NOTE: 3-27-17... ~ 1yr later. Did I write this? It's gonna take a week+ to recall this mindset!

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So... first, I want to mention that quadrature signalling is used for communication... I don't fully understand the details, but I think it's used for FM radio transmissions in order to send the Stereo audio-data over a single transmission carrier-wave. So, in a sense, it achieves communication of *two* different data-streams over a single wire, at the same bit-clock...

This is a little bit different than that, I think, because its intent is to send *digital* data, and... two separate data-streams? Nah, too complex for me to figure out right now...

Back to the wired-realm, where there's a "clock" signal separate from the "data" signal(s)...

So, is this maybe better/faster than, say LVDS?

Well, one interesting discovery of this system is the fact that its "lock-step" design--based on a state-machine looking for comparisons--apparently allows it to determine the "position" regardless of its actually running in a lock-step fashion... What do I mean by this...? Using nothing but simple comparisons (e.g. from a comparator, or several?) between the four signals received at the receiving-side (+clock, -clock, +data, -data), a handful of comparators could emulate anaQuad2x... Looking at the outputs of those comparators a digital value is achieved representing the "phase" or "position" of the quadrature-signal.

Low-and-behold... LVDS inputs *are comparators*... so, maybe, one LVMDS signal combined with several LVDS receivers could actually give a somewhat digital output... in this case, I don't mean digital as in a single digital *bit*, but more like an entire *nibble* received within one clock-cycle. Take it a step further, the "lock-step" design requires a bit of processing (I think) to iterate through those comparisons in order to find the new "position"... so...? We have generally accepted that long-distance communication at high-data-rates is usually quite a bit slower than the processors/FPGAs/Logic receiving them... The receiver has a state-machine running at 8x the transmitted signal... Bam.

So, is this a good idea...? What benefit is there, really...? If LVDS is slowed to some maximum rate due to its ability to swing levels to reliably-readable values fast enough... then wouldn't this system (LVMDS) run into that same problem...? Wouldn't it limit the "nibble-rate" to that same limit...?

This is where I'm not yet certain... On the one hand, maybe the "nibble-rate" is limited to a full-swing signal... which, for anaQuad, would be the equivalent of a 90-degree positional-change... (Actually, this limitation is probably a good one for several reasons... first of all, it means that the signal "transition" will never exceed that of an LVDS signal "transition", so should work in the same electrical/physical conditions, and second, the "auto-positioning" of the system works to -135 to 180deg, but is a bit iffy around the 180 and -180 marks).

Anyways, plausibly, instead of using direct multi-level digital transmission, wherein each "position" represents a binary value, instead, maybe, use multi-level digital *change*... wherein each "position" represents a *change* in binary-value...

I haven't thought this whole thing through, completely...

As far as physical implementation in the experimental-realm:

I think reception of anaQuad2x could be handled by four LVDS receivers, or even just four (fast) comparators... I need to think this one through a bit, still... And, transmission...? We'll come back to that.