Presentation of a Linear Adaptive System to Eliminate Single-Frequency Jammer Effect

In this paper, a linear two-stage adaptive filter is designed in which single-frequency signal interference      (Jammer single frequency) from messages in throughput wideband signals is removed. As a result, in the proposed system which includes the Doppler Effect, unknown frequency interference is automatically earned at the entrance and is removed. The proposed system is implemented using two Normalized least mean square (NLMS) linear adaptive filter. The specific innovation of the proposed filter is that even if the jammer with a reference signal frequency is different, at first it calculates the difference between them. Then the second filter is detected the interference that discover by the first filter which is considered as a reference signal. So, when there is Doppler Effect, the proposed system by combination two filters is accurately detect and easily removed jammer. The simulation results for the proposed interference cancellation system for the broadband QPSK signal which is impregnated with the strong interaction, is achieved. Results show that for the QPSK signal jammer with  single-frequency wideband message is effected on them as a strong interference. The proposed system shows up to 80 dB improvement in the Signal-to-Jammer ratio (SJR). In other words, the proposed system can be effectively used for the defense systems which are installed in front of jammers on a variety of birds.