SL871 Family Product User Guide
1VV0301170 Rev. 9
Page 61 of 89
2021-07-15
Not Subject to NDA
its passband. Because of the nature of the address and data lines, this would be
broadband digital noise at a relatively high level.
Such devices are required to adhere to a regulatory standard for emissions such as FCC
Part 15 Subpart J Class B or CISPR 22. However, these regulatory emission levels are far
higher than the GNSS signal strength.
Shielding
Shielding the RF circuitry generally is ineffective because the interference is received by
the GNSS antenna itself, the most sensitive portion of the RF path. The antenna cannot
be shielded because then it could not receive the GNSS signals.
There are two solutions, one is to move the antenna away from the source of interference,
and the other is to shield the digital interference source to prevent it from getting to the
antenna.
