Tektronix TDSUSB2, Manual

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TDSUSB2 Universal Serial Bus Measurement Package
233
Glossary
Cross-Over Points
The Cross-Over point is defined as the intersection of the D+ and D– single-
ended signals. For differential signals, the Cross-Over is zero crossings of the
differential signal.
Downstream
The direction of data flow from the host or away from the host. A downstream
port is the port on a hub electrically farthest from the host that generates
downstream data traffic from the hub. Downstream ports receive upstream data
traffic.
EOP
End-of-Packet.
EOP (E), Idle (I), J, K
The different bus states of the USB signal.
Eye Pattern
A representation of the USB signal that provides minimum and maximum
voltage levels, as well as the signal jitter.
Eye Violation
Any part of the waveform that crosses the defined eye mask.
Full-speed
USB operation at 12 Mb/s.
High-speed
USB operation at 480 Mb/s.
Host
The host computer system where the USB Host Controller is installed. This
includes the host hardware platform (CPU, bus, etc.) and the operating system in
use.
Host Controller
The host’s USB interface.