octagonal/rdsp-experiments
1
1
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Finalizes fft, working-ish bfsk

Browse Source
This commit is contained in:
Albin Chaboissier
2025-09-26 17:12:48 +02:00
parent 00b4756138
commit 25a2dd47c3
9 changed files with 169 additions and 4941 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
src/fft/rader.rs
View File

@ -4,7 +4,9 @@ use std::f32::consts::PI;
use crate::{
complex::Complex32,
fft::{create_fft, dft::NaiveDFT, is_prime, DFTAlgorithm, FFTDirection},
fft::{
DFTAlgorithm, FFTDirection, create_fft, dft::NaiveDFT, is_prime, mixed_radix::MixedRadixFFT,
},
};
pub struct RaderFFT {
@ -31,21 +33,23 @@ impl DFTAlgorithm for RaderFFT {
let permutations: Box<[usize]> = (0..(size - 1)).map(|i| exp_mod(g, i + 1, size)).collect();
// Compute fourrier transform of twiddle factors
//let mut convolution_fft = create_fft(size - 1, FFTDirection::Forward);
let mut convolution_fft = Box::new(NaiveDFT::create(size - 1, FFTDirection::Forward));
let mut convolution_operand = (0..(size - 1))
.map(|i| {Complex32::cexp(-2. * direction.sign() * PI * (permutations[i] as f32) / (size as f32))})
let twiddle_factors = (0..(size - 1))
.map(|i| {
Complex32::cexp(
-2. * PI * direction.sign() * (permutations[i] as f32) / (size as f32),
)
})
.collect::<Vec<Complex32>>();
convolution_fft.execute(&convolution_operand);
convolution_operand = Vec::from(convolution_fft.get_output());
let mut convolution_fft = create_fft(size - 1, FFTDirection::Forward);
convolution_fft.execute(&twiddle_factors);
RaderFFT {
permutations,
convolution_operand: convolution_operand.into(),
convolution_operand: convolution_fft.get_output().iter().copied().collect(),
//convolution_ifft: create_fft(size - 1, FFTDirection::Inverse),
convolution_ifft: Box::new(NaiveDFT::create(size - 1, FFTDirection::Inverse)),
//convolution_fft,
convolution_fft,
convolution_ifft: create_fft(size - 1, FFTDirection::Inverse),
output: vec![Complex32::zero(); size].into(),
size,
@ -70,13 +74,16 @@ impl DFTAlgorithm for RaderFFT {
self.convolution_ifft.execute(&self.output);
self.output[0] = input[0];
self.output[0] = Complex32::zero();
for x in input {
self.output[0] = self.output[0] + *x;
}
for i in 0..(self.size - 1) {
// Actually compute the output
let k = self.permutations[i];
self.output[k] = (self.convolution_ifft.get_output()[i] / (self.size - 1) as f32) + input[0];
self.output[0] = self.output[0] + input[i + 1];
self.output[k] =
(self.convolution_ifft.get_output()[i] / (self.size - 1) as f32) + input[0];
}
}