The port or ports at which measurements are made✓Ճիշտ պատասխան
The relative time between measurements
Relative quality of the data
Frequency order of the measurements
Բացատրություն
Each subscript names a port: the first identifies the port at which the outgoing wave is measured and the second the port at which the signal is applied. They carry no information about timing, data quality or the order in which measurements were taken.