NXP Semiconductors
UM10491
BGU7004 GPS LNA EVB
UM10491
© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1.0 — 14 June 2011
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1
Freq 1.575 GHz
Ch1 Arb Channel Base Start -25 dBm
Stop 15 dBm
Trc1
S21
dB Mag 1 dB / Ref 16 dB Cal int PCax
•
M 1
M 2
-25.00
9.30
dBm
dBm
16.289
15.286
dB
dB
S21
M 1
M 2
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1
Freq 1.575 GHz
Ch1 Arb Channel Base Start -25 dBm
Stop 15 dBm
Trc1
S21
dB Mag 1 dB / Ref 16 dB Cal int PCax
•
M 1
M 2
-25.00
14.42
dBm
dBm
16.288
15.289
dB
dB
S21
M 1
M 2
Fig 10. 1dB Gain compression 1.575 GHz 850 Mhz
jammer
Fig 11. 1dB Gain compression 1.575 GHz 1850 Mhz
jammer
7. Noise figure as function of jammer power at 850 MHz and 1850 MHz
Noise figure under jamming conditions is a measure of how the LNA behaves when e.g.
a GSM TX interfering signal is at the input of the GPS antenna. To measure this behavior
the setup shown in
The jammer signal is coupled via a directional coupler to the DUT: this is to avoid the
jammer signal damaging the noise source. The GPS BPF is needed to avoid driving the
second-stage LNA in saturation.
Fig 12. Noise under jamming measurement setup
, the noise figure as a function of jammer power is given for 850 MHz
and 1850 MHz jammer signals.
