PAM-7Q - Hardware Integration Manual
UBX-13003143 - R06
Early Production Information
Product handling
Page 19 of 26
Example of EMI protection measures on the RX/TX line using a ferrite bead:
TX
RX
G
P
S
R
e
c
e
iv
e
r
FB
FB
BLM15HD102SN1
>10mm
Figure 7: EMI Precautions
VCC can be protected using a feed thru capacitor.
Intended use
In order to mitigate any performance degradation of a radio equipment under EMC disturbance, system
integration shall adopt appropriate EMC design practice and not contain cables over three meters on
signal and supply ports.
5.3.5
Applications with cellular modules
GSM uses power levels up to 2 W (+33 dBm). Consult the Data Sheet for the absolute maximum power input at
the GNSS receiver.
5.3.5.1
Isolation between GPS and GSM antenna
In a handheld type design, an isolation of approximately 20 dB can be reached with careful placement of the
antennas relative to the GPS receiver.
5.3.5.2
Increasing jamming immunity
Jamming signals come from in-band and out-band frequency sources.
5.3.5.3
In-band jamming
With in-band jamming the signal frequency is very close to the GPS frequency of 1575 MHz (see
Figure 8). Such
jamming signals are typically caused by harmonics from displays, micro-controller, bus systems, etc.
1525
1550
1625
GPS input filter
characteristics
1575
1600
0
-110
Jammin
g signal
1525
1550
1625
Frequency [MHz]
Power [dBm]
GPS input filter
characteristics
1575
1600
0
Jamming
signal
GPS
signals
GPS Carrier
1575.4 MHz
Figure 8: In-band jamming signals