Abstrait

SIDELOBE DEDUCTION BY PIECEWISE NON LINEAR FREQUENCY MODULATION WAVEFORM

DjoeIsac Thomas, C. Kamalanathan, Dr. S.Valarmathy

The Linear Frequency Modulation (LFM) waveform is the most commonly and extensively used signal in practical radar system. This paper introduces a new scheme of Piecewise Nonlinear Frequency Modulation (PNFM) for generating good code sets. Each code set has good autocorrelation with small peak sidelobes and cross-correlation. A weighting function is usually applied in order to reduce the sidelobes. In an effort to achieve low autocorrelation sidelobe level without applying weighting function, PNFM signal has been investigated. The new class codes is shown to have good ambiguity function with the ability to tolerate a realistic range of Doppler shift. At the receiver a matched filter is used which improvement in Doppler detection with good SNR