| Term |
Definition |
| QA |
Quality Assurance. |
| QADC |
Queued Analog to Digital Converter. |
| QAM |
Quadrature Amplitude Modulation/Modulator. |
| QCIF |
Quarter Common Intermediate Format. |
| QoS |
"Quality of Service" refers to the idea that transmission rates, error rates and other transmission factors can be measured, manipulated and, to some extent, guaranteed in advance. Certain types of continuous high-bandwidth data transmissions such as video and multimedia information may require guaranteed minimum transmission speeds and maximum error rates. |
| QPSK |
Quadrature Phase Shift Keying. |
| QSAM |
Queued Sequential Access Method. |
| QSIF |
Quarter Standard Interface Format. |
| Quad |
A slang term used to describe a cable conductor which has two twisted pairs (or four single untwisted wires) which are separately insulated. |
| Quadrature Amplitude Modulation |
A method of combining amplitude modulation with phase shift modulation which allows for the transfer of several bits of information at the same time expressed as one of 16 or 32 different states. |
| Quadrature Modulation |
The modulation of two carrier components, which are 90 degrees apart in phase. |
| Quantization |
The process in which the continuous range of values of an input signal is divided into sub-ranges and to each value of the sub-range a discrete value of the output is assigned. |
| Quantization Distortion |
With the restriction of a finite number of produced amplitude steps, a difference inevitably occurs between the information which can be transmitted and the original information. This difference is called quantization distortion. |
| Quantization Distortion Power |
The power of the distortion component of the output signal resulting from the process of quantization. |
| Quantization Error |
An error introduced by the quantization process. For example if a continuous analog signal is represented in digital form and error equal to one half of the least significant digital it will be introduced (a rounding error). |
