This document discusses the design and implementation of digital pulse compression in pulsed radars using linear frequency modulation (LFM) waveforms on an FPGA. It describes how LFM waveforms achieve pulse compression to overcome peak power limitations while maintaining range resolution. The key aspects covered are:
1) The LFM waveform is generated digitally using counters, PROMs, and DACs to produce the frequency modulated signal.
2) Matched filtering is used at the receiver to compress the received signal through correlation with the known transmitted LFM waveform. This is implemented using an FFT.
3) Simulation results on the FPGA show generation of the LFM waveform and resolution of multiple targets after pulse compression
Performance and Analysis of OFDM Signal Using Matlab SimulinkIJMER
Multi-carrier modulation is an attractive technique for fourth generation .OFDM is based on
multicarrier modulation technique. In OFDM system the bit stream is divided into many different sub
channels. An efficient and distortionless scheme for peak power reduction in OFDM is proposed. In this
paper, a set of mapping where the actual transmit signal is selected. From this set of signal reduced
PAPR. Simulation results are shown. The lowest PAPR is compared with conventional work. It is also
compared BER to SNR and best result is achieved.
PAPR REDUCTION OF OFDM SIGNAL BY USING COMBINED HADAMARD AND MODIFIED MEU-LAW...IJCNCJournal
Orthogonal frequency division multiplexing (OFDM) is a technique which gives high quality of service (QOS) to the users by mitigating the fading signals as well as high data rates in multimedia services. However, the peak-to-average power ratio (PAPR) is a technical challenge that reduces the efficiency of RF power amplifiers. In this paper, we propose the combined Hadamard transform and modified meu-law companding transform method in order to lessen the effects of the peak-to-average power ratio of the
OFDM signal. Simulation results show that the proposed scheme reduces PAPR compared to other companding techniques as well as the Hadamard transform technique when used on its own.
Performance and Analysis of OFDM Signal Using Matlab SimulinkIJMER
Multi-carrier modulation is an attractive technique for fourth generation .OFDM is based on
multicarrier modulation technique. In OFDM system the bit stream is divided into many different sub
channels. An efficient and distortionless scheme for peak power reduction in OFDM is proposed. In this
paper, a set of mapping where the actual transmit signal is selected. From this set of signal reduced
PAPR. Simulation results are shown. The lowest PAPR is compared with conventional work. It is also
compared BER to SNR and best result is achieved.
PAPR REDUCTION OF OFDM SIGNAL BY USING COMBINED HADAMARD AND MODIFIED MEU-LAW...IJCNCJournal
Orthogonal frequency division multiplexing (OFDM) is a technique which gives high quality of service (QOS) to the users by mitigating the fading signals as well as high data rates in multimedia services. However, the peak-to-average power ratio (PAPR) is a technical challenge that reduces the efficiency of RF power amplifiers. In this paper, we propose the combined Hadamard transform and modified meu-law companding transform method in order to lessen the effects of the peak-to-average power ratio of the
OFDM signal. Simulation results show that the proposed scheme reduces PAPR compared to other companding techniques as well as the Hadamard transform technique when used on its own.
Low Peak to Average Power Ratio and High Spectral Efficiency Using Selective ...theijes
A low complexity peak to average power ratio (PAPR) reduction scheme for orthogonal frequency division multiplexing (OFDM) systems is proposed. All pass filters technique used PAPR is reduction but small amount of reduction, So use Selective Mapping (SLM) technique reduce PAPR and SNR increases.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Analysis Predicted Location of Harmonic Distortion in RF Upconverter StructureTELKOMNIKA JOURNAL
A new mathematical analysis to predict the magnitude size of the distortion products from the
signal up-conversion process output is presented. The signal up-conversion process converts the digital
baseband from the analog baseband into a radio frequency signal. When the signal baseband involves
frequency offsetting then occurring a number of distortion products which can reduce the dynamic range
so it is difficult to meet the spectrum mask requirements within the operating band. This paper will focus on
methods of new mathematical analysis using a continuous frequency range and only applies to a single
side band tone, with constant amplitude into any value of frequency offsets. The novel contribution to the
analysis starts at generating the gate signal and convolution of the gate signal into the reference carrier
signal. The results show very close between the simulation results and the calculation of the predicted
location of the distortions.
