Cypress CY3631, Руководство пользователя

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CY3631 WirelessUSB™ Manufacturing Test Kit User Guide, Doc. # 001-66724 Rev. *B 9
Kit Operation
Figure 2-3. DUT Fixture
Press the START button on the test fixture. The BUSY light comes on for a short time. If the test is
successful, then the PASS light comes on when the test is completed. If the test exceeds the error
threshold settings, the test fixture indicates test failure by lighting the FAIL light.
2.3 Calibration
The test station is calibrated by using one or more known good reference devices to determine the
maximum attenuation that the system can have installed before the radio loses good contact. This
must be done periodically to compensate for environmental effects, and at least once any time the
DUT design is changed or the test station is switched to testing a different device model.
Antenna distance and orientation, to each other and to the walls of the test chamber, are important
for signal attenuation. Therefore it is vital that the calibration and test procedure be run with the
antenna and DUT installed in the same location and orientation every time. It is recommended that
you use a test fixture, or some other means, to ensure proper placement of the DUT each time. If
alignment guides are added to the chamber, they should be kept to a very low profile and they
should be constructed out of a non reflecting material. One option is to cut a shallow impression in
the foam at the bottom of the chamber that holds the DUT in the proper alignment.
Note that the foam in some test chambers is conductive. While testing bare boards, be sure to use a
fixture or some other means to insulate the board from the foam. A test fixture that holds the board in
exactly the same place every time is strongly recommended.
Any wires or battery packs that are placed in the chamber to power the DUT also need to be in the
same location every time, as these can reflect the RF energy and change the overall attenuation of
the signal. Batteries should ideally be used and placed in their final location, as they will be in the fin-
ished product. The battery position can affect the test results. If the battery is not in the finished prod-
uct's position, the test works fine, as long as the batteries are in the same position each time the test
is run.