What I suggest you do, is concentrate on what you need now. As I wrote in an earlier post, I've got a simple sampler in the desk drawer now, at an early stage of construction. It's on an FPGA board, hence I don't have to worry much about the logic or the memory, up to a point.

If you don't have time for it now, you can always contact me via email and I'll provide you with whatever information, diagrams, pictures, code, etc, I hve available.

My first venture into logic analyzers was a sampler/multiplexer built using some relatively fast 4-bit RAM, shift-register inputs, a bunch of counters, a data selector, and a DAC, by means of which I was able to feed each trace, sequentially onto a 50-ohm cable to my oscilloscope. That only displayed 16 channels, but it sampled at 50 MHz, which was, for the time, very fast, and it sampled 4K times before the buffer was filled.
That was a good start.

Likewise, you need to figure out what you need now. Once you've got your immediate needs met, you can speculate about what you might build. You've already got a project ahead of you, so you don't need to have to build hardware in order to complete your project. If you're going to build hardware for a living, you'll need an oscilloscope, a good signal generator, and, in fact, two or more, so you can use one with which to stimulate the others in order to persuade them to produce the signals you need. You will probably also want a logic analyzer that can sample at a minimum of 4 times as fast as the fastest signals you hope to capture with it. After you've bought one or two of them, you'll learn what features are really important to you. That's just the way things are. The first time or two is for learning, and after that, it gets serious.

Feel free to contact me if you find you have time or need for this sort of instrument.

RE