m-labs · Apr 5, 2015 · Apr 5, 2015
Showing with 28 additions and 40 deletions.

+8 −15 artiq/devices/pdq2/driver.py

+6 −0 artiq/test/wavesynth.py

+5 −24 artiq/wavesynth/compute_samples.py

+9 −1 artiq/wavesynth/interpolate.py
diff --git a/artiq/devices/pdq2/driver.py b/artiq/devices/pdq2/driver.py
@@ -6,13 +6,16 @@
 
 import serial
 
+from artiq.wavesynth.interpolate import discrete_compensate
+
+
 logger = logging.getLogger(__name__)
 
 
 class Segment:
     max_time = 1 << 16  # uint16 timer
     max_val = 1 << 15  # int16 DAC
-    max_out = 10. # Volt
+    max_out = 10.  # Volt
     out_scale = max_val/max_out
     cordic_gain = 1.
     for i in range(16):
@@ -53,24 +56,13 @@ def pack(widths, values):
                          values, widths, ud, fmt, e)
             raise e
 
-    @staticmethod
-    def compensate(coef):
-        """compensates higher order spline coefficients for integrator chain
-        latency"""
-        order = len(coef)
-        if order > 2:
-            coef[1] += coef[2]/2.
-        if order > 3:
-            coef[1] += coef[3]/6.
-            coef[2] += coef[3]
-        return coef
-
     def bias(self, amplitude=[], **kwargs):
         """Append a bias line to this segment.
 
         Amplitude in volts
         """
-        coef = self.compensate([self.out_scale*a for a in amplitude])
+        coef = [self.out_scale*a for a in amplitude]
+        discrete_compensate(coef)
         data = self.pack([0, 1, 2, 2], coef)
         self.line(typ=0, data=data, **kwargs)
 
@@ -83,7 +75,8 @@ def dds(self, amplitude=[], phase=[], **kwargs):
         phase[2] in turns*(sample_rate/2**shift)**2
         """
         scale = self.out_scale/self.cordic_gain
-        coef = self.compensate([scale*a for a in amplitude])
+        coef = [scale*a for a in amplitude]
+        discrete_compensate(coef)
         if phase:
             assert len(amplitude) == 4
         coef += [p*self.max_val*2 for p in phase]

diff --git a/artiq/test/wavesynth.py b/artiq/test/wavesynth.py
@@ -116,3 +116,9 @@ def drive(self):
 
     def test_run(self):
         x, y = self.drive()
+
+    @unittest.skip("manual/visual test")
+    def test_plot(self):
+        import cairoplot
+        x, y = self.drive()
+        cairoplot.scatter_plot("plot.png", [x, y])
diff --git a/artiq/wavesynth/compute_samples.py b/artiq/wavesynth/compute_samples.py
@@ -1,22 +1,16 @@
 from copy import copy
 from math import cos, pi
 
-
-def discrete_compensate(c):
-    if len(c) > 2:
-        c[1] += c[2]/2
-    if len(c) > 3:
-        c[1] += c[3]/6
-        c[2] += c[3]
-    return c
+from artiq.wavesynth.interpolate import discrete_compensate
 
 
 class Spline:
     def __init__(self):
         self.c = [0.0]
 
     def set_coefficients(self, c):
-        self.c = discrete_compensate(copy(c))
+        self.c = copy(c)
+        discrete_compensate(self.c)
 
     def next(self):
         r = self.c[0]
@@ -32,7 +26,8 @@ def __init__(self):
 
     def set_coefficients(self, c):
         self.c0 = c[0]
-        self.c[1:] = discrete_compensate(c[1:])
+        self.c[1:] = c[1:]
+        discrete_compensate(self.c[1:])
 
     def clear(self):
         self.c[0] = 0.0
@@ -128,17 +123,3 @@ def trigger(self):
             except StopIteration:
                 self.line_iter = None
                 return r
-
-
-def main():
-    from artiq.test.wavesynth import TestSynthesizer
-    import cairoplot
-
-    t = TestSynthesizer()
-    t.setUp()
-    x, y = t.drive()
-    cairoplot.scatter_plot("plot.png", [x, y])
-
-
-if __name__ == "__main__":
-    main()
diff --git a/artiq/wavesynth/interpolate.py b/artiq/wavesynth/interpolate.py
@@ -23,7 +23,15 @@ def _interpolate(time, data, sample_times, order=3):
     return coeffs
 
 
-def _zip_program(times, channels, target=):
+def discrete_compensate(c):
+    if len(c) > 2:
+        c[1] += c[2]/2
+    if len(c) > 3:
+        c[1] += c[3]/6
+        c[2] += c[3]
+
+
+def _zip_program(times, channels, target):
     for tc in zip(times, *channels):
         yield {
             "duration": tc[0],