Working clarinet example

Filters.py

@@ -40,6 +40,43 @@ def freqz(self):
         return freqz(self.b, self.a)
 
 
+class OneZeroFilter:
+    def __init__(self, zero=-1.0):
+        self.in1 = self.in2 = self.out1 = 0.0
+        self.set_zero(zero)
+
+    def tick(self, in_sample):
+        self.in1 = in_sample
+        self.out1 = self.b1 * self.in2 + self.b0 * self.in1
+        self.in2 = self.in1
+
+        return self.out1
+
+    def set_zero(self, zero):
+        # Normalize coefficients for unity gain
+        self.b0 = 1.0 / (1.0 + zero) if zero > 0 else 1.0 / (1.0 - zero)
+        self.b1 = -zero * self.b0
+
+    # TODO could be broken
+    def phase_delay(self, frequency, fs=44100):
+        omega_t = 2 * np.pi * frequency / fs
+        real = 0.0
+        imag = 0.0
+        real += self.b0 * np.cos(0)
+        imag -= self.b0 * np.sin(0)
+        real += self.b1 * np.cos(omega_t)
+        imag += self.b1 * np.sin(omega_t)
+        phase = np.arctan2(imag, real)
+        phase = -phase % (2 * np.pi)
+        return phase / omega_t
+
+    def set_coefficients(self, b0, b1):
+        self.b0 = b0
+        self.b1 = b1
+
+    def clear(self):
+        self.in1 = self.in2 = self.out1 = 0.0
+
 # One-pole lowpass with feedback coefficient of 0.5
 class OnePoleFilter:
     def __init__(self, g=0.5, p=0.5):
@@ -52,6 +89,8 @@ def tick(self, in_sample):
         self.z_1 = out_sample
         return out_sample
 
+    def clear(self):
+        self.z_1 = 0.0
 
 class TwoZeroFilter:
     def __init__(self):

Generators.py

@@ -1,3 +1,5 @@
+import numpy as np
+
 class ImpulseGenerator:
     def __init__(self):
         self.is_first_sample = True
@@ -11,8 +13,27 @@ def reset(self):
         self.is_first_sample = True
 
 class NoiseGenerator:
+    def __init__(self, gain=1.0):
+        self.gain = gain
+
     def tick(self):
-        return np.random.uniform(low=-1.0, high=1.0)
+        return self.gain * np.random.uniform(low=-1.0, high=1.0)
 
     def reset(self):
         return self
+
+# Very naive implementation
+class SineGenerator:
+    def __init__(self, fs=44100):
+        self.fs = fs
+        self.frequency = 1.0
+        self.amplitude = 1.0
+        self.t_radians = 0.0
+
+    def tick(self):
+        out_sample = self.amplitude * np.sin(self.t_radians)
+        self.t_radians += 2 * np.pi * self.frequency / self.fs
+        return out_sample
+
+    def set_frequency(self, frequency):
+        self.frequency = frequency