Which statement describes spread spectrum technology in wireless communications?
A . Signal is spread across optical pulses.
B . Signal is spread across variations of amplitudes.
C . Signal is spread across one frequency.
D . Signal is spread across a whole band of frequencies.
Answer: D
Explanation:
spread-spectrum techniques are methods by which a signal with a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth. Spread spectrum generally makes use of a sequential noise- like signal structure to spread the normally narrowband information signal over a relatively wideband (radio) band of frequencies.
http://en.wikipedia.org/wiki/Spread_spectrum