[hpsdr] Questions about Ethernet and Bandwidth

[Chris Albertson]

If you "own" the wire.  That is it's not a shared Ethernet you can get about
90% of the 1Gbps.  I've seen this between systems using FTP to send large
amounts of data.   However if the wire is used for
general purpose networking then 70% is a reasonable number.

Yes computers can handle multiple Ethernet interfaces

It is possible to compress the data before it is sent and get a little more
bandwidth but you don't gain much if the data are noisy.

On Wed, Aug 24, 2011 at 6:00 PM, Timothy Powell <kd4iky at gmail.com> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
>
> I’m new to SDR and I’m trying to learn as much as I can.  I think I have a
> high level understanding of some of it but I have a few questions I was
> hoping someone could help me with it.
>
> I’m curious about how much information, signal samples, can be sent to a
> computer and processed.  I’d like to know how much of the Mercury sample
> data could be sent to a PC and processed compared to how much is currently
> being sent.
>
> Here is what I think I understand, please correct me where I’m wrong,
> thanks.  After reading the website about Mercury it’s my understanding
> that the ADC can sample up to 55 MHz of radio spectrum, more if you use
> under sampling which I don’t understand yet.  That information is sent to
> the FPGA which is used as a digital down convert that takes the real signal
> and converts it to a complex (I,Q) baseband signal centered at zero
> frequency (yes, no) and it also lowers the sampling rate (yes, no).  Then
> this data can be sent to a Metis board that sends it over the network to the
> PC and then the PC does its work.
>
> Some questions I have are:
>
> Knowing that data sent over a network are wrapped in protocols like UDP/IP
> which uses bits, what is the maximum amount of sample data that can be sent
> to the computer using a 1Gbs network connection assuming a Metis board is
> connected directly to a computer?  How much of the radio spectrum
> (bandwidth) would that be?  How could it be calculated or estimated?
>
> Would a current computer be able to handle that amount of data?
>
> What is the current maximum amount of data sent to a computer from Mercury?
> I’m wondering what the limitations are for the amount of data Mercury could
> send to a computer and how much of that data the computer could handle.
>
> Thanks
> Timothy - KD4IKY
>
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-- 

Chris Albertson
Redondo Beach, California
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