The impact of the bias or DC term on the performance of a second-order Volterra least-mean-square (LMS) filter is discussed. Without the DC term the filter may itself produce a biased output. It is shown that including a DC term always degrades adaptive system performance, in terms of both convergence and steady state. Unlike the usual LMS approach, the second-order scheme converges nonuniformly, even with white inputs. For deterministic signals an approximate transfer function descriptor is obtained for the second-order LMS filter. Jury (1964) tables are used to obtain explicit stability conditions. >
['Miroslav Dokic', 'Peter M. Clarkson']
On the performance of a second-order adaptive Volterra filter