Agilent Technologies 83491, Руководство пользователя

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2-11
Operation
To Display a Signal
To Display a Signal
1 Install the module as described in “To install the module” on page 1-3 . Be sure
to connect all of the cables as described in the procedure.
2 Repeatedly press the
SELECT
key on the clock recovery module until the front-
panel light indicates the proper data rate of the signal.
• If the
UNLOCKED
light is on (or
TRIGGER LOSS
light on the Agilent 83494A), clock
recovery cannot be established on the signal.
• Avoid selecting a data rate that is a multiple of the input signal. For example,
don’t select a 622 Mb/s data rate if the signal is really at 155 Mb/s.
• If you cannot get the clock recovery module to lock on the signal, make sure
that you have selected the correct data rate and that the Agilent 83480A (or
Agilent 54750A) mainframe trigger level is adjusted appropriately.
• Signals displayed using a data trigger are less reliable than using a recovered
clock. Signals triggered on data can also vary depending upon the trigger
level.
Green and red data-rate lights
The data-rate indicator lights on the Agilent 83491/2/3A and Agilent 83494A Option 106
change color between red and green to show which data rate is selected. A red light
does
not indicate a problem. A red light shows that the adjacent red data rate label is
selected. A green light shows that the adjacent green data rate label is selected.
Repeatedly pressing the SELECT key cycles through the selections in one color before
switching to the opposite color. On Agilent 83491A modules for example, the first selec-
tion cycle shows 155 Mb/s selected. The second selection cycle shows 1062 Mb/s
selected.
Agilent 83494A modules use only the green data-rate indicator light to show which data
rate is selected. Repeatedly pressing the SELECT key cycles through the available data
rates, as well as the Trigger On Data bypass mode.
book.book Page 11 Monday, January 7, 2002 2:12 PM