Question

A direct-coupled amplifier has a low-frequency gain of 40 dB, poles at 2 MHz and 20 MHz, a zero on the negative real axis at 200 MHz, and another zero at infinite frequency. Express the amplifier gain function in the form of Equations and sketch a Bode plot for the gain magnitude. What do you estimate the 3-dB frequency fH to be?

Answer 1

Answer:

Explanation:

Low frequency gain is= 40db= 20logK=>100 poles at 2MHz,20MHz

Zero at -200MHz, zero at infinity.

A) A(s) = 100FH(s)

B) Poles (1): 2 pi × 2 × 10^6= 4pi × 10^6MHz

              (2): 2pi × 20 × 10^6= 4pi × 10^6 MHz

 Zeroed: 2pi × 10^6 × 200= 400pi × 10^6, at infinity.

T/(S) = (1 + S/400π × 10^6)/S(1 + S/4π × 10^6)(1 + S/4π × 10^6)