question about amplifier and Oscillator Thank you 2 Consider

question about amplifier and Oscillator. Thank you

2) Considering a receiver subsystem which picks up AM modulated signals and frequency down-converts the as shown below. Antenna 13 RF tuned Local oscillator The incoming signal spectra at point A of the system is shown below. Assuming that the wanted signal Adjacent channel Wanted component 50 kHz 150 kHz 100 kHz (a) A tuned amplifier needs to be designed to pick up the wanted signal, while blocking the adjacent interfering channels. The tuned amplifier can be implemented using the LCR resonator as shown.

Solution

a) w= 1/ sqrt(LC)

W = 2*Pi*f = 40*pi= 135 Hz

damping ratio = R/2 sqrt(L/C)= 1

R = 10000 Hz

L = 1.2 H

C= 0.5micro farad

c) T = (R + R2) * C

= 1.4 sec