Orthogonal Frequency Division Multiplexing (OFDM) is deployed to overcome the interference. However,
OFDM has a relatively large OOB emissions. In spectrum sharing approaches such as dynamic spectrum
access networks, the OOB power levels of secondary transmissions should be kept below a certain level, in
order not to interfere with primary transmissions. . The difficulties such as sidelobes and PAPR caused by
OFDM is reduced by convex optimization and PTS technique respectively. In this technique each OFDM
subcarrier is multiplied with a real-valued weight that is determined in order not to interfere with adjacent
users. The problem with the SW technique is involving a very complex optimization. We propose a heuristic
approach called convex optimization. It can achieve considerable sidelobe suppression while requiring
significantly less computational resources than the optimal solution. Implementation results prove that it
can be introduced for real-time transmissions. Optimizing the subcarrier weights and SINR is complex, for
which we use the technique of convex optimization. For reducing the PAPR we use Partial Transmit
Sequence (PTS) technique.
Index terms : OFDM (Orthogonal Frequency Division Multiplexing), PAPR (Peak Average Power
Ratio), OOB (Out Of Band), IFFT (Inverse Fast Fourier Transform).
Orthogonal Frequency Division Multiplexing with Offset Quadrature Amplitude Modulation
(OFDM / OQAM) is a multicarrier modulation scheme that can be considered as an alternative
to the conventional Orthogonal Frequency Division Multiplexing (OFDM) with Cyclic Prefix
(CP) for transmission over multipath fading channels. In this paper, we investigate the
combination of the OFDM/OQAM with Alamouti system with Time Reversal (TR) technique.
TR can be viewed as a precoding scheme which can be combined with OFDM/OQAM and
easily carried out in a Multiple Input Single Output (MISO) context such as Alamouti system.
We present the simulation results of the performance of OFDM/OQAM system in SISO case
compared with the conventional CP-OFDM system and the performance of the combination
Alamouti OFDM / OQAM with TR compared to Alamouti CP-OFDM. The performance is
derived by computing the Bit Error Rate (BER) as a function of the transmit signal-to-noise
ratio (SNR).
MIMO Channel Estimation Using the LS and MMSE AlgorithmIOSRJECE
Wireless Communication Technology has developed over the past few yearsfor other objectives.The Multiple InputMultiple Output (MIMO) is one of techniques that is used to enhancethe data rates, in which multiple antennas are employed both the transmitter and receiver. Multiple signals are transmitted from different antennas at the transmitter using the same frequency and separated space. Various channel estimation techniques are employed in order to judge the physical effects of the medium present. In this paper, we analyze and implementvarious estimation techniques for MIMO Systems such as Least Squares (LS), Minimum Mean Square Error (MMSE),these techniques are therefore compared to effectively estimate the channel in MIMO System. The results demonstrate that SNR required to support different values of bit error rate varies depending on different low correlation between the transmitting and the receiving antennas .In addition, it is illustrated that when the number of transmitter and receiver antennas increases, the performance of TBCE schemes significantly improves. The Same behavior isalso observed for MIMO system. Performance of both MMSE and LSestimation are the same for allkinds of modulation at small value of SNR but the more we increase the SNR value the more performance gap goes on increasing.
The development of a system simulation platform for Adaptive Cruise Control (ACC) radar working at 77 GHz is presented. The simulation platform allows us to test different radar architectures, modulation formats and detection algorithms as well as to simulate different scenarios, which improves the decision-making before and during the hardware development.
