Spectrum Emission Mask (Sem) - Keysight N9340B Demo Manual

Section 13

Spectrum Emission Mask (SEM)

Figure 21. Spectrum emission mask
SEM is a relative measurement of the out-of-channel emissions to the
in-channel. The purpose for this test is to measure the excess emissions that
would interfere with other channels or with other systems.
The N9340B includes spectrum emission mask (SEM) as a standard feature.
The user can set the parameters of the main channel, out-of-channel frequency
bands, and the limit lines. Moreover, it provides Pass/Fail testing for the overall
spectrum emission mask and each individual out-of-channel frequency range.
The N9340B will trigger the failure indicator once any measurement result
violates the mask. It displays the main channel power and the power level
vectors relative to in-channel power for each out-of-channel frequency range.
The user can save the spectrum scan, the mask, the data or screen shot for
later analysis and reporting.
As it applies to W-CDMA (3GPP), this is the power contained in a specified
frequency bandwidth at certain offsets relative to the total carrier power. It may
also be expressed as a ratio of power spectral densities between the carrier and
the specified offset frequency band. For WLAN, the reference power is taken as
the peak PSD in the signal, and all offset results are also the peak PSD in that
offset as opposed to the integrated power. The N9340B's default setup for SEM
is W-CDMA (3GPP).
In the following demo, you can use any source available as long as it has
W-CDMA signal generation capability.
Instruction
Connect the signal generator's output to the
RF IN port.
Turn on the SEM function.
Enter the parameters depend required for
your test.
29
Key strokes
[MEAS], {SEM}