Agilent Technologies N5980A Manual do Utilizador descarregar pdf (Página 5)

J-BERT N4903A High-Performance Serial BERT Data Sheet 5

Figure 5: Spectral jitter decomposition for debugging jitter

sources in a design.

Figure 6: Eye contour with colors indicating BER-level.

Figure 7: BERT Scan incl. Rj/Dj separation, total jitter.

User Interface and Measurement Suite

Quick Eye Diagram

The quick eye diagram allows a one-shot check for a

valid signal. Due to the higher sampling depth of a

BERT, the eye contour lines visualize the measured

eye at a deeper BER level for more accurate results.

Extrapolated eye contour lines display the eye open-

ing for even lower BER levels, such as 10

-15

reducing the measurement time significantly. The dis-

play shows numerical results for 1-/0-level, eye

amplitude and width, total jitter and more. The

screen can be printed and saved for documenting

test results. (See figure 4)

Spectral Jitter Decomposition

It measures the spectral decomposition of jitter com-

ponents. When debugging designs, the jitter decompo-

sition simplifies identifying deterministic jitter

sources. (See figure 5)

Eye Contour

The eye opening is a key characteristic of a device.

The BER is displayed as a function of sampling delay

and sampling threshold. Different views are available:

Eye Contour (see Figure 6), pseudo colors and

equal-BER plots.

BERT Scan including RJ/DJ separation

This measurement shows the BER versus the sam-

pling point delay, which is displayed as a “bathtub”

curve or as histogram. The measurement results are

displayed in a table with set-up and hold time over

phase margin, total jitter in rms or peak- to-peak,

and random and deterministic jitter. The measure-

ment method is equivalent to IEEE 802.3ae. (See fig-

ure 7)

Figure 4: Quick eye diagram with BER contour.

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Agilent Technologies N5980A Manual do Utilizador Página 5