Relationship Between Time-constants and 3dB Cutoff of High-Order Damped LTI Systems

This paper deals with linear time-invariant (LTI) systems and examines the link between the 3dB cutoff and time-constants. It shows that the cutoff frequency of a low-pass damped network can be estimated from the reciprocal of a p-norm calculated from the system\u27s time-constants. Furthermore, to achieve good accuracy the p factor must have a fractional value, for example, p=1.7. Two formulas are derived, and their performance evaluated using Monte Carlo simulations which reveal a sub-3% error for most cases

On the SCTC-OCTC Method for the Analysis and Design of Circuits

This paper discusses guidelines that emphasize the relevance of short-circuit- and open-circuit-time constant (SCTC and OCTC, respectively) methods in the analysis and design of electronic amplifiers. It is demonstrated that it is only necessary to grasp a few concepts in order to understand that the two shortand open-circuit cases fall into a single case that can be easily addressed by low-pass and high-pass filters duality. Instead of just teaching the methods as “recipes” for frequency-performance systems analysis, SCTC and OCTC can be efficiently explained in basic analog electronic courses so as to elucidate their underlying principles. The discussion presented here will include two analysis and design examples, used to highlight the benefits gained by the approximated analysis technique, as well as a section that examines the accuracy of the technique