Deck 5: M-Ary Signalling and Pulse Shaping Techniques

Question 1

In an M-ary signalling scheme two or more bits are grouped together to form a_________    

A)chip
B)symbol
C)byte
D)pattern

Answer 1

symbol

Question 2

M-ary signalling techniques are not sensitive to timing jitters.

Answer 2

False

Question 3

M-ary modulation schemes have very good power efficiency.

Answer 3

False

Question 4

What is the radius of the circle in M-ary PSK on which message points are equaly spaced?

A)?es
B)?eb
C)eb
D)es

Question 5

As the value of M_________        the bandwidth efficiency_________      

A)increases, same.
B)increases, decreases
C)increases, increases
D)decreases, same

Question 6

The power efficiency of the M ary PSK decreases because of the_________

A)freely packed constellation
B)increment of bandwidth efficiency
C)fixed null bandwidth
D)densely packed constellation

Question 7

In QAM, the amplitude is_________    and phase is_________    

A)varied, constant
B)varied, varied
C)constant, varied
D)constant, constant

Question 8

M-ary QAM signal have constant energy per symbol.

Question 9

In comparison to M-ary PSK, M-ary QAM bandwidth efficiency is_________and power efficiency is_________      

A)identical, superior
B)less, superior
C)identical, identical
D)superior, superior

Question 10

The bandwidth efficiency of an M-ary FSK signal_________      with_________      in M.

A)constant, increase
B)increases, increase
C)decreases, increase
D)decreases, decrease

Question 11

Power efficiency of M-ary FSK increases, since_________        

A)constellation is densely packed
B)m signals are non-orthogonal
C)fixed null bandwidth
D)m-signals are orthogonal

Question 12

The method in which the tail of one pulse smears into adjacent symbol interval is called as

A)intersymbol interference
B)interbit interference
C)interchannel interference
D)none of the mentioned

Question 13

If each pulse of the sequence to be detected is in_________shape, the pulse can be detected without ISI.

A)sine
B)cosine
C)sinc
D)none of the mentioned

Question 14

What is symbol rate packing?

A)maximum possible symbol transmission rate
B)maximum possible symbol receiving rate
C)maximum bandwidth
D)maximum isi value allowed

Question 15

A nyquist pulse is the one which can be represented by_________shaped pulse multiplied by another time function.

A)sine
B)cosine
C)sinc
D)none of the mentioned

Question 16

Examples of nyquist filters are

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

Question 17

The minimum nyquist bandwidth for the rectangular spectrum in raised cosine filter is

A)2t
B)1/2t
C)t2
D)2/t

Question 18

Roll off factor is the fraction of

A)excess bandwidth and absolute bandwidth
B)excess bandwidth and minimum nyquist bandwidth
C)absolute bandwidth and minimum nyquist bandwidth
D)none of the mentioned

Question 19

A pulse shaping filter should satisfy two requirements. They are

A)should be realizable
B)should have proper roll off factor
C)should be realizable & have proper roll off factor
D)none of the mentioned

Question 20

Examples of double side band signals are

A)ask
B)psk
C)ask & psk
D)none of the mentioned

Question 21

ISI is_________      by increasing channel bandwidth.

A)maximized
B)minimized
C)zero
D)infinite

Question 22

Why is pulse shaping technique used?

A)to increase isi
B)to increase spectral width of modulated signal
C)to reduce isi
D)to reduce power spectral density

Question 23

Raised cosine filter does not satisfy Nyquist criteria.

Question 24

As the roll off factor in raised cosine rolloff filter_________          the occupied bandwidth

A)manchester_________      
B)faraday
C)graham bell
D)nyquist

Question 25

Gaussian pulse shaping filter follows Nyquist criterion.