The 1Gbit might be a bandwidth limitation of the Altera Aria LCDS channels as well as memory bandwidth. They might be using only 2-4 pairs LVDS feeding a network PHY. This wouldn't have been an issue with a Stratix, but, I suspect putting in an 4-8k$ FPGA would double the price of the scope.
Wouldn't the FPGA have an internal gigabit transceiver which can drive the SFP port (network) directly? A Xilinx Spartan6 which costs a few tens of dollars has no problem with that.
Yes, and they are using a 2 pair gigabit transceivers for the gigabit Ethernet/optical networking.
They didn't want to go further than that.
They are using the ' 5AGXBA1D4F31C5N ', a 260$ fpga in lots of 27.
It has 6.5536 Gbps transceivers, not the 10.3125 Gbps or 12.5 Gbps required for a 10Gbit lan connection.
The DDR3 ram controller works at 533Mhz or 667Mhz depending on configuration and wiring.
They also started development around 3 years ago, so, back then, there were no Aria FPGA in the series which had the 10Gbps and were also affordable. Like it or not, we are stuck with 1Gbps lan and would need to wait for the next version of the scope for the 10Gbps lan support.
I'm not sure but the speed and width of the ram and simultaneous sampling with network transfer may also be a factor. I only saw 4 ram chips on the PCB, however, pausing the sampling during the network transfer would make things faster. They would need 40 gigabit per second transfer rate for real time transfer of all 4 channels at full sampling speed.
Since they have full firmware update-ability, they wont be using Altera's cheap quick-asic mask version.