Viavi MSAM, Manual

Page: 43 / 74

Chapter 3 Diphase Testing
Measuring round trip delay
Data Communications and Diphase Testing Manual
January 2016 21148872, Rev. 002 Page 27
To perform BER analysis of a circuit
1 Configure the instrument. For details, see:
– “Specifying the clock frequency” on page 25
– “Specifying data settings” on page 26
– “Selecting a BER pattern” on page 16
2 If this is the first test you are performing today, perform a self-test (see “Step 2:
Performing a self test” on page 7 ).
3 Connect to the circuit under test (see “Step 3: Connecting the instrument to the
circuit” on page 8 ).
4 Start the test (see “Step 4: Starting the test” on page 8 ).
5 Verify that the PATTERN SYNC LED is illuminated.
6 Insert the error (or errors) using the Error Insert action button.
7 Observe the test results, particularly the results in the BERT and the G.821 cate-
gories (see
“Step 5: Viewing test results” on page 9 ).
BER analysis is complete.
Measuring round trip delay
Measuring round trip delay involves selecting the
R-TRIP DELAY
BER pattern, config-
uring the remaining settings for the test, connecting to the circuit, starting the test, and
then viewing test results. When you start the test, the instrument inserts 16 consecutive
bit errors into the transmitted
R-TRIP DELAY
pattern, and then measures the amount
of time (in milliseconds) before 16 consecutive bit errors are detected on the received
R-TRIP DELAY
pattern.
The scenario below provides the basic steps involved; you may need to configure addi-
tional settings for your particular circuit.
To measure round trip delay
1 Configure the instrument. For details, see:
– “Specifying the clock frequency” on page 25
– “Specifying data settings” on page 26
2 Select the R-TRIP DELAY pattern (see “Selecting a BER pattern” on page 26 ).
3 If this is the first test you are performing today, perform a self-test (see “Step 2:
Performing a self test” on page 7 ).
4 Connect to the circuit under test (see “Step 3: Connecting the instrument to the
circuit” on page 8 ).
5 Establish a hard loopback at the far end.
6 Start the test (see “Step 4: Starting the test” on page 8 ).
7 Verify that the PATTERN SYNC LED is illuminated.