C2 = 1 μF、C3 = 2 μF、gm = 2 mA/V、 ro = 50 kΩ,求此電路之
(二)3 dB 截止頻率(3 dB cutoff frequency)fH =?(Hz)(10 分)