I am using ADSP BF 548 evaluation board in my project,i need to perform 4096 point FFT on the acquired ADC samples, I am using hamming window before performing Real point FFT,i have done the array declaration for FFT as below, the memory section "local_buf" is the SDRAM memory i used as a Data memory,here the problem is FFT peak amplitude is varying for different frequencies with constant voltages, as for the FFT theory whatever the frequency the FFT peak amplitude should not change, i saw the array declaration for Twiddle table , FFT output and input array should not be in same memory location in VDSP++5.0 C/C++ Compiler and Library Manual for Blackfin Processors,can anyone please tell me whether the array declaration is correct with respect to memory segment?
#define N_FFT 4096
#pragma section ("local_buf")
#pragma section ("L1_data_a")
Suggest us if any correction to be made.