[amp_mcq option1=”BPSK” option2=”8-PSK” option3=”DQPSK” option4=”AFSK” correct=”option3″]
The correct answer is C. DQPSK.
DQPSK stands for Differential Quadrature Phase Shift Keying. It is a modulation technique that uses two phases, 0° and 90°, to represent two binary digits, 0 and 1. The phase of the carrier signal is shifted by 90° between each symbol. This makes it more robust to noise than other modulation techniques, such as BPSK (Binary Phase Shift Keying).
BPSK uses only two phases, 0° and 180°, to represent two binary digits. This makes it less robust to noise than DQPSK.
8-PSK uses eight phases, 0°, 45°, 90°, 135°, 180°, 225°, 270°, and 315°, to represent eight binary digits. This makes it more efficient than DQPSK, but it is also less robust to noise.
AFSK stands for Audio Frequency Shift Keying. It is a modulation technique that uses changes in the frequency of a carrier signal to represent binary digits. This is a very old modulation technique that is not very efficient or robust.
In conclusion, the correct answer is C. DQPSK.