Language Reference

ADCTRG

Selects the source of the ADC trigger.

Item

Description

 

 

Preset State

ADCTRG FREE

Example

Description

OUTPUT 723;"ADCTRG POSEDGE;"

The ADCTRG command selects the type of external triggering used by the optical spectrum analyzer's analog-to-digital converter. The TTL-compatible trigger signal from the light source is connected to the rear-panel EXT TRIG IN connector. The following types of triggering can be selected:

Softkey

Type of Triggering

ADCTRIG FREE

External triggering is ignored. The ADC is triggered

 

during sweeps by the optical spectrum analyzer's

 

internal clock.

ADCTRIG POSEDGE

ADC is triggered by the rising edge of the external

 

trigger signal.

ADCTRIG NEGEDGE

ADC is triggered by the falling edge of the external

 

trigger signal.

ADCTRIG AC

ADC is alternately triggered by rising and ￿lling

 

edges of the external trigger signal. The amplitudes

 

measured on opposite edges are subtracted and

 

the absolute value of the result becomes the trace

 

amplitude value.

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