ISRO Scientist or Engineer Electronics 2012

For a Phase Locked Loop system, the open loop transfer function is G(s)=$$\frac{1000}{s (\frac{s}{1192}+1)}$$
The phase margin is $$50^\circ$$ and the crossover frequency is approximately 1000 rad/s. A time delay is introduced in the phase detector reducing the phase margin to $$40^\circ$$ . The maximum permissible time delay ( in seconds)is :

In this circuit, the relationship between $$V_{i}  \&  V_{o}$$, is:

Output Impedanceof a source follower is :

For a negative feedback system shown in figure,

the equivalent transfer function is :

If $$(146)_{x}+(313)_{x-2}=(246)_{8}$$, then the value of base x is

The truth table for implementing a boolean variable F is given by

where d represents don’t care states. The minimized expression for F is

The state transition diagram for a sequence generator is shown in figure

It is designed using D F/Fs and combinational logic blocks $$L_{1}, L_{2}, \& L_{3}$$ and is initialized at $$(Q_{2} = 1 ,Q_{1} = 0, Q_{0} = 1)$$

The minimized expressions for O0, O1, & O2 are:

The number of comparators needed in a 8-bit flash type A to D converteris

The register in the 8085A that is used to keep track of the memory address of the next op-code to be run in the program is the :

The Complement Accumulator (CMA) instruction of 8085 processor on execution affects