Struct dft_resampler_params¶

`struct` dft_resampler_params dft ¶

struct dft_resampler_params { … }

Parameters for constructing a dft_resampler .

The resampling factor is restricted to a power of two (positive for upsampling, negative for downsampling, zero for filter-only). The lowpass filter is designed with a Kaiser window from the desired stopband attenuation and transition width.

`variable` shift ¶

int shift

Resampling factor as a power of 2 (e.g. 1 for 2x, -1 for 0.5x, 0 for filter-only).

Fully qualified name: kfr::dft_resampler_params::shift

Declared at dft/dft_resampler.hpp:55

`variable` cutoff ¶

fbase cutoff

Normalised cutoff frequency (0..1], where 1.0 = Nyquist of the output rate.

Fully qualified name: kfr::dft_resampler_params::cutoff

Declared at dft/dft_resampler.hpp:56

`variable` stopband_atten_db ¶

fbase stopband_atten_db

Desired stopband attenuation in dB (e.g. 144). Controls Kaiser beta.

Fully qualified name: kfr::dft_resampler_params::stopband_atten_db

Declared at dft/dft_resampler.hpp:57

`variable` transition_width ¶

fbase transition_width

Transition bandwidth normalised to the lower-rate Nyquist (0..1].

Fully qualified name: kfr::dft_resampler_params::transition_width

Declared at dft/dft_resampler.hpp:58

`variable` input_block_size ¶

size_t
    input_block_size

Computed FFT block size (power of two) satisfying the overlap-save constraint.

Fully qualified name: kfr::dft_resampler_params::input_block_size

Declared at dft/dft_resampler.hpp:61

`function` factor() ¶

size_t factor() const noexcept

Returns the absolute resampling factor (2^|shift|).

Fully qualified name: kfr::dft_resampler_params::factor()

Declared at dft/dft_resampler.hpp:64

`function` is_downsampling() ¶

bool is_downsampling() const noexcept

Returns true if this is a downsampling configuration.

Fully qualified name: kfr::dft_resampler_params::is_downsampling()

Declared at dft/dft_resampler.hpp:66

`function` stage_factor() ¶

double stage_factor() const noexcept

Returns the per-stage conversion ratio (>1 for upsampling, <1 for downsampling).

Fully qualified name: kfr::dft_resampler_params::stage_factor()

Declared at dft/dft_resampler.hpp:68

`constructor` dft_resampler_params(int, fbase, fbase, fbase) ¶

dft_resampler_params(int shift, fbase cutoff = 1, fbase stopband_atten_db = 144,
                     fbase transition_width = 0.02) noexcept

Constructs resampler parameters.

Parameters
shift	Resampling factor as a power of 2 (positive=up, negative=down, 0=filter-only).
cutoff	Normalised cutoff frequency (0..1] relative to the output Nyquist.
stopband_atten_db	Desired stopband attenuation in dB.
transition_width	Transition bandwidth normalised to the lower-rate Nyquist (0..1).

Note

input_block_size is computed from the Kaiser filter-length formula and rounded up to the next power of two.

Fully qualified name: kfr::dft_resampler_params::dft_resampler_params(int, fbase, fbase, fbase)

Declared at dft/dft_resampler.hpp:79

Fully qualified name: kfr::dft_resampler_params

Declared at dft/dft_resampler.hpp:53

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Struct dft_resampler_params¶