typedef uint32_t ncoftw_t;
typedef int32_t ncoftwi_t;
#define NCOFTWBITS 32 // количество битов в ncoftw_t
#define FTWROUND(ftw) ((uint32_t) (ftw))
#define FTWAF001(freq) (((int_fast64_t) (freq) << NCOFTWBITS) / ARMI2SRATE100)
#define FTWAF(freq) (((int_fast64_t) (freq) << NCOFTWBITS) / ARMI2SRATE)
static FLOAT_t omega2ftw_k1; // = POWF(2, NCOFTWBITS);
#define OMEGA2FTWI(angle) ((ncoftwi_t) ((FLOAT_t) (angle) * omega2ftw_k1 / (FLOAT_t) M_TWOPI)) // angle in radians -pi..+pi to signed version of ftw_t
// Convert ncoftw_t to q31 argument for arm_sin_cos_q31
// The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179].
#define FTW2_SINCOS_Q31(angle) ((ncoftwi_t) (angle))
// Convert ncoftw_t to q31 argument for arm_sin_q31
// The Q31 input value is in the range [0 +0.9999] and is mapped to a radian value in the range [0 2*PI).
#define FTW2_COS_Q31(angle) ((q31_t) ((((ncoftw_t) (angle)) + 0x80000000uL) / 2))
#define FAST_Q31_2_FLOAT(val) ((q31_t) (val) / (FLOAT_t) 2147483648)
static RAMFUNC FLOAT_t getsinf(ncoftw_t angle)
{
FLOAT_t v;
const q31_t sinv = arm_sin_q31(FTW2_COS_Q31(angle));
//v = FAST_Q31_2_FLOAT(sinv); // todo: use arm_q31_to_float
arm_q31_to_float(& sinv, & v, 1);
return v;
}
static RAMFUNC FLOAT_t getcosf(ncoftw_t angle)
{
FLOAT_t v;
const q31_t cosv = arm_cos_q31(FTW2_COS_Q31(angle));
//v = FAST_Q31_2_FLOAT(cosv); // todo: use arm_q31_to_float
arm_q31_to_float(& cosv, & v, 1);
return v;
}
static RAMFUNC FLOAT32P_t getsincosf(ncoftw_t angle)
{
FLOAT32P_t v;
q31_t sincosv [2];
#if 1
sincosv [0] = arm_sin_q31(FTW2_COS_Q31(angle));
sincosv [1] = arm_cos_q31(FTW2_COS_Q31(angle));
#else
arm_sin_cos_q31(FTW2_SINCOS_Q31(angle), & sincosv [0], & sincosv [1]);
// at index 0 all fine
// at index 1 with sidetones
#endif
arm_q31_to_float(sincosv, v.ivqv, 2);
return v;
}
static RAMDTCM ncoftw_t anglestep_lout2 = FTWAF(5600), anglestep_rout2 = FTWAF(6300);
static RAMDTCM ncoftw_t angle_lout2, angle_rout2;
static int get_lout24(void)
{
// Формирование значения для LOUT
//const int v = arm_sin_q31(angle_lout2 / 2) / 256;
const int v = getcosf(angle_lout2) * INT24_MAX;
angle_lout2 = FTWROUND(angle_lout2 + anglestep_lout2);
return v;
}
После перехода с таблицы 90 градусов из 16385 float без апроксимации на CMSIS DSP спектр стал лучше
