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Terrestrial television reception disturbances

Augustyniak L.

Przegląd Elektrotechniczny

2012

R. 88, nr 9b

296-297

The aim of the article is comparison of analogue and digital terrestrial television reception susceptibility to external disturbances. Advantages and disadvantages DTT versus analogue TV are represented. Different sources of television reception interference are depicted and special attention is paid to echo signals.

W artykule przedstawiono porównanie wrażliwości na zakłócenia odbioru naziemnej telewizji analogowej i cyfrowej.

Influence of a real radio channel parameters on the quality of the OFDM signal in mobile applications. Estimation of parameters of the channel as an element of improvement of the transmission quality

Bożek K.

Journal of Automation Mobile Robotics and Intelligent Systems

2007

Vol. 1, No. 3

64-68

The article deals with issues related to transmission of a signal with the OFDM multitude modulation in a real radio channel. Following short characteristics of the OFDM modulation, the article includes an analysis of typical radio channels from the angle of amplitude and phase on the basis of delay profiles referred to in the literature. The study contains results of simulated receipt of the OFDM signal in the multi-path conditions. On the basis of diagrams of constellation of the modulation symbols, the author presented differences in the quality of the signal before and after the phase correction and improvement in the quality due to application of cyclic prefix. Influence of noise as well as the fact that the terminals are non-stationary on operation of the frequency characteristics estimation algorithm was analyzed. At the end, an example was presented of application of a linear model of estimation of phase characteristics of a channel with the shift in frequency occurring in mobile systems as a consequence of the Doppler effect being compensated.

A solution for increasing data rate of Doppler-RAKE system

Nguyen Nguyen M., Modelski J.

Journal of Telecommunications and Information Technology

2003

nr 3

130-134

Doppler-RAKE detection in the CDMA system has been further developed and offers better performances in comparison to conventional RAKE detection, especially in fast-fading environments. Also, the multi-user Doppler-RAKE system works more effectively with channel coding applications. However, by means of exploring the Doppler effect, the system's data rate is decreased. We propose a simple solution to increase the data rate for the system while keeping the Doppler gain.