When a unit step voltage drives a lag network the output

. For the three systems the values of ??_n are 1.8, 2.5 and 2 respectively.

Hence values of T are 0.55, 0.4 and 0.5 respectively.

Since there are two sign changes in the first column, hence two roots in right half plane.

since ? = 1, ?_n = 3.5 Hence 2 + 2k = 3.5² = 12.25 or K = 5.125 .

R = X_C, voltage drops across R and X_C are equal and at 90° with respect by each other. V₀ lags V_i by 45°.

.

For stability poles must be in left half plane. Zeros in left half plane lead to minimum phase shift.

Transfer function = .

Hence characteristic equation is .

In force voltage analogy force is analogous to voltage and velocity to current. Just as , force/velocity = mechanical impedance.

A signal (image) can interfere with a superheterodyne receiver if fits the following equation.

Image = Signal +/- 2 x I.F.

Which says that a signal has the capacity to interfere with a superhet receiver if its frequency is equal to the signal frequency (1200 kHz in our question) plus or minus twice the IF (455 kHz in our question).

So one possible image is: 1200 + ( 2 x 455 ) = 2110 kHz (possible).

And the other: 1200 - ( 2 x 455 ) = 290 kHz (not likely).