21.
Entropy is
A
Information in a signal
B
Amplitude of signal
C
Average information per message
D
All of the above
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Entropy is
Information in a signal
Amplitude of signal
Average information per message
All of the above
Information rate is defined as
Average number of bits of information per second
rH
Information per unit time
All of the above
Matched filters may be used
In parameter estimation problems
To estimate the distance of the object
To estimate the frequency of the received signal
All of the above
In Adaptive Delta Modulation, the slope error reduces and
Quantization error increases
Quantization error remains same
Quantization error decreases
None of the above
The digital modulation technique in which the step size is varied according to the variation in the slope of the input is called
PCM
Adaptive delta modulation
Delta modulation
PAM
Granular noise occurs when
There is interference from the adjacent channel
Step size is too small
Bandwidth is too large
Step size is too large
DPCM is a technique
Where digital codes are the quantized values of the predicted value
To convert analog signal into digital signal
All of the above
Where difference between successive samples of the analog signals are encoded into n-bit data streams
In Delta Modulation, the bit rate is
N times the nyquist criteria
N times the sampling frequency
None of the above
N times the modulating frequency
The error probability of a PCM is
Calculated using power spectral density
Calculated using noise and inter symbol interference
All of the above
Gaussian noise + error component due to inter symbol interference
In PCM, the parameter varied in accordance with the amplitude of the modulating signal is
Phase
Amplitude
None of the above
Frequency
The modulation techniques used to convert analog signal into digital signal are
Adaptive delta modulation
Pulse code modulation
All of the above
Delta modulation
One factor in the accuracy of a reconstructed PCM signal is the
Number of bits used for quantization
Signal bandwidth
Baud rate
Carrier frequency
Modulation is used to
Ensure that information may be transmitted over long distances
Reduce the bandwidth
Allow the use of practicable antennas
Separate differing transmission
In modems
Digital signal is amplified
Several digital signal are multiplexed
None of these above
A digital signal changes some characteristics of a carrier wave
In PCM
Non-linear coding scheme is undertaken
Digital signal is converted into analog signal
None of these
Pulse Amplitude modulation samples are quantized
The qualifier differential to PSK means that
phase shift is with reference to the previous bit transmitted
it uses phase shifts of multiple of 90 degree
none of these above
it uses phase shifts of 180 degree
ASK is rarely used in modems because
it takes care of amplitude only
it shifts only between ON and OFF states
none of the above
it is highly susceptible to noise
ASK is a result of combination of Shift keying and
Amplitude modulation
Digital modulation
None of these above
Analog modulation
Codec uses
PCM and Delta modulation
Pulse code modulation technique only
None of these
Delta modulation only
Two binary values are represented by two different frequencies in :
phase-shift-keying
amplitude-shift-keying
none of these above
frequency-shift-keying