Agilent Technologies N4962A Podręcznik Użytkownika Pobierz pdf (Strona 10)

BER testing >12.5 Gb/s

The N4962A serial BERT 12.5 Gb/s can be used for testing > 12.5 Gb/s. The

pattern generator section is capable of operating up to 15 Gb/s, but the error

detector section does not operate above 12.5 Gb/s. However BER measure-

ments can be made above 12.5 Gb/s by using a 1:2 DeMux (N4968A clock and

data demultiplexer 44 Gb/s) before the error detector input and checking both

de-multiplexed data signals independently. In the example below the N4962A

serial BERT 12.5 Gb/s is operating at 14.2 Gb/s—pattern generator runs at

14.2 Gb/s into DUT then into the N4968A configured as 1:2 DeMux, then to the

error detector at 7.1 Gb/s(two data streams Data Out1 and Data Out3, tested

individually). The sampling scope is optional but can help with timing setup.

The N4968A clock and data demultiplexer 44 Gb/s internal clock dividers are set to:

• Divider #1, #2 - divide by 2

• Divider #3, #4 - divide by 1

Figure 11. Block diagram – BER measurements above 12.5 Gb/s using a 1:2 demultiplexer

Clock and data demultiplexer

Sampling scope

DUT

10G BERT

Splitter

Signal generator

1 2 ... 5 6 7 8 9 10 11 12

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Agilent Technologies N4962A Podręcznik Użytkownika Strona 10