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The digital correlator is one of the most crucial data processing components of a radio telescope array. With the scale of radio interferometeric array growing, many efforts have been devoted to developing a cost-effective and scalable correlator in the field of radio astronomy. In this paper, a 192-input digital correlator with six CASPER ROACH2 boards and seven GPU servers has been deployed as the digital signal processing system for Tianlai cylinder pathfinder located in Hongliuxia observatory. The correlator consists of 192 input signals (96 dual-polarization), 125-MHz bandwidth, and full-Stokes output. The correlator inherits the advantages of the CASPER system, for example, low cost, high performance, modular scalability, and a heterogeneous computing architecture. With a rapidly deployable ROACH2 digital sampling system, a commercially expandable 10 Gigabit switching network system, and a flexible upgradable GPU computing system, the correlator forms a low-cost and easilyupgradable system, poised to support scalable large-scale interferometeric array in the future. [ABSTRACT FROM AUTHOR]

Copyright of Eurasian Physical Technical Journal is the property of E.A. Buketov Karaganda University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Large scale Radio Telescopes for Radio Astronomy highly depend on the availability of large (digital) processing capacities for imaging. Estimates concerning power efficiency for future Radio Telescopes lead to anticipated power consumption numbers beyond feasibility. To reduce the power budget, the use of approximate multipliers within the correlator is explored. A baseband equivalent executable model of a radio synthesis telescope is constructed to assess the effects of approximate multipliers. Besides ideal multipliers with floating point accuracy, the use of accurate 8-bit multipliers and 4 different types of approximate multipliers is explored. For each of these multipliers, the energy efficiency of an individual multiplier is known and used to determine the energy efficiency improvement of a correlator when using approximate multipliers. The effects of approximation are quantified by 3 metrics (Signal-to-Noise-Ratio (SNR), Spurious-Free-Dynamic-Range (SFDR) and Root-Mean-Square (RMS) level) derived from maps constructed by the executable model based on an empty sky with only a single point source. This is considered to be the worst case scenario. For illustration purposes, a more realistic input is processed by the model as well. The metrics have been determined based on different SNR levels at the input of each antenna element. For input SNR levels up to 10 dB, all types of approximate multipliers used in this paper can be exploited to improve energy efficiency of correlators, leading to a maximum energy reduction of 19 %. For input SNR values up to 30 dB an energy improvement up to 12 % can be achieved. These percentages are based on implementations in a 40nm low power IC technology at 1 GHz. [ABSTRACT FROM AUTHOR]

The digital correlator is one of the most crucial data processing components of a radio telescope array. With the scale of radio interferometeric array growing, many efforts have been devoted to developing a cost-effective and scalable correlator in the field of radio astronomy. In this paper, a 192-input digital correlator with six CASPER ROACH2 boards and seven GPU servers has been deployed as the digital signal processing system for Tianlai cylinder pathfinder located in Hongliuxia observatory. The correlator consists of 192 input signals (96 dual-polarization), 125-MHz bandwidth, and full-Stokes output. The correlator inherits the advantages of the CASPER system, for example, low cost, high performance, modular scalability, and a heterogeneous computing architecture. With a rapidly deployable ROACH2 digital sampling system, a commercially expandable 10 Gigabit switching network system, and a flexible upgradable GPU computing system, the correlator forms a low-cost and easily-upgradable system, poised to support scalable large-scale interferometeric array in the future.

In an electronic warfare environment, radar signals must be rapidly discriminated. A digital frequency discriminator (DFD) collects I and Q data from a phase correlator and determines the radar signal frequency in 500 ns. Distortion is introduced into the IQ data as the detected radar signal passes through the analog and preprocessor parts, resulting in an inaccurate DFD output frequency. This paper proposes a technique to improve DFD frequency accuracy. The output is corrected by interpolating the difference between the DFD output frequency and the reference frequency. We confirmed that the proposed technique improves frequency accuracy from 2.25 MHz to 0.063 MHz and reduces the maximum frequency error from 6 MHz to 2 MHz. [ABSTRACT FROM AUTHOR]

