On the Implementation of Optimal Receivers for LFM Signals using Fractional Fourier Transform

We present a novel receiver structure for the detection and parameter estimation of linear frequency modulated signals. The proposed structure is based on the relations between the fractional Fourier transform and the ambiguity function. It has been shown that the optimal ML receiver, which is the peak detector in the ambiguity plane, can be implemented at a reduced search complexity with the proposed method. The proposed method uses two 1-dimensional search operations in two different fractional Fourier domains instead of a 2-dimensional search over the ambiguity plane. The performance of the method is illustrated with an example.


Prospects of FMCW-based frequency diverse array radar
Cetiner, Ramazan; Cetintepe, Cagri; Demir, Şimşek; Hizal, Altunkan (2019-11-01)
The linear frequency modulated (LFM) frequency modulated continuous wave (FMCW)-based frequency diverse array (FDA) radar concept is investigated in detail. The radar operates as a linear pulsed FMCW/FDA in the transmission (TX) mode while it operates as a pulsed FMCW/phased array (PA) in the receiving mode. The issues such as low signal-to-noise ratio (SNR) of FDA, the time-angle scanning and time-range ambiguities are studied. It is shown that the local instantaneous frequency bandwidth is much smaller th...
On the Eigenstructure of DFT Matrices
Candan, Çağatay (Institute of Electrical and Electronics Engineers (IEEE), 2011-03-01)
The discrete Fourier transform (DFT) not only enables fast implementation of the discrete convolution operation, which is critical for the efficient processing of analog signals through digital means, but it also represents a rich and beautiful analytical structure that is interesting on its own. A typical senior-level digital signal processing (DSP) course involves a fairly detailed treatment of DFT and a list of related topics, such as circular shift, correlation, convolution operations, and the connectio...
A Study on the Performance of a Complementary Auxiliary Antenna Pattern for Maisel Sidelobe Blanker
DINLER, Dogancan; Candan, Çağatay; KOC, Sencer (2018-04-27)
The problem of coupling between probability of target blanking (P-TB) and probability of blanking (P-B) in Maisel sidelobe blanker (SLB) is addressed and a complementary auxiliary antenna pattern is proposed for phased array radar systems. The numerical results indicate that the complementary pattern provides an improvement on P-TB and P-B especially for the cases where antennas have poor mainlobe-to-sidelobe ratio.
A Method For Fine Resolution Frequency Estimation From Three DFT Samples
Candan, Çağatay (2011-06-01)
The parameter estimation of a complex exponential waveform observed under white noise is typically tackled in two stages. In the first stage, a coarse frequency estimate is found by the application of an N-point DFT to the input of length N. In the second stage, a fine search around the peak determined in the first stage is conducted. The method proposed in this paper presents a simpler alternative. The method suggests a nonlinear relation involving three DFT samples already calculated in the first stage to...
On the detection of sinusoidal signals under sinusoidal interference
Balcı, Burak; Candan, Çağatay; Department of Electrical and Electronics Engineering (2010)
A complex exponential waveform embedded in white noise can be optimally detected by matched filtering which is equivalent to Discrete Fourier Transform (DFT). However, if the input includes multiple complex exponentials, the DFT processing is not optimal. The frequency spectrum of the complex exponential signal with finite observation interval is not impulse. The spectrum includes side-lobes called spectral leakage.Because of the strong side-lobes, weak components can be masked, or side-lobes can be interpr...
Citation Formats
Ç. Candan, “On the Implementation of Optimal Receivers for LFM Signals using Fractional Fourier Transform,” 2008, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/47962.