Topic: Communication Systems
The information rate to be transmitted is 900 bits/sec, FEC is $3/4$, the symbol rate of QPSK modulation scheme is
- A. 225 symbols/sec
- B. 450 symbols/sec
- C. 600 symbols/sec
- D. 675 symbols/sec
Answer: C. 600 symbols/sec
Explanation: Information rate $= 900~bits/sec$. Forward error correction is $3/4$. So, total number of bits/sec $= 900\times\frac{4}{3} = 1200~bits/sec$. Since it is QPSK modulation, so symbol rate is $=\frac{R_{b}}{2} = \frac{1200}{2} = 600~bits/sec$.