A nonuniform multi-Gabor expansion (MGE) scheme is studied under proportional time and frequency (TF) shifts among different window indices m . In particular, TF parameters for each m are different, but proportional and relevant to windows' TF patterns. The generation of synthesis waveforms for nonuniform MGE is generally difficult. We show constructively that there is a set of basic synthesis MGE waveforms at each window index under proportional parameter settings. Nonuniform MGE adapts to signal frequency dynamics effectively, and eliminates unnecessary overlapping redundancies of a uniform MGE. Examples of the evaluation of synthesis waveforms are provided. Efficiency comparison of TF analysis using nonuniform and uniform MGEs is also discussed.