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This set of Communication Engineering Multiple Choice Questions & Answers (MCQs) focuses on Communication Engineering Set 7

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