An Adaptive Approach to Switching Coded Modulation in OFDM System Under AWGN ...ijsrd.com
In this paper we have studied the OFDM for different Quadrature amplitude modulation technique (QAM) The scatter plot and their output signal to noise ratio, dependent bit error rate variation is analyzed for every type of modulation in OFDM. After observing the BER for each SNR in the system, switching threshold range has been prepared and now system is ready to face the Adaptive coded modulation (ACM).The results shows the switching of modulation technique.
Low Peak to Average Power Ratio and High Spectral Efficiency Using Selective ...theijes
A low complexity peak to average power ratio (PAPR) reduction scheme for orthogonal frequency division multiplexing (OFDM) systems is proposed. All pass filters technique used PAPR is reduction but small amount of reduction, So use Selective Mapping (SLM) technique reduce PAPR and SNR increases.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Analysis Predicted Location of Harmonic Distortion in RF Upconverter StructureTELKOMNIKA JOURNAL
A new mathematical analysis to predict the magnitude size of the distortion products from the
signal up-conversion process output is presented. The signal up-conversion process converts the digital
baseband from the analog baseband into a radio frequency signal. When the signal baseband involves
frequency offsetting then occurring a number of distortion products which can reduce the dynamic range
so it is difficult to meet the spectrum mask requirements within the operating band. This paper will focus on
methods of new mathematical analysis using a continuous frequency range and only applies to a single
side band tone, with constant amplitude into any value of frequency offsets. The novel contribution to the
analysis starts at generating the gate signal and convolution of the gate signal into the reference carrier
signal. The results show very close between the simulation results and the calculation of the predicted
location of the distortions.
Orthogonal Frequency Division Multiplexing (OFDM) is deployed to overcome the interference. However,
OFDM has a relatively large OOB emissions. In spectrum sharing approaches such as dynamic spectrum
access networks, the OOB power levels of secondary transmissions should be kept below a certain level, in
order not to interfere with primary transmissions. . The difficulties such as sidelobes and PAPR caused by
OFDM is reduced by convex optimization and PTS technique respectively. In this technique each OFDM
subcarrier is multiplied with a real-valued weight that is determined in order not to interfere with adjacent
users. The problem with the SW technique is involving a very complex optimization. We propose a heuristic
approach called convex optimization. It can achieve considerable sidelobe suppression while requiring
significantly less computational resources than the optimal solution. Implementation results prove that it
can be introduced for real-time transmissions. Optimizing the subcarrier weights and SINR is complex, for
which we use the technique of convex optimization. For reducing the PAPR we use Partial Transmit
Sequence (PTS) technique.
Index terms : OFDM (Orthogonal Frequency Division Multiplexing), PAPR (Peak Average Power
Ratio), OOB (Out Of Band), IFFT (Inverse Fast Fourier Transform).
Orthogonal Frequency Division Multiplexing with Offset Quadrature Amplitude Modulation
(OFDM / OQAM) is a multicarrier modulation scheme that can be considered as an alternative
to the conventional Orthogonal Frequency Division Multiplexing (OFDM) with Cyclic Prefix
(CP) for transmission over multipath fading channels. In this paper, we investigate the
combination of the OFDM/OQAM with Alamouti system with Time Reversal (TR) technique.
TR can be viewed as a precoding scheme which can be combined with OFDM/OQAM and
easily carried out in a Multiple Input Single Output (MISO) context such as Alamouti system.
We present the simulation results of the performance of OFDM/OQAM system in SISO case
compared with the conventional CP-OFDM system and the performance of the combination
Alamouti OFDM / OQAM with TR compared to Alamouti CP-OFDM. The performance is
derived by computing the Bit Error Rate (BER) as a function of the transmit signal-to-noise
ratio (SNR).
