Type of Timestamp - fCal Data Logging

[rwjmoore]

Hello,

I am currently recording ultrasound image data from a BK3500 ultrasound machine along with pose from a NDI Spectra using fCal. In the .MHA file there is a timestamp. I have two questions:

1. What format is this timestamp? Is it in seconds, milliseconds?
2. Where is this timestamp coming from? The NDI tracker or the ultrasound? How are the data streams (NDI tracker and ultrasound) synchronized/interpolated?

Many Thanks,
Randy