Technical data

50 DSOX4USBSQ USB 2.0 Signal Quality Analysis Application Electrical Testing Notes
3 Host Signal Quality Testing
Host Low Speed Signal Quality Test
To set up and run the Host Low Speed signal quality tests:
1 Connect the USB Device, test fixtures, and equipment. See "Host Low
Speed Connection" on page 52.
2 Set up the test signal/packet that will be analyzed.
To generate bus traffic, connect a known good Low Speed device to the
port under test and capture a Low Speed packet to perform the eye
pattern analysis.
3 On the oscilloscope's front panel, press the [Analyze] key.
4 In the Analyze Menu, press the Features softkey; then, select USB Signal
Quality.
5 Press the Te st softkey and select the Host Low Speed Signal Quality test.
6 Press the Signals softkey. In the USB Signal Quality Signals Menu:
a Press the D+ Source softkey and select the analog input source
channel connected to the D+ signal (channel 2 in the previous
connection instructions).
b Press the D- Source softkey and select the analog input source
channel connected to the D- signal (channel 3 in the previous
connection instructions).
On 4- channel oscilloscopes, you are forced to use different channel
pairs for the D+ and D- signals. This provides the maximum sample
rate. (Channels 1 and 2 are one pair and channels 3 and 4 are the
other pair.)
7 Press the Auto Setup softkey to automatically set up the oscilloscope for
the selected test.
Table 8 Equipment Used in Host Downstream Low Speed Signal Quality Test
Quantity Item Description/Model
1 Oscilloscope Agilent 4000 X-Series
2 Passive probes Probes included with the oscilloscope are
sufficient.
1 Host test bed computer Any computer with the Windows XP,
Windows 7, or Windows 8 operating system
and hi-speed USB ports.
1 SQiDD board Agilent E2646A/B
1low speed USB device Any USB mouse