Deck 6: Signal Filtering and Equalization Techniques

Question 1

Gaussian filter has zero crossings at adjacent symbol peaks.

Answer 1

False

Question 2

Which of the following is true for a Gaussian filter?

A)large bandwidth
B)minimum isi
C)high overshoot
D)sharp cut off

Answer 2

sharp cut off

Question 3

Gaussian pulse shaping filter reduces the spectral occupancy and ISI.

Answer 3

False

Question 4

Gaussian pulses are used when cost and power efficiency are major factors.

Question 5

The method in which small amount of controlled ISI is introduced into the data stream rather than trying to eliminate it completely is called as

A)correlative coding
B)duobinary signalling
C)partial response signalling
D)all of the mentioned

Question 6

From digital filter we will get the output pulse as the_________    of the current and the previous pulse.

A)summation
B)difference
C)product
D)ratio

Question 7

In duobinary signalling method, for M-ary transmission, the number of output obtained is

A)2m
B)2m+1
C)2m-1
D)m2

Question 8

The method using which the error propagation in dubinary signalling can be avoided is

A)filtering
B)precoding
C)postcoding
D)none of the mentioned

Question 9

In precoding technique, the binary sequence is_________with the previous precoded bit.

A)and-ed
B)or-ed
C)exor-ed
D)added

Question 10

The duobinary filter, He (f) is called as

A)sine filter
B)cosine filter
C)raised cosine filter
D)none of the mentioned

Question 11

The method which has greater bandwidth efficiency is called as

A)duobinary signalling
B)polybinary signalling
C)correlative coding
D)all of the mentioned

Question 12

In polybinary signalling method the present bit of binary sequence is algebraically added with_________  number of previous bits.

A)j
B)2j
C)j+2
D)j-2

Question 13

The primary advantage of this method is

A)redistribution of spectral density
B)to favor low frequencies
C)redistribution of spectral density & to favor low frequencies
D)none of the mentioned

Question 14

Source encoding procedure does

A)sampling
B)quantization
C)compression
D)all of the mentioned

Question 15

The range of amplitude difference gives the value of

A)width
B)distortion
C)timing jitter
D)noise margin

Question 16

As the eye opens, ISI_________    

A)increases
B)decreases
C)remains the same
D)none of the mentioned

Question 17

The index value n, in transversal filter can be used as.

A)time offset
B)filter coefficient identifier
C)time offset & filter coefficient identifier
D)none of the mentioned

Question 18

The over-determined set of equations can be solved using

A)zero forcing
B)minimum mean square error
C)zero forcing & minimum mean square error
D)none of the mentioned

Question 19

If the filter's tap weight remains fixed during transmission of data, then the equalization is called as

A)preset equalization
B)adaptive equalization
C)fixed equalization
D)none of the mentioned

Question 20

Equalization method which is done by tracking a slowly time varying channel response is

A)preset equalization
B)adaptive equalization
C)variable equalization
D)none of the mentioned

Question 21

Preamble is used for

A)detect start of transmission
B)to set automatic gain control
C)to align internal clocks
D)all of the mentioned

Question 22

The disadvantage of preset equalizer is that

A)it doesnot requires initial training pulse
B)time varying channel degrades the performance of the system
C)all of the mentioned
D)none of the mentioned

Question 23

For AWGN, the noise variance is

A)n0
B)n0/2
C)2n0
D)n0/4

Question 24

A Gaussian distribution into the non linear envelope detector yields

A)rayleigh distribution
B)normal distribution
C)poisson distribution
D)binary distribution

Question 25

The DPSK needs_________      Eb/N0 than BPSK.

A)1db more
B)1db less
C)3db more
D)3db less