User guide

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 approximate clock rate

must be specified in the Clock Rate field (with an accuracy of 0.01%).

Clock Rate

This field is used to specify the approximate clock rate for CDR mode. Serial

BERT needs this value to be about 0.01% accurate to find the actual bit rate in the

data stream.

Use the numeric keypad to enter the value followed by the unit that you can select

with the G/n, M/μ, k/m, and X1 keys on the front panel.

Alternatively, you can select a value from the Preset list.

Setting up the Error Detector 5

Agilent J-BERT N4903B High-Performance Serial BERT 179