Q.1
In the plot of reactance v/s frequency of a crystal oscillator, the reactance between series resonant frequency and parallel resonant frequency is:
  • capacitive
  • inductive
  • both capacitive and inductive
  • none of the mentioned
Q.2
A quartz crystals equivalent circuit is a series LCR circuit and has a series resonant frequency.
  • true
  • false
Q.3
Quartz crystal and tourmaline used in oscillators work on the principle of:
  • photo electric effect
  • piezo electric effect
  • raman effect
  • black body radiation
Q.4
In an oscillator, the resonant feedback circuit must have must have a low Q in order to achieve stable oscillation.
  • true
  • false
Q.5
One condition to be satisfied in an oscillator circuit so that stable oscillations are produced is:
  • positive feedback is to be achieved
  • negative feedback is to be achieved
  • 1800 phase shift is required between the transistor input and output.
  • none of the mentioned
Q.6
Expression for over all noise figure of a mismatched amplifier is:
  • 1+ (f-1)/ (1 -│Г│2)
  • 1
  • 1+ (f-1)
  • (f-1)/ (1 -│Г│2)
Q.7
Noise equivalent temperature of Wilkinson coupler having a gain of 1/is given as:
  • t (2l-1)
  • t (2l+1)
  • t (2l*1)
  • t / (2l-1)
Q.8
For a Wilkinson power divider of insertion loss L and the coupler is matched to the external circuitry, and then the gain of the coupler in terms of insertion loss is:
  • 2l
  • 1/2l
  • l
  • 1/l
Q.9
Noise equivalent temperature of a 2 stage cascade network is given by:
  • te1 + te2/ g1
  • te1 + te1
  • te1 / te1
  • none of the mentioned
Q.10
Expression for noise of a two port network considering the noise due to transmission line and other lossy components is:
  • gktb + gnadded
  • gktb
  • gnadded
  • none of the mentioned
Q.11
Noise figure can be defined for any microwave network irrespective of any other constraints.
  • true
  • false
  • topic 5.6 low noise amplifier design
Q.12
The equivalent noise temperature of a network given the noise figure of the network or system is:
  • t0(f-1)
  • t0(f+1)
  • t0(f)
  • t0/f
Q.13
is defined as the ratio of input signal to noise ratio to the output signal to noise ratio.
  • noise figure
  • noise temperature
  • snro
  • none of the mentioned
Q.14
is defined as the ratio of desired signal power to undesired noise power.
  • signal to noise ratio
  • noise to signal ratio
  • noise figure
  • noise temperature
Q.15
Amplifier efficiency is the ratio of RF output power to DC input power. This parameter determines the performance of an amplifier.
  • true
  • false
Q.16
For Colpitts oscillator, the capacitors C1 and C2 in the feedback network are 1 µF andµF respectively. Then the β value of the transistor is:
  • 35
  • 000.76
  • 25
  • 0.0025
Q.17
Colpitts oscillator in the feedback section has an inductance of 4 mH and capacitors ofnH and 4 nH. Then the resonant frequency of Colpitts oscillator is:
  • 50.4 khz
  • 35.1 khz
  • 45.9 khz
  • none of the mentioned
Q.18
Hartley oscillator has inductance values ofmH and 4 mH in the feedback section and a capacitor of 4 nF. Then the resonant frequency of the circuit is:
  • 19.89 khz
  • 25 khz
  • 45 khz
  • 12 khz
Q.19
An inductor is operating at frequency ofMHz. Its inductance is 0.1 µH, and then the series resistance associated with the inductor is: (Qo=100)
  • 0.31 Ω
  • 1.32 Ω
  • 1 Ω
  • 1.561 Ω
Q.20
Colpitts oscillator operating atMHz has an inductor in the feedback section of value 0.10µH. then the values of the capacitors in the feedback section is:
  • 100 pf, 100 pf
  • 100 pf, 50 pf
  • 70 pf, 130 pf
  • 80 pf, 60 pf
0 h : 0 m : 1 s