File spectral_core.h

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Spectral module — public C API.

• #include "clib_common.h"

Public Functions

Public Functions Documentation

function hann_window

Fill w with a Hann window of lengthw_len .

void hann_window (
    float * w,
    size_t w_len
) 

w[k] = 0.5 * (1 - cos(2π k / (N-1))), k = 0..N-1

Peak side-lobe −31.5 dB, ENBW = 1.5 bins. Zero-parameter alternative to Kaiser when moderate rejection is sufficient.

Parameters:

• w Output buffer, length w_len.
• w_len Window length ≥ 1.

function kaiser_enbw

float kaiser_enbw (
    const float * w,
    size_t w_len
) 

function kaiser_window

void kaiser_window (
    float * w,
    size_t w_len,
    float beta
) 

function magnitude_db_cf32

Convert a CF32 spectrum to F32 dB, bin by bin.

void magnitude_db_cf32 (
    const float _Complex * in,
    size_t n,
    float * out,
    float lin_floor,
    float offset_db
) 

out[k] = 20*log10(max(|in[k]|, lin_floor)) + offset_db

Avoids per-call Python overhead on the hot FFT→display path.

Parameters:

• in CF32 spectrum, length n.
• n Number of bins.
• out F32 output, length n.
• lin_floor Amplitude floor before log10 (e.g. 1e-12f).
• offset_db Calibration/level offset added to every bin.

function magnitude_db_cf64

Convert a CF64 spectrum to F32 dB, bin by bin.

void magnitude_db_cf64 (
    const double _Complex * in,
    size_t n,
    float * out,
    double lin_floor,
    float offset_db
) 

Same as magnitude_db_cf32() but accepts double-precision input. Output is F32 (sufficient for display).

Parameters:

• in CF64 spectrum, length n.
• n Number of bins.
• out F32 output, length n.
• lin_floor Amplitude floor before log10 (e.g. 1e-12).
• offset_db Calibration/level offset added to every bin.

The documentation for this class was generated from the following file native/inc/spectral/spectral_core.h