Measurement conventions, experimental set-up standards

[jto2]

Hello,

For the longest time I've been trying to find a single source of information about the proper way to set-up experiments with electrical signals being generated, measured and recorded. There are so many options when choosing equipment and components. Over time I've figured out what I need to know for my specific cases, but I always find it difficult to find the answer I'm looking for. We're so often concerning ourselves with signal integrity, so why is it so hard to find the right information? There's great peer-to-peer passing of knowledge, this forum for example, but that's not the best way to do it.

For instance: 

What type of wires should be used when measuring small/large fast/slow voltage signals? What size, material, braided or unbraided, coax, shielded, etc... how to know what to use and when?

How should the connections be (solder, alligator clips, clamps, etc) and what is preferred?

Grounding principles between instruments and the experimental set-up.

Oscilloscope fundamentals

Buffers, amplifiers, differential amplifiers, instrumental amplfiers

Input/Output impedance issues

The list goes on.

What are the common resources you guys use to help figure this stuff out? I feel like there should be a compendium of some sort.

Thanks for the help.

[REDS]

Hello John,

I think that a single source of information regarding all of what you mentioned would be rather hard to find. Regarding the grounding principles, a good source of information is The Field Wiring and Noise Considerations white paper. I haven’t come across some of the other topics you are looking that would be in a single source. Normally we have KB (Knowledge Base articles) for problems you experience. For example, if you experience ghosting in your measurements, one of the possibilities could be an impedance mismatch. You would get to the cause by searching the symptoms, in that case.

[jto2]

Ok thanks! I understand that it would be difficult to combine all these into one place.

What about the choice of wire, for instance? Aluminum/copper, stranded/solid, gauge, shielded, braided... Do you know of a selection guide for that sort of thing?

Thanks,

John

[johnsold]

John,

The choice of wire/cable types depends on the nature of the signals being carried and the nature of the interference trying to be avoided.

The size of the wire is determined by the current, the frequency, and the allowable voltage drop.  Material influences cost, weight, and types of connections. Stranded or solid: How flexible does the wire need to be?  Shielded, braided, coaxial, twisted pair, and combinations: Frequency, interference, number of signals, and so on.  And what about insulation? Dielectric strength, losses, temperature tolerance, mechanical behavior, ...

So many combinations and differing requirements exist that I doubt you will find any comprehensive document covering all these.  For example there are complete books just on the topic of shielding.

Some wire and cable manufacturers may provide selection guides and white papers covering a range of these topics.

Lynn