scholarly journals AMTI Filter Design for Radar with Variable Pulse Repetition Period

2016 ◽  
Vol 67 (2) ◽  
pp. 131-136 ◽  
Author(s):  
Michal Řezníček ◽  
Pavel Bezoušek ◽  
Tomáš Zálabský

Abstract This paper presents a design of a Doppler AMTI filter, for a radar with a variable pulse repetition period (stagger). The filter can suppress ground and volume clutter echoes simultaneously. The maximum filter impulse response length is limited to 5 coefficients due to a limited radar system stability and a radar antenna movement.

Author(s):  
Sergey Ziatdinov ◽  
Leonid Osipov

 Introduction: We discuss the problem of correlated noise suppression by adaptive complex notch filters of various orders. In order to eliminate the dependence of the transmission coefficient of the useful signal on its frequency, the pulse repetition period is modulated. Purpose: Studying the influence of pulse repetition period modulation on the correlated noise suppression coefficient. Methods: The notch filter parameters were optimized with the criterion of minimum average dispersion of correlated noise at the output of the filters during the repetition period modulation. Results: Expressions are obtained for the variance of correlated noise at the output of complex adaptive filters of various orders when the repetition period is modulated. Relationships are given for finding the optimal values ​​of the tuning frequency and coefficients of the notch filters which minimize the correlated noise level at their output. Expressions are obtained for the coefficients of correlated noise suppression by notch filters in the context of pulse repetition period modulation. The graphs are presented showing how the correlated noise suppression coefficient depends on the relative value of the probing signal repetition period deviation for various values ​​of the correlated noise spectral density width at optimal or non-optimal values ​​of the tuning frequency and coefficients of the notch filters. It is shown that the use of probing pulse repetition period modulation leads to a decrease in the correlated noise suppression coefficient. On the other hand, the adaptation of the weighting coefficients for the adopted models of notch filters and correlated interference provides an increase in the suppression coefficient. Practical relevance: When developing or studying correlated noise suppression systems, the obtained results make it possible, taking into account the permissible losses of the suppression coefficient, to reasonably choose the input pulse repetition period deviation value in order to eliminate the effect of “blind” frequencies.


2015 ◽  
Vol 58 (1) ◽  
pp. 38-45
Author(s):  
E. A. Bukvarev ◽  
M. V. Martynyuk ◽  
L. A. Pasmanik ◽  
V. A. Smirnov

Author(s):  
M. V. Buhaiov ◽  
S. P. Samoilyk

When designing pulse-Doppler radar, one of the key points is the choice of the pulse repetition period, which determines the boundaries of unambiguous measurement of range and radial velocity and creates contradictions in the measurement of these values. This contradiction is especially acute in the analysis of signals reflected from the propellers and turbines of aircraft. The main approaches to solving the problem of expanding the boundaries of unambiguous measurement of range and radial velocity is the use of variable pulse repetition period and the creation of signal ensembles to separate them by shape. Generation of an ensemble of sounding signals for a pulsed radar must be carried out taking into account both cross-correlation and auto-correlation properties. An approach to the generation of multicomponent signal trains with the possibility of pulse separation inside the train is proposed. Each of the pulses in the train is formed by adding a number of chirp signals, which differ in the values of amplitude and frequency deviation. As the frequency deviation increases, the amplitude of the component decreases. Reducing the cross-correlation coefficient of multicomponent signals from the formed ensemble can be achieved by increasing the number of components of each signal. The size of the signal ensemble, which can be formed on the basis of multicomponent chirp signals, depends on the requirements for the cross-correlation coefficient and auto-correlation function of the signals. It is shown that in order to expand the limits of coordinate measurement at a fixed wavelength, it is necessary to increase the number of pulses in the train. The results of the research demonstrate the potential possibility of using the proposed multicomponent chirp signal to form train of pulses with its subsequent separation.


2020 ◽  
Vol 3 (1) ◽  
pp. 1-8
Author(s):  
Ashraf Adamu Ahmad ◽  
Sagir Lawan ◽  
Mohammed Ajiya ◽  
Zainab Y. Yusuf ◽  
Lawal M. Bello

A common technique used by military to realize low probability of intercept (LPI) is linear frequency modulation (LFM) in the field of electronic intelligence (ELINT). This paper estimates the pulse width (PW) and the pulse repetition period (PRP) of LFM signal using instantaneous powers. The instantaneous powers were obtained either using time-marginal or power maxima approximated from a modified version of the Wigner-Ville distribution (WVD). The instantaneous power was also gotten directly from the signal by multiplication with its conjugate. Measurement was then carried out when the instantaneous power is ‘ON’ (the PW) and when it is ‘OFF’ (the PRP) at carefully selected thresholds. Thereafter, the mWVD-based algorithm was tested in the presence of additive white Gaussian noise (AWGN) at various signal-to-noise ratios. Results obtained during the test showed that the time marginal method emerged the best with minimum signal-to-noise ratio (SNR) of -5dB followed closely by the direct method with minimum SNR of -1dB at different thresholds. The results show that the proposed algorithm based on this modified WVD can be deployed in the practical field to determine radar’s performance and function


1975 ◽  
Vol 18 (3) ◽  
pp. 473-474
Author(s):  
I. S. Zholkina ◽  
V. I. Chernyshev

Author(s):  
S. Rakesh ◽  
K. S. Vijula Grace

Finite impulse response (FIR) filters find wide application in signal processing applications on account of the stability and linear phase response of the filter. These digital filters are used in applications, like biomedical engineering, wireless communication, image processing, speech processing, digital audio and video processing. Low power design of FIR filter is one of the major constraints that researchers are trying hard to achieve. This paper presents the implementation of a novel power efficient design of a 4-tap 16-bit FIR filter using a modified Vedic multiplier (MVM) and a modified Han Carlson adder (MHCA). The units are coded using Verilog hardware description language and simulated using Xilinx Vivado Design Suite 2015.2. The filter is synthesized for the 7-series Artix field programmable gate array with xc7a100tcsg324-1 as the target device. The proposed filter design showed an improvement of a maximum of 57.44% and a minimum of 2.44% in the power consumption compared to the existing models.


2021 ◽  
pp. 204-268
Author(s):  
Victor Lazzarini

This chapter now turns to the discussion of filters, which extend the notion of spectrum beyond signals into the processes themselves. A gentle introduction to the concept of delaying signals, aided by yet another variant of the Fourier transform, the discrete-time Fourier transform, allows the operation of filters to be dissected. Another analysis tool, in the form of the z-transform, is brought to the fore as a complex-valued version of the discrete-time Fourier transform. A study of the characteristics of filters, introducing the notion of zeros and poles, as well as finite impulse response (FIR) and infinite impulse response (IIR) forms, composes the main body of the text. This is complemented by a discussion of filter design and applications, including ideas related to time-varying filters. The chapter conclusion expands once more the definition of spectrum.


2018 ◽  
Vol 232 ◽  
pp. 02042
Author(s):  
Enhao Wang ◽  
Jin Pan ◽  
Deqiang Yang ◽  
Wenzhe Liu ◽  
Tao Tang

This paper proposes an oscillator based on a deformed structure parallel coupled line filter design. The requirements of this design are the output power meet 10dBm, and phase noise is below -90dBc/Hz at 10kHz off the centre point. This work adopts parallel positive feedback form, and it use Parallel Coupled Line Filter, making this design simple in structure and low in cost. This design has low phase noise and high output power features, working at 2.4GHz, intended to use in a through-the-wall radar system.


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