Q.1
In microwave oscillators, negative resistance transistors and diodes are used in order to generate oscillations in the circuit.
  • true
  • false
Q.2
If SWR=1.5 with a wavelength of 4 cm and the distance between load and first minima is 1.48cm, then the reflection coefficient is:
  • 0.0126+j0.1996
  • 0.0128
  • 0.26+j0.16
  • none of the mentioned
Q.3
The klystron tube used in a klystron amplifier is a                    type beam amplifier.
  • linear beam
  • crossed field
  • parallel field
  • none of the mentioned
Q.4
In crossed field tubes, the electron beam traverses the length of the tube and is parallel to the electric field.
  • true
  • false
Q.5
A major disadvantage of klystron amplifier is:
  • low power gain
  • low bandwidth
  • high source power
  • design complexity
Q.6
Magnetrons are microwave devices that offer very high efficiencies of about 80%.
  • true
  • false
Q.7
Klystron amplifiers have high noise output as compared to crossed field amplifiers.
  • true
  • false
Q.8
2 IMPEDANCE MATCHING
  • swr, first voltage minimum
  • swr, first voltage maximum
  • characteristic impedance, first voltage minimum
  • characteristic impedance, first voltage maximum
Q.9
High gain is not achievable at microwave frequencies using BJT amplifiers because:
  • device construction
  • complex architecture
  • ports are not matched at high frequencies
  • none of the mentioned
Q.10
The transfer function of an RF oscillator is given by:
  • a/ (1-ah (ω))
  • a/ (1+ah (ω))
  • a/ (-1+ah (ω))
  • 1/ (1-ah (ω))
Q.11
A major advantage of differential amplifiers is:
  • high gain
  • low input impedance
  • higher output voltage swing
  • none of the mentioned
Q.12
Along with a differential amplifier,hybrid is used both at the input and output.
  • true
  • false
Q.13
is a non linear circuit that converts DC power to an AC waveform of desired frequency based on the oscillator design.
  • attenuator
  • amplifier
  • oscillator
  • none of the mentioned
Q.14
In conventional amplifiers, a flat gain response is achieved at the cost of reduced gain. But this drawback can be overcome by using:
  • balanced amplifiers
  • distributed amplifiers
  • differential amplifiers
  • none of the mentioned
Q.15
The criterion on which oscillations are produced in the oscillator circuit is called:
  • shannon’s criteria
  • barkhausen criteria
  • colpitts criteria
  • none of the mentioned
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