A high-speed adaptive antenna array with simultaneous multibeam-forming capability

This paper traces the development of three-phase induction motor controls using the Semikron advanced integration (SKAI) power electronics system. The SKAI was developed for hybrid and electric vehicles and integrates all the components of a three-phase inverter. As such, it promises to deliver significant cost savings. The SKAI utilizes a digital signal processor (DSP) controller. However, Semikron does not supply the necessary software for the DSP controller. The DSP used in the controller is manufactured by Texas Instruments. Texas Instruments provides an array of DSP programming utilities. This paper discusses aspects of programming and testing the DSP controller

The development of modern technologies has fundamentally transformed the field of radar signal and data processing. With the use of advanced algorithms and computational power, radars are now capable of extracting crucial information from received signals, facilitating improved target identification and tracking. This article presents some of the advanced technologies employed in radar signal and data processing and their impact on adaptability of radar systems. It traces the evolution of radar technology from old systems to the present, emphasizing the benefits of adaptive radar signal processing, which includes algorithms such as adaptive beamforming, Space-Time Adaptive Processing, and the integration of Machine Learning and Artificial Intelligence. In conclusion, challenges, and future prospects in the field of radar systems are discussed, with a focus on the potential integration of Artificial Intelligence methods, Cognitive radars, and Multiple Input Multiple Output technologies. Despite technical obstacles, opportunities emerge to enhance the performance of radar systems and achieve new levels of efficiency.

In this paper, a Digital Signal Processing (DSP) control system which is used in the multiple degree-of-freedom (DOF) giant magnetostrictive smart structure (GMSS) is proposed. The control system includes two parts - DSP Card and analog circuit through which DSP Card can get the detection signal and output control signal to giant magnetostrictive actuator (GMA). A adaptive least mean-square (LMS) control algorithm is embedded in DSP Cardpsilas Flash Memory for controlling GMSS to weaken the micro-vibration outside. Work flow and control approach of the GMSS with the DSP control system are introduced. The experiment results indicate that the DSP control system in this paper has better control precision and real-time property, and the damping effect is up to 20-30 dB.

In this paper, the direction of arrival (DOA) and adaptive antenna array beamforming for the smart antenna applications are realized by using Minimum Variance Distortionless Response (MVDR) algorithm of DOA estimation. The MVDR supported by joint approximate diagonalization of eigenmatrices (JADE) algorithm is used to estimate the direction of arrivals of coherent signals in non-coherent groups. The generalized steering vectors using JADE algorithm are first estimated, and then the spectrum methods are realized to estimate the DOA of each signal. Root mean square error (RMSE) values are computed in different scenarios for the proposed method as well as JADE-MUSIC and the corresponding results are compared. Although both methods resolved the signals correctly, simulation results show that JADE based MVDR has better performances in the cases of low number of antenna elements and snapshots. The DOAs obtained are then processed using LMS adaptive beamforming algorithm to steer the main lobe of the radiation pattern to desired angles (signals) and the nulls to undesired angles (signals). The simulation results also reveal that adaptive beamforming is successfully done by annihilating the effects of undesired signals significantly.

A variable frequency oscillator is normally used to generate the master frequency for an accelerator. For the Low Energy Booster at SSC the prospects of using a Direct Digital Synthesizer (DDS) to vary the frequency from 47MHz to 59MHz are considered. A Digital Signal Processor (DSP) which can be loaded with the desired frequency values is interfaced to the DDS. These values are launched on the DDS at known intervals to ramp the frequency smootly. In this paper the observations made while ramping the frequency are discussed. The design principal of the digital synchronization of Low Energy Booster frequency source with the Medium Energy Booster frequency source is also briefly discussed. When developed it can be used to synchronize the two machines.

In this paper, we describe an analog delay line (DL) used for virtual clock enhancement in a direct digital synthesis (DDS). The novelty of the proposed method is the immediate application of the output signal of the phase accumulator for the generation of the desired frequency. To obtain the necessary spectral purity of the generated frequency, additional digital signal processing (DSP) based on a delay-locked loop (DLL) and noise shaping is applied. The consequences of nonlinear effects within the DL for the spectral performance of the DDS are explained.

The performance of an adaptive antenna array is strongly affected by the electromagnetic characteristics of the array. The mutual coupling effect degrades the performance significantly, especially when the inter element spacing is decreased. A method to eliminate the effect of mutual coupling was proposed by R.S. Adve and T.K. Sarkar (see AP-S Int. Symp. Digest, p.1164-67, 1996). The method of moments (MOM) is used to model the mutual coupling effect on the weights and on the final directivity pattern of the adaptive array. Using an example of a two-element half wavelength adaptive dipole array, it is shown that the mutual coupling between the elements of an adaptive array causes significant degradation in the performance of the array and thus should not be neglected. It is demonstrated that, using the algorithm proposed by Adve and Sarkar, the effects of mutual coupling in adaptive arrays can be eliminated successfully.

Multipath fading and human body influence affect the performance of a Low Earth Orbit Satellite (LEOS) handheld terminal. In this research, the effectiveness of optimum combining is compared with selection diversity and omni-directional antenna systems. By using the electric field and magnetic field antennas, zero correlation can be provided. In the presence of interference, adaptive antennas can nullify the interference. In the absence of interference, adaptive antennas can maximise the final Signal to Noise Ratio (SNR). In this case, an adaptive antenna is the same as a maximum ratio combiner. An adaptive antenna system provides a 2.0dB gain on average when its performance is compared with the selection diversity system. The adaptive antenna system also provides a 9.5dB gain on average when its performance is compared with the omni-directional antenna system. Finally, adaptive antennas can automatically resolve the phase ambiguity effect, so that differential coding is not required. Therefore, an extra 3dB gain can be obtained.

