Teledyne LeCroy QPHY-USB3-Tx-Rx - Manual (Page 19)

QPHY-USB3-Tx-Rx Software Option
917719 Rev A
19
Custom Init Sequence: No Disconnect Support (Default)
Output ALIGN/S KP: unchecked
Click the Connect to PUT button. The Initialize setting Loopback (blind / no handshake) causes the PeRT
3
to
skip through the LFPS handshake and behave as if the link is up. In this state the PeRT
3
can be used to generate
USB3 signals wit hout the RX inputs connected. By connecting the TX out puts to the oscilloscope the jitter,
amplitude and pre-emphasis can be measured.
Next, click on the CH1 tab and the following dialog is shown:
Adjust the controls on the dialog to apply the amplitude, pre-emphasis and jitter as desired. You can also choose
a pattern.
Note: The USB3 specification refers to de-emphasis, not pre-emphasis. They are effectively the same. How ever, for pre-emphasis the
amplitude refers to the amplitude of the bits before emphasis is added. For de-emphasis the amplitude refers to the amplitude of the bits
before emphasis is removed. Since the PeRT
3 controls are for pre-emphasis the target amplitude is low er than the USB3 specification. For
example, if the desired amplitude of the emphasized bits is 750mV and the amount of emphasis is 3.5dB the amplitude setting f or the PeRT 3 is
3.5dB less than 750mV, w hich is 500mV.
After setting up the channel cont rols click on the Main tab. Configure the controls as follows:
Termination For: All Channels
Termination Type: Run Forever
Now, click the Start button to begin sending out the pattern chosen with the applied jitter, amplitude and pre-
emphasis.