0195136047.pdf

PROBLEMS 193

+−

+−

+++

+++

H 0

H 1

H 2

(a)

(b)

G 1 G 2

G 1 G 4 (H 0 + G 2 G 3 )

H 3

H 3 (H 1 + H 2 )

G 3 G 4

Figure P3.4.25

−

+ +

+

H 1

G 1

R(s)

ΣΣG 2 C(s)

H 2

G 3

Figure P3.4.26

−

+

+

−

+

−

H 1

G 1

R(s)

ΣΣG 2 C(s)

H 2

H 3

Σ G 3

Figure P3.4.27

3.4.26The block diagram of Figure P3.4.26 represents a

multiloop control system.

(a) Determine the transfer functionC(s)/R(s).

(b) ForG 2 G 3 H 2 =1, evaluateC(s)/R(s).

*3.4.27Determine the transfer functionC(s)/R(s)ofthe
nested-loop feedback system shown in Figure
P3.4.27.
3.4.28The equations for a two-port network are given by
V 1 =z 11 I 1 +z 12 I 2
0 =z 21 I 1 +(z 22 +ZL)I 2
V 2 =−I 2 ZL

(a) Satisfying the equations, develop a block dia-

gram.

(b) Find the transfer functionV 2 /V 1.

3.5.1In the circuit shown in Figure P3.5.1 the switch

opens att =0. Develop and execute a PSpice

program to solve forv(t), and use PROBE to

obtain a plot ofv(t).

Hint:Use the following analysis request:

• TRAN 0.1 MS 50 MS 0 0.1 MS UIC

3.5.2Obtain a plot of the currenti(t)in the circuit of

Figure P3.5.2 by writing a PSpice program and

using the following analysis request:

• TRAN 0.2 MS 80 MS 0 0.2 MS UIC
  Hint:Note that a sinusoidal voltage source is spec-
  ified in PSpice by the statement
  VSIN NODEPLUS NODEMINUS
  SIN (VDC VPEAK FREQ TD
  DF PHASE)