hello:
    Recently, I am debugging a hs usb system,and want to use 1480A to capture data so that I can analyze data.But most of time when I add 1480A into my system,my system can not work correctly.My system consist of a ARM based processor which is acted as host,and a web camera which acted as a device. And the 1480A can work correctly when I use my PC as host.
    Could you please give me some advice on how to solve such problems.
    Best Regards
Cao Fei
ps: If I directly plug the camera to my arm board,at least then enumeration process can finish.

Please email the temp.usb trace to 'support @ international test instruments . com' (remove spaces). We have an updated 1480A software that we will soon release that likely will resolve your issue. The .usb trace will tell us more. Thank you.

hello:
    I am sorry but you may misunderstood my meaning. I mean that if I connect like this:
        My ARM Board  <=> web camera
    my system can work properly.But if I connect like this:
        My ARM Board  <=> 1480A  <=> web camera
    my system can not work,even the enumeration process can not finish.(and the 1460A can sometimes capture some data)
    Then , could you please give me some advice.
    Best Regards
Cao Fei

Please capture the connection sequence data with the 1480A when set up in the failing configuration (" ARM Board  <=> 1480A  <=> web camera"). We can then look at the trace (temp.usb) to find out what goes wrong. We have had a couple of instances where the 1480A transceiver had to be slightly reprogrammed. The trace will tell us if your setup is one of these cases.

hello:
    I have upload the data,you will receive my email soon.
    Recently ,I tried many solutions,and found:
    if I connect like this :
    My ARM Board  <=>active hub<=> web camera  ---- my system can work
    if I connect like this :
    My ARM Board <=> 1480A <=>active hub<=> web camera ---- my system can not work and you can get the corresponding data from my email.
    if I connect like this :
    My ARM Board <=> 1480A <=> USB flash disk ---1480A can work correctly.
    Best Regards
Cao Fei

We have downloaded the .usb file and we have contacted you directly via email to continue detailed debugging.

We understand that you can capture okay when using the following connection to your embedded ARM board:

"if we connect like this: ARM board <=> Link <=>1480A <=>web camera. the 1480A can work correctly"

Possibly, your other failing scenario (below) is due to signal integrity issues (i.e. the cables used):

"but if we connect like this: ARM board <=> 1480A <=>Link <=>web camera the 1480A can not work correctly "

Based on our experience in our lab, such bad connections could be due to signal integrity due to bad impedance matching of certain devices or hubs. When connecting a USB analyzer in the circuit, the slight but noticable additional load by the USB analyzer in addition to the larger interference by the device or hub may cause the total signal quality to no longer meet the required specifications.

Please use a short cables as possible to reduce the risk of reflections (ringing) causing similar problems.