Background. In radar systems, phase code-domain keying signals are widely used. Continuous signals of this kind have the advantage of low side lobes of the cross-correlation function and high noise immunity, but have limitations on the size of the area of view associated with the presence of ambiguity peaks. Aim. The paper considers the possibility of increasing the unambiguity of determining the time delay of the phase-code shift keyed signal in a correlation meter based on a combined FPGA-based coding rule. Methods. To achieve this goal, a numerical simulation of a correlation time delay meter with modulating signals formed by different coding rules was performed. Results. It is proposed in the correlation meter with continuous reception of the phase-code shift keyed signal to improve the accuracy of measuring the time delay and the unambiguity of determining the location of remote objects, as a modulating signal, use a signal formed by two pseudo-random sequences that are the same according to the coding rule, but different in duration. The results of numerical simulation of the post-detection digital processing system based on the proposed method are presented. Conclusion. The application of the proposed coding rule makes it possible to implement a correlation meter with a minimum amount of computing resources while increasing the unambiguity and expanding the range of measured time delays.

Global Navigation Satellite System (GNSS) multipath has always been extensively researched as it is one of the hardest error sources to predict and model. External sensors are often used to remove or detect it, which transforms the process into a cumbersome data set-up. Thus, we decided to only use GNSS correlator outputs to detect a large-amplitude multipath, on Galileo E1-B and GPS L1 C/A, using a convolutional neural network (CNN). This network was trained using 101 correlator outputs being used as a theoretical classifier. To take advantage of the strengths of convolutional neural networks for image detection, images representing the correlator output values as a function of delay and time were generated. The presented model has an F score of 94.7% on Galileo E1-B and 91.6% on GPS L1 C/A. To reduce the computational load, the number of correlator outputs and correlator sampling frequency was then decreased by a factor of 4, and the convolutional neural network still has an F score of 91.8% on Galileo E1-B and 90.5% on GPS L1 C/A.

This letter presents a novel approach for receiving the communication data integrated with radar signals based on chirp sequence (CS). The receiving procedure mainly depends on evaluating a part of the receive signal and correlating it with a reference chirp within a narrow band to reduce the costs compared to the condition when the whole radar bandwidth is also appointed for communication purposes. The transmit signal, in its turn, is an adaption of long-range (LoRa) communications to support both radar and communication features. A measurement setup including a field-programmable gate array as a proof concept is presented to evaluate the radar functionality. Finally, simulations and measurements in terms of the symbol error ratio (SER) are adopted to ensure the capability of the proposed method of integrating communication data within the radar signals. [ABSTRACT FROM AUTHOR]

Aerial acoustic communication (AAC) has been developed for a variety of Internet-of-things (IoT) applications, thanks to the merit of embedding small amounts of data directly into audio contents and transmitting them through commercial off-the-shelf (COTS) devices without additional infrastructure. However, AAC has clear limitations due to ambient noise, severely frequency-selective acoustic channels, and high power consumption of COTS devices. We adopt chirp spread spectrum (CSS) modulation and design new quaternary symbols to overcome frequency selectivity of audio interfaces of COTS devices. We also develop a computation-efficient method to demodulate the proposed symbols, aiming to reduce the power consumption of COTS devices. We employ a frame combining technique without increasing computational complexity, to mitigate the effects of multipath fading and ambient noise in acoustic channels. To evaluate the proposed methods, we conduct extensive experiments with several smartphones in various environments. The experimental results and evaluation demonstrate that the proposed symbols and frame combining method contribute to improving the frame reception ratio by up to 59.8%p (267.9%) and 14%p (84.3%), respectively. The frame combining increases the possibility of receiving a frame within two attempts at extremely low SNR, by up to 107.9%, resulting in reduced excessive delay. The method to demodulate the proposed symbols lowers power consumption by tens to hundreds of milliwatts, depending on the device. Our proposal significantly helps to achieve high reliability and low power consumption of COTS devices in AAC.

Deep learning has become a way of solution for the realization of complex computations. As electronic communication starts to use more complex channels, the systems need to handle tough computations. For this reason, research on the use of deep learning in communication has increased recently. These researchers aim to realize many applications used in communication with deep learning. Frame detection is one of the first things a receiver must handle, and it may require a lot of hard computations. Deep learning-based frame detection can be an alternative approach. This study aims to build models that perform frame detection with deep learning. The proposed models provide the performance of correlationbased frame receivers commonly used for frame detection. The mean square root error of the prediction deviation is used as an evaluation metric to compare the proposed model to classic systems. [ABSTRACT FROM AUTHOR]

A mathematical description of a coherent optical correlator for the multi-raster input of long signals is given. It is shown that such an input makes it possible to reduce the value of false correlation maxima that are generally found at the output of a correlator with a single-raster input. It is shown that false maxima do not appear when processing signals with a thumbtack ambiguity function, allowing one to do without a multi-raster input. The results of the theoretical analysis are confirmed by experiments with chirp signals and M-sequence type signals.

