Impulsive noise measurements and characterization in a UHF digital TV channel

This paper presents the results of a study covering measurement and charact erization of the wide-band impulsive noise present in a digital TV radio ch annel, Measurements were conducted at a frequency of 762 MHz in different o utdoor and indoor environments using vertical and horizontal polarization, The measurement system was built on commercial equipment only, The calibrat ion process, which is an important stage of this kind of measurements, is d escribed. To analyze the measurements the impulsive noise has been modeled as a pulse train where the pulse amplitude, pulse duration and elapsed time between pulses are considered random variables. It has been found that the pulse duration and elapsed time between pulses is not dependent on the ant enna polarization while the pulse amplitude is, especially in the case of t he noise generated by a fluorescent lamp. It has also been found that the p ulse duration of the noise measured in the outdoor environments presents so me clustering features and is correlated with the pulse amplitudes. This co rrelation may be caused by a RF noise bandwidth that is larger than the ban dwidth of the measurement system. The noise in busy streets presents larger pulse durations, larger amplitude, and shorter elapsed time between pulses that the noise measured in a pedestrian area. Several statistical tests ha ve been done to find the distribution function that best fits these random variables, Power Rayleigh, lognormal, exponential, Poisson, and Gamma distr ibutions have been tested. According to the assessment carried out, none of the distribution functions is adequate to model the pulse amplitudes or th e elapsed time between pulses, while the pulse duration seems to be Gamma d istributed.