Narrowband Filtering Effects on Frequency-Hopped Signals
Kevin A. Waters · 2002
A low complexity solution to remove follower, narrowband tone jamming signals which are randomly dispersed within the bandwidth of a hop without causing non-linear phase distortions in a frequency-hopping (FH) system is explored. Forward and reverse processed narrow stopband, elliptical infinite impulse response (IIR) filters are designed and applied to known audio and digital data. Analysis focuses on narrowband filtering one hop of a FH signal in the absence of noise. The results are compared with the output of equivalent finite impulse response (FIR) filters and equivalent forward processed IIR filters. This analysis demonstrates the effectiveness of forward and reverse narrow bandstop IIR filtering to eliminate unwanted tone jamming signals while preserving the phase of the received FH signal. These results also suggest that a FH system with narrow bandstop filtering can operate reliably in the presence of a high power tone jamming signal.