DVB-T Receiver performance: measurement of receiver noise floor and definition of difficult channels

A DTG receiver group seminar on DVB-T receiver performance was held at BBC R&D at Kingswood Warren on Friday 6th February 1998. At this seminar, it was agreed that in addition to front end noise figure, an important parameter in receiver design was the receiver noise floor, Px. Measurement of receiver noise floor is a difficult challenge. There are no direct methods of measuring the overall value. Nonetheless, Px should still be considered an important parameter. The presentations at the meeting showed that difficult channels do exist which will test the performance of receivers – and an unnecessarily high receiver noise floor will make successful reception in these difficult channels much less likely. There are two main reasons for measuring Px – firstly it is a single parameter that represents the overall performance impairment that will be suffered by the receiver in difficult receiving conditions. Secondly, by specifying an overall value for Px rather than the individual components, it allows manufacturers the freedom to trade off the different noise sources – for example phase noise and ADC quantising noise. This document offers some suggestions to the receiver industry as to possible methods for measuring receiver noise floor, and the components of the noise floor. Some of the methods suggested will only be appropriate to limited groups of people (e.g. receiver front end designers), but it is hoped that by offering a number of methods, individuals may choose an approach appropriate to their particular requirements, or as an aid to identifying dominant noise contributions. DVB-T Receiver performance: measurement of receiver noise floor and definition of difficult channels C. R. Nokes and J.E. Salter