Can someone explain the difference between signal ground, analog ground, digital ground, earth ground, system ground, chassis ground in a board and a complete system. How do they interact.
Explain it to me like a 10 year old cos this is really weird concept hearing it from 2 different people.
I think Chassis ground=system ground- this is where you ground all your capacitive filters and power supply filters.
Analog ground should be seperated from chassis ground on a PCB and should join at start ground point.
Please let me know.
Thanks..

This is a pretty broad topic. They all describe a common reference point or return point for a circuit. The "signal" "analog" etc... just describe what type of circuit it is for. There are many reasons why you would want to split up your ground into multiple sections. The links below list some of them.

I think one of the hardest concepts to learn if you do not pick it up early is 'ground.'

For instance, you do not need to connect a circuit to earth ground a.k.a. chassis ground (usually the chassis is connected to earth ground via a 3 prong plug) to make it work.

However, it does require a common path for charge to flow back to the source. Think of something that is battery powered. It is not connected to earth (chassis) ground. 'Ground' is the common point to where all measurements are referenced to. Since it is the common point, many people will call it 'common.'

You also start to get into the concept of floating supplies. Fun stuff!

After reading the articles i redesigned a circuit (medical industry) with a channel for analog ground, one for power ground and one for earth ground on the circuit. The earth ground has all capacitors that actually filter out transient signals from ESD discharges and which are more suseptable to noise. It has a 0 ohm resistor path to the mounting holes,Another optional connection to power ground via a 0 ohm resistor and finally a 2M ohm optional resistor to analog ground with a 1000pF capacitor in parallel.
This is a grounding scheme i employed.