Transducer Arrays Over A²B Networks in Industrial and Automotive Applications: Clock Propagation Measurements

Abstract

Advanced automotive applications like Active Noise Cancellation (ANC) and Individual Listening Zones (ILZ) require a high number of transducers (i.e., microphones, accelerometers, and loudspeakers) usually arranged as arrays. Transducer arrays are widely employed in several applications besides automotive field, such as teleconferencing systems, industrial and civil monitoring of noise and vibrations. Automotive Audio Bus ( $\text{A}^{2}\text{B}$ ) is an audio transport protocol that solves the latest requirements of automotive and industrial fields. $\text{A}^{2}\text{B}$ allows transporting up to 32 channels in a multi-node daisy chain network and guarantees synchronization and low deterministic latency. This paper aims to develop a clock propagation model of an $\text{A}^{2}\text{B}$ network composed by transducer arrays. This model will be useful to evaluate the impact of the bus on the array performance. Firstly, a theoretical description of the $\text{A}^{2}\text{B}$ protocol and jitter analysis is provided. It follows a description of the jitter measures carried out on the clocks distributed along the $\text{A}^{2}\text{B}$ network. Lastly, latency introduced by nodes of the network is investigated.