add an ideal ADC transfer function to generate data sets

3269c97e · Juan David Gonzalez Cobas · 95d851b6 · 3269c97e
Commit 3269c97e authored Jan 30, 2011 by Juan David Gonzalez Cobas
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ideal.py ideal.py +40 -0

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--- a/ideal.py
+++ b/ideal.py
+#!  /bin/sh
+#   coding: utf-8
+#   vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
+
+def ideal_adc(vals, N, Vmin, Vmax, mid_tread=False):
+    """computes an ideal ADC characteristic function
+
+    vals is a vector of values to be converted by an 
+    ideal ADC whose characteristic is defined by the Vmin and Vmax full
+    scale range, and the N number of bits. The optional mid_tread
+    parameter allow to use the mid_tread convention as per
+    IEEE 1241 sec. 1.2.
+
+    A vector of converted vals object is returned, taking into account
+    saturation at both ends of scale
+    """
+
+    FS = float(Vmax - Vmin)
+    lsb = FS / 2**N
+
+    if mid_tread:
+        vals = vals + lsb/2
+
+    t = (vals - Vmin) / lsb
+    print vals, t
+    code = array(t, dtype=int)
+    code[code<0] = 0
+    code[code>(2**N-1)] = 2**N-1
+    return code
+
+if __name__ == '__main__':
+
+    from numpy import *
+    from matplotlib import pyplot as pl
+
+    v = linspace(-1.0, 11, 3000)
+    print v
+    my_adc = ideal_adc(v, 4, 0, 10.0, mid_tread=1)
+    pl.plot(v, my_adc)
+    pl.show()