SDBC-DK3UG Datasheet, PDF (16/76 Pages) Silicon Laboratories – 4 buttons and 4 LEDs for custom purposes

SDBC-DK3 UG
If an Antenna Diversity card is fitted then the 'Antenna Mode' option on the 3rd screen will be available, this line is
automatically removed when non-antenna diversity cards such as the 4432-DKDB1 are inserted. With this options
users have the ability to select antenna 1, antenna 2 or both (antenna diversity enabled). For typical operation
select “1&2”.
This screen also allows users to setup the PA output levels of the of the radio. Figure 18 demonstrates an output
power of +20 dBm selected.
Figure 18. Screen 3: RF Parameters (Antenna Diversity Card Fitted)
7.1.4. Understanding Antenna Diversity and Where to Use It
Antenna Diversity is a technique that is use to improve the quality and reliability of a wireless link. The technique is
particularly useful in city-like urban and indoor environments where clear lines of sight between the transmitter and
the receiver cannot be achieved.
In environments where clear lines-of-sight (LOS) are not possible, signals reflect along multiple pathways
(multipath) before being received, each reflection can introduce phase shifts, time delays, attenuations and
distortions that can disrupt the quality of the signal which can cause problems for the receiver. Antenna diversity
assists the receiver by allowing it to see the signal from two slightly different positions through the use of multiple
antennas. Studies have shown that antenna diversity in both indoor and urban environments can recover 8–10 dB
of the link budget that is usually lost to the environment when receivers use only single antenna implementations.
The technique however does not provide any major benefits in open environments and often this mis-
understanding can cause confusion during range test exercises. In fact, due to the extra components used in the
antenna switch it is possible that there maybe a small addition loss in the link budget thus reducing range. See
Table 3 and Table 4.
Table 3. Illustrative Effects of Antenna Diversity in Indoor/Urban—Multipath Environments
Transmit Power
Receive Sensitivity
Multipath Losses
Loss in Matching/Switch
Link Budget
Single Antenna Implementation
+20 dBm
–118 dBm
–10 dBm
–2 dBm
126 dBm
Multiple Antenna Implementation
+20 dBm
–118 dBm
–2 dBm
–3 dBm
133 dBm
Table 4. Effects of Antenna Diversity in Line of Sight (LOS)—Open Air Environments
Single Antenna Implementation
Multiple Antenna Implementation
Transmit Power
Receive Sensitivity
Multipath Losses
Loss in Matching/Switch
Link Budget
+20 dBm
–118 dBm
0 dBm
–2 dBm
136 dBm
+20 dBm
–118 dBm
0 dBm
–3 dBm
135 dBm
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