Viavi 87339, Руководство по эксплуатации

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I - 1
Appendix I - Direct Connecting to GPS Receivers
Hardware Requirements:
Antenna Load Simulators using the VIAVI GPSG-1000 and Optional Kit
Some GPS receivers require a resistive load be present on the antenna port of the
receiver for proper operation. If a resistive load is not present, the receiver indicates an
antenna fault and the system self-test indicates a failure.
The components within GPSG
- optional kit provide a resistive load that is required by
some GPS receivers when direct connecting the GPSG-1000 to the RF input of the
receiver. This load prevents some GPS receivers from failing their internal self-tests.
The Bias-Tee and RF terminator provided within the GPSG
- 1000 optional kit simulates a
26 mA load in a 5 Vdc system. Other load values may be required depending on the
needs of the individual GPS receiver under test. The content of the GPSG - 1000 optional
kit is not required if using the GPSG-1000 RF coupler to transmit GPS data to the
antenna of the GPS receiver under test.
GPSG Dual Antenna Coupler Kit Connection
STEP PROCEDURE
1. Connect the RF terminator (P/N 113102) to Port C (DC IN) of the Bias-Tee (P/N
113101).
2. Connect the TNC to SMA coaxial cable (P/N 113103) from Port B (DC OUT) of the
Bias-Tee (P/N 113101) to the GPS antenna input connector of the receiver under
test.
3. Connect the GPSG-1000 to Port A (DC BLOCK) of the Bias-Tee (P/N 113101)
using the TNC to TNC coaxial cable (supplied with the GPSG-1000).
4. Add the loss factor of the TNC coaxial cable supplied with the GPSG-1000 with
0.3 dB (typical) for the Bias Tee loss and 0.95 (typical) for the Coax Assy (P/N
113103). Enter this value into the Direct Connect cable loss in the GPSG-1000
Setup I/O Window. If the supplied cables are not used, the cables used should be
characterized and the values entered.
5. Using the GPSG-1000 User’s Manual as a reference, set up and begin a GNSS
simulation on the GPSG-1000.