1. The performance specification of a communications channel or system.
Note: QOS may be quantitatively indicated by channel or system performance parameters, such as signal-to-noise ratio (S/N), bit error ratio (BER), message throughput rate, and call blocking probability.
2. A subjective rating of telephone communications quality in which listeners judge transmissions by qualifiers, such as excellent, good, fair, poor, or… (Read More →)

A process in which the continuous range of values of an analog signal is sampled and divided into nonoverlapping (but not necessarily equal) subranges, and a discrete, unique value is assigned to each subrange.
Note: An application of quantization is its use in pulse-code modulation. If the sampled signal value falls within a given subrange, the sample is assigned the… (Read More →)

Synonym quantizing distortion.

In the quantization process, the discrete value assigned to a particular subrange of the analog signal being quantized.

Synonym quantizing noise.

In a digital feedback loop, the digital signal that is fed back.
Note 1: Several forms of analog-to-digital converters contain a quantized feedback loop following the basic A-D converter.
Note 2: The feedback signal is often processed before introducing it to the loop.

Distortion that results from the quantization process. Synonym quantization error.

In digital transmission, the number of discrete signal levels transmitted as the result of signal digitization.

Noise caused by the error of approximation in quantization.
Note: Quantizing noise is dependent on the particular quantization process used and the statistical characteristics of the quantized signal. Synonym quantization noise.

In an optical source or detector, the ratio of the number of output quanta to the number of input quanta.
Note: Input and output quanta need not both be photons.