diff options
Diffstat (limited to 'libaf/window.c')
| -rw-r--r-- | libaf/window.c | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/libaf/window.c b/libaf/window.c index 0230c33673..2b2923afc9 100644 --- a/libaf/window.c +++ b/libaf/window.c @@ -46,7 +46,7 @@ void af_window_boxcar(int n, FLOAT_TYPE* w) /* // Triang a.k.a Bartlett // -// | (N-1)| +// | (N-1)| // 2 * |k - -----| // | 2 | // w = 1.0 - --------------- @@ -60,7 +60,7 @@ void af_window_triang(int n, FLOAT_TYPE* w) FLOAT_TYPE k2 = 1/((FLOAT_TYPE)n + k1); int end = (n + 1) >> 1; int i; - + // Calculate window coefficients for (i=0 ; i<end ; i++) w[i] = w[n-i-1] = (2.0*((FLOAT_TYPE)(i+1))-(1.0-k1))*k2; @@ -79,7 +79,7 @@ void af_window_hanning(int n, FLOAT_TYPE* w) { int i; FLOAT_TYPE k = 2*M_PI/((FLOAT_TYPE)(n+1)); // 2*pi/(N+1) - + // Calculate window coefficients for (i=0; i<n; i++) *w++ = 0.5*(1.0 - cos(k*(FLOAT_TYPE)(i+1))); @@ -138,23 +138,23 @@ void af_window_flattop(int n,FLOAT_TYPE* w) int i; FLOAT_TYPE k1 = 2*M_PI/((FLOAT_TYPE)(n-1)); // 2*pi/(N-1) FLOAT_TYPE k2 = 2*k1; // 4*pi/(N-1) - + // Calculate window coefficients for (i=0; i<n; i++) *w++ = 0.2810638602 - 0.5208971735*cos(k1*(FLOAT_TYPE)i) + 0.1980389663*cos(k2*(FLOAT_TYPE)i); } -/* Computes the 0th order modified Bessel function of the first kind. -// (Needed to compute Kaiser window) -// +/* Computes the 0th order modified Bessel function of the first kind. +// (Needed to compute Kaiser window) +// // y = sum( (x/(2*n))^2 ) // n */ -#define BIZ_EPSILON 1E-21 // Max error acceptable +#define BIZ_EPSILON 1E-21 // Max error acceptable static FLOAT_TYPE besselizero(FLOAT_TYPE x) -{ +{ FLOAT_TYPE temp; FLOAT_TYPE sum = 1.0; FLOAT_TYPE u = 1.0; @@ -183,10 +183,10 @@ static FLOAT_TYPE besselizero(FLOAT_TYPE x) // Gold (Theory and Application of DSP) under Kaiser windows for more // about Beta. The following table from Rabiner and Gold gives some // feel for the effect of Beta: -// +// // All ripples in dB, width of transition band = D*N where N = window // length -// +// // BETA D PB RIP SB RIP // 2.120 1.50 +-0.27 -30 // 3.384 2.23 0.0864 -40 @@ -203,8 +203,8 @@ void af_window_kaiser(int n, FLOAT_TYPE* w, FLOAT_TYPE b) FLOAT_TYPE k1 = 1.0/besselizero(b); int k2 = 1 - (n & 1); int end = (n + 1) >> 1; - int i; - + int i; + // Calculate window coefficients for (i=0 ; i<end ; i++){ tmp = (FLOAT_TYPE)(2*i + k2) / ((FLOAT_TYPE)n - 1.0); |