diff options
| author | Jacob Gilbert <jacob.gilbert@protonmail.com> | 2021-01-22 21:30:45 -0800 |
|---|---|---|
| committer | mormj <34754695+mormj@users.noreply.github.com> | 2021-01-25 07:51:48 -0500 |
| commit | fabb155ccc2010021ba6e7a3d4818b851c331478 (patch) | |
| tree | 7cdee57561a1ff62ec492647585fa4c8f702cc14 /gr-fft/lib/window.cc | |
| parent | 8ae605cecdb2c9e413f660a638fc6180edc8d6f3 (diff) | |
gr-fft: adding additional window options to win_type enum
Adding Nuttall, Welch, Parzen, Exponential, Riemann, Gaussian, and Tukey window options to the win_type enum for use with the various filter design functions
Signed-off-by: Jacob Gilbert <jacob.gilbert@protonmail.com>
Diffstat (limited to 'gr-fft/lib/window.cc')
| -rw-r--r-- | gr-fft/lib/window.cc | 53 |
1 files changed, 48 insertions, 5 deletions
diff --git a/gr-fft/lib/window.cc b/gr-fft/lib/window.cc index faebdd4f56..98f0b897eb 100644 --- a/gr-fft/lib/window.cc +++ b/gr-fft/lib/window.cc @@ -50,7 +50,7 @@ double freq(int ntaps) { return 2.0 * GR_M_PI / ntaps; } double rate(int ntaps) { return 1.0 / (ntaps >> 1); } -double window::max_attenuation(win_type type, double beta) +double window::max_attenuation(win_type type, double param) { switch (type) { case (WIN_HAMMING): @@ -66,7 +66,7 @@ double window::max_attenuation(win_type type, double beta) return 21; break; case (WIN_KAISER): - return (beta / 0.1102 + 8.7); + return (param / 0.1102 + 8.7); break; case (WIN_BLACKMAN_hARRIS): return 92; @@ -77,6 +77,33 @@ double window::max_attenuation(win_type type, double beta) case (WIN_FLATTOP): return 93; break; + case WIN_NUTTALL: + return 114; + case WIN_NUTTALL_CFD: + return 112; + case WIN_WELCH: + return 31; + case WIN_PARZEN: + return 56; + case WIN_EXPONENTIAL: + // varies slightly depending on the decay factor, but this is a safe return value + return 26; + case WIN_RIEMANN: + return 39; + case WIN_GAUSSIAN: + // not meaningful for gaussian windows, but return something reasonable + return 100; + case WIN_TUKEY: + // low end is a rectangular window, attenuation exponentialy approaches Hann + // piecewise linear estimate, determined empirically via curve fitting, median + // error is less than 0.5dB and maximum error is 2.5dB; the returned value will + // never be less than expected attenuation to ensure that window designed filters + // are never below expected quality. + if (param > 0.9) + return ((param - 0.9) * 135 + 30.5); + else if (param > 0.7) + return ((param - 0.6) * 20 + 24); + return (param * 5 + 21); default: throw std::out_of_range("window::max_attenuation: unknown window type provided."); } @@ -358,12 +385,12 @@ std::vector<float> window::gaussian(int ntaps, float sigma) } std::vector<float> -window::build(win_type type, int ntaps, double beta, const bool normalize) +window::build(win_type type, int ntaps, double param, const bool normalize) { // If we want a normalized window, we get a non-normalized one first, then // normalize it here: if (normalize) { - auto win = build(type, ntaps, beta, false); + auto win = build(type, ntaps, param, false); const double pwr_acc = // sum(win**2) / len(win) std::accumulate(win.cbegin(), win.cend(), @@ -390,11 +417,27 @@ window::build(win_type type, int ntaps, double beta, const bool normalize) case WIN_BLACKMAN_hARRIS: return blackman_harris(ntaps); case WIN_KAISER: - return kaiser(ntaps, beta); + return kaiser(ntaps, param); case WIN_BARTLETT: return bartlett(ntaps); case WIN_FLATTOP: return flattop(ntaps); + case WIN_NUTTALL: + return nuttall(ntaps); + case WIN_NUTTALL_CFD: + return nuttall_cfd(ntaps); + case WIN_WELCH: + return welch(ntaps); + case WIN_PARZEN: + return parzen(ntaps); + case WIN_EXPONENTIAL: + return exponential(ntaps, param); + case WIN_RIEMANN: + return riemann(ntaps); + case WIN_GAUSSIAN: + return gaussian(ntaps, param); + case WIN_TUKEY: + return tukey(ntaps, param); default: throw std::out_of_range("window::build: type out of range"); } |