Digital Control Systems Mid - II, November - 2014

1.If Kp=∞, _____ input becomes zero in response of steady state actuating error.
  • Unit step
  • Unit impulse
  • Unit ramp
  • Unit Circle
Answer: A
2.A constant frequency locus W=W1 in the s-plane is mapped into a _________ of constant angle TW1 in z-plane.
  • Circle
  • Radial Line
  • Spiral
  • Rectangle
Answer: B
3.The _______ is the time required for the response to reach half the final value the very first time.
  • Rise time
  • Peak time
  • Delay time
  • Unit time
Answer: C
4.The interior of the unit circle in z-plane corresponds to the ______ of the s-plane.
  • Right
  • Left
  • Right half
  • Left half
Answer: D
5.A mapping which preserves both the size and the sense of angles is called
  • Mapping
  • Similarity mapping
  • Normal mapping
  • Conformal mapping
Answer: D
6.___________________ compensation is commonly used for improving stability margins.
  • Phase lag
  • Phase
  • Phase lead
  • PID
Answer: C
7.By the use of Lead-lag compensator, the low frequency gain can be _______. At the same time the system band-width and stability margins can be ________.
  • Increased, Decreased
  • Increased, Increased
  • Decreased, Decreased
  • Decreased, Increased
Answer: B
8.In polar form z can be expressed as
  • z = rejw
  • z = re-jw
  • z = -rejw
  • z = -re-jw
Answer: A
9.Which is used to test the stability of continuous data systems?
  • R-H criteria
  • Nyquist
  • Root-locus
  • all
Answer: D
10.The Matrix ‘L’ of state observability is
  • L=[D1 A1 D1 (A1)2 D1 ……………(A1)n-1D1]
  • L=[C1 A1 C1 (A1)2 C1 ……………(A1)n-1C1]
  • L=[B1 A1 B1 (A1)2 B1 ……………(A1)n-1B1]
  • L=[G1 A1 G1 (A1)2 G1 ……………(A1)n-1G1]
Answer: A
11.If the state observer estimates all th4 state variables regardless of whether some are available for direct measurement or not, it is called a ________________ observer.
Answer: Full order
12.The _____________ is the time required for the response to reach the first peak of the overshoot.
Answer: Peak Time
13.Phase lag compensation _______________ the system gain at higher frequencies without reducing the system gain at lower frequencies.
Answer: Reduces
14.R-H criteria is not used for _______________
Answer: Z- Domain
15.Lipanov is used to study the stability of _______________ systems.
Answer: Linear & Non-Linear
16.W in Z-transformation is _______________
Answer: Z-1/Z+1
17.The concept of observability is complement of _______________
Answer: Controllability
18.The linear time invariant system is completely observable if & only if the Gramin Matrix is _______________
Answer: Non-Singular
19.The LTI system is completely state controllable, if and only if the rows of the n*n matrix are _______________ independent.
Answer: Linearly
20.In Jury’s stability test tabulation a singular case is signified by either having the first and last elements of a row be zero, or having a complete row of _______________
Answer: Zeros