# basic concepts of GROUND,EARTH,DIFFERENTIAL SIGNAL ,single ended ,FLOATING SIGNAL

Discussion in 'General Electronics Chat' started by hitu, Mar 3, 2012.

1. ### hitu Thread Starter New Member

Mar 2, 2012
1
0
i m confused all the time with differential and single ended signals.
(1) Suppose if we have a sine wave of some frequency and phase from function generator then is it a single ended signal or a differential signal? if it is a single ended then what kind of signals can be classified as differential signal.
(2) Is it necessary to have a differential system we must have two different signals.
(3) In a differential system where is the ground,i mean with respect to which reference we takes all the measurements?
(4) what are the floating systems and their examples? how floating systems has advantages over other single ended systems.

plz reply to this thread,and share ur invaluable knowledge.

2. ### crutschow Expert

Mar 14, 2008
22,807
6,750
(1) When the signal is referenced to ground (common) it is a single-ended signal. If the signal has two wires with equal and opposite signal polarity then it is differential (each signal may be referenced to ground but the signals are referenced to each other).

(2) A differential system has nothing to do with two different signals. It is primarily use to minimize noise since any noise pickup gives an equal value voltage and polarity on both wires. This is ignored by the differential receiver since it only responds to the desired differential signal which has an opposite polarity on both lines.

(3) The differential signal measured is referenced between each of the two differential signal wires. The measuring circuit must be connected across these two wires and have reasonable isolation from ground. The signal will also have some voltage to ground but that is not the signal of interest and must be ignored by the measuring circuit.

(4) An example of a floating system is a switching converter power supply with a transformer between the input and output power. The output ground can float with respect to the input which is useful if you want ground isolation between input and output (for safety or noise considerations).

A floating system is unrelated to a single-ended system. You are trying to compare apples and oranges. A floating system can be single-ended or differential.