Q factor

n. Short for quality, the Q of an inductor, capacitor, or circuit made from these components is the ratio of its ability to store energy to the total of all energy losses in the component.

where X is reactance and R is resistance.

QA

(as letters) abbr. See quality assurance.

QNX

(cue-nix) 1. N. A popular Unix-like real-time operating system that has been widely used to develop real-time systems based on PC-like x86 platforms. The latest versions of QNX are well-known for their ability to run on any standard PC and for their nifty Linux ABI compatibility features, though other processors and platforms are also supported.

2. N. The company that makes the QNX RTOS. Short for QNX Software Systems.

quadrature

adj. The condition when two signals are 90 degrees out of phase. See also phase.

quadrature encoder

n. A type of rotary encoder. A mechanical device, the quadrature encoder produces two outputs 90 degrees out of phase. By counting transitions of these outputs, a computer can decode the shaft s position and its direction of motion. Contrast with binary encoder, Gray code encoder.

The optical path of a quadrature encoder showing its two out-of-phase rings, each of which blocks a light source as the device rotates.

quality

n. An oxymoron when applied to software of any sort. Software quality is an important and elusive issue. A hot topic today, debates rage about its meaning. Does quality imply bug-free code? On large systems, zero bugs is pretty...