3-19
Using the Optical Spectrum Analyzer
The Bandwidth/Sweep Menus
To select an external trigger
1
Press the front-panel
Bandwidth/Sweep
key.
2
Press the
More BW/Sweep Functions....
softkey.
3
Press the
Trigger Mode....
softkey.
4
Press the
External
softkey.
External triggering synchronizes the sweep with a signal connected to the
rear-panel
EXT TRIG IN
connector. External triggering requires a TTL-com-
patible signal with a minimum of 0 V and a maximum of +5 V. There is a time
delay between the external trigger signal and the data measurement that is set
by the Trigger Delay value.
To select the
ADC
trigger
1
Press the front-panel
Bandwidth/Sweep
key.
2
Press the
More BW/Sweep Functions....
softkey.
3
Press the
Trigger Mode....
softkey.
4
Press either the
ADC+
,
ADC–
, or
ADC AC
softkey.
The softkeys in the menu select the type of triggering for the analog-to-digital
converter in the data acquisition hardware of the OSA. The
ADC+
softkey trig-
gers the OSA on the rising edge of the external trigger signal, and the
ADC–
softkey triggers it on the falling edge. The
ADC AC
softkey alternately triggers
on the rising and falling edge of the external trigger signal. The amplitude
measured on opposite edges are subtracted and the absolute value of the
result becomes the trace amplitude value. The delay between the external
trigger and the triggering of the analog-to-digital converter is set by the trigger
delay value.
book.book Page 19 Monday, January 31, 2000 10:34 AM
