Novel analytic technique for obtaining the spectrum associated with piecewise-linear frequency modulation

1975 ◽  
Vol 122 (7) ◽  
pp. 710
Author(s):  
A.G.J. Holt ◽  
G. Salkeld
2020 ◽  
Vol 13 (44) ◽  
pp. 4465-4473
Author(s):  
Chandu Kavitha ◽  

Background/Objectives: The design of appropriate Non-Linear Frequency Modulation (NLFM) signals continues to be the focus of research in radar pulse compression theory for sidelobe reduction. This study focuses on a heuristic design and optimization algorithm to optimize the side lobe values of the NLFM signal designed using two-piece wise linear frequency modulation (LFM) functions. Methods: 1) Heuristic search identifies the optimum B1, T1, and B2, T2, which yield the lowest sidelobe value of the designed function.2) Compute all the side lobe values of the designed NLFM signal using an algorithm developed in Python scripting language. To plot a complete contour map for all the calculated side lobe values, which helps identify the associated variations in the range of side lobe values. Finally, optimize the side lobe values keeping the main lobe width and time-bandwidth (BT) product unchanged by designing a dynamic optimization algorithm. Findings: The algorithm developed considered all side lobe levels after the main lobe for optimization. The focus is mainly on the peak sidelobe ratio (PSLR) value without affecting the other parameters. The results demonstrate that the achieved side lobes exhibit their desired levels. Novelty: The method is useful in all types of hardware associated with weather radar applications to military solutions. The technique can be extended to other multistage signals consisting of piecewise linear Segments. Keywords: Contour; LFM; NLFM; optimization; PSLR


Author(s):  
Michael J. Nowak ◽  
Zhiping Zhang ◽  
Yang Qu ◽  
Dimitri A. Dessources ◽  
Michael Wicks ◽  
...  

2017 ◽  
Vol 7 (1.5) ◽  
pp. 84
Author(s):  
G S Krishnam Naidu Yedla ◽  
D. Siva Sankar Prasad ◽  
P. Raghavendra Rao ◽  
M Siva Kumar ◽  
M VenuGopala Rao

We propose a waveform that includes Linear frequency modulation and non linear frequency modulation wave applicable for MIMO radar. The wave form consists of three segments where the boundary segment consists of LFM content and the middle segment consists of NLFM. The time frequency component in the middle segment is controlled. The range and Doppler side lobe suppression is improved. The genetic algorithm is implemented to suppress the side lobes in the auto correlation and cross correlation functions. The performance is analysed by using ambiguity function.


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