A closed loop system has the characteristic function $$\left( {{s^2} - 4} \right)\left( {s + 1} \right) + K\left( {s - 1} \right) = 0.$$
Its root locus plot against $$K$$ is

The algebraic equation
$$F\left( s \right) = {s^5} - 3{s^4} + 5{s^3} - 7{s^2} + 4s + 20$$
$$F\left( s \right) = 0$$ has

A software delay subroutine is written as given below:

How many times $$DCR$$ $$L$$ instruction will be executed?

A student has made a-$$3$$ bit binary down counter and connected to the $$R$$-$$2R$$ ladder type $$DAC$$ [Gain $$=$$ $$\left( { - 1k\Omega /2R} \right)$$ as shown in figure to generate a staircase waveform.

The output achieved is different as shown in figure. What could be the possible cause of this error?