Waveform Design of Linear Frequency Modulation Pulse Signal Based on Ambiguity Function

2018 ◽  
pp. 485-496
Author(s):  
Bin Wang
Keyword(s):  
Frequency Modulation ◽  
Pulse Signal ◽  
Waveform Design ◽  
Ambiguity Function ◽  
Linear Frequency Modulation ◽  
Linear Frequency

scholarly journals Cell ID and Timing Estimation Techniques for Underwater Acoustic Cellular Systems in High-Doppler Environments

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4147
Author(s):  
Muhammad Asim ◽  
Mohammed Saquib Khan ◽  
Tae Ho Im ◽  
Yong Soo Cho
Keyword(s):  
Frequency Modulation ◽  
Doppler Shift ◽  
Base Station ◽  
Ambiguity Function ◽  
Cellular Systems ◽  
Linear Frequency Modulation ◽  
Sensor Nodes ◽  
Underwater Acoustic ◽  
Linear Frequency ◽  
The Time Domain

In an underwater acoustic cellular (UAC) system, underwater equipment or sensor nodes need to detect the identity of an underwater base station (UBS) and synchronise it with a serving UBS. It is known that, in an underwater acoustic channel, the temporal variability of the ocean coupled with the low speed of sound in water may induce a significant Doppler shift. In this paper, two different types of cell search techniques (CSTs) are proposed to detect the cell ID and correct timing of the UBS in UAC systems with a Doppler shift: CST based on linear frequency modulation with full bandwidth in the time domain (LFM-FT) and CST based on linear frequency modulation in the frequency domain (LFM-FF). The performances (auto-correlation, cross-correlation, ambiguity function, and cross ambiguity function) of the proposed techniques are analysed and compared with simulation results. It is demonstrated by simulation that the proposed techniques perform better than previous techniques in both AWGN and multipath channels when a Doppler shift exists. It is also shown that the LFM-FF-CST achieves the best performance in the presence of a Doppler shift and is suitable for mobile UAC systems.

Linear Frequency Modulation Pulse Signal

2017 ◽  
pp. 83-118
Author(s):  
Ruliang Yang ◽  
Haiying Li ◽  
Shiqiang Li ◽  
Ping Zhang ◽  
Lulu Tan ◽  
...  
Keyword(s):  
Frequency Modulation ◽  
Pulse Signal ◽  
Linear Frequency Modulation ◽  
Linear Frequency

Effects of Plasma Sheath on Parameter Estimations of Linear Frequency Modulation Pulse Signal

2019 ◽  
Vol 47 (11) ◽  
pp. 4934-4943
Author(s):  
Bowen Bai ◽  
Yi Ding ◽  
Fangfang Shen ◽  
Yanming Liu ◽  
Xiaoping Li ◽  
...  
Keyword(s):  
Frequency Modulation ◽  
Pulse Signal ◽  
Plasma Sheath ◽  
Linear Frequency Modulation ◽  
Linear Frequency ◽  
Parameter Estimations

scholarly journals An improved time reversal mirror based on standard linear frequency modulation waveform

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yongkang Wang ◽  
Han Zhang ◽  
Huiling Li ◽  
Jianfeng Zheng ◽  
Liang Guo
Keyword(s):  
Frequency Modulation ◽  
Time Reversal ◽  
Pulse Signal ◽  
Linear Frequency Modulation ◽  
Transport Channel ◽  
Channel Response ◽  
Linear Frequency ◽  
High Bandwidth ◽  
Standard Linear ◽  
Time Reversal Mirror

AbstractTime reversal mirror (TRM) technology is the adaptive focusing method evolved from the phase conjugate method in optics. Conventional incentive method in TRM technology is a narrow pulse signal with a high bandwidth. In this paper, the autocorrelation property of the TRM was proved from the time-reversal symmetry of the wave equation. The linear frequency modulation (LFM) signal is adopted as the exciting signal in the TRM, which gives the dual autocorrelation function waveform, including the exciting signal and transport channel response. Theoretical results show that the peak value of the transducer array’s focusing signal is determined by the pulse width of the LFM signal and the number of array elements. In addition, the adaptive filtering deconvolution method is used to precisely regulate the input signal to ensure that the final detecting signal is the expected LFM waveform, which eliminates the effect of the transport channel and enhances matched filtering effects. The results hold great theoretical significances for the development of TRM technology in ultrasonic detection.

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