Range and frequency dependence of transfer function phase

The phase trend in multi-degree-of-freedom systems can be determined by an algorithm that tracks the relative signs of adjacent resonances in a modal expansion of transfer functions. This algorithm is expressed in analytical form for two-dimensional systems. The analytical expression shows the transition from input function phase to the reverberant phase limit. The phase trend for two-dimensional systems greatly exceeds that of the average response of such systems and the reason for this difference is analyzed.