User`s guide

Agilent PXT Wireless Communications Test Set
User’s Guide
206
2. Set the trigger delay = 2 ms by pressing Func Setup > Trigger> Internal Trigger > Trigger Delay,
2, ms.
Figure 6-11: SEM measurement (TDD)
Measurement Setup
The frequency span of the measurement is fixed at 70 MHz. This is the span required for the 20 MHz
system bandwidth.
Select the Meas Setup front-panel key to access the settings described below.
Use the Select Mask menu key to select from ten masks. Masks are initially undefined. A mask can either
be defined from scratch by enabling the required number of segments and then editing each segment or
use the Load Default Mask menu key and edit that mask.
The Measurement Interval defines the time interval over which samples are taken. The spectrum is
computed using multiple FFT computations from samples in sub-intervals of the measurement interval.
The FFT outputs are averaged by frequency bin to yield the spectrum. The sub-intervals used for the FFT
computation can be specified to be adjacent or overlapping using the FFT Overlap setting. An FFT Overlap
setting of 0 means sub-intervals are adjacent and not overlapping.
The Edit Mask menu key accesses a sub-menu for specifying each segment of the mask. The segment to
be edited is selected by pressing the Segment menu key and entering the segment index numerically or by
using the RPG or the Up / Down arrows. A segment’s state is toggled by pressing the Segment menu key.
Segment 0, if enabled, is used to define the carrier power spectrum. For this reason the Start Freq is fixed
at 0 Hz. For all other segments both the Start Freq and the Stop Freq of the segment can be specified.
Segments can be specified to overlap.