Re: USRP with USB/IP


#1

On Fri, 2009-06-05 at 12:14 -0700, Firas A. wrote:

Hi,

— On Fri, 6/5/09, Patrick S. <patrick.
removed_email_address@domain.invalid> wrote:

Hello!

ednet[1] and RaidSonic[2] sell boxes that can forward USB
ports over
via the Linux USB/IP[3] system.

Patrick

From the web site the transfer rate of these boxes is
10/100Mb/s. So theoretically it should transfer a maximum of
12.5MByte/sec which is far below the required 32Mbyte/sec
of USRP1.

Hello Firas.
Just for my understanding:
The 32Mbyte/s requirement is for a full speed - 4 channel USRP
operation.
But if we suppose a simpler application, e.g. 1 TX/RX channel only,
wouldn’t this fit in the USB/IP?

Thanks
for your reply.
BR
Alberto

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#2

On Saturday 06 June 2009 00:23:54 Alberto T. wrote:

Just for my understanding:
The 32Mbyte/s requirement is for a full speed - 4 channel USRP
operation.
But if we suppose a simpler application, e.g. 1 TX/RX channel only,
wouldn’t this fit in the USB/IP?

This still on the decimation/interpolation rate. Each complex sample is
4
byte. Theoretically 100MBit Ethernet could sustain 3 MSample/s, so the
decimation rate has to be 22 or higher (most probably substantially
higher, as
there is some overhead by the TCP(UDP?)/IP headers, but 32 (2MSample)
should
be fine).

As Ethernet is full duplex, this is the number of samples/s that can be
sustained per direction, in constrast to USB, where the bandwidth is
shared.

This will for sure add some latency, you will have to figure this out by
yourself.

Bottom Line: 1TX/1RX, 2 MSample/s, complex samples should be possible.

Stefan


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