SE868-V3 Product User Guide
1VV0301205 r4 – 2016-01-20
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
Page 46 of 76
Mod. 0805 2015-02 Rev.4
9.8.
RF Interface
9.8.1.
RF Input
The RF input (RF-IN) pin accepts GNSS signals in the range of 1561 MHz to 1606 MHz at a
level between -125 dBm and -165 dBm into 50 Ohm impedance.
No DC voltage can be applied to the RF input.
The RF input pin is ESD sensitive.
The SE868-V3 contains an integrated LNA and pre-select SAW filter. This allows the module
to work well with a passive GNSS antenna. If the antenna cannot be located near the module,
then an active antenna (that is, an antenna with a built in low noise amplifier) should be used.
Antenna Characteristics:
•
Passive antenna: isotropic gain of greater than -6 dBi.
•
Active antenna: noise figure of less than 1.0 dB will offer the best performance.
See
Section 4.10 Internal LNA f
or recommendations and maximum ratings for active antenna
(or external LNA) gain.
9.8.2.
External Active Antenna Voltage
If an active antenna (or external LNA) is used, an external bias-T is required to provide voltage
to it. A DC blocking capacitor is also required to prevent DC voltage from being applied to RF-
IN pin.
9.8.3.
Burnout Protection
The receiver accepts without risk of damage a signal of +10 dBm from 0 to 2 GHz carrier
frequency, except in band 1560 to 1610 MHz where the maximum level is –10 dBm.
9.8.4.
Jamming Rejection
Jamming Rejection can be used for solving narrow band (CW) EMI problems in the customer’s
system. It is effective against narrow band clock harmonics. Jamming Rejection is not effective
against wide band noise, e.g. from a host CPU memory bus or switching power supply because
these sources typically cannot be distinguished from thermal noise. A wide band jamming
signal effectively increases the noise floor and reduces GNSS signal levels.
Please refer to
Section 4.9 Jamming Rejection
