申論題

4.Consider a CC-CE amplifier such as that in Fig. 5 with the following specifications: I₁ = I₂ = 1 mA and identical transistors with β = 100, = 400 MHz, and = 2 pF. Thermal voltage = 25 mV. Let the amplifier be fed with a source having a resistance = 4 kΩ, and assume a load resistance = 4 kΩ. Find the midband voltage gain Vo/vsig and estimate the 3-db frequency fH by the method of open-circuit time constants (please show the value of each time constant).