Providing common I/O clock for wireless distributed platforms

We propose a novel synchronization scheme for distributed audio-video input and output on heterogeneous general purpose computers (GPC) such as laptops, tablets, PDA, smart telephones, audio recorders, and camcorders. These devices typically possess sensors such as microphones and possibly cameras, and actuators such as loudspeakers and displays. In order to combine them wirelessly into a distributed array signal processing system, it is necessary to provide relative time synchronization to sensors and actuators. In this work we propose a setup and an algorithm to synchronize input and output for a network of distributed multichannel audio sensors and actuators connected to GPC. An IEEE 802.11 wireless network is used to deliver the global clock to distributed GPC, while the interrupt mechanism is employed to distribute the clock between I/O devices. Experimental results demonstrate a precision in A/D D/A synchronization precision better than 50 /spl mu/s (a couple of samples at 48 kHz).