From cf73a158a92476ec5a129b8e4eece130bb8d181f Mon Sep 17 00:00:00 2001
From: Roman Zeyde <roman@cloudendure.com>
Date: Thu, 26 Jun 2014 20:05:45 +0300
Subject: [PATCH] WIP

---
 drift.py | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 pll.py   |  13 -------
 2 files changed, 105 insertions(+), 13 deletions(-)
 create mode 100644 drift.py

diff --git a/drift.py b/drift.py
new file mode 100644
index 0000000..1668161
--- /dev/null
+++ b/drift.py
@@ -0,0 +1,105 @@
+import numpy as np
+import itertools
+
+import recv
+import common
+
+class Filter(object):
+    def __init__(self, b, a):
+        self.b = b
+        self.a = a
+        self.x = [0] * len(b)
+        self.y = [0] * len(a)
+
+    def __call__(self, x):
+        self.x = [x] + self.x[:-1]
+        assert len(self.x) == len(self.b)
+        assert len(self.y) == len(self.a)
+        y = np.dot(self.x, self.b) - np.dot(self.y, self.a)
+        self.y = [y] + self.y[:-1]
+        return y
+
+def overlap_iter(x, n, overlap=0):
+    assert overlap >= 0
+    assert overlap < n
+    res = []
+    x = iter(x)
+    while True:
+        res.extend(itertools.islice(x, n - len(res)))
+        if len(res) < n:
+            break
+        yield tuple(res)
+        res = res[n - overlap:]
+
+def test_overlap():
+    assert list(overlap_iter(range(7), 3, 1)) == [(0,1,2), (2,3,4), (4,5,6)]
+    assert list(overlap_iter(range(7), 3, 0)) == [(0,1,2), (3,4,5)]
+
+def calib(S):
+    for S0, S1 in overlap_iter(S, 2, overlap=1):
+        dS = S1 / S0
+        yield dS
+
+class Interpolator(object):
+    def __init__(self, resolution=1000, width=20):
+        self.width = width
+        self.resolution = resolution
+        self.N = resolution * width
+        u = np.arange(-self.N, self.N, dtype=float)
+        window = (1 + np.cos(0.5 * np.pi * u / self.N)) / 2.0
+        h = np.sinc(u / resolution) * window
+        self.filt = []
+        for index in range(resolution):  # split into multiphase filters
+            self.filt.append(h[index::resolution])
+
+    def get(self, x, offset):
+        k = int(offset)
+        j = np.round((offset - k) * self.resolution)
+        h = self.filt[(self.resolution - int(j)) % self.resolution]
+
+        offset = np.ceil(offset)
+        begin, end = offset - self.width, offset + self.width
+        return np.dot(h, x[begin:end])
+
+class Sampler(object):
+    def __init__(self, src, frame_size):
+        self.src = src
+        self.freq = 1.0
+        self.offset = 0
+        self.frame_size = frame_size
+        self.buff = []
+
+    def frame(self):
+        self.buff.extend()
+
+
+    def
+
+if __name__ == '__main__':
+    import pylab
+    if 0:
+        f0 = 10e3
+        t, x = common.load('recv_10kHz.pcm')
+        S = recv.extract_symbols(x, f0)
+        S = np.array(list(S))
+
+        y = S #np.array(list(calib(S)))
+        pylab.subplot(1,2,1)
+        pylab.plot(y.real, y.imag, '.'); pylab.axis('equal')
+        pylab.subplot(1,2,2)
+        pylab.plot(np.unwrap(np.angle(y)))
+        pylab.grid('on')
+
+    t = np.arange(64) * common.Ts
+    x = np.sin(2 * np.pi * 3.456e3 * t)
+    r = Interpolator()
+
+    # pylab.figure()
+    y = []
+    k = 32 + np.linspace(-5, 5, 1001)
+    for offset in k:
+        y.append( r.get(x, offset) )
+
+    pylab.figure()
+    pylab.plot(t, x, '.', k * common.Ts, y, '-')
+    pylab.show()
diff --git a/pll.py b/pll.py
index 5815832..31ad335 100644
--- a/pll.py
+++ b/pll.py
@@ -31,19 +31,6 @@ class PLL(object):
         self.phase += self.Kphase * self.filtered_err
         self.phase += 2 * np.pi * self.freq * self.Ts
 
-class Filter(object):
-    def __init__(self, b, a):
-        self.b = b
-        self.a = a
-        self.x = [0] * len(b)
-        self.y = [0] * len(a)
-
-    def __call__(self, x):
-        self.x = [x] + self.x[:-1]
-        y = np.dot(self.x, self.b) + np.dot(self.y, self.a)
-        self.y = [y] + self.y[:-1]
-        return y
-
 def test():
     f = 1.2345678e3
     Fs = 32e3