The BER Test measures the bit error ratio for the given channel. This test requires that the BERT emits a test pattern signal through the ISI channel board, to then be equalized by the TUSB1146, and finally read again by the BERT. The BERT compares the sent and received signal to detect errors.

This test follows the same setup details as the Eye Test. The BERT needs to be configured with the same pattern and settings. The TUSB1146 registers, the No EQ test, and longer channel lengths can be configured in the same way. The startup procedure in this test is also the same as the previous test.

BER Test:

1. Configure the hardware setup in Figure 2-2. For the "No EQ" configuration, remove the TUSB1146 from the channel path and connect remaining devices.

2. Select a channel length for the trial and modify the ISI channel board.

3. For static EQ, Fast AEQ, and Full AEQ configuration tests, turn on the redriver and configure the selected EQ type as described in EQ Configuration.

4. On the BERT, run the BER test for 1E13 bits and record the value.

5. Repeat steps 2-4 for each trial length.

Similar to the Eye Test, this test needs to be repeated to complete the clean signal test and JTOL test for each EQ configuration