Digital signal processors (DSPs) have traditionally been used in real-time applications with very high data throughput. For this reason, system designers have been reluctant to accept the degradation in performance inherent in machine code compiled from high-level languages such as C. The problem is compounded by the fact that DSPs use pipelined architectures to achieve their high data throughput, resulting in hazards and latencies between instructions. Simple compiler implementation cannot take advantage of latent instructions, resulting in a conservative and inefficient executable program. This problem has been addressed in the C compiler package for the AT&T WE DSP32 by the addition of a postoptimizer and an extensive application library. The authors give an overview of the DSP32 family architecture, describe the operation of the basic compiler and optimization strategies, and provide an example of the use of the compiler. >

Performances of an adaptive array antenna system for land mobile communications have been investigated through computer simulation and experiments. The adaptive array antenna system can automatically form nulls in the direction of undesired wave on receiving directional pattern. First, it is verified by computer simulation that only desired wave is received without interference by the system controlled on the basis of CMA, when the desired and undesired waves arrive at the receiving point together. Next, it is experimentally indicated that the undesired wave is suppressible by approximately 20 dB, even if the antenna element of the system has not an omni-directional pattern. From these studies, it is confirmed that the adaptive array antenna system is very useful for high quality land mobile communications.

This paper presents the use of the viciLogic viciLab tool suite for prototyping of audio digital signal processing (DSP) hardware on remote or locally connected PYNQ Systems on Chip (SoCs), along with flexible computer control software interfaces. The tool suite enables rapid prototyping of DSP hardware components, including demonstration, control and visualisation of components on local or remote hardware. Hardware components can be developed directly in existing hardware description languages (HDLs) or using higher-level design interfaces such as MathWorks HDL coder. Two configurable software control interfaces are presented: a low-level console builder facilitating fast graphical user interface (GUI) creation for hardware interaction, along with script-based automation; and a high-level Python-based GUI console creator integrates audio sampling, automated DSP hardware effect selection and SoC control, audio streaming and playback, and real-time waveform graphing. The two interfaces presented in this paper are illustrated through a series of DSP examples of increasing complexity: 8- and 16-tap FIR filters (with user-created VHDL model source); distortion and tremolo DSP functions (developed MathWorks HDL coder VHDL model source); and combinations of these components.

This paper proposes a mathematical framework for evaluating, in saturated and non-saturated traffic conditions, the performance of an 802.11 wireless network in which the nodes are equipped with adaptive antenna systems. The analysis, validated by simulations, adopts detailed models for the antenna behavior and the propagation environment, taking into account multipath and interference. The developed model is used to investigate the proper parameter settings that lead to throughput maximization, providing a simplified method to obtain the optimum contention window when adaptive arrays are employed.

Adaptive beamforming techniques are widely used in radar, communication, sonar, navigation and other signal processing fields. The conventional experimental systems for adaptive beamforming are often carried out with a large number of Radio Frequency equipment, which leads to high cost and complexity. Therefore, it is necessary to construct an experimental system with low cost and high flexibility to verify the performance of adaptive beamforming algorithms. In this paper, an experimental adaptive beamforming platform by utilizing the microphone array is designed, where the principle of adaptive beamforming, the structure and function of each part of whole experiment system are introduced clearly. Furthermore, the corresponding experiments are deployed to verify the adaptive beamforming algorithms for radar system. The experimental results show that the designed experimental platform can validate the adaptive beamforming algorithms easily and effectively. (5 pages)

Recently, real-time simulation of renewable energy sources are indispensible for evaluating the performance of the maximum power point tracking (MPPT) controller, especially in the photovoltaic (PV) system in order to reduce cost in the testing phase. Nowadays, real time PV simulators are obtained by using analog and/or digital components. In this paper, a real-time simulation of a PV system with a boost converter was proposed using only the digital signal processor (DSP) processor with two DC voltage sources to emulate the temperature and irradiation in the PV system. AMATLAB/ Simulink environment was used to develop the real-time PV system with a boost converter into a C-program and build it into a DSP controller TMS320F28335. Besides, the performance of the real-time DSP-based PV was tested in different temperature and irradiation conditions to observe the P-V and V-I characteristics. Further, the performance of the PV with a boost converter was tested at different temperatures and irradiations using MPPT algorithms. This scheme was tested through simulation and the results were validated with that of standard conditions given in the PV data sheets. Implementation of this project helped to attract more researchers to study renewable energy applications without real sources. This might facilitate the study of PV systems in a real-time scenario and the evaluation of what should be expected for PV modules available in the market.

While inverters currently do exist, the main focus of this investigation is to provide a DSP based design that will significantly reduce the cost of the current system. The proposed approach relies on an efficient pushpull DC-DC converter, a digital signal processor (DSP) control mechanism for the DC-AC conversion, and a rigorous cost reduction approach for this inverter. A low cost Texas Instruments, TMS320LF2407 DSP provides the control for the DC-AC converter allowing compliance to the total harmonic distortion (THD) specification of less that 5%. Moreover, the DSP allows convenient communication between the fuel cell and the inverter. The results section of this paper presents our laboratory data. A new closed-loop control scheme is also introduced which reduces the distortion caused by non-linear loads.