I came across few different ground names (digital, analog, signal, power, mecca, EM, shield, etc).
I do understand most of them - but mecca is a new one for me. Can someone please explain this mecca ground?
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Definition of mecca:
a place regarded as a center for a specified group, activity, or interest
This suggests the same as "star" topology, where items connect to a central point or "hub." Given this, I would take it to mean that grounds in the system are connected to a single common point at ground potential.
See Multipoint ground for a different grounding system.
I feel as if the answer above is incorrect as I have done mecca grounding and in fact it it is pretty much the opposite of a single point ground. The idea is to introduce little "meccas" at each stage of circuitry of a multi-stage single ended analog circuit. Each mecca is concentrated at each stage but the circuitry and physical implementation are such that the lines between stages are run quasi-differentially. This is strictly for the signal path. Power is done in a star formation. The idea is that other ground currents can't pollute the signal when it transverses a distance because of the differential run. But each op-amp will have its own little mecca.
My understanding of this started in the early days of TV broadcast. RCA ran into the problem of ground loops between pieces of equipment injecting noise and hum. They solved it by lowering the impedance of all of the grounds by running huge woven ground busses between the equipment. Another broadcaster - if I remember correctly it was Westinghouse - solved the problem by bringing all of the grounds from the individual pieces of equipment to a single ground point, called the Mecca ground (as in "All roads lead to Mecca"); these ground lines did not need to be very big.
When I layout boards, I create separate ground plane islands for analog circuitry and each switching power supply and make their connection to the ground plane at large at the lowest impedance point which is often the ground connection at the battery if battery powered.