1 In which circuit we use positive feedback?
Ans Oscillator circuits use positive feedback.
2 What is feedback? Mention different types of Feedback.
Ans Feedback refers to feeding fraction of out signal to the input of the circuit.
Types: Positive and negative feedback
3 Which feedback system gives stabilized system?
Ans Negative feedback
4 Which feedback system gives improved frequency response?
Ans Negative feedback
5 Which feedback system gives reduced noise system?
Ans Negative feedback
6 Which feedback system gives more linear system?
Ans Negative feedback
7 What is piezoelectric effect?
Ans A quartz crystal exhibits the property that when mechanical stress is applied across
the faces of the crystal, a difference of potential develops across opposite faces of
the crystal. This property of a crystal is called the piezoelectric effect.
8 What are the advantages of crystal oscillator?
Ans High frequency stability, low phase noise, and high Q factor
9 What is resolution of ADC?
Ans The resolution of an Analog-to-Digital Converter (ADC) refers to the smallest
change in the analog input signal that the ADC can detect, which is directly
related to the number of bits used in the conversion process
10 What is resolution of DAC?
Ans The resolution of a DAC is given by the number of bits, N. The resolution is the
smallest increment of output that the DAC can produce
11 What are the advantages of wave-guides?
Ans waveguides are simpler to manufacture than coaxial lines, power-handling
ability is good
12 What is dominant mode of waveguide?
Ans The natural mode of operation for a waveguide is called the dominant mode.
13 Mention the applications of Cavity resonator.
Ans Used as Tuned LC circuits or resonant transmission lines, but naturally at much
higher frequencies
14 What is duct?
Ans An ionosphere region above the earth surface with high refractive index
15 Mention different ways of propagation.
Ans Types: Ground, Sky and space
16 What is the maximum frequency through Ground way we can transmit?
Ans Upto 2Mhz
17 What is the frequency range a sky wave can transmit?
Ans The range is 2 to 30 Mhz
18 What is the frequency range of line of sight propagation?
Ans Above 30 Mhz
19 An antenna ha its radiation resistance of 40Ω and loss resistance of 10Ω. Find
the efficiency of the antenna.
Ans η=[Rr/(Rr+RL]=80%
20 What is phased array?
Ans A phased array is a group of antennas, connected to the -one transmitter or
receiver, whose radiation beam can be adjusted electronically
21 Mention the applications of phased array?
Ans Used in Radar also in satellite communications.
22 Identify whether the signal g(t) = 10+ t + cos(20t), is Even or Odd signal
Ans Neither even or nor odd
23 Find the period of the signal x(n)=cos(0.3n+π)
Ans Aperiodic
24 The system y(t)=2x(t)+A is a Non linear system or not ? Justify your answer
Ans Yes Nonlinear system. The system has constant A
25 Mention the applications of PLL.
Ans PLLs are versatile circuits used in many applications, including frequency
synthesis, demodulation, clock generation, and data synchronization
26 Determine the even and odd components of :
1) x(t) = 1-2t + t2
2) x(t) = cost + sint + tant
Ans 1) x(t) = 1-2t + t2
xe(t) = 1 + t2 xo(t) = -2t
2) x(t) = cost + sint + tant
xe(t) = cost xo(t) = sint + tant
27 What are the disadvantages of digital communication?
Ans 1). More BW 2) Synchronization 3) Need A/D and D/A converters
28 What are the advantages of digital communication?
Ans 1)Regenerate 2) Encrypt 3) Easy to store
29 Mention different multiplexing techniques
Ans TDMA, FDMA and CDMA
30 Which multiplexing techniques use code word?
Ans CDMA
31 Which multiplexing techniques use synchronization?
Ans TDMA
32 Which multiplexing techniques use high data rate?
Ans CDMA
