General Description
R&S
®
CMW-KN5xx
20
User Manual 1176.7690.02 ─ 05
3.7.3 Spectrum Emission Mask
The energy that spills outside the designated radio channel increases the interference
with adjacent channels and decreases the system capacity. The amount of unwanted
off-carrier energy is assessed by the out-of-band emissions (excluding spurious emis-
sions) that are specified in terms of the spectrum emission mask and the Adjacent
Channel Leakage power Ratio (ACLR).
3GPP specifies spectrum emission masks depending on the type of the eNodeB, the
channel bandwidth and the operating band.
In the configuration dialog you can define one spectrum emission mask per channel
bandwidth. The figure below shows the default settings for a channel bandwidth of 1.4
MHz.
Fig. 3-10: Emission mask settings for 1.4 MHz channel bandwidth
For each emission mask area you can define the start and stop frequencies, set an
upper absolute and an upper relative power limit and select the resolution bandwidth to
be used.
The start and stop frequencies are defined relative to the edge of the channel band-
width. Example: Assume 0 MHz as start frequency and 1 MHz as stop frequency for a
channel bandwidth of 1.4 MHz. The resulting area ranges from +0.7 MHz to +1.7 MHz
relative to the carrier frequency. As all ranges are symmetrical, it ranges also from -0.7
MHz to -1.7 MHz relative to the carrier frequency.
The absolute power limit is configured via a <power> parameter and a <slope> param-
eter. The absolute limit line is calculated from these parameters, the configured start
frequency <start> and the <frequency> relative to the channel edge, using the follow-
ing formula:
absolute limit = <power> + <slope> * (<frequency> - <start>)
The relative power limit is defined as power relative to the "TX Power" measurement
result. If the relative limit is enabled, the less stringent of the two limits applies (abso-
lute or relative power limit).
Limit Settings and Conformance Requirements
深圳德标仪器
135-1095-0799
