Title :
Intermodulation distortion of the PLL FM demodulator in the presence of FM interference
Author_Institution :
Lehrstuhl fur Nachrichtentech., Erlangen-Nurnberg Univ., Germany
Abstract :
The intermodulation (IM) distortion of the PLL FM demodulator in the presence of FM interference is evaluated using Monte Carlo simulation. Both the desired signal and the interferer are considered to be frequency modulated by Gaussian random signals. The simulation is based on solving the nonlinear integrodifferential equation of the PLL FM demodulator, considering the amplitude and distorted phase modulation of the filtered FM signals. The IM distortion of the second-order loop PLL FM demodulator with Butterworth and Bessel input bandpass filters is given for co-channel and adjacent channel FM interferers. Bessel filters of order greater than two are shown to compare favourably with Butterworth filters in front of the PLL FM demodulator in the presence of an adjacent channel FM interferer
Keywords :
Butterworth filters; Monte Carlo methods; adjacent channel interference; band-pass filters; cochannel interference; demodulation; demodulators; frequency modulation; integro-differential equations; intermodulation distortion; phase locked loops; Bessel input bandpass filters; Butterworth input bandpass filters; FM interference; Gaussian random signals; IM distortion; IMD; Monte Carlo simulation; PLL FM demodulator; adjacent channel FM interferers; co-channel FM interferers; intermodulation distortion; nonlinear integrodifferential equation; Band pass filters; Demodulation; Frequency modulation; Integrodifferential equations; Interference; Intermodulation distortion; Nonlinear distortion; Phase distortion; Phase locked loops; Phase modulation;
Conference_Titel :
Electronics, Circuits, and Systems, 1996. ICECS '96., Proceedings of the Third IEEE International Conference on
Conference_Location :
Rodos
Print_ISBN :
0-7803-3650-X
DOI :
10.1109/ICECS.1996.584442