1 files changed, 56 insertions, 0 deletions
diff --git a/tran/eqbandv.alg b/tran/eqbandv.alg
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+; general order-2 IIR filter.
+; a0 is assumed to be unity.
+; for a1 and a2, our sign convention is opposite to Matlab's.
+
+(EQBANDVVV-ALG
+(NAME "eqbandvvv")
+(ARGUMENTS ("sound_type" "s1") ("sound_type" "hz"))
+;;           ("sound_type" "gain") ("sound_type" "width") )
+(START (MIN s1 hz)) ;; gain width))
+(TERMINATE (MIN s1 hz )) ;; gain width))
+(LOGICAL-STOP (MIN s1 hz)) ;; gain width))
+(SAMPLE-RATE (MAX s1))
+(INTERNAL-SCALING s1)
+(INLINE-INTERPOLATION T)
+(ALWAYS-SCALE hz)
+(STEP-FUNCTION hz gain width)
+(STATE	("double" "scale1" "s1->scale")
+        ("double" "w1" "0.0")
+        ("double" "sw" "0.0")
+        ("double" "cw" "0.0")
+        ("double" "J" "0.0")
+        ("double" "g" "0.0")
+        ("double" "b0" "0.0")
+        ("double" "b1" "0.0")
+        ("double" "b2" "0.0")
+        ("double" "a0" "0.0")
+        ("double" "a1" "0.0")
+        ("double" "a2" "0.0"))
+(DEPENDS ("w1" "hz" "PI2 * hz / s1->sr")
+         ("sw" "hz" "sin(w1)")
+         ("cw" "hz" "cos(w1)")
+         ("b1" "hz" "-2.0 * cw")
+         ("a1" "hz" "-b1")
+         ;; ("J" "gain" "sqrt(gain)")
+         ;; ("recompute" "width" "true")
+         ("recompute" "hz" "true")
+         ;; ("recompute" "gain" "true")
+)
+;; (JOINT-DEPENDENCY (("width" "hz")
+;;"if (recompute) {"
+;;"    recompute = false;"
+;;"    g = sw * sinh(log_of_2_over_2 * width * w1 / sw);"
+;;"    b0 = 1.0 + g * J;"
+;;"    b2 = 1.0 - g * J;"
+;;"    a0 = 1.0 + g / J;"
+;;"    a2 = g / J - 1.0;"
+;;"}"))
+(FORCE-INTO-REGISTER recompute)
+(STEP-FUNCTION hz) ;; gain width)
+(CONSTANT "w1" "sw" "cw" "J" "g" "b0" "b1" "b2" "b3" "a0" "a1" "a2")
+(INNER-LOOP-LOCALS "double z0;")
+(INNER-LOOP "    z0 = s + a1*z1 + a2*z2;
+    output = (sample_type) (z0*b0 + z1*b1 + z2*b2);
+    z2 = z1; z1 = z0;")
+)
+