Agilent Technologies J-BERT N4903B, User Manual, Page: 142 / 572

To set the bit rate:
1 If the external clock source has a frequency of 10 MHz, connect the clock source
to the pattern generator's 10 MHz Ref In port. If the clock has another
frequency, connect it to the Clock In port.
2 Click
Bit Rate Setup
menu item from the
PG Setup
submenu.
3
Select the appropriate clock source:
–
Internal Clock Source
This setting uses the internal clock oscillator.
–
10 MHz Reference Clock
This locks the clock generator to an external 10 MHz reference.
–
External Clock Source
This connects the external clock directly to the clock generator.
4
If you have chosen an
External Clock Source
, decide between manual or
automatic mode.
– In automatic mode, the clock rate of the external source is automatically
measured and used. If the source frequency varies, the generated clock
varies as well.
– In manual mode, you can measure and set the rate of the external clock
source by clicking the respective button. If the source frequency varies, you
will be alerted.
– If you need SJ and SSC simultaneously, use an external modulated SSC
signal from 6.75Gb/s to 12.5Gb/s and use the J-BERTs SJ for additional
jitter generation. To generate data rates below 6.75Gb/s, the external clock
must be divided.
5 Select a clock rate:
– For
Internal Clock Source
, you can either select a clock rate from the
Presets
list, or enter a clock rate in the
Value and Units
field.
– For
10 MHz Ref Clock Source
, the clock rate connected to the 10 MHz Ref
In port must be 10 MHz.
The selected clock rate applies to the pattern generator. This is also the clock
rate generated at the pattern generator's Clock Out port.
If the error detector receives its clock from the pattern generator, it runs at the
same clock rate.
4
Setting up the Pattern Generator
142 Agilent J-BERT N4903B High-Performance Serial BERT