Feb 2, 2015 #1 S shan14 Member level 3 Joined Aug 18, 2014 Messages 61 Helped 0 Reputation 0 Reaction score 0 Trophy points 6 Activity points 393 different type of FFTs ; Is output same?? Hi I have few questions 1) does output of radix 2 and radix 4 FFT are same if inputs are same?? 2) does output of radix 2 and radix 4 FFT are same if one FFT is floating point and other is fixed point?? 3) also twiddle factors are different of both FFTs hence output can not be same, Is it right?? Last edited: Feb 2, 2015
different type of FFTs ; Is output same?? Hi I have few questions 1) does output of radix 2 and radix 4 FFT are same if inputs are same?? 2) does output of radix 2 and radix 4 FFT are same if one FFT is floating point and other is fixed point?? 3) also twiddle factors are different of both FFTs hence output can not be same, Is it right??
Feb 6, 2015 #2 M MagicianT Junior Member level 1 Joined Aug 16, 2014 Messages 16 Helped 3 Reputation 6 Reaction score 3 Trophy points 13 Location Montreal, QC, Canada. Activity points 113 Re: different type of FFTs ; Is output same?? shan14 said: Hi I have few questions 1) does output of radix 2 and radix 4 FFT are same if inputs are same?? 2) does output of radix 2 and radix 4 FFT are same if one FFT is floating point and other is fixed point?? 3) also twiddle factors are different of both FFTs hence output can not be same, Is it right?? Click to expand... 1). Yes. 2). Depends how you interpret "the same", is "float X" and "int32_t X" the same? 3).Twiddle factors are sine and cosine functions, they are always the same, but radix-2 needs 45 and 135 degrees and radix-4 doesn't.
Re: different type of FFTs ; Is output same?? shan14 said: Hi I have few questions 1) does output of radix 2 and radix 4 FFT are same if inputs are same?? 2) does output of radix 2 and radix 4 FFT are same if one FFT is floating point and other is fixed point?? 3) also twiddle factors are different of both FFTs hence output can not be same, Is it right?? Click to expand... 1). Yes. 2). Depends how you interpret "the same", is "float X" and "int32_t X" the same? 3).Twiddle factors are sine and cosine functions, they are always the same, but radix-2 needs 45 and 135 degrees and radix-4 doesn't.