Modern and upcoming radio telescopes at low frequencies are often characterized by hundreds or thousands of antenna elements operating at wide bandwidths up to about 0.5 GHz. A spectral correlator for such an array is required to estimate the cross-power spectrum of the response of each element with that of every other element with a high spectral resolution. The resulting all-to-all connectivity between signals from the entire array poses a serious bottleneck. In this paper, we propose a simple digital receiver architecture that interfaces the digitized time series from a large number of antenna elements to a High-Performance Computing (HPC) cluster through a communication switch to overcome the data ingest bottleneck. Each HPC node can then perform wideband processing in steps of finite but significant time-slices for the entire array. We explain in detail the implementation of our architecture for the proposed expansion of the Ooty Wide Field Array (OWFA) into a 1056 element array. Since the proposed digital receiver is based on Field Programmable Gate Array (FPGA), it can be reconfigured for different applications. This is illustrated by considering the case of Phased Array Feeds (PAF) for the proposed expanded Giant Metrewave Radio Telescope (eGMRT). [ABSTRACT FROM AUTHOR]

This study aimed to explore the psychological situation and the influence of the outbreak of COVID-19 on college students. An online questionnaire survey was conducted among 3,092 Chinese college students who were quarantined at home as a result of the COVID-19 pandemic. The survey tools included the Generalized Anxiety Disorder 7-Item Scale (GAD-7), the Perceived Stress Scale (PSS-10), and the Self-Rating Scale of Sleep (SRSS). Of all the respondents, the prevalence of anxiety symptoms, sleep problems, any of the two, and both of the two, were 16.8, 13.5, 25.1, and 5.3%, respectively. Of the participants, 43.7% of the college students had higher perceived stress. Factors associated with anxiety symptoms included reading the daily news with higher frequency (1–3 times; 4–7 times; more than 7 times), having sleep problems, higher stress, and carelessness with the number of remaining masks. Factors associated with sleep problems included postgraduates, reading the news with higher frequency daily (1–3 times), the frequency of going out per week (1–3 times), having anxiety symptoms and higher stress. Factors associated with higher perceived stress included reading the daily news with higher frequency (4–7 times), anxiety about the number of remaining masks (1–10; more than 20), having anxiety symptoms, and having sleep problems. The prevalence of anxiety symptoms, sleep problems, and higher perceived stress among college students was high during the COVID-19 outbreak. Particular attention should be paid to psychological support for college students quarantined at home, especially those at high risk of psychological problems.

This study aimed to explore the psychological situation and the influence of the outbreak of COVID-19 on college students. An online questionnaire survey was conducted among 3,092 Chinese college students who were quarantined at home as a result of the COVID-19 pandemic. The survey tools included the Generalized Anxiety Disorder 7-Item Scale (GAD-7), the Perceived Stress Scale (PSS-10), and the Self-Rating Scale of Sleep (SRSS). Of all the respondents, the prevalence of anxiety symptoms, sleep problems, any of the two, and both of the two, were 16.8, 13.5, 25.1, and 5.3%, respectively. Of the participants, 43.7% of the college students had higher perceived stress. Factors associated with anxiety symptoms included reading the daily news with higher frequency (1–3 times; 4–7 times; more than 7 times), having sleep problems, higher stress, and carelessness with the number of remaining masks. Factors associated with sleep problems included postgraduates, reading the news with higher frequency daily (1–3 times), the frequency of going out per week (1–3 times), having anxiety symptoms and higher stress. Factors associated with higher perceived stress included reading the daily news with higher frequency (4–7 times), anxiety about the number of remaining masks (1–10; more than 20), having anxiety symptoms, and having sleep problems. The prevalence of anxiety symptoms, sleep problems, and higher perceived stress among college students was high during the COVID-19 outbreak. Particular attention should be paid to psychological support for college students quarantined at home, especially those at high risk of psychological problems. [ABSTRACT FROM AUTHOR]

