@whitequark Ah, ok, thanks for the clarification. Do they have somehow coupled the LOs in order to get them coherent? Because usually that's the tricky part. AD's "standalone" modulators and demodulators have dedicated LO inputs and outputs so you can daisy-chain them. I always wanted to build a MIMO SDR with them, too.
@whitequark But doesn't the AD9361S still only have 2 Rx and 2 Tx chains? It does have twice as many outputs and thrice as many inputs, but those can't be used simultaneously, right?
@ChuckMcManis@SteveBellovin I would rather say, they're completing the work Sun started with Solaris. systemd isn't a clone of Windows' services, systemd is a clone of Solaris' svcs.
@BrucePerens_K6BP The actual demodulation code is the same, since it's running on the processor, but e.g. the spectrum calculation takes place in the FPGA. A lot of interaction with the programmable logic is hidden in the kernel driver which is controlled via ioctls. The forked KiwiSDR code can be found here https://github.com/RaspSDR/server/tree/master, but the source code of the kernel module unfortunately not.
@BrucePerens_K6BP That's because the KiwiSDR uses a standalone FPGA that communicates with the SBC over SPI, while the Web-888 uses a Zynq-7000 SoX and shared memory for interaction between PL and PS parts.
@BrucePerens_K6BP Unfortunately not open. They neither published the FPGA block design nor the source code for their kernel module. You don't even get a schematic.