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SE873 Family Product User Guide
Electrical Interface
1VV0301216
Rev.4
Page 41 of 69
2018-08-24
RF Interface
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.
A maximum of 3 V DC can be applied to the RF input.
The RF-IN pin is ESD sensitive.
The SE873 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
for recommendations and maximum ratings for active antenna (or
external LNA) gain.
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.
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.
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
Jamming Rejection – Continuous Wave (CW) Jamming Mitigation
for further details.
Frequency Plan
Signal
Frequency (MHz)
TCXO Frequency
26.000
LO Frequency
1588.6
Table 8-13 Frequency Plan
Local Oscillator Leakage
Signal
Level
LO Leakage
-70 dBm (typical)
Table 8-14 LO Leakage
Содержание SE873 Series
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