NS API Structure Definitions#

group ns_defs

Defines

NS_FRAME_ADVANCE#: Length of the frame of data on which the NS will operate.

NS_PROC_FRAME_LENGTH#: Time domain samples block length used internally.

NS_PROC_FRAME_BINS#: Number of bins of spectrum data computed when doing a DFT of a NS_PROC_FRAME_LENGTH length time domain vector. The NS_PROC_FRAME_BINS spectrum values represent the bins from DC to Nyquist.

NS_INT_EXP#: The exponent used internally to keep q1.31 format.

NS_WINDOW_LENGTH#: The length of the window applied in time domain

struct ns_state_t#

#include <ns_state.h>

NS state structure.

This structure holds the current state of the NS instance and members are updated each time that ns_process_frame() runs. Many of these members are exponentially-weighted moving averages (EWMA) which influence the behaviour of the NS filter. The user should not directly modify any of these members.

Public Members

bfp_s32_t S#: BFP structure to hold the local energy.

bfp_s32_t S_min#: BFP structure to hold the minimum local energy within 10 frames.

bfp_s32_t S_tmp#: BFP structure to hold the temporary local energy.

bfp_s32_t p#: BFP structure to hold the conditional signal presence probability

bfp_s32_t alpha_d_tilde#: BFP structure to hold the time-varying smoothing parameter.

bfp_s32_t lambda_hat#: BFP structure to hold the noise estimation.

int32_t data_S[NS_PROC_FRAME_BINS]#: int32_t array to hold the data for S.

int32_t data_S_min[NS_PROC_FRAME_BINS]#: int32_t array to hold the data for S_min.

int32_t data_S_tmp[NS_PROC_FRAME_BINS]#: int32_t array to hold the data for S_tmp.

int32_t data_p[NS_PROC_FRAME_BINS]#: int32_t array to hold the data for p.

int32_t data_adt[NS_PROC_FRAME_BINS]#: int32_t array to hold the data for alpha_d_tilde.

int32_t data_lambda_hat[NS_PROC_FRAME_BINS]#: int32_t array to hold the data for lambda_hat.

bfp_s32_t prev_frame#: BFP structure to hold the previous frame.

bfp_s32_t overlap#: BFP structure to hold the overlap.

bfp_s32_t wind#: BFP structure to hold the first part of the window.

bfp_s32_t rev_wind#: BFP structure to hold the second part of the window.

int32_t data_prev_frame[NS_PROC_FRAME_LENGTH - NS_FRAME_ADVANCE]#: int32_t array to hold the data for prev_frame.

int32_t data_ovelap[NS_FRAME_ADVANCE]#: int32_t array to hold the data for overlap.

int32_t data_rev_wind[NS_WINDOW_LENGTH / 2]#: int32_t array to hold the data for rev_wind.

float_s32_t delta#: EWMA of the energy ratio to calculate p.

float_s32_t alpha_d#: EWMA of the smoothing parameter for alpha_d_tilde.

float_s32_t alpha_s#: EWMA of the smoothing parameter for S.

float_s32_t alpha_p#: EWMA of the smoothing parameter for p.

float_s32_t one_minus_aplha_d#: EWMA of the 1 - alpha_d parameter.

float_s32_t one_minus_alpha_s#: EWMA of the 1 - alpha_s parameter.

float_s32_t one_minus_alpha_p#: EWMA of the 1 - alpha_p parameter.

unsigned reset_period#: Filter reset period value for auto-reset.

unsigned reset_counter#: Filter reset counter.