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NXP Semiconductors
UM10497
BGU8007 GPS LNA EVB
UM10497
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1.0 — 5 October 2011
9 of 16
6. Linearity
At the average power levels of –130 dBm that have to be received by a GPS receiver,
the system will not have in-band intermodulation problems caused by the GPS-signal
itself. Strong out-of-band cell phone TX jammers however can cause linearity problems,
and result in third-order intermodulation products in the GPS frequency band. In this
chapter the effects of these Jammer-signals on the Noise and Gain performance of the
BGU8007 are described. The effect of these Jammers on the In-band and Out-of-Band
Third-Order Intercept points are described in more detail in a separate User Manual:
UM10453: 2-Tone Test BGU7005 and BGU7007 GPS LNA.
6.1 1 dB gain compression at 1575 MHz with 850 MHz or 1850 MHz
jammers
As already stated before, signal levels in the GPS frequency band of –130 dBm average
will not cause linearity problems in the GPS band itself. This of course is also valid for the
1 dB gain compression in-band. The 1 dB compression point at 1575 MHz caused by cell
phone TX jammers however is important. Measurements have been carried out using the
set-up shown in
Fig 6
. The jammer signal is coupled via a directional coupler to the DUT.
For the P1dB measurements this not required, but connecting it this way the setup can
also be used for NF-measurements as described in the next paragraph.
Fig 6. Noise under jamming measurement setup
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