  In this paper, we propose to simultaneously estimate all the sampling rate
offsets (SROs) of multiple devices. In a distributed microphone array, the SRO
is inevitable, which deteriorates the performance of array signal processing.
Most of the existing SRO estimation methods focused on synchronizing two
microphones. When synchronizing more than two microphones, we select one
reference microphone and estimate the SRO of each non-reference microphone
independently. Hence, the relationship among signals observed by non-reference
microphones is not considered. To address this problem, the proposed method
jointly optimizes all SROs based on a probabilistic model of a multichannel
signal. The SROs and model parameters are alternately updated to increase the
log-likelihood based on an auxiliary function. The effectiveness of the
proposed method is validated on mixtures of various numbers of speakers.