MIMO Channel Estimation Using the LS and MMSE AlgorithmIOSRJECE
Wireless Communication Technology has developed over the past few yearsfor other objectives.The Multiple InputMultiple Output (MIMO) is one of techniques that is used to enhancethe data rates, in which multiple antennas are employed both the transmitter and receiver. Multiple signals are transmitted from different antennas at the transmitter using the same frequency and separated space. Various channel estimation techniques are employed in order to judge the physical effects of the medium present. In this paper, we analyze and implementvarious estimation techniques for MIMO Systems such as Least Squares (LS), Minimum Mean Square Error (MMSE),these techniques are therefore compared to effectively estimate the channel in MIMO System. The results demonstrate that SNR required to support different values of bit error rate varies depending on different low correlation between the transmitting and the receiving antennas .In addition, it is illustrated that when the number of transmitter and receiver antennas increases, the performance of TBCE schemes significantly improves. The Same behavior isalso observed for MIMO system. Performance of both MMSE and LSestimation are the same for allkinds of modulation at small value of SNR but the more we increase the SNR value the more performance gap goes on increasing.
The development of a system simulation platform for Adaptive Cruise Control (ACC) radar working at 77 GHz is presented. The simulation platform allows us to test different radar architectures, modulation formats and detection algorithms as well as to simulate different scenarios, which improves the decision-making before and during the hardware development.
An Adaptive Approach to Switching Coded Modulation in OFDM System Under AWGN ...ijsrd.com
In this paper we have studied the OFDM for different Quadrature amplitude modulation technique (QAM) The scatter plot and their output signal to noise ratio, dependent bit error rate variation is analyzed for every type of modulation in OFDM. After observing the BER for each SNR in the system, switching threshold range has been prepared and now system is ready to face the Adaptive coded modulation (ACM).The results shows the switching of modulation technique.
Discurso de Sesión Inaugural del Curso 2016 de la Real Academia de Medicina y Ciencias Afines de la Comunidad Valenciana: 'Historia del corazón mecánico', por el Ilmo. Sr. Dr. D. José Anastasio Montero Argudo.
This is the powerpoint presentation I presented to a focus group of leaders in the innovation and investment industry in June of 2016 along with other presenters.
This presentation was given to the Florissant City Council and Mayor at a Council meeting in 2002, covering the inconsistencies of the TIF proposal given to the Florissant City Council for the Cross Keys redevelopment.
Sidelobe reduction in Synthetic Aperture Radar (SAR) using Multi Stages of Li...ijceronline
A commonly used Synthetic Aperture Radar (SAR) pulse is the Linear Frequency Modulated (LFM) pulse. It has the advantage of greater bandwidth while keeping the pulse duration short and the envelope constant. However, the matched filter output of this signal contains range sidelobes with the first sidelobe at a level of -13.2 dB to the peak of the main lobe. In this paper, the linear frequency modulation (LFM) waveform and matched filter response are introduced. The principle of Multi Stages of Linear Frequency Modulation (MS-LFM) is also discussed. Simulation results of the proposed MS-LFM signal are presented, where sidelobe level reduction of more than -20 dB can be achieved
Ofdm-cpm Ber Performance and FOBP Under IEEE802.16 ScenarioCSCJournals
The application of Orthogonal frequency domain modulation-Continuous Phase Modulation (OFDM-CPM) in multipath Stanford University Interim (SUI) channels is presented in this paper. OFDM-CPM is proposed for IEEE 802.16 standards as an alternative technique of orthogonal frequency division multiplexing (OFDM) in physical layer. It is shown that, in addition to 0dB Peak to Average Power Ratio (PAPR) and power efficiency, un-coded OFDM-CPM exploits the frequency diversity of multipath channel. Taking into account the Input Power Back off (IBO), OFDM-CPM is shown to outperform OFDM at high bit energy-to-noise density ratios (Eb/N0). However, at low Signal to Noise Ratio (SNR), the OFDM-CPM phase demodulator receiver suffers from a threshold effect. In addition, this paper compares the spectral fractional out of band power of OFDM-CPM for different modulation indices.
