Non-Invasive Monitoring of the Technical Condition of Power Units Using the FAM-C and FDM-A Electrical Methods

This article presents the selected results of analytical and structural work conducted at the Air Force Institute of Technology (pl. ITWL) in the field of building a measuring apparatus for non-invasive monitoring of the technical condition of aircraft power units. Presented innovative FAM-C and FDM-A methods allow for observation of frequency modulation parameters as well as identification and diagnostic classification of particular mechanical subassemblies supplying the on-board generator and thus enable non-invasive monitoring of technical condition of the aircraft power unit and the aircraft propulsion system. The main purpose of this article is to present the measurement apparatus errors that occur in the signal conditioning system in the FAM-C and FDM-A methods. In spite of the fact that the measuring instrument was built on the basis of digital technology and that it uses typical solutions of electronic frequency measurement, due to the specificity of the applied diagnostic method there occur specific measuring errors which are presented in this article.

Development of a word frequency lists and textscorpus of russian pre-reform language

The paper is devoted to the development of the Russian language corpus in pre-reform spelling and the development of a frequency word list based on this corpus of the Russian language of the 18th - early 20th centuries. Existing approaches to solving this problem are considered and analyzed, including an overview of a number of the most popular electronic national corpuses – Russian, British and Czech. The model of the internal organization of the electronic frequency word list and its functionality are formulated. The software implementation of the Russian pre-reform language corpus and the frequency word list based on it is described using the programming languages Python and Javascript and the Mongo DB database. The issues of web application implementation for access to the developed electronic dictionary are considered.

Ultrafast and Wideband Microwave Photonic Frequency-Hopping Systems: A Review

The increasing demands to enhance information security in data transmission, providing countermeasures against jamming in military applications, as well as boosting data capacity in mobile and satellite communication, have led to a critical need for high-speed frequency-hopping systems. Conventional electronics-based frequency-hopping systems suffer from low data rate, low hopping speed, and narrow hopping-frequency bandwidth. Unfortunately, those are important aspects to facilitate frequency-hopping in emerging microwave systems. The recent advancement of microwave photonics—the use of light to process microwave signals—provides promising solutions to tackle the challenges faced by electronic frequency-hopping systems. In this paper, the challenges of achieving real-time frequency-hopping systems are examined. The operation principles and results of various microwave photonics-enabled frequency-hopping systems are comprehensively discussed, which have wide hopping-frequency bandwidth and frequency-hopping speed from nanoseconds to tens of picoseconds. Lastly, a bio-inspired jamming-avoidance system that could potentially be used for adaptive frequency-hopping is also introduced.

Frequency-adjustable electric drive for energy saving and optimization of technological processes in electrical complexes

The relevance of the study lies in the search for energy-saving technologies. So, at present, the most common type of electric drive in industry is asynchronous, most of which are unregulated. Replacing an unregulated electric drive with an adjustable one in various units can significantly reduce energy consumption, increase the life of the mechanical part of the drive and improve the quality of the adjustable process parameter. The replacement consists in installing an electronic frequency converter between the network and the motor of the device. This device changes the rotational speed of the motor rotor by changing the frequency and amplitude of the supply voltage. The most common are frequency converters with an intermediate DC link. Such devices are built on electronic keys, which are made on IGBT (Insulated Gate Bipolar Transistor) transistors. Using the NI Multisim14 software, a model was created to determine power savings during the implementation of VFD.The paper gives the rationale for the introduction of a frequency-controlled electric drive (VFD) to optimize technological processes in electrical complexes and systems, in particular, a complete analysis of the energy efficiency of VFD application in pumped water supply systems is presented as an example. The calculation of its economic efficiency for a particular installation is also given.

300 GHz Optoelectronic Transmitter Combining Integrated Photonics and Electronic Multipliers for Wireless Communication

THz communications systems at carrier frequencies above 200 GHz are the key to enable next-generation mobile communication networks with 100 Gbit/s wireless data rates. One of the key questions is, which carrier frequency generation technique will be the most suitable. This is currently addressed by two separate approaches, electronics-based and photonics-based. We present in this paper a truly microwave photonic approach that benefits from the main key features of each, bandwidth, tunability, stability and fiber compatibility from photonics and power handling capability from the electronics. It is based on a Photonic Local Oscillator (PLO), generating a 100 GHz frequency, fed into an electronic frequency multiplier. A high speed uni-travelling carrier photodiode (UTC-PD) provides the 100 GHz PLO for Schottky tripler diodes, generating 300 GHz signal. To feed the UTC-PD, we present a photonic integrated mode locked laser source. According to the simulations and measurements, the developed transmitter can produce a maximum of 12 μW of THz power at 280 GHz.