Agilent Technologies N5416A Manuel d'utilisateur télécharger pdf (Page 23)

10%-90% variations

• As designs move to smaller process technology the

edge rates are increasing

• USB 2.0 specification limits RT/FT to 500ps as

measured at 10%-90%

• Errors in consistency of these measurements due to:

– Shape of signal edge

– Noise

– Amplitude variations

– Probe peaking due to insufficient BW

• Slow corners give 10/90

rise time that is slower than

actual edge rate

• RT/FT faster than 400ps have observed

• Oscilloscope AND Probe BW must be at least 2.5Ghz

to accurately observe and measure these fast edges

Rise and Fall time

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Agilent Technologies N5416A Manuel d'utilisateur Page 23