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Code No: 07A5EC09 Set No. 2
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
III B.Tech. I Sem., I Mid-Term Examinations, September – 2010
DIGITAL COMMUNICATIONS
Objective Exam
Name: ______________________________ Hall Ticket No.
Answer All Questions. All Questions Carry Equal Marks.Time: 20 Min. Marks: 20.
I Choose the correct alternative:
1) The quantization error in PCM when Δ is the step size [ ]
A) Δ 2 /12 B) Δ 2 /2 C) Δ 2 /4 D) Δ 2 /3
2) Quantization noise occurs in [ ]
A) TDM B)FDM C) PCM D)PWM
3) Non Uniform quantization is used to make [ ]
A) (S/N) q
is uniform B) (S/N) q
is non-uniform
C) (S/N) q
is high D) (S/N) q
is low
4) Slope Overload distortion in DM can be reduced by [ ]
A) Increasing step size B)Decreasing step size
C) Uniform step size D)Zero step size
5) Which of the following requires more band width [ ]
A) ASK B)PSK C)FSK D)DPSK
6) Companding results in [ ]
A) More S/N ratio at higher amplitudes B) More S/N ratio at lower amplitudes
C) Uniform S/N ratio throughout the signal D) Better S/N ratio at lower frequencies
7) Mean square quantization noise in the PCM system with step size of 2V is [ ]
A)1/3 B)1/12 C)3/2 D)2
8) Word length in Delta modulation in Delta modulation is [ ]
A)3 bits B)2 bits C)1 bit D)2 n bits
9) Which of the following gives minimum probability of error [ ]
A)FSK B)ASK C)DPSK D)PSK
10) QPSK is an example of M-ary data transmission with M= [ ]
A)2 B)8 C)6 D)4
A
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