Narrow Results

This paper presents the design of tunable heterodyne filter that can be used very effectively in the elimination of narrowband interference in wide-band communications. The filter makes use of the heterodyne process to create a tunable notch filter from a fixed coefficient high-pass filter. It has been shown that it is possible to generate a signal that can be used to set the heterodyne frequency to match the tunable heterodyne notch filter to the center of the detected interference through the use of a simple second order IIR band-pass filter to detect the narrowband interference. Moreover various options have been illustrated for the implementation of heterodyne filters using Xilinx Virtex field programable gate arrays (FPGAs).

Narrowband interference can severely degrade the performance of pulse signal detection. This paper presents a simple and efficient suppression scheme with temporal and frequency processing techniques. We implement a stand-alone interference suppressor on field programmable gate array (FPGA) based on digital tuning and 1st-order notch filtering. When a pulse signal along with narrowband interference is detected through spectral measurements, the interference signal is translated to zero frequency using down-converter and filtered out by a simple high-pass infinite impulse response (IIR). The original pulse signal is translated to its previous frequency using corresponding up-converter after alleviating the effects of interference. Furthermore, we deduce the frequency interval between pulse signal and narrowband interference to satisfy interference suppression performance. Experimental results show that the proposed interference suppressor can reduce narrowband interference and detect a pulse signal with acceptable RMS performance.