循环移位离散Chirp-Fourier变换

Circularly Shifting Discrete Chirp-Fourier Transform

离散Fourier变换(DFT)具有循环移位的特性。同样,源于DFT的离散Chirp-Fourier变换(DCFT)也具有循环移位的特性。该文提出了循环移位DCFT的概念,并根据这一概念给出了一种新的chirp信号的检测方法。该方法充分利用了chirp信号和噪声的特点,即chirp信号的调频率和初始频率不随时间变化而噪声的调频率和初始频率随时间随机变化,因此该方法具有更好的检测性能。与DCFT方法相比,实验结果表明,在低信噪比下该文提出的chirp信号的检测方法达到了良好的效果。

The Discrete Fourier Transform （DFT） has circular shift properties. Similarly, the Discrete Chirp- Fourier Transform （DCFT） motivated by DFT also has circular shift properties. This paper introduces the circular shift of DCFT and proposes a new method to detect chirp. The new method utilities not only the chirp characteristic, but also the noise characteristic, i.e., chirp rates and initial frequencies of chirp are invariant in time, whereas chirp rates and initial frequencies of noise are random in time, therefore, it has better detection performance, Comparing with DCFT, some experimental results are provided to demonstrate the better performance of the detection method proposed by this paper in low Signal-to-Noise ratio （SNR） environments.