Basic definitions related to codes Flashcards
Information rate is defined as
a. Information per unit time
b. Average number of bits of information per second
c. rH
d. All of the above
All of the above
The mutual information
a. Is symmetric
b. Always non negative
c. Both a and b are correct
d. None of the above
Both a and b are correct
In Alternate Mark Inversion (AMI) is
a. 0 is encoded as positive pulse and 1 is encoded as negative pulse
b. 0 is encoded as no pulse and 1 is encoded as negative pulse
c. 0 is encoded as negative pulse and 1 is encoded as positive pulse
d. 0 is encoded as no pulse and 1 is encoded as positive or negative pulse
0 is encoded as no pulse and 1 is encoded as positive or negative pulse
Advantages of using AMI
a. Needs least power as due to opposite polarity
b. Prevents build-up of DC
c. May be used for longer distance
d. All of the above
All of the above
Entropy is
a. Average information per message
b. Information in a signal
c. Amplitude of signal
d. All of the above
Average information per message
The expected information contained in a message is called
a. Entropy
b. Efficiency
c. Coded signal
d. None of the above
Entropy
Overhead bits are
a. Framing and synchronizing bits
b. Data due to noise
c. Encoded bits
d. None of the above
Framing and synchronizing bits
Timing jitter is
a. Change in amplitude
b. Change in frequency
c. Deviation in location of the pulses
d. All of the above
Deviation in location of the pulses
Probability density function defines
a. Amplitudes of random noise
b. Density of signal
c. Probability of error
d. All of the above
Amplitudes of random noise
Regenerative repeaters are used for
a. Eliminating noise
b. Reconstruction of signals
c. Transmission over long distances
d. All of the above
All of the above
Scrambling of data is
a. Removing long strings of 1’s and 0’s
b. Exchanging of data
c. Transmission of digital data
d. All of the above
Removing long strings of 1’s and 0’s
The polarities in NRZ format use
a. Complete pulse duration
b. Half duration
c. Both positive as well as negative value
d. Each pulse is used for twice the duration
Complete pulse duration
The channel capacity is
a. The maximum information transmitted by one symbol over the channel
b. Information contained in a signal
c. The amplitude of the modulated signal
d. All of the above
The maximum information transmitted by one symbol over the channel
Pulse shaping is done
a. to control Inter Symbol Interference
b. by limiting the bandwidth of transmission
c. after line coding and modulation of signal
d. All of the above
All of the above
Roll – off factor is defined as
a. The bandwidth occupied beyond the Nyquist Bandwidth of the filter
b. The performance of the filter or device
c. Aliasing effect
d. None of the above
The bandwidth occupied beyond the Nyquist Bandwidth of the filter
The interval of frequencies outside which the spectrum is zero is called as ________
a) null to null bandwidth
b) normalized bandwidth
c) absolute bandwidth
d) none of the mentioned
absolute bandwidth
The characteristics of compressor in μ-law companding are
a. Continuous in nature
b. Logarithmic in nature
c. Linear in nature
d. Discrete in nature
Continuous in nature
Impulse noise is caused due to
a. Switching transients
b. Lightening strikes
c. Power line load switching
d. All of the above
All of the above
In coherent detection of signals,
a. Local carrier is generated
b. Carrier of frequency and phase as same as transmitted carrier is generated
c. The carrier is in synchronization with modulated carrier
d. All of the above
All of the above
Synchronization of signals is done using
a. Pilot clock
b. Extracting timing information from the received signal
c. Transmitter and receiver connected to master timing source
d. All of the above
All of the above
What is meant by aliasing effect?
Aliasing effect takes place when sampling frequency is less than Nyquist rate Under such condition, the spectrum of the sampled signal overlaps with itself. Hence higher frequencies take the form of lower frequencies. This interference of the frequency components is called as aliasing effect.
