First-order global AM-FM decomposition and application to music analysis and transformation

A refined estimation and tracking of the instantaneous frequency variations is desirable for a variety of audio applications (audio coding, singer segregation, music transcription and transformations, etc). In the present paper, we extend the periodic modeling with global amplitude and frequency modulation approach. We introduce a first order approximation producing an additive term involving the derivative of the `normalized waveform´ multiplied by the instantaneous FM signal. The variations of the global FM get expressed through a subsampled representation and estimated using a simple least-squares scheme.