An identification of the tolerable time-interleaved analog-todigital convert...IJECEIAES
High-speed Terahertz communication systems has recently employed orthogonal frequency division multiplexing approach as it provides high spectral efficiency and avoids inter-symbol interference caused by dispersive channels. Such high-speed systems require extremely high-sampling time-interleaved analog-to-digital converters at the receiver. However, timing mismatch of time-interleaved analog-to-digital converters significantly causes system performance degradation. In this paper, to avoid such performance degradation induced by timing mismatch, we theoretically determine maximum tolerable mismatch levels for orthogonal frequency division multiplexing communication systems. To obtain these levels, we first propose an analytical method to derive the bit error rate formula for quadrature and pulse amplitude modulations in Rayleigh fading channels, assuming binary reflected gray code (BRGC) mapping. Further, from the derived bit error rate (BER) expressions, we reveal a threshold of timing mismatch level for which error floors produced by the mismatch will be smaller than a given BER. Simulation results demonstrate that if we preserve mismatch level smaller than 25% of this obtained threshold, the BER performance degradation is smaller than 0.5 dB as compared to the case without timing mismatch.
Design Ofdm System And Remove Nonlinear Distortion In OFDM Signal At Transmit...Rupesh Sharma
although OFDM seems to be a solution to keep up with
the demand of increasing data rates, it has some drawbacks.
Sensitivity to high PAPR is the most significant of these
drawbacks. The main objective of this paper was to investigate
and document the effects of PAPR on the performance of OFDM
based digital communications under different channel conditions.
A step-by-step approach was adopted in order to achieve the
objective of this paper. The first step is to provide a basic
background on the principles of OFDM. The reasons for the
PAPR and a theoretical analysis of these effects on OFDM
systems are documented. The OFDM system has a high peak-toaverage
power ratio (PAPR) that can cause unwanted saturation
in the power amplifiers, leading to in-band distortion and out-ofband
radiation. To be able to observe the system behavior, the
simulation results for different channel models are presented in
graphical form. Next, the simulation results obtained in this work
are compared to the simulation results reported in related studies
Performance evaluation on the basis of bit error rate for different order of ...ijmnct
Today, we have required to accommodate a large number of users under a single base station. This can be
possible only if we have some flexibility over the spectrum. Previously we have lots of multiplexing methods
to accommodate large number of signals in time and frequency domain. But now we have required to
accommodate a large number of users in the same bandwidth, without any fading over the received signal.
So, orthogonality can be maintained over the frequency response. This technology is now more popular in
the mobile communication domain, called Orthogonal Frequency Division Multiplexing (OFDM). Actually
user data can be converted into the parallel form and then they are modulated using digital modulation
techniques. Finally, they have followed by OFDM Modulator and cyclic prefix can be inserted into the
OFDM symbols. Here, I have worked on the measurement of Bit error rate for different modulation
techniques in OFDM technology. It has been considered that subchannel size is not constant. According to
that I have concluded the overall idea regarding the performance under OFDM technology.
Designing and Performance Evaluation of 64 QAM OFDM SystemIOSR Journals
Abstract (11Bold) : — In this report, the performance analysis of 64 QAM-OFDM wireless communication
systems affected by AWGN in terms of Symbol Error Rate and Throughput is addressed. 64 QAM (64 ary
Quadrature Amplitude Modulation) is the one of the effective digital modulation technique as it is more power
efficient for larger values of M(64). The MATLAB script based model of the 64 QAM-OFDM system with
normal AWGN channel and Rayleigh fading channel has been made for study error performance and
throughput under different channel conditions. This simulated model maximizes the system throughput in the
presence of narrowband interference, while guaranteeing a SER below a predefined threshold. The SER
calculation is accomplished by means of modelling the decision variable at the receiver as a particular case of
quadratic form D in complex Gaussian random variables. Lastly comparative study of SER performance of 64
QAM-OFDM simulated & 64 QAM-OFDM theoretical under AWGN channel has been given. Also
performance of the system is given in terms of throughput (received bits/ofm symbol) is given in a plot for
different SNR. Keywords (11Bold) –64 QAM, BPSK, OFDM, PDF, SNR.
