The receiver testing/verification procedure consist of sending a known test signal to the base station (BS) radio to verify the receive path. It provides commands and responses to verify proper operation of the base station radio receiver path. The quality metric referred to is the bit error rate (BER) value measured during the testing procedure and is specified by the manufacturer (or a network operator). Manufacturers have different requirements for receiver sensitivity, so check with the appropriate manufacturer for their specification.
Caution
To minimizes or eliminates disruption of service to system users, take the base station radio out of service or perform these procedures during off-peak hours.
This section outlines a basic test setup and measurement procedure for testing the following base station radios:
1. Connect the TB3 Base Station and S412E to the MA25200A Input Protection Module as shown below:
Airbus TB3 Base Station Setup
2. Connect the TB3 base station to a PC with the test software.
S412E Setup
1. Set S412E to TETRA Analyzer Mode.
2. Ensure that the Modulation Type is set to “Base Station”
Setup -> Mod Type = Base Station
3. Set S412E Frequencies:
• Set Rx frequency to Tx frequency of TB3
• Set Tx frequency to Rx frequency of TB3
4. Set the S412E Amplitude:
• Set Input and Output Offset to 40 dB Loss. This will compensate for the loss through the MA25200A. Both Input and Output ports will have the same loss of 40 dB.
• Set the Reference Level to +50 dBm. This is to avoid overdriving the ADC.
• Set the Output Level to your desired test level – Note that the 40 dB loss is already taken into account. For example, if you want –110 dBm output, set the Output Level to –110 dBm.
5. Set up TETRA Base Station Receiver Sensitivity Mode:
Measurement -> TETRA BS Sensitivity -> Base Station = Airbus TB3 0 or 1
• Airbus TB3 0 will set the ECC to 0
• Airbus TB3 1 will set the ECC to Airbus Recommended Test Default
Set Up Airbus Test Software
6. Make sure the Airbus BS is transmitting and verify that the ECC displayed on the S412E is what is expected.
7. Do not start measuring the BER until the S412E signal generator starts transmitting.
8. Start the S412E BS Sensitivity test by selecting the “Start Test” button in the TETRA BS Sensitivity menu.
9. WAIT for the “Start Test” button to change to “Stop Test” – this lets you know that the signal generator has synchronized to the BS frame structure and is playing the TCH/7.2 signal.
10. Start the BER measurement on the TB3 BS.
• The signal from the S412E will restart every 60 seconds, so make sure that the BER measurement is made within this time interval.
11. You can now go to the Amplitude menu and change the Amplitude to your desired level.
Note
If you go back to the BS Sensitivity menu, the test will stop and you can restart it by following the same procedure.