We present an overview of the Graphics Processing Unit (GPU)-based spatial processing system created for the Canadian Hydrogen Intensity Mapping Experiment (CHIME). The design employs AMD S9300x2 GPUs and readily available commercial hardware in its processing nodes to provide a cost- and power-efficient processing substrate. These nodes are supported by a liquid-cooling system which allows continuous operation with modest power consumption and in all but the most adverse conditions. Capable of continuously correlating 2048 receiver-polarizations across 400 MHz of bandwidth, the CHIME X-engine constitutes the most powerful radio correlator currently in existence. It receives 6.6 Tb/s of channelized data from CHIME's FPGA-based F-engine, and the primary correlation task requires 8. 3 9 × 1 0 1 4 complex multiply-and-accumulate operations per second. The same system also provides formed-beam data products to commensal FRB and Pulsar experiments; it constitutes a general spatial-processing system of unprecedented scale and capability, with correspondingly great challenges in computation, data transport, heat dissipation, and interference shielding. [ABSTRACT FROM AUTHOR]

One of the main technologies to open up a wider field of view for today's radio telescopes are phased arrays. This is especially the case for radio astronomy instruments operating below 2 GHz. Nowadays, the existing dish-type instruments are being upgraded with phased array feeds (PAF) in the focal plane. This increases the field of view at the expense of needing more analog electronics and digital signal processing. One of the digital signal processing functionalities used to combine the digitized signals from the PAF is a beam-former which creates multiple high sensitivity beams within the field of view of the dish. Before beams can be formed, the signals from the PAF need to be calibrated using a correlator. In this paper, we present a solution where these two operations are combined by using the beam-former also as a correlator. The statistics unit used as part of the beam-former implementation, can be used as well for calculating correlation products. With the proper settings of the beam-former weight of each beamlet, a frequency sub-band with a direction, can be used as a single cross correlation product. By implementing the correlator on the beam-former, the digital resources and development time can be reduced. To validate the idea, two versions of the algorithm are implemented in the Apertif PAF system on the Westerbork Synthesis Radio Telescope (WSRT). Results show that two full-bandwidth correlation matrices per beam, needed to determine the static beam weights for the calibration, and a single column of the correlation matrix, used to compensate for any drift between the receiver chains, can be performed. [ABSTRACT FROM AUTHOR]

A $128\times128$ cross-correlator for radiometric imaging using interferometric aperture synthesis is presented in this article. It can achieve a landmark performance of 16.384 trillion correlations/s in a single device by calculating cross-correlation between two inputs having 128 channels each, sampled at 1 GHz, which is so far unreported. Passive imaging using interferometric aperture synthesis requires a large number of antennas and wide bandwidth to provide good radiometric sensitivity. The major challenge for realizing an imager using such a technique is the complexity of the correlator. Use of analog technology for large-scale correlation is not feasible, if not impossible. Even the digital correlator requires a very complex data distribution network that must connect every input signal to multiple processing devices while maintaining the same path lengths for equal delays in all the channels. By implementing a massive correlation in a single field-programmable gate array (FPGA), this correlator design provides a way to reduce the complexity by reducing the number of devices needed to achieve the required processing. Processing of high-speed input data is realized in partially parallel datapaths to achieve a bandwidth of 1 GHz. Integrating a large number of correlator channels in a single device is enabled by the hierarchical design approach. It is implemented using Xilinx Kintex UltraScale XCKU115 device. Its functional verification is performed in simulation to check the correctness of the correlation results. Hardware testing is performed using linear-feedback shift registers for on-chip random data generation, and the results are compared with the expected results calculated offline using MATLAB. [ABSTRACT FROM AUTHOR]

In this paper, we present a prototype ultra-fast hopping spread spectrum transceiver front-end that realizes 20 dB of processing gain in the RF before any amplification occurs along the receiver chain. This means that a narrow-band in-band interferer is rejected by 20 dB before the low noise amplifier (LNA). The correlation function at RF is made possible by using a passive mixer-first receiver architecture that is driven by an ultra-fast hopped local oscillator (LO) signal. The 47 MHop/s LO is generated using an all-digital oscillator circuit that is followed by a memoryless digital-to-analog converter (DAC). The prototype chip fabricated in a Taiwan Semiconductor Manufacturing Company (TSMC) 65 nm RF CMOS process occupies 3.1 mm2 of active area. The receiver and the transmitter each consume ≈25 mW from a 1 V power supply. [ABSTRACT FROM AUTHOR]

