Communication Engineering Set 7 MCQs

Q1 | In an M-ary signalling scheme two or more bits are grouped together to form a

chip

symbol

byte

pattern

Q2 | M-ary signalling techniques are not sensitive to timing jitters.

true

false

Q3 | M-ary modulation schemes have very good power efficiency.

true

false

Q4 | What is the radius of the circle in M-ary PSK on which message points are equaly spaced?

√es

√eb

eb

es

Q5 | As the value of M the bandwidth efficiency

increases, same.

increases, decreases

increases, increases

decreases, same

Q6 | The power efficiency of the M ary PSK decreases because of the

freely packed constellation

increment of bandwidth efficiency

fixed null bandwidth

densely packed constellation

Q7 | In QAM, the amplitude is and phase is

varied, constant

varied, varied

constant, varied

constant, constant

Q8 | M-ary QAM signal have constant energy per symbol.

true

false

Q9 | In comparison to M-ary PSK, M-ary QAM bandwidth efficiency is and power efficiency is

identical, superior

less, superior

identical, identical

superior, superior

Q10 | The bandwidth efficiency of an M-ary FSK signal with in M.

constant, increase

increases, increase

decreases, increase

decreases, decrease

Q11 | Power efficiency of M-ary FSK increases, since

constellation is densely packed

m signals are non-orthogonal

fixed null bandwidth

m-signals are orthogonal

Q12 | The method in which the tail of one pulse smears into adjacent symbol interval is called as

intersymbol interference

interbit interference

interchannel interference

none of the mentioned

Q13 | If each pulse of the sequence to be detected is in shape, the pulse can be detected without ISI.

sine

cosine

sinc

none of the mentioned

Q14 | What is symbol rate packing?

maximum possible symbol transmission rate

maximum possible symbol receiving rate

maximum bandwidth

maximum isi value allowed

Q15 | A nyquist pulse is the one which can be represented by shaped pulse multiplied by another time function.

sine

cosine

sinc

none of the mentioned

Q16 | Examples of nyquist filters are

root raised cosine filter

raised cosine filter

root raised & raised cosine filter

none of the mentioned

Q17 | The minimum nyquist bandwidth for the rectangular spectrum in raised cosine filter is

2t

1/2t

t2

2/t

Q18 | Roll off factor is the fraction of

excess bandwidth and absolute bandwidth

excess bandwidth and minimum nyquist bandwidth

absolute bandwidth and minimum nyquist bandwidth

none of the mentioned

Q19 | A pulse shaping filter should satisfy two requirements. They are

should be realizable

should have proper roll off factor

should be realizable & have proper roll off factor

none of the mentioned

Q20 | Examples of double side band signals are

ask

psk

ask & psk

none of the mentioned

Q21 | ISI is by increasing channel bandwidth.

maximized

minimized

zero

infinite

Q22 | Why is pulse shaping technique used?

to increase isi

to increase spectral width of modulated signal

to reduce isi

to reduce power spectral density

Q23 | Raised cosine filter does not satisfy Nyquist criteria.

true

false

Q24 | As the roll off factor in raised cosine rolloff filter the occupied bandwidth

manchester

faraday

graham bell

nyquist

Q25 | Gaussian pulse shaping filter follows Nyquist criterion.

true

false