Designing and Performance Evaluation of 64 QAM OFDM SystemIOSR Journals
In this report, the performance analysis of 64 QAM-OFDM wireless communication
systems affected by AWGN in terms of Symbol Error Rate and Throughput is addressed. 64 QAM (64 ary
Quadrature Amplitude Modulation) is the one of the effective digital modulation technique as it is more power
efficient for larger values of M(64). The MATLAB script based model of the 64 QAM-OFDM system with
normal AWGN channel and Rayleigh fading channel has been made for study error performance and
throughput under different channel conditions. This simulated model maximizes the system throughput in the
presence of narrowband interference, while guaranteeing a SER below a predefined threshold. The SER
calculation is accomplished by means of modelling the decision variable at the receiver as a particular case of
quadratic form D in complex Gaussian random variables. Lastly comparative study of SER performance of 64
QAM-OFDM simulated & 64 QAM-OFDM theoretical under AWGN channel has been given. Also
performance of the system is given in terms of throughput (received bits/ofm symbol) is given in a plot for
different SNR
Reduction of Outage Probability in Fast Rayleigh Fading MIMO Channels Using OFDMIJERA Editor
Multiple-input multiple-output (MIMO) techniques are used in wireless communications for achieving high spectral efficiency; however, a fast fading spatial channel can increase the outage probability of a MIMO system if not taken care of. This paper investigates the use of orthogonal frequency division multiplexing (OFDM) modulation technique for a MIMO system operating in fast Rayleigh fading channels with the aim of eliminating outage probabilities in the MIMO systems. Simulation results show that the MIMO-OFDM system gives significant reduction in outage probabilities compared to the conventional MIMO system.
BER Analysis ofImpulse Noise inOFDM System Using LMS,NLMS&RLSiosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Minimize MIMO OFDM interference and noise ratio using polynomial-time algorit...IJECEIAES
In the distributed transmit antenna MIMO OFDM system, each transmitting antenna has different frequency offset between each transmitting antenna and receiver due to the use of independent crystal oscillator. This paper proposes Polynomial-time algorithm for correcting the frequency offset in a received signal by maximizing the conditional average signal. The algorithm focus on reducing to interference and noise ratio of each subcarrier on the receiving antenna by frequency offset. The simulation result shows the performance of the proposed algorithm is slightly improved compared with the existing frequency offset correction algorithm, and the complexity is reduced by 50% or more.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
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2. Fig. 1: LFM waveform and its compression:
(a) Transmitted waveform;
(b) Frequency of the transmitted waveform;
(c) Representation of the time waveform;
(d) Output of the pulse-compression filter;
(e) Same as (b) but with decreasing frequency.
2.2. Matched Filtering and Correlation
A correlation operation at the radar receiver indicates the
presence of a received echo by compressing the received
signal in time using its time-correlation properties. Matched
Filter performs the correlation operation. In fact, it can be
mathematically shown that matched filter using the time
reversed complex-conjugate of a signal is equivalent to
correlating with the signal. Consider the matched filter
operation between a signal x (t) and an impulse response h
(t):
(6)
Replacing h (t) by x*
(−t) in equation (6) convert the
matched filter operation into an auto correlation operation
for signal x (t).
(7)
Thus it is obvious that the auto-correlation operation
is mathematically equivalent to matched filter with a
time-reversed complex conjugate of the signal. In the
frequency domain, the product of the Fourier transforms of
the signal x(t) and its time-reversed complex-conjugate can
represent the matched filter.
(8)
For the purposes of simulation and digital
implementation, the above operation can also be
represented using a discrete-time representation. Suppose x
(t) is sampled using a sampling duration Ts and has a finite
number of samples N = T/Ts, the auto-correlation sequence
can be obtained as:
m=0, 1, ….., N-1 (9)
Since the auto-correlation sequence is symmetric, it is
sufficient to consider only the positive lags. The above
operation can be implemented using the matched filter
operation. By defining , we have:
(10)
(11)
(12)
Where, the FFT and IFFT operations were used to
simplify the Correlation operation.
