Technical data

TRIGger Commands SCPI Commands Reference
Agilent 81133A/81134A Pulse Generator Programming Guide, March 2007 87
:TRIGger:SOURce
Syntax :TRIG:SOUR[?]
Form Set & Query
Description This command is used to switch the timebase mode between
Internal (
IMMediate ) and External ( EXTernal ).
With :TRIGger:SOURce IMMediate (internal timebase) the frequency
(or period) is controlled with the
[:SOURce]:FREQuency (or
[:SOURce][:PULSe]:PERiod ) command.
With :TRIGger:SOURce EXTernal , the frequency (or period) is
controlled by the external signal applied to the external clock
input connector (Clock In).
Parameter IMMediate|EXTernal|REFerence|IDIRect|EDIRect
•IMMediate
The clock is derived from the internal oscillator.
•EXTernal
Enables the external clock input (Clock In) to accept an external
clock signal that forms the time base. The frequency is measured
once by selecting the Measure function from the user interface
or as a remote SCPI command (
:MEASure:FREQuency? ).
This value is then used to calculate frequency- dependent values,
like the pulse width or the phase (available at the Channel
page).
•REFerence
Enables the external clock input (Clock In) to apply a 10 MHz
reference clock. This clock is used as a reference for all timing
parameters.
• IDIRect|EDIRect
The direct modes allow changes of frequency without dropouts
in the range of 1:2. They are used for applications (precise clock
source), where dropouts would make a measurement impossible,
for example, PLL frequency sweep and micro processor clock
sweep.
–IDIRect
Allows you to vary the clock derived from the internal
oscillator in the range of one octave.