Teledyne LeCroy QPHY-USB - Manual (Page 42)

42
QPHY-USB Operator’s Manual Rev F
RECEIVER SENSITIVITY
The receiver sensitivity is measured for devices and the upstream ports of hubs. Receiver sensitivity is measured
by applying a signal from a data generator to the input of the device or hub and observing the response of the
device or hub. The data generator is setup to transmit IN packets to be acknowledged by the device or hub. The
sensitivity is determined by reducing the level of the signal from the data generator and observing when the DUT
no longer responds. The data generator can be an arbitrary waveform generator or a pattern generator. The test
procedure is as follows:
1. Make sure the TEST/INIT switch on the Test Fixture is in the INIT position. Connect the “B” socket (J10)
of the “Sensitivity Receiver” section of the fixture to a High-Speed port on the Test Bed Computer.
Connect the “A” socket (J11) of the “Sensitivity Receiver” section of the Test Fixture to the device under
test.
2. Start the USB-IF HS Electrical Test Tool, select Device and then click Test. Click the Enumerate Bus
button once to force enumeration of the newly connected device. The device under test should be
enumerated with the device’s VID shown.
3. Load the “MIN_ADD1” waveform into the generator (see Appendix A for details on creating this
waveform). This generates “IN” packets (of compliant amplitude) with a 12-bit SYNC field. Connect the
generator to the “Sensitivity Receiver” section of the Test Fixture, using the supplied SMA cables. When
connecting the outputs of the generator make sure to connect the first channel to the D+ SMA (J9) and
the second channel to the D- SMA (J15).
4. Connect the differential probe from channel 1 of the oscilloscope to the differential probe header J12 of
the “Sensitivity Receiver” section of the Test Fixture. Recall the HSRcvrSensitivity.lss panel file on the
oscilloscope, using the File
Recall Setup menu. Use the Browse button in the “Recall Panel From
File” control to select the file from the D:\Applications\USB2\Setups directory. Press the Recall Now
button to select this setup file.
Figure 45. Receiver Sensitivity Test Setup