u-blox M8 Series Hardware Integration Manual page 23

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Out-band interference
Out-band interference is caused by signal frequencies that are different from the GNSS carrier (see
Figure 17). The main sources are wireless communication systems such as GSM, CDMA, WCDMA,
Wi-Fi, BT.
P ower [dBm]
0 0
GPS input filter GPS input filter
characteristics characteristics
-110 -110
0 0 500 500
Figure 17: Out-band interference signals
Measures against out-band interference include maintaining a good grounding concept in the design
and adding a SAW or band pass ceramic filter (as recommend in section 4) into the antenna input line
to the GNSS receiver (see Figure 18).
Figure 18: Measures against out-band interference
☞
For design-in recommendations in combination to Cellular operation see the Appendix.
☞
See the GPS Implementation and Aiding Features in u-blox wireless modules [10].
UBX-16010549 - R08
C1-Public
G P S
G P S
G S M
G S M
1575
s ignals
950
900
1000 1500 1500
Product handling
NEO-M8L - Hardware integration manual
G S M G S M
1800 1900
F requency [MHz]
2000 2000
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