1. Loop filter is a ______ used to reduce noise.
a) Low pass filter
b) High pass filter
c) Band pass filter
d) Band reject filter
Explanation: Loop filter is a low pass filter used to reduce noise.
2. A stationary stochastic process has
a) Finite energy signal
b) Infinite zero signal
c) Zero energy signal
d) None of the mentioned
Explanation: A stationary stochastic process is an infinite energy signal and hence its fourier transform does not exist.
3. The power spectral density function of the stochastic process is
a) Real
b) Odd
c) Real & odd
d) None of the mentioned
Explanation: The power spectral density function of a stochastic function is real and even.
4. For a periodic function, the spectral density and auto correlation functions form
a) Fourier transform pair
b) Laplace transform pair
c) Hilbert transform pair
d) Z transform pair
Explanation: For a periodic function, the spectral density and auto correlation function forms fourier transform pair
5. The capacity of a channel is given by
a) Number of digits used in coding
b) Volume of information it can take
c) Maximum rate of information transmitted
d) Bandwidth requires information
Explanation: The capacity of the channel is given by a maximum rate of information transmitted
6. In a communication system, a process in which statistical averages and time averages are equal is called as
a) Stationary
b) Ergodic
c) Gaussian
d) Poisson
Explanation: In ergodic process statistical averages and time averages are equal
7. A rectangular pulse of duration T is applied to a matched filter. The output of the filter is a
a) Rectangular pulse of duration T
b) Rectangular pulse of duration 2T
c) Triangular pulse
d) Sine function
Explanation: The output of the matched filter when a rectangular pulse of duration T is applied is a triangular pulse
8. The line code has a zero dc component for pulse transmission of random binary data is
a) NRZ
b) RZ
c) Alternate mark inversion
d) None of the mentioned
Explanation: The line code has a zero dc component for pulse transmission of random binary data is alternate mark inversion
9. The auto-correlation of white noise is
a) A delta function
b) A constant
c) Gaussian
d) None of the mentioned
Explanation: The auto-correlation of white noise is a delta function.
10. Ionospheric communication can take place in
a) High frequency band
b) Very high frequency band
c) Ultra high frequency band
d) Super high frequency band
Explanation: Ionospheric communication takes place in high frequency band