3. Model of Pulse Compression
By taking the pulse width is 102.4µs, the phase curve is a
quadratic curve start from 64π to zero at the center of the
pulse then goes up again to 64π at the end of pulse, and the
bandwidth of the chip signal is 2.5MHz.
3.1. Model of LFM Transmitted Signal
By applying the previous condition of phase equation we
get that:
(13)
Where
a=1.220703125*1010
,
b=-1.25*106
c=64π
By finding the equation of frequency we differentiate the
phase equation
(14)
LFM signal (also known as the mathematical expression
of the Chirp signal):
(15)
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3. Fig. 2: Time vs. Phase
Fig. 3: Time vs. Frequency
Hence, the real and imaginary parts of LFM transmitted
signal in time domain will be
Fig. 4: Real & Imaginary Parts of LFM Transmitted Signal
3.2. Model of Matched Filter
The matched filter impulse response of signal in
time-domain should be as follows:
(16)
Where is the filter additional delay. Theoretical
analysis, can make , so, equation(16) could be
rewrite as follows:
(17)
By substituting from equation (15) into equation (17)
we get:
(18)
Fig. 5: LFM Signal Matched Filter
As shown in figure 5, we get the output signal from
the input signal after passing through the matched
filter
(19)
(20)
(21)
When
(22)
(23)
(24)
And when
(25)
By merge equation (22) and equation (25), we get that:
(26)
Equation (26) is the output impulse response of the
LFM matched filter, where the constant carrier frequency is
, and when the envelope approximately (sinc)
function.
(27)
Fig. 6: The Matched Filter Output Signal
The simulation results for the output of the matched filter
shown in Figure 7:
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4. Fig. 7: Chirp Signal after Matched Filtering
3.3. 3Targets Simulation Results:
In this simulation, we can see how the pulse compression
affects the range resolution of the radar. Consider the
following parameters in (Table 1):
Table 1
Parameters of Model Simulation
Max range 150 Km
Signal waveform LFM signal
Bandwidth 2.5 MHz
Pulse width 102.4
Target 1 35.5 Km
Target 2 111Km
Target 3 120Km
Target 4 125Km
Target 5 130Km
The simulation results shown in Figure 8.
Fig. 8: Simulation Results
4.Hardware Implementation
4.1. Implementation of Transmitted LFM Waveform
The LFM waveforms are digitally produced when
PROMs are addressed by counters initialized by
instructions from the radar control process software. The
LFM waveforms, consisting of I and Q values, are D/A
converted and applied to transmit IF generation circuits.
Twelve parallel bits representing the count are output from
the counter function and presented to a phase PROM and a
timing PROM. The timing PROM is used to determine the
start and end of the transmit gate and the waveform
generator cutting gate. Waveform generators no. 1 and 2
transmit gates are ORed to provide a complete gate for the
duration of the final transmit waveform used by the exciter.
The timing PROM provides countdown/up and stop
information to the counter. Initially the counter counts
down until a zero count is reached. Then the timing PROM
changes the counter instruction to count up. An up count
continues until the timing PROM sends a stop command.
The phase PROM has been programmed to produce the
addresses for the sine/cosine PROMs upon receipt of the
counter output. A 4:1 multiplexer selects one of four
sine/cosine sources that allow the waveform generator to
produce LFM waveforms.
