How many complex multiplications are performed in computing the N-point DFT of a sequence using divide-and-conquer method if N=LM?
A. N(L+M+2)
B. N(L+M-2)
C. N(L+M-1)
D. N(L+M+1)
Answer:A
How many complex multiplications are performed in computing the N-point DFT of a sequence using divide-and-conquer method if N=LM?
A. N(L+M+2) B. N(L+M-2) C. N(L+M-1) D. N(L+M+1)
Explanation: The expression for N point DFT is given as The first step involves L DFTs, each of M points. Hence this step requires LM2 complex multiplications, second require LM and finally third requires ML2. So, Total complex multiplications= N(L+M+1).