To Select An External Trigger; To Select The Adc Trigger - HP 86140A Series User Manual

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 trigger
ADC
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.
Using the Optical Spectrum Analyzer
The Bandwidth/Sweep Menus
3-19