Module real

FFT on real inputs (RFFT)

This implementation takes advantage of the symmetry properties of the FFT to compute an N-point RFFT by internally invoking an N/2-point CFFT, roughly doubling the computation speed compared to used a full N-point CFFT.

The produced output is the first half out the output returned by the corresponding N-point CFFT, i.e. the real DC value and N/2 - 1 positive-frequency terms. Additionally, the real-valued coefficient at the Nyquist frequency is packed into the imaginary part of the DC bin. The negative-frequency terms are not computed, since they can be calculated from the positive-frequency terms and are therefore redundant.

Functions

rfft_2

Perform an in-place 2-point RFFT.

rfft_4

Perform an in-place 4-point RFFT.

rfft_8

Perform an in-place 8-point RFFT.

rfft_16

Perform an in-place 16-point RFFT.

rfft_32

Perform an in-place 32-point RFFT.

rfft_64

Perform an in-place 64-point RFFT.

rfft_128

Perform an in-place 128-point RFFT.

rfft_256

Perform an in-place 256-point RFFT.

rfft_512

Perform an in-place 512-point RFFT.

rfft_1024

Perform an in-place 1024-point RFFT.

rfft_2048

Perform an in-place 2048-point RFFT.

rfft_4096

Perform an in-place 4096-point RFFT.

rfft_8192

Perform an in-place 8192-point RFFT.