Extraction of circuit transfer functions with SuTra analyses

Finding node admittance and voltage gain transfer functions with SuTra (Suspendance and Trajectance) analyses are introduced in this paper. All other transfer functions are obtained when the two fundamental node admittance and voltage gain transfer functions are calculated. The numerator of the node admittance is obtained by Suspendance analysis and the numerator of the voltage gain is obtained by Trajectance analysis. The denominator of both transfer functions are obtained by Suspendance analysis when the input node of the circuit is shorted to ground. To calculate Suspendance, passive components are shorted at a time and their admittances are multiplied by the Suspendance of the remaining circuit which will be calculated recursively. Components shorted earlier are then removed from the circuit in following steps of Suspendance calculation. All results are added together to get the overall Suspendance. To calculate Trajectance, all paths that connect the input and output nodes through sequential passive components and dependent active sources are determined. Segments of these paths are shorted to ground and the Suspendance of the remaining circuit is calculated. The admittance contributions of each path is multiplied by its corresponding Suspendance and all results are added together to calculate Trajectance. A four-node two-stage BJT amplifier is analyzed and characterized in this paper. Results fully match with those obtained from Spice simulation verifying the effectiveness of the Suspendance and Trajectance analyses.