Protocol Settings
R&S
®
EX-IQ-BOX
192
User Manual 1409.5570.32 ─ 05
Example to Low Level BER Test using CPRI RE test mode
DUT
PRBS
UL
DL
BER
result
Fig. 7-72: Low Level BER Test
For testing a signal execute the following steps.
1. Define a signal in the downlink tab: Select "Physical Source > PRBS" in the downlink
tab and configure the AxC parameters regarding "Pattern Length" and position by
means of adjusting the "Word and Bit address" inside the CPRI frame.
2. Define a signal in the uplink tab: Select "Signal Output > BER Test"", and set the
same values for AxC "Pattern length" and position as in the downlink tab
Note:
For testing the function itself, the signals in the downlink and uplink tab must
be identical.
3. Apply the Tx and Rx settings.
4. Set the connected DUT to CPRI loopback mode.
Note:
The integrated loop-back function in the CPRI breakout board provides sending
and receiving signals, without plugging in an SFP module.
5. Reset the PRBS Test, if necessary.
Note:
It is recommended that you reset the "PRBS Test", after you have changed the
settings at the DUT, or unplugged external cables.
6. The function extracts received data from the uplink signal and compares it with the
expected PRBS data. The total number of received words and the calculated BER
are displayed.
The bit error rate test function embeds a known PRBS sequence in the CPRI protocol
and synchronizes the analysis on the receiver side with the received (looped) signal.
It synchronizes the data which are returned internally, compares these data with the
data being sent, and counts the bit errors. The ratio of the number of error bits to the
total number of bits is the BER-result.
Use this function to see whether the link is working properly. You can monitor the test
result continuously in the "Test & Diagnostics" tab.
Expected Results:
When you send a signal and the settings for the received signal are identical, the error
must be "0".
CPRI
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