Agilent Technologies DisplayPort Manual do Utilizador descarregar pdf (Página 43)

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DisplayPort Test Implementation Group 43 Agilent J-BERT N4903B & 90000A/X/Q Series Sink Draft2

Scope based ISI measurement for RBR

A horizontal histogram which slices through the center of the crossing point is used to measure jitter

The scope is triggered by a signal from J-BERT’s clock or trigger output.

Scope settings:

• Set up scope for a measurement on a differential signal either by using a differential SMA probe head

or HW based channel subtraction (channel 1-3 or channel 2-4)

• Use 1kpts acquisition depths

• Set display mode to color grade

• Adjust crossing point to center of the display with two eyes

• Activate an horizontal histogram Analyze ! Histogram and select a thin window from the center of

the left eye to the center of the right eye

• Activate an histogram peak to peak measurement

J-BERT settings:

• Select a clk/2 pattern (1010) on J-BERT for the no ISI measurement and select a PRBS 2

-1 pattern

for the pp measurement with ISI

• Select 1V

diff

amplitude for the data output

• Deactivate SSC and all jitter sources

• Set data rate to 1.62Gb/s

For the measurement clear the display and let the scope run for a fixed amount of time, e.g. 2 minutes.

Note the hist

reading and repeat for at least five times. Average the results for the pp no ISI

measurements. Repeat for the hist

with ISI measurements.

Figure 40: RBR ISI measurement step 1 for jitter base line

1 2 ... 38 39 40 41 42 43 44 45 46 47 48 ... 55 56

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Agilent Technologies DisplayPort Manual do Utilizador Página 43