firdecim_rrrf

Finite impulse response (FIR) decimator

Public Functions

firdecim_rrrf	firdecim_rrrf_create(unsigned int _M, float * _h, unsigned int _h_len)
firdecim_rrrf	firdecim_rrrf_create_kaiser(unsigned int _M, unsigned int _m, float _as)
firdecim_rrrf	firdecim_rrrf_create_prototype(int _type, unsigned int _M, unsigned int _m, float _beta, float _dt)
firdecim_rrrf	firdecim_rrrf_copy(firdecim_rrrf _q)
int	firdecim_rrrf_destroy(firdecim_rrrf _q)
int	firdecim_rrrf_print(firdecim_rrrf _q)
int	firdecim_rrrf_reset(firdecim_rrrf _q)
unsigned int	firdecim_rrrf_get_decim_rate(firdecim_rrrf _q)
int	firdecim_rrrf_set_scale(firdecim_rrrf _q, float _scale)
int	firdecim_rrrf_get_scale(firdecim_rrrf _q, float * _scale)
int	firdecim_rrrf_freqresp(firdecim_rrrf _q, float _fc, float complex * _H)
int	firdecim_rrrf_execute(firdecim_rrrf _q, float * _x, float * _y)
int	firdecim_rrrf_execute_block(firdecim_rrrf _q, float * _x, unsigned int _n, float * _y)

Interfaces

firdecim_rrrf firdecim_rrrf_create(unsigned int _M, float * _h, unsigned int _h_len)∞

Create decimator from external coefficients

• _M : decimation factor, 2 <= _M
• _h : filter coefficients, shape: (_h_len, 1)
• _h_len : filter length, _M <= _h_len

firdecim_rrrf firdecim_rrrf_create_kaiser(unsigned int _M, unsigned int _m, float _as)∞

Create decimator from filter prototype prototype (Kaiser-Bessel windowed-sinc function)

• _M : decimation factor, 2 <= _M
• _m : filter delay [symbols], 1 <= _m
• _as : stop-band attenuation [dB], 0 <= _as

firdecim_rrrf firdecim_rrrf_create_prototype(int _type, unsigned int _M, unsigned int _m, float _beta, float _dt)∞

Create decimator object from filter prototype

• _type : filter type (e.g. LIQUID_FIRFILT_RCOS)
• _M : interpolation factor, 1 < _M
• _m : filter delay (symbols), 0 < _m
• _beta : excess bandwidth factor, 0 <= _beta <= 1
• _dt : fractional sample delay, -1 <= _dt <= 1

firdecim_rrrf firdecim_rrrf_copy(firdecim_rrrf _q)∞

Copy object including all internal objects and state

int firdecim_rrrf_destroy(firdecim_rrrf _q)∞

Destroy decimator object, freeing all internal memory

int firdecim_rrrf_print(firdecim_rrrf _q)∞

Print decimator object properties to stdout

int firdecim_rrrf_reset(firdecim_rrrf _q)∞

Reset decimator object internal state

unsigned int firdecim_rrrf_get_decim_rate(firdecim_rrrf _q)∞

Get decimation rate

int firdecim_rrrf_set_scale(firdecim_rrrf _q, float _scale)∞

Set output scaling for decimator

• _q : decimator object
• _scale : scaling factor to apply to each output sample

int firdecim_rrrf_get_scale(firdecim_rrrf _q, float * _scale)∞

Get output scaling for decimator

• _q : decimator object
• _scale : scaling factor to apply to each output sample

int firdecim_rrrf_freqresp(firdecim_rrrf _q, float _fc, float complex * _H)∞

Compute complex frequency response \(H\) of decimator on prototype filter coefficients at a specific frequency \(f_c\)

• _q : decimator object
• _fc : normalized frequency for evaluation
• _H : pointer to output complex frequency response

int firdecim_rrrf_execute(firdecim_rrrf _q, float * _x, float * _y)∞

Execute decimator on _M input samples

• _q : decimator object
• _x : input samples, shape: (_M, 1)
• _y : output sample pointer

int firdecim_rrrf_execute_block(firdecim_rrrf _q, float * _x, unsigned int _n, float * _y)∞

Execute decimator on block of _n*_M input samples

• _q : decimator object
• _x : input array, shape: (_n*_M, 1)
• _n : number of _output_ samples
• _y : output array, [_size: _n x 1]