Overview
1
Keysight E6960A User Guide and Method of Implementation
41
Transmitter Output Droop Negative Test Information
This test measures the negative output droop of the transmitter.
Reference [1] specifies the negative output droop of a compliant PHY. The negative
droop measured with respect to an initial value at 4 ns after the zero crossing and a
final value of 16 ns after the zero crossing, shall be less than 10%.
The application triggers the Test Mode 6 signal on the falling edge and determines
the time the negative peak occurred at 4 ns after the zero crossing. The application
then measures the voltage 12 ns after the initial peak crossing. The Droop is
calculated as:
Droop = 100 X (Vd/Vpk)%
Where:
– Vd is the magnitude of the droop.
– Vpk is the initial peak after the zero crossing.
