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Added an audio FFT view in Wideband FM receive

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Tried speeding up fill_rectangle for clearing the waveform widget
This commit is contained in:
furrtek 2018-05-21 18:46:48 +01:00
parent b11c3c94b6
commit b813b32593
19 changed files with 259 additions and 38 deletions
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21
firmware/common/dsp_fft.hpp
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@ -100,25 +100,26 @@ void fft_swap_in_place(std::array<T, N>& data) {
/* http://www.drdobbs.com/cpp/a-simple-and-efficient-fft-implementatio/199500857?pgno=3 */
template<typename T, size_t N>
void fft_c_preswapped(std::array<T, N>& data) {
void fft_c_preswapped(std::array<T, N>& data, const size_t from, const size_t to) {
static_assert(power_of_two(N), "only defined for N == power of two");
constexpr auto K = log_2(N);
if ((to > K) || (from > K)) return;
constexpr size_t K_max = 8;
static_assert(K <= K_max, "No FFT twiddle factors for K > 8");
static constexpr std::array<std::complex<float>, K_max> wp_table { {
{ -2.0f, 0.0f },
{ -1.0f, -1.0f },
{ -0.2928932188134524756f, -0.7071067811865475244f },
{ -0.076120467488713243872f, -0.38268343236508977173f },
{ -0.019214719596769550874f, -0.19509032201612826785f },
{ -0.0048152733278031137552f, -0.098017140329560601994f },
{ -0.0012045437948276072852f, -0.049067674327418014255f },
{ -0.00030118130379577988423f, -0.024541228522912288032f },
{ -2.0f, 0.0f }, // 2
{ -1.0f, -1.0f }, // 4
{ -0.2928932188134524756f, -0.7071067811865475244f }, // 8
{ -0.076120467488713243872f, -0.38268343236508977173f }, // 16
{ -0.019214719596769550874f, -0.19509032201612826785f }, // 32
{ -0.0048152733278031137552f, -0.098017140329560601994f }, // 64
{ -0.0012045437948276072852f, -0.049067674327418014255f }, // 128
{ -0.00030118130379577988423f, -0.024541228522912288032f }, // 256
} };
/* Provide data to this function, pre-swapped. */
for(size_t k = 0; k < log_2(N); k++) {
for(size_t k = from; k < to; k++) {
const size_t mmax = 1 << k;
const auto wp = wp_table[k];
T w { 1.0f, 0.0f };