Teledyne-lecroy QPHY-USB3-Tx-Rx Manuel d'utilisateur télécharger pdf (Page 29)

QPHY-USB3-Tx-Rx Software Option

917719 Rev A 29

At the completion of the CP0 Jitter Test the oscilloscope is in the following configuration:

Figure 15 - Oscilloscope Configuration after CP0 Jitter Test

On this screen there are 2 traces visible. They are the TIE Histogram and the Bathtub Curve. Again, the Tj, Rj

(spectral) and Dj (spectral) are displayed in the SDA Jitter section. However, as per the USB 3.0 SuperSpeed

Electrical Compliance Test Specification, the Rj that was measured on CP1 is injected into this measurement.

Additionally the minimum pulse width in the acquired waveform is measured in P1. Average UI is not shown on

the screen, but is reported with the other results.

Figure 16 - Test Report from Jitter Tests

Test 1.3.2 Phase Jitter Slew Rate

The purpose of this test group is to verify that the jitter slew rate is within the specification limits . This is a

measure of how fast the PLL in a USB3.0 receiver has to change in order to keep up with changes in the clock

frequency. Performing this test requires calculation of the first derivative of the PLL Track. The PLL Track is a

waveform that shows the phase change that the PLL was able to follow and track out of the signal. By taking the

first derivative of the PLL Track we can easily measure the minimum and maximum phase jitter slew rate on the

derivative waveform.

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Teledyne-lecroy QPHY-USB3-Tx-Rx Manuel d'utilisateur Page 29