Radio telescopes allow a 24 × 7 observation time window of those regions of the space which appear dark in the visible region. But, the major problem with a single radio telescope is its poor resolution. In this article, the method of interferometry in radio astronomy is discussed by citing the example of a two-element interferometer. Interferometry provides improved resolution.With a single telescope as well, the resolution can be improved for the radio sources along the ecliptic which are smaller in angular spread as compared to the Moon. The theoretical principle behind the technique of occultation is discussed using its optical analog of diffraction. [ABSTRACT FROM AUTHOR]

The present article relates in general to digital demodulation of Binary Frequency Shift Keying (BFSK waveform) . New processing methods for demodulating the BFSK-signals are proposed here. Based on Sampler Correlator, the hardware consumption for the proposed techniques is reduced in comparison with other reported. Theoretical details concerning limits of applicability are also given by closed-form expressions. Simulation experiments are illustrated to validate the overall performance.

The paper presents a multiloop system for noncoherent tracking of the radionavigation parameters of global navigation satellite system (GNSS) signals in autonomous satellite navigation system. Comparative analysis of accuracies of traditional tracking system with discriminators and filter in the tracking loop and the proposed system without discriminators is conducted. RMS errors of estimates, pull-in range and the probability of signal acquisition are studied under various SNR values. Experimental tests of derived noncoherent tracking loop are performed. [ABSTRACT FROM AUTHOR]

This paper presents a 1.8 GHz six-port-based impedance modulator using CMOS technology, which can select an arbitrary load impedance with switch control. The proposed 1.8-GHz impedance modulator comprises a Wilkinson power divider, three quadrature hybrid couplers, and four SP3T switches for each load impedance selection. The measured insertion loss of -13 dB and the input/output return losses of >10 dB are achieved in the range of 1.4～2.2 GHz. The low drop output regulator for a stable 3.3 V DC power and the serial peripheral interface(SPI) for an easy digital control are integrated. The chip size, including the pads, is 1.7×1.8 mm2. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, a self-interference signal cancellation(SIC) circult for In-band Full-Duplex has been developed and tested in RF/analog region. By use of this SIC circuit, a FM two-way radio has been developed working at FRS(Family Radio Service) band. The two-way radio device is transmitting the FM modulated signal and demodulating the wanted FM signal at the same time. A circulator is used to enable a single antenna to transmit and receive simuultaenously. The receiver circuit needs to cancel out the self-interference signal due to the transmit signal. A vector modulator(VM) is used to control the phase and magnitude of the esitmated signal. And in-phase and quadrature correlators are used to figure out the optimal coefficients of the VM to remove the self-interference signal according to the change of channel environment. In this work, SA58646 has been used as the FM transceiver, and the system is tested with a frequency of 465 MHz and a bandwidth of 12.5 kHz FM signal. The output power is 17.2 dBm at the antenna port, and the self intererence signal level is measured -49.2 dBm at the receiver end. Therefore the SIC level is measured by 66.4 dB. [ABSTRACT FROM AUTHOR]

Modern global navigation satellite system (GNSS) front ends sample the received radio-frequency signal at an intermediate frequency (IF) and, then, downconvert it to baseband in the digital domain. A locally generated spreading code is subsequently correlated with the baseband signal at the sampling frequency. This can mean that the receiver correlates at an unnecessarily high frequency (sometimes more than four times the chipping rate). The power consumption is, thus, high. If the baseband signal is downsampled after appropriate filtering, the correlator can process at a fraction of the sampling frequency. The power dissipation is considerably reduced as a result. Furthermore, by resampling at an integer submultiple of the sampling frequency, not only is downsampling jitter eliminated, but also architectural configurability in the correlator is possible, allowing further reductions in power and resource consumption. In this paper, a dynamically configurable decimator for a matched filter correlator is presented. The mathematical model of the signal processing is analyzed for various downsample rates. The effective postcorrelator signal-to-noise-plus interference ratio is estimated in theory and measured by experiment, illustrating that the proposed decimator correlator outperforms the resample IF correlator. [ABSTRACT FROM AUTHOR]

In paper the various methods for suppressing pulse interference have been analyzed, the features of their application in the track receivers of tone rail circuits have been investigated. Simulation results showed a high noise immunity of the system «broadband filter – limiter – correlator».

