Simplified technique for syllabic companding in log-domain filters
نویسندگان
چکیده
Introduction: Fig. 1a shows a first-order log-domain filter [1] which is ideally linear and time-invariant (LTI) [1, 2] between the large signal currents i1p and i4p in its input and output transistors (Fig. 1a, assuming i1p > 0). i1p is the sum of an AC input signal iin and a bias Ibias. In traditional implementations, Ibias is a constant. The output ioutp is obtained by subtracting (I2/I3)Ibias from i4p as shown in Fig. 1a (I2/I3 is the DC gain of the filter [1, 2]).
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