WOUND HEALING IN HUMANS BY OPTIMIZATION OF LOW FREQUENCY SIGNAL FOR PULSED ELECTROMAGNETIC FIELD THERAPY

A wound, in clinical terms, is any tissue injury that causes skin rupture which penetrates epidermis and dermis layers leading to uncovering of underneath tissues or organs. Wounds can be superficial or deep, acute or chronic, with minor to serious implications depending on the source, extent, and location. Pulsed Electromagnetic Fields (PEMF) may have varying effects depending on the type of target tissue. Triggering a biological event requires a specific signal to be applied. The effectiveness of a PEMF device is mostly determined by the waveforms utilized in conjunction with the pulsing frequency. Choosing the right PEMF signal is a crucial step in developing a device that can address the challenges associated with chronic wound healing and speed up the healing process. Therefore, the optimization of the signal generator unit in the PEMF system for wound healing applications is a necessity before starting the further process. Hence, the present work of optimization of the PEMF system was carried out by selecting an optimal signal on the signal generator which produces a significant quantity of current in the particular tissue site to provide improved wound healing results. A total of 120 signal generator designs were simulated and optimized to six signal generators having frequencies of 10Hz, 20Hz, 30Hz, 40Hz, 50Hz, and 100Hz and duty cycle 25%. For both groups, the average frequency and duty cycle were calculated and tested using independent samples t-test to see if there were any differences between them. No statistically significant difference was found for frequency (p=0.9977) and duty cycle (p=0.5090). Because of the necessity of the right PEMF signal selection for every trial to be successful, this work will act as a gateway for selecting, understanding,` and considering the proper signal which could initiate the respective biological effect and accelerate the wound healing process.

Specific Radar Recognition Based on Characteristics of Emitted Radio Waveforms Using Convolutional Neural Networks

With the increasing complexity of the electromagnetic environment and continuous development of radar technology we can expect a large number of modern radars using agile waveforms to appear on the battlefield in the near future. Effectively identifying these radar signals in electronic warfare systems only by relying on traditional recognition models poses a serious challenge. In response to the above problem, this paper proposes a recognition method of emitted radar signals with agile waveforms based on the convolutional neural network (CNN). These signals are measured in the electronic recognition receivers and processed into digital data, after which they undergo recognition. The implementation of this system is presented in a simulation environment with the help of a signal generator that has the ability to make changes in signal signatures earlier recognized and written in the emitter database. This article contains a description of the software’s components, learning subsystem and signal generator. The problem of teaching neural networks with the use of the graphics processing units and the way of choosing the learning coefficients are also outlined. The correctness of the CNN operation was tested using a simulation environment that verified the operation’s effectiveness in a noisy environment and in conditions where many radar signals that interfere with each other are present. The effectiveness results of the applied solutions and the possibilities of developing the method of learning and processing algorithms are presented by means of tables and appropriate figures. The experimental results demonstrate that the proposed method can effectively solve the problem of recognizing raw radar signals with agile time waveforms, and achieve correct probability of recognition at the level of 92–99%.

Teaching Electromagnetism through a Transmission and Reception System of Electromagnetic Waves

The learning of phenomena related to electromagnetic waves develops in an evident way when students are stimulated significantly and, one of the possible ways are contextualized experimental practices. In this way, a system was developed that allows the sending and reception of electromagnetic waves, which can be provided by a signal generator or by a transmitting radio. For the implementation of the system, two Yagi-Uda antennas were built, intended for the transmission and reception of signals; for the emission of signals a low-power transmitter radio and for the measurement of the intensity of the received signals, a signal intensity meter was constructed from a multimeter in which a circuit was added that converts the signals received into direct current proportional to their intensity. The system was used in the physics discipline of high school, where it was observed that using this system, the students presented a better understanding of the phenomena related to electromagnetic waves.

Design of sweep frequency signal source in residual stress detection platform based on Zynq

The signal generator based on DDS technology has high frequency and resolution, and is widely used in many fields such as instrument technology, radar, satellite timing, remote control and telemetry, and is one of the important directions of current signal generator research. In order to achieve a cost-effective, high frequency resolution signal source to stimulate the sensors in the residual stress detection system, this paper selects the Zynq-7020 on-chip system to control the 14-bit direct digital frequency synthesis chip AD9954 to obtain a 40Hz~1MHz sinusoidal signal output. Finally, the performance and technical parameters of the system are tested experimentally. The output signal of the signal source is stable, the signal-to-noise ratio is high, and the frequency error is within 0.1%.

Calibration of NMR Receiver using Spectrometer Characteristics

This article describes the measurement of the relation between input and output signals using two techniques: with a signal generator and with the thermal noise of a known resistance. Each of the techniques has its advantages and disadvantages. Both methods are tested and the results are compared. The input signal of the receiver is known in volts, while the output signal is in ADC (analogue-to-digital converter) units. It is the main difference versus the gain. Knowledge of the relation enables recalculation of the output signal into the input of the receiver or vice versa. It is important in some experiments. The method with the harmonic signal requires a suitable NMR spectroscopic console, generator of the harmonic signal and an attenuator, the method with the noise requires only the NMR console. It indicates that both methods are simple and cheap. The measured data are processed on a standard PC using common programs.