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GATE 2014 EC (EC3) – Question 61

Communications · Digital Communications · 2 marks · Numerical answer

A PCM system samples $m(t)=\sin(100\pi t)+\cos(100\pi t)$ V at the Nyquist rate and uniformly quantizes with step 0.75 V. Find minimum data rate (bits/s).

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Correct answer: 199 to 201

Explanation

The message sin(100πt)+cos(100πt) has highest frequency50Hz and peak amplitude√2V. Nyquist sampling needs100samples/s. Its full range2√2V divided by0.75V requires ceil(2√2/0.75)=4levels, or2bits/sample. Therefore the minimum rate is **100×2=200bits/s**.