Explanation:
( a )
The four types of spread spectrum techniques are as follows -
1. Direct sequence spread spectrum .
2. frequency hopping spread spectrum .
3. chirp spread spectrum .
4. time hopping spread spectrum .
( b )
The Direct sequence spread spectrum was devised for eavesdropping in the military .
In the field of telecommunications , the Direct sequence spread spectrum , it is the technique of spread spectrum modulation which is used to reduce the overall inference of the signal .
