Agilent Technologies Agilent 33500 Series Operating And Service Manual page 146

Waveform Generation Tutorial
Three-Cycle Burst Waveform
For bursts, the trigger source can be an external signal, an internal timer, the key, or a command from the remote
interface. The input for external trigger signals is the rear-panel Ext Trig connector. This connector accepts TTL-com-
patible levels and is referenced to chassis ground (not floating ground). When not used as an input, the Ext Trig con-
nector can be configured as an output to enable the instrument to trigger other instruments at the same time that its
internal trigger occurs.
An N-Cycle burst always begins and ends at the same point in the waveform, called the start phase.
In GATed burst mode, the output waveform is on or off, based on the signal at the rear-panel Ext Trig connector.
Select this signal's polarity using BURSt:GATE:POLarity. When the gate signal is true, the instrument outputs a con-
tinuous waveform. When the gate signal goes false, the current waveform cycle is completed and the instrument stops
and remains at the voltage level corresponding to the waveform's starting burst phase. For a noise waveform, the out-
put stops immediately when the gate signal goes false.
Frequency Sweep
Frequency sweeping is similar to FM, but no modulating waveform is used. Instead, the instrument sets the output
frequency based on either a linear or logarithmic function, or a list of up to 128 user-specified frequencies. A linear
sweep changes the output frequency by a constant number of Hz per second, and a logarithmic sweep changes the
frequency by a constant number of decades per second. Logarithmic sweeps let you cover wide frequency ranges
where resolution at low frequencies could be lost with a linear sweep.
Frequency sweeps are characterized by a sweep time (during which the frequency changes smoothly from the start
frequency to the stop frequency), a hold time (during which the frequency stays at the stop frequency), and a return
time (during which the frequency returns smoothly and linearly to the start frequency). Trigger settings determine
when the next sweep begins.
Agilent 33500 Series Operating and Service Guide 145