[hpsdr] Questions about Ethernet and Bandwidth

[Timothy Powell]

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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