singleended

Single-ended refers to a signaling or measurement approach in which a signal is defined with respect to a single reference point, typically ground. In contrast to differential or balanced signaling, where information is carried by the voltage or current difference between two conductors, single-ended signaling uses one active line and a common reference return.

Applications include audio and video electronics, coaxial cabling, and many instrumentation scenarios where simplicity and cost are paramount. An input or output is described as single-ended when it is referenced to ground rather than to a second signal line. In op-amp circuits, a single-ended input or output stage uses one input pin relative to ground; in RF and video systems, coaxial cables commonly carry single-ended signals with the shield serving as the reference.

Advantages of single-ended design are simplicity, lower cost, and ease of driving and interfacing. Disadvantages include susceptibility to ground noise and hum, poorer common-mode rejection, and limited performance over long runs or in electrically noisy environments. Differential signaling mitigates these issues by using paired conductors that carry opposite-phase signals, improving noise immunity and allowing longer cable runs.

Historically, single-ended configurations were used in early vacuum-tube amplifiers (single-ended triodes) and remain common in certain niche audio and measurement applications. In such contexts, even-order harmonic distortion is a characteristic feature and can be aesthetically valued by some listeners.

In summary, single-ended denotes signaling referenced to a single node, offering simplicity and cost advantages at the expense of noise immunity and flexibility compared with differential or balanced approaches.