The sine/cosine PROMs contain sine and cosine tables
that produce digitally preprogrammed sine and cosine
values. The PROM tables contain the sine and cosine
values in offset binary code. Every 100 nanoseconds (10-
MHz clock cycle), PROM data is read out. This yields a
minimum of 8 points per cycle for the highest pulse
frequency. The multiplexer selects the counter output for
application to the sine/cosine PROMs. This address
controls the sine/cosine PROM readout to provide a CW
signal at the frequency selected that is represented by I and
Q output. Fixed maximum or zero outputs may also be
selected. The digital LFM waveform outputs, I from the
cosine PROM and Q from the sine PROM, are applied to
the D/A converters. The D/A converters produce the analog
LFM cosine and sine (I and Q) waveforms from the digital
outputs of the PROMs. Note that the LFM signal starts at
maximum frequency, decreases linearly to zero frequency,
and then increases linearly to maximum frequency.
Fig. 9: FPAG Design of Transmitted LFM Waveform
4.2. Implementation of Matched Filter
The pulse compressor is the matched filter of the radar
receiver. The received signal is correlated to the known
transmitted spectrum. Only those target returns that result
from transmitter radiation are identified. Interference
signals generated externally to the radar are suppressed.
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5. The pulse-compressor function (Figure 10) is equivalent
to the matched filtering provided by a bandpass filter in a
conventional radar IF amplifier. A conventional receiver's
matched filter extracts amplitude modulation only; phase is
irrelevant. A pulse-compression receiver extracts phase
information and correlates it to the quadratic phase
modulation resulting from the transmitter LFM.
A fast Fourier transform in the pulse-compressor function
correlates the received signal return spectrum with the
known spectrum of the transmitted signal. The FFT is
analogous to a spectrum analyzer.
Fig. 10: Pulse Compression Block Diagram
Implementation of FFT
A complete FFT-4 is shown in (Figure 11). The FFT
matched filter, performing like a spectrum analyzer,
samples the input target to determine if all the spectral
components are present. These components identify the
input waveform as a true target. (Figure 11) shows four
groups of phasors similar to the one shown in Figure 3-46.
Each group of phasors responds to a separate spectral
component. Sum 0 sums the zero phase shift component.
Sum 1 sums those spectral components with multiples of
π/2 (90 degrees) phase rotation between taps; sum 2 sums π
(180 degrees) multiples; and sum 3 sums [1-1/2π] (270
degrees) multiples. If the output port A0, A1, A2 and A3
outputs are summed, a maximum response results in
correlation. For example, the response of sum A1, output
port can be shown as:
(28)
Fig. 11: FFT-4 Phasor Diagram
Although the two basic components of the FFT, the
phasors and the summation, have been described as
theoretically separate items, (Figure 12) shows the actual
FFT-4 implementation. The circles of the diagram represent
arithmetic logic units (ALU) which function as simple
binary adders and provide the summation quality of the
FFT. Each adder has two inputs; each input has either a
plus or minus sign indicating the operation (addition or
subtraction) performed. If addition is performed, no phase
shift results. Subtraction, however, causes a 180 degrees (Π)
phase shift.
Fig. 12: FFT-4 Adder Implementation
5. Results
Experimental results measured from the implemented
radar processing model presented in Figure 10. All the
synthesized results are single realizations obtained using
Altera-Cyclon II FPGA. Using a EP2C8Q208C8N chip and
Quartus II as a software design tool, simulation and logic
analyzer tool, we get the results as following:
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6. 5.1. Generation of 4-bit LFM waveform
Fig. 12: Generation of I & Q channels of LFM waveform
5.2. Resolving of one target:
Fig. 11: Time response for matched filter for one target
6. Conclusion
A flexible real time implementation of digital pulse
compression suitable for all-digital radar receiver
architecture. Experimental results obtained presented a very
good agreement with the theory. The developed system can
further be enhanced to be used for surveillance pulsed
radars. The realization based on the FPGA chips makes it
easy to change the radar working parameters to adapt the
design to different situations which following the concept
of software defined radio (SDR).
The proposed architecture is a single chip solution for
both generation and receiver processing of pulse
compression.
Future research work requires additional investigation in
the windowing processing, and also we recommend testing
novel windows in frequency domain using FPGA.
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