Global Navigation Satellite System (GNSS) multipath has always been extensively researched as it is one of the hardest error sources to predict and model. External sensors are often used to remove or detect it, which transforms the process into a cumbersome data set-up. Thus, we decided to only use GNSS correlator outputs to detect a large-amplitude multipath, on Galileo E1-B and GPS L1 C/A, using a convolutional neural network (CNN). This network was trained using 101 correlator outputs being used as a theoretical classifier. To take advantage of the strengths of convolutional neural networks for image detection, images representing the correlator output values as a function of delay and time were generated. The presented model has an F score of 94.7% on Galileo E1-B and 91.6% on GPS L1 C/A. To reduce the computational load, the number of correlator outputs and correlator sampling frequency was then decreased by a factor of 4, and the convolutional neural network still has an F score of 91.8% on Galileo E1-B and 90.5% on GPS L1 C/A., Competing Interests: Author AG was employed by the Company 3D Aerospace. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Guillard, Thevenon and Milner.)

In this paper, we analyze the performance of code acquisition system in atmospheric optical code division multiple access (OCDMA) communications using optical orthogonal codes. Memory introduced by temporal correlation of optical fading process precludes us from using the Markov chain model for a code acquisition analysis. By considering this issue, we discuss how to extend the applicability of the Markov chain model to the atmospheric OCDMA communications. We analyze and compare the performance of correlator and chip level detector (CLD) structures in the acquisition system. In our analysis, we consider the effects of free space optical channel impairments, multiple access interference, and receiver thermal noise in the context of semi-classical photon-counting approach. Furthermore, we evaluate the performance of various two stage schemes that utilize different combinations of active correlator, matched filter, and CLD in search and verification stages, and we find the optimum acquisition scheme among them. Numerical results show significant improvement in reducing the acquisition time and required power for synchronization using our optimum scheme in the wireless OCDMA communications. [ABSTRACT FROM AUTHOR]

The Global Positioning System (GPS) has become widespread in many civilian applications. GPS signals are vulnerable to interference and even low-power interference can easily spoof GPS receivers. In this paper, two techniques are proposed based on correlators and adaptive filtering to diminish the effect of spoofing on GPS-based positioning. The suggested algorithms are implemented in the tracking loop of the receiver. As a first method, a high-resolution correlator is utilised to avoid big parts of the influence of interference. To improve the results, a multicorrelator technique is also employed. In the second method, an adaptive filter is used for estimating the parameters of authentic plus spoof signals. Interference elimination is performed by subtracting the estimated conflict effects from the measured correlation function. These techniques provide easy-to-implement quality assurance tools for anti-spoofing. As a primary step, in this article, the proposed algorithms have been implemented in a Software Receiver (SR) to prove the concept of idea in multipath-free environments. [ABSTRACT FROM AUTHOR]

According to the characteristics of the 21CMA correlator algorithm, we propose a novel high-efficient method to implement this specific algorithm on the Hadoop+CUDA platform, and it out-­performs the MPI alone and MPI+CUDA solutions. The proposed method improves the parallel model of the correlator. Compared to the earlier MPI solution, it greatly enhances the running performance by utilizing the advantages of GPU for FFT processing, vector multiplication and vector addition. The Hadoop software architecture, a big-data platform, is employed in the method by using Hadoop Streaming tool to realize parallel execution of non-Java programs running on distributed systems, and linear speed-ups on clusters are easily obtained. In addition, the resutt data and procedure logs can be flexibly managed in the parallel file system of the Hadoop HDFS, which provides a well precondition for future big-data analysis. [ABSTRACT FROM AUTHOR]

The present article relates in general to digital demodulation of Binary Frequency Shift Keying (BFSK waveform). New processing methods for demodulating the BFSK-signals are proposed here. Based on Sampler Correlator, the hardware consumption for the proposed techniques is reduced in comparison with other reported. Theoretical details concerning limits of applicability are also given by closed-form expressions. Simulation experiments are illustrated to validate the overall performance. [ABSTRACT FROM AUTHOR]

The two ways of management of the peak-frequency characteristic of the doppler multichannel filter for the purpose of combining its resection zone with a passive hindrance spectrum have been offered.