Teledyne LeCroy PeRT3 Eagle Systems - Manual (Page 33)

PeRT 3 Eagle User Manual Version 1.6
LeCroy Corporation
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Signal
The Signal panel allows the user to control the amplitude and bias of the
differential signal. By default, the Signal panel is inactive (turned off)
when the system is first turned on, as shown by the circle in the lower
right corner of the panel. Before any testing can take place, the user
must turn this on (click to change to a check mark) and specify the
desired signal characteristics.
Signal amplitude (Amp) can be controlled over the range from 100 mV
to 2200 mV in increments of 5 mV. Signal amplitude is the nominal
voltage of the differential signal, and is a measure of the overall signal
power. Low signal amplitude can be used to test for the limits of receiver
sensitivity (additional losses due to connectors and cables should be taken into account).
High signal amplitudes can be used to test for receiver saturation or even damage limits
to electronics.
Signal bias can be controlled over the range -1800 mV to +1800 mV in increments of 5
mV. Signal bias is the offset (from ground) that is applied to the differential signal, or in
other words, the DC component of the signal.
Note: All signal impairment controls are turned off by default. All controls
must first be turned on by clicking the circle in the bottom right corner
of each panel. When the control is active, the circle will change to a
check mark
Pre-Emphasis
The Pre-Emphasis panel allows the user to control the amplitude and
duration of the pre-emphasis applied to the signal. By default,
Pre-Emphasis is turned off.
Pre-emphasis amplitude (Amp) can be controlled over the range 0 to
15 (nominal values). Pre-emphasis amplitude is used to adjust the
amplitude of the overshoot and undershoot on transitions, and can be
manually adjusted (while examining the signal on an oscilloscope) to
obtain a desired waveform. Pre-emphasis is not usually needed if the
SMA cables connecting to the DUT are short and trace lengths on any
test fixtures used are minimal.
Pre-emphasis duration ("Dur") can be controlled over the range from 0 to 15 (again,
nominal values). Pre-emphasis duration is used in combination with pre-emphasis
amplitude to control the overshoot on electrical transitions in the bit stream.