u-blox NEO-D9C, Руководство по интеграции

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NEO-D9C - Integration manual
Parameter Specification
Typical gain
30 dB
1
Maximum gain 50 dB
Active antenna recommendations
Maximum typical noise figure 4 dB
L1 band antenna gain 1559 - 1606 MHz: 3 dBic typ.
L2/E5b/L6 band antenna gain
2
1197 - 1285 MHz: 2 dBic typ.
Polarization RHCP
Axial ratio 2 dB max at zenith
Phase center variation <10 mm over elevation/azimuth
Group delay variation in-band
3 10 ns max at each GNSS system bandwidth. Note:
Inter-signal requirement 50 ns max.
EMI immunity out-of-band
4
30 V/m
Out-of-band
3
Rejection
40 dB typ
ESD circuit protection 15 kV human body model air discharge
Table 6: Antenna specifications for NEO-D9C modules
The antenna system should include filtering to ensure adequate protection from nearby
transmitters. Care should be taken in the selection of antennas placed close to cellular or Wi-Fi
transmitting antennas.
4.2.1 Antenna bias
Active antennas have an integrated low-noise amplifier that contributes an additional current of
typically 5 to 20 mA to the system's power consumption budget.
If the supply voltage of the NEO-D9C module matches the supply voltage of the antenna (e.g. 3.0
V), you can use the filtered supply voltage VCC_RF output to supply the antenna. However a current
limiting resistor is required to prevent against short circuits destroying the bias-t inductor.
The bias-t inductor must be chosen for multi-band operation, a value of 47 nH ±5% is
recommended for the recommended Murata L part. It has a self-resonance frequency of 1
GHz and a high impedance (> 500 Ω) at L-band frequencies.
The recommended bias-t inductor (Murata LQG15HS47NJ02) has a maximum current capacity of
300 mA. Hence the current is limited to 70 mA at 3.3V using an active limiter in the recommended
circuit shown in
Figure 22 below. A 10 Ω resistor (R2) is provided to measure the current. This resistor
power rating must be chosen to ensure reliability in the chosen circuit design.
1 LNA gain, no cable loss or signal divider loss. 20 dB at module RF_IN.
2
Measured with a ground plane d=150 mm
3
GNSS system bandwidths: 1559… 1563 MHz; 1573… 1578 MHz; 1598… 1606 MHz; 1192… 1212 MHz; 1197… 1217
MHz; 1223… 1231 MHz; 1242… 1249 MHz
4
Exception L1 and L2 bands +/- 200 MHz, emphasis on cellular bands
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