  Phase recovery of modified spectrograms is a major issue in audio signal
processing applications, such as source separation. This paper introduces a
novel technique for estimating the phases of components in complex mixtures
within onset frames in the Time-Frequency (TF) domain. We propose to exploit
the phase repetitions from one onset frame to another. We introduce a reference
phase which characterizes a component independently of its activation times.
The onset phases of a component are then modeled as the sum of this reference
and an offset which is linearly dependent on the frequency. We derive a complex
mixture model within onset frames and we provide two algorithms for the
estimation of the model phase parameters. The model is estimated on
experimental data and this technique is integrated into an audio source
separation framework. The results demonstrate that this model is a promising
tool for exploiting phase repetitions, and point out its potential for
separating overlapping components in complex mixtures.
