Stanford Research Systems SR780, Operating Manual And Programming Reference

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Source Menu 4-53
SR780 Network Signal Analyzer
Trigger Caution
If the Noise source is selected and the Burst is less than 100%, the triggered FFT
measurement phase is stable only if the input signals are derived from the triggered
source output. Turn the source off (or set it to Sine) when making triggered
measurements of external signals (not the source).
Command: STYP (?) {i}
Arbitrary
Set the source output to Arbitrary and display the Arbitrary Setup menu.
The Arbitrary source plays a waveform stored in memory. The waveform can be either
Capture buffer or the Arbitrary Waveform memory. Use the <Memory Allocation> menu
to allocate memory between the capture buffer, waterfall storage and the arbitrary source
waveform. The Capture buffers may not be selected as the Arbitrary source if they do not
contain data.
The Arbitrary waveform memory can be loaded via the computer interfaces, from a disk
file or from a stored trace. The Capture buffer is filled by capturing an input signal.
The Arbitrary source can play a portion of memory starting at a specified point. The
output sampling rate can also be specified. The amplitude of the source is set relative to 1
V (up to a maximum of 5 V).
Triggering
The Arbitrary source is triggered by External triggers. Set the Trigd Source Mode to
trigger once (1-Shot) or with every trigger (Continuous).
In the 1-Shot case, the source only triggers on the first trigger after [Start/Reset]. This
same trigger starts the measurement (and waterfall). This is useful when the source length
is very long compared to the measurement time. This allows a sequence of many
measurements to be triggered at the start of a single playback of a long source.
In the Continuous case, the source triggers on every trigger, with a minimum trigger
period set by the Arbitrary Source Length. This is useful when the source length is the
same as the FFT time record length.
Source trigger outputs the source continuously over and over. The FFT time records are
synchronized to the source start.
Free Run Trigger Mode outputs the source continuously over and over.
Do not use Ch1 or Ch2 input trigger since the output will not start until a trigger is
received.
Trigger Caution
If the Arbitrary source is selected, the triggered FFT measurement phase is stable only if
the input signals are derived from the triggered source output. Turn the source off (or set
it to Sine) when making triggered measurements of external signals (not the source).