Agilent Technologies J-BERT N4903, Руководство пользователя

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5 Clock rates that are frequently used can be saved as presets in the
Preset list.
The Preset list always displays the presets within a certain frequency
range. Use the CDR Range selection list to display the presets of
another range.
To select a clock rate from the Preset list, click on it. The clock rate
appears in the Clock Rate field.
6
Specify the Loop Bandwidth within the range of 100 KHz to 12MHz.
Press the
Advanced button to select Peaking and Fine Adjust. When using
a Preset, this is only required when you want to change these values.
7 Enable Spread Spectrum; and adjust the deviation (%) as required.
8 Either enter the transition density manually, or run a measurement to
update this value.
Clock Setup - Reference
The Clock Setup window contains the following elements:
Error Detector Bit Rate
The bit rate of the data reaching the error detector is displayed in the
lower right corner of the user interface.
The bit rate of the error detector is set by the clock signal received by
the error detector. If the output bit rate of your device is not equal to
its input bit rate, the pattern generator and error detector will be
operating at different frequencies.
Clock Mode
The error detector supports two different clock modes:
• External Clock Source
If this mode is selected, the Serial BERT uses the clock signal that is
connected to the Clock In port.
•
Clock Data Recovery
If this mode is selected, the Serial BERT derives the exact bit rate
from the incoming data stream. To make this function work, the
4
Setting up the Error Detector
122 Agilent J-BERT N4903 High-Performance Serial BERT