kfr

commit 56f4aea6c6fb2716543f806193e19e883e34e914
parent dc1f7e4e50d56d4ce4c5fd5bfaf68d80178ffc2e
Author: d.levin256@gmail.com <d.levin256@gmail.com>
Date:   Fri, 19 Aug 2016 22:10:40 +0300

Add documentation for biquad filter functions

Diffstat:
M
include/kfr/dsp/biquad.hpp
 | 
15
+++++++++++++++
M
include/kfr/dsp/biquad_design.hpp
 | 
49
+++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 64 insertions(+), 0 deletions(-)
diff --git a/include/kfr/dsp/biquad.hpp b/include/kfr/dsp/biquad.hpp
@@ -44,6 +44,9 @@ enum class biquad_type
     highshelf
 };
 
+/**
+ * @brief Structure for holding biquad filter coefficients.
+ */
 template <typename T>
 struct biquad_params
 {
@@ -162,12 +165,24 @@ struct expression_biquads : public expression<E1>
 };
 }
 
+/**
+ * @brief Returns template expressions that applies biquad filter to the input.
+ * @param bq Biquad coefficients
+ * @param e1 Input expression
+ */
 template <typename T, typename E1>
 CMT_INLINE internal::expression_biquads<1, T, internal::arg<E1>> biquad(const biquad_params<T>& bq, E1&& e1)
 {
     const biquad_params<T> bqs[1] = { bq };
     return internal::expression_biquads<1, T, internal::arg<E1>>(bqs, std::forward<E1>(e1));
 }
+
+/**
+ * @brief Returns template expressions that applies cascade of biquad filters to the input.
+ * @param bq Array of biquad coefficients
+ * @param e1 Input expression
+ * @note The current implementation introduces delay of N - 1 samples, where N is the filter count.
+ */
 template <size_t filters, typename T, typename E1>
 CMT_INLINE internal::expression_biquads<filters, T, internal::arg<E1>> biquad(
     const biquad_params<T> (&bq)[filters], E1&& e1)
diff --git a/include/kfr/dsp/biquad_design.hpp b/include/kfr/dsp/biquad_design.hpp
@@ -31,6 +31,12 @@
 namespace kfr
 {
 
+/**
+ * @brief Calculates coefficients for the all-pass biquad filter
+ * @param frequency Normalized frequency (frequency_Hz / samplerate_Hz)
+ * @param Q Q factor
+ * @return Biquad filter coefficients
+ */
 template <typename T = fbase>
 CMT_INLINE biquad_params<T> biquad_allpass(identity<T> frequency, identity<T> Q)
 {
@@ -46,6 +52,12 @@ CMT_INLINE biquad_params<T> biquad_allpass(identity<T> frequency, identity<T> Q)
     return { b0, b1, b2, a0, a1, a2 };
 }
 
+/**
+ * @brief Calculates coefficients for the low-pass biquad filter
+ * @param frequency Normalized frequency (frequency_Hz / samplerate_Hz)
+ * @param Q Q factor
+ * @return Biquad filter coefficients
+ */
 template <typename T = fbase>
 CMT_INLINE biquad_params<T> biquad_lowpass(identity<T> frequency, identity<T> Q)
 {
@@ -60,6 +72,12 @@ CMT_INLINE biquad_params<T> biquad_lowpass(identity<T> frequency, identity<T> Q)
     return { 1.0, b1, b2, a0, a1, a2 };
 }
 
+/**
+ * @brief Calculates coefficients for the high-pass biquad filter
+ * @param frequency Normalized frequency (frequency_Hz / samplerate_Hz)
+ * @param Q Q factor
+ * @return Biquad filter coefficients
+ */
 template <typename T = fbase>
 CMT_INLINE biquad_params<T> biquad_highpass(identity<T> frequency, identity<T> Q)
 {
@@ -74,6 +92,12 @@ CMT_INLINE biquad_params<T> biquad_highpass(identity<T> frequency, identity<T> Q
     return { 1.0, b1, b2, a0, a1, a2 };
 }
 
+/**
+ * @brief Calculates coefficients for the band-pass biquad filter
+ * @param frequency Normalized frequency (frequency_Hz / samplerate_Hz)
+ * @param Q Q factor
+ * @return Biquad filter coefficients
+ */
 template <typename T = fbase>
 CMT_INLINE biquad_params<T> biquad_bandpass(identity<T> frequency, identity<T> Q)
 {
@@ -88,6 +112,12 @@ CMT_INLINE biquad_params<T> biquad_bandpass(identity<T> frequency, identity<T> Q
     return { 1.0, b1, b2, a0, a1, a2 };
 }
 
+/**
+ * @brief Calculates coefficients for the notch biquad filter
+ * @param frequency Normalized frequency (frequency_Hz / samplerate_Hz)
+ * @param Q Q factor
+ * @return Biquad filter coefficients
+ */
 template <typename T = fbase>
 CMT_INLINE biquad_params<T> biquad_notch(identity<T> frequency, identity<T> Q)
 {
@@ -102,6 +132,13 @@ CMT_INLINE biquad_params<T> biquad_notch(identity<T> frequency, identity<T> Q)
     return { 1.0, b1, b2, a0, a1, a2 };
 }
 
+/**
+ * @brief Calculates coefficients for the peak biquad filter
+ * @param frequency Normalized frequency (frequency_Hz / samplerate_Hz)
+ * @param Q Q factor
+ * @param gain Gain in dB
+ * @return Biquad filter coefficients
+ */
 template <typename T = fbase>
 CMT_INLINE biquad_params<T> biquad_peak(identity<T> frequency, identity<T> Q, identity<T> gain)
 {
@@ -133,6 +170,12 @@ CMT_INLINE biquad_params<T> biquad_peak(identity<T> frequency, identity<T> Q, id
     return result;
 }
 
+/**
+ * @brief Calculates coefficients for the low-shelf biquad filter
+ * @param frequency Normalized frequency (frequency_Hz / samplerate_Hz)
+ * @param gain Gain in dB
+ * @return Biquad filter coefficients
+ */
 template <typename T = fbase>
 CMT_INLINE biquad_params<T> biquad_lowshelf(identity<T> frequency, identity<T> gain)
 {
@@ -164,6 +207,12 @@ CMT_INLINE biquad_params<T> biquad_lowshelf(identity<T> frequency, identity<T> g
     return result;
 }
 
+/**
+ * @brief Calculates coefficients for the high-shelf biquad filter
+ * @param frequency Normalized frequency (frequency_Hz / samplerate_Hz)
+ * @param gain Gain in dB
+ * @return Biquad filter coefficients
+ */
 template <typename T = fbase>
 CMT_INLINE biquad_params<T> biquad_highshelf(identity<T> frequency, identity<T> gain)
 {