Re: [Discuss-gnuradio] USRP B200 host BW with USB 3.0/2.0

[Jorge Gallo]

How is that possible since only 8MHz can be placed over USB 2.0 ?

On one hand I have a B200 which is supposed to deliver 56 MHz.

On the other hand, for my final application, I am thinking of a low-cost host (such as BeagleBone Black) which I am afraid only has USB 2.0

 

My question was about getting 40MHz BW over USB 2.0 without tuning the central frequency of the USRP several times.

Regards,

Jorge

On 29 January 2015 at 16:35, Ralph A. Schmid, dk5ras <address@hidden> wrote:

I made tests with the bladeRF at 30 MHz bandwidth, and I was able to see the spectrum just fine, not matter if I used a USB2 or a USB3 cable. No hacks, no switching chunks of the spectrum, just using a standard receiver program. The lost samples are not a problem as longs as you do not want to listen in.

Ralph.

 

From: discuss-gnuradio-bounces+ralph=address@hidden [mailto:discuss-gnuradio-bounces+ralph=address@hidden] On Behalf Of Jorge Gallo
Sent: Thursday, January 29, 2015 4:07 PM
To: Martin Braun
Cc: GNURadio Discussion List
Subject: Re: [Discuss-gnuradio] USRP B200 host BW with USB 3.0/2.0

 

Martin,

 

The alternative of a USB 3.0 is not having 5 USRPs. It is just reading 5 times at different centrer frequencies in order to get 40MHz information although that information will not be gathered at the same time.

 

For my application I just need to "see" the sprectrum. I do not need to demodulate data so that it would be fine to proceed that way. However i would rather get 40MHz in a row.

 

Many thanks, 

Jorge

 

On 29 January 2015 at 14:07, Martin Braun <address@hidden> wrote:

On 01/29/2015 01:48 PM, Jorge Gallo wrote:
> I understand the given values of host bandwidth for each protocol:
>
> USB 2.0                  8 (MS/s @ 16-bit I/Q)

If you go down to 8-bit I&Q, you will get twice that amount, if that's
any help.

> USB 3.0                61.44 (MS/s @ 16-bit I/Q)
>
>
>
> However I would like to process 40MHz of analogue BW in GNURadio over
> USB 2.0
>
>
> I fully understand  a continuous reception is not possible to manage
> since it would require 40 IQ MS/s and I am limited to 8MS/s.
>
>
>
> However, is it possible to take snapshots of 40MHz over the time so that
> I am able to receive bits of 40MHz with USB 2.0 which are not continuous
> in time?
>
> Are there buffers in the FPGA that manage this kind of operation?

None big enough for anything useful.

It seems like attaching a USB3.0 connector would be simpler than running
5 USRPs? Not that I would complain about the sales :)

M

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