Teledyne LeCroy QPHY-USB3-Tx-Rx - Manual (Page 18)

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917719 Rev A
LFPS Ping using the PeRT 3
To send an LFPS Ping from the PeRT
3
the PeRT
3
TX+ and TX- should be connected to RX+ and RX- of the PUT.
The PeRT
3
controls should be set as follows:
Count Type: Bit Errors
Initialize: Custom Sequence
Custom Init Sequence: TX Test Init
Then click Connect to P UT. The TX Test Init sequence sets the PeRT
3
output to electrical idle to prepare for
sending an LFPS Ping. (Some USB3 implementations have been observed to react to the TX Test Init as an LFPS
Ping.) Next, change the Custom Init Sequence to TX Test Ping. Then click Connect to PUT to send an LFPS
Ping. It is convenient to view the output of the P UT on the screen and watch the pattern change when the Ping is
sent.
Loopback Mode using the PeRT 3
To place a USB3 product in loopback both the TX and RX of the PeRT
3
must be connected to the P UT. The
PeRT
3
controls should be set as follows:
Count Type: Bit Errors
Initialize: Loopback
Custom Init Sequence: No Disconnect Support (Default)
Output ALIGN/S KP: Checked
The PUT should be turned off. Click Connect to PUT. The PeRT
3
sends out LFPS and waits to see LFPS from
the PUT. Next, turn on the P UT. For devices, VBUS power may need to be applied as well . The PUT should now
be connected.
Clicking the Main tab shows the following dialog:
The Termination controls how long a receiver test runs. The termination can be set separat ely for individual
channels or for all channels at once using the Termination For control. Verify the PUT is correctly in loopback by
setting the controls as follows:
Termination For: All Channels
Termination Type: Run Forever
Now, click the Start button. The Status Me ssage should indic ate that the PeRT
3
is running and Pattern Locked
should appear in the top right with a green light next to it. It may take a few seconds to load the pattern the first
time Start is pressed before it changes to the Pattern Locked state. If the PeRT
3
cannot obtain a pattern lock it
stops running after a short time. If this occurs, using other Initialize and Custom Init Sequence settings may
help debug the problem. Debugging loopback operation is beyond the scope of this manual. Please consult the
PeRT
3
documentation for more guidance.
Receiver Test Calibration using the PeRT 3
Receiver testing involves applying a fix ed amount of jitter to a signal and controlling the amplitude and pre -
emphasis. It is important that these be applied correct ly and therefore it is desirable to measure the jitter,
amplitude and pre-emphasis of the PeRT
3
. Setup the PeRT
3
to output the receiver test signal by setting the
controls on the PeRT
3
dialog as follows:
Count Type: Bit Errors
Initialize: Loopback (blind / no handshake)