Tektronix TDSUSB2, Руководство пользователя

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Application Examples
Signal Quality Tests for High Speed Devices
Specifying the Equipment-Signal Quality Tests for High Speed Devices for
Upstream Testing
The following equipment is needed for signal quality tests on a High Speed
device for upstream testing:
Tektronix digital oscilloscope
TDSUSB2 application
TDSUSBF compliance test fixture
One P6248 differential probe
Typical Equipment Setup-Signal Quality Tests for High Speed Devices for Upstream
Testing
To set up the equipment for the High Speed Signal Quality test, follow these
steps:
1. Set the S6 switch to the Init position.
2. Connect the standard USB cable between the Device SQ Init port and the
host port.
3. Connect the A receptacle from the Device SQ test port of the test fixture to
the unit under test (device).
4. Configure the measurement and select the command button to run the
application.
5. Place the device in the test mode Test_Packet from the host controller.
6. Set the test Init switch to the test position to isolate the unit under test while
maintaining the bus power.
7. Select OK after acquiring a waveform. Verify that it is a correct waveform.
8. If the signal is clipped, follow these steps to increase the vertical scale:
9. In the oscilloscope menu, select Vertical>Vertical Setup to display the
Channel screen.
10. In the Scale field, increase the vertical scale values until the waveform is
completely displayed in the screen.
TDSUSB2 Universal Serial Bus Measurement Package 95