Hi,
It depends what the person who started the thread is doing. Maybe it would be better classed under 'Analog Circuit Design' or perhaps 'Analog Integrated Circuit (IC) Design, Layout and Fabrication', or possibly 'RF Microwave, Antennas and Optics'. I have no idea as I do not know what their end goal is.
Definitely not "RF Microwave, Antennas, and Optics." "Analog ICs" could work in principle, but we really need a separate space for
digital circuits, layout, logic gates, and logic solutions, and nothing looks obvious in the top-level categories. Analog guys are all about PLLs, power supplies, bandgaps, antennas, transmission lines, etc. In digital, we generally try to pound all analog signals into square waves or flat lines, and pack everything as densely as possible. This is relevant to ASICs far more than to Analog ICs.
I've seen a few digital circuits/gate solutions appear in "Digital Signal Processing," but that forum is primarily about the math. Also in "Elementary Electronic Questions," but these concerns are beyond elementary.
It is a distinct subset of ASIC design methodology, but I'd much prefer to have a category for "Digital Circuits and Logic."
On a related note, where would "Mixed Signal Design" belong?