The Q-factor (Quality) is used as a quality factor in active and passive electronic circuits in audio and RF technology, as well as in sound reinforcement and optical transmission technology.
- The Q factor is a measure of the quality of optical transmission links. It is given as a numerical value that reflects the quality of the optical transmission signal. "Q" is not an acronym for quality, but the mathematical symbol for the Gaussianerror integral. The Q factor allows direct conclusions to be drawn about the expected bit error rate. The Q factor is determined via the eye diagram, which is wider open at a higher Q value than at a lower one.
- In audio and RF technology, the Q factor is used to evaluate the quality of filters. In equalizers, for example, it defines the bandwidth of the controlled frequency band. The quality factor is determined from the quotient of center frequency and bandwidth. For example, a filter with a center frequency of 10 kHz and a bandwidth of 1 kHz has a quality factor of 10. The higher the quality factor, the narrower the bandwidth.
- In sound reinforcement technology, the quality factor is a measure of the frequency, damping and transient response ofloudspeakers and their natural resonance, and of the directivity of loudspeakers. It is a frequency-dependent number that results from the quotient of the sound power on the average dispersion plane of the loudspeaker to the sound power in all directions of the room. A high Q-factor indicates a high directivity.