Scientific paper ID 483 : 2011/1

In the paper a method of first ? order sensitivity analysis of signal ? flow graph of synthesized complex continuous- and discrete-time filters is presented. It is based on a nullor model of the signal ? flow graph of the real and imagine parts of the complex filter. Using nullors a reduced matrix is obtained with elements that are corresponding of the transmission coefficients of the SFG. The method takes into consideration the symmetry and anti-symmetry of the signal-flow graph. As a result, a matrix of transfer function is received, between mixed and source vertexes of the signal ? flow graph, that lets electrical devices with many inputs and outputs to be considered. Simplification of the expressions is gotten, when the transmission coefficient is connected only with a mixed vertex or a source vertex. The method developed is especially oriented to the sensitivity analysis of complex active RC-, switched-capacitor- or digital filters. Formulas for the evaluation of first ? order SFG transfer function sensitivities matrixes are obtained without restrictions about the kind of the signal ? flow graph and the numbers of the input and output vertices. An example is presented and the first ? order sensitivity of signal-flow graph of the real and imagine parts of the transfer function of the complex continue filter with respect to a passive element is determined.