Nonfeedback

Nonfeedback refers to the absence of a feedback mechanism within a system, process, or interaction, meaning that the system's output does not influence its future input or behavior. In engineering and related fields it is commonly used interchangeably with 'open-loop' control. Nonfeedback contrasts with feedback-enabled designs where the output is measured and used to adjust inputs.

In control engineering, a nonfeedback or open-loop system applies a predetermined control signal to its actuators without using measurements of the actual output to modify the signal. Such systems can be simple and fast, with no sensor latency or controller complexity. They rely on predictable conditions and are vulnerable to disturbances, parameter changes, or external variations, which can cause output errors.

In information theory and communications, a nonfeedback channel is one in which the transmitter does not receive information about the received signal or channel state. This can simplify design and maximize throughput in stable environments, but limits the ability to correct errors or adapt to changing channels, reducing reliability compared with feedback-enabled schemes.

In other domains, nonfeedback may describe instructional approaches, organizational processes, or user interfaces that do not provide or rely on evaluative feedback. In practice, many real-world systems blend open-loop and feedback components to balance speed, cost, and robustness.

See also: open-loop control, closed-loop control, feedback, feedforward.