Topic: Communications
A 70 MHz carrier is QPSK modulated by a 1.544 Mbps T1 data stream. The transmitter employs a raised-cosine filter with α = 0.2. What is the transmitted bandwidth of the signal?
- A. 3705.6 KHz
- B. 1852.8 KHz
- C. 308.8 KHz
- D. 926.4 KHz
Answer: D. 926.4 KHz
Explanation: F_c = 70 MHz, R_b = 1.544 Mbps, α = 0.2. BW_min = (R_b / 2) * (1 + α) = (1.544 / 2) * (1 + 0.2) = 926.4 kHz.