synchronizing sound cards in a cluster

[Robert G. Brown]

On Thu, 13 Mar 2003, Jim Lux wrote:

> Anybody have any good ideas on how to synchronize the sampling from 
> multiple sound cards in a cluster using Ethernet as the interconnect. The 
> application would grab data from the sound card (notionally at 100 
> ksamples/second total, for two channels) and do a ton of signal 
> processing.  At some point in the processing, the streams of data need to 
> be shared between processors (i.e. to do beamforming), and so, needs to be 
> time registered.
> The bandwidth isn't a real challenge here (with, say, 16 processors, that's 
> only about 32 Mbps total), nor is latency, but synchronization is.
> 
> One can fairly easily synchronize to a millisecond over Ethernet, but this 
> application needs sync to, at worst, 1 sample time (20 microseconds) 
> although order of a microsecond would be nice.

a) Check out the documentation on http://www.ntp.org/documentation.html.