/mcpDefining Analog Voice Document ID: 8628 Contents Introduction Prerequisites Requirements Components Used Conventions Analog Voice Characteristics Analog Voice Measurement Milliwatt and Hertz The Decibel Decibel Measurement Relative to One Milliwatt Transmission Level Point Noise Measurement Units Related Information Introduction This document discusses how analog voice signals are measured, the units used, and the points of reference used when you measure. The quality of a transmission system is defined by the difference between spoken voice at one end and reproduced voice at the other end. Anyone who uses the telephone experiences both good and bad connections, and can probably describe the quality of a particular connection in a subjective way. But how can you define good and bad quality in an objective way? In transmission, the first step to answer this question is to decide upon these questions: What is to be measured? • What are the measurement units? • What is the reference point for the measurements? • This document answers these questions. Prerequisites Requirements There are no specific requirements for this document. Components Used This document is not restricted to specific software and hardware versions. Conventions Refer to the Cisco Technical Tips Conventions for more information on document conventions.