Added initial designs

infnoise.py

@@ -0,0 +1,33 @@
+from random import random
+from math import sin
+from math import pi
+
+def updateA(A, Vsup, noise, offset):
+    """This could be built with one opamp for the multiplier, a comparator with
+    rail-to-rail outputs, and switches and caps and resistors."""
+    A += noise
+    Vref = Vsup/2.0 # Resistor divider
+    # A 3 resistor divider is used to deal with opamp offset voltage
+    # The problem is that 0.0*1.9 == 0, and if the op-amp thinks 0V is actually -1e-6*1.9V,
+    # it will try to drive as low as it can, getting stuck at 0V forever.
+    # About a 1% shift should be enough.
+    A = Vref + 0.99*(A - Vref)
+    if A > Vref:
+        # Possitive offset is the bad direction in this case
+        A = Vsup - (Vsup - (A+offset))*1.9
+        print "\b1",
+    else:
+        # Negative offset is the bad direction in this case
+        A = (A-offset)*1.9
+        print "\b0",
+    return A
+
+A = -0.01 # Just to test that it can recover from Opamp offset voltage
+Vsup = 3.3
+for i in range(2000):
+    # Model noise as a large predictable sin wave and a 1fV (fempto-volt) small unpredictable noise source
+    # The important point is that the 1fV of noise is enough to randomize the output.
+    noise = 0.1 * sin(i*2*pi/16) + 1.0e-15*(random() - 0.5)
+    # In comparison, without the 1fV of noise, the same result is computed every time:
+    #noise = 0.1 * sin(i*2*pi/16)
+    A = updateA(A, Vsup, noise, 0.001)