On 05/29/2018 12:51 PM, Felix via USRP-users wrote:
Hi Marcus,
The B200 has hardware revision 5. I am using a Lenovo T450 with an
Intel(R) USB 3.0 eXtensible-Hostcontroller.
One thing I can think of is power fade. Try with external power, or use
one of those
"Y" cables that allow you to siphon power from two ports on a USB
connection.
Date: Mon, 28 May 2018 12:36:53 -0400
From: "Marcus D. Leech" <mle...@ripnet.com <mailto:mle...@ripnet.com>>
This sounds like a problem with your USB controller -- what type is it?
What hardware rev of b200 do you have?
On 05/28/2018 08:11 AM, Felix via USRP-users wrote:
>
> Hi everyone,
>
> currently, I am trying to calibrate the TX power a USRP B200 device
> for different gain values. To realize this, I am calling the UHD
> function ?tx_samples_from_file? to send sine waves on different
> frequencies over cable to a frequency analyzer.
>
> The calibration itself works fine. As I am trying over a range of
> frequencies and gain values I call and close the UHD function several
> times.
>
> The problem I always run into is that the USB connection will
> sporadically break down at some point when I call the function again.
> I receive the error message:
>
> ERROR: Environment Error: IOError: usb tx2 transfer status:
> LIBUSB_TRANSFER_STALL
>
> This happens at some random time of calling the ?tx_samples_from_file?
> function but once it happened, everytime I call the function again the
> error reappears and the sine signal is not sent. I need to reconnect
> the B200 to recover from this error. Even though the USB error occurs
> I am still able to connect to the B200 so my routine will not notice
> any issues and just record very low TX power values. This is a big
> issue as I cannot catch the error which makes automation of the
> routine difficult.
>
> Has anybody seen a similar problem or has an idea how this connection
> issue might be fixed?
>
> Some remarks:
>
> * I use Windows 7 with UHD version 3.11.0.0-release
> * I use a similar routine for RX calibration with
>?rx_samples_to_file? and I do not run into any issues there
>
> Best regards,
>
> Felix
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