CC BY
0
УДК 53
Аманбердиев Д.О.,
преподаватель
Институт Инженерно-технических и транспортных коммуникаций Туркменистана ANTENNA FEEDER STRUCTURES AND MOBILE RADIO COMMUNICATION
Key words:
radio line, radio beacon, antenna, signals.
All signals sent over a radio line are divided by a radio transmitter or a radio receiver antenna, which is reflected back to the transmitter antenna in the form of a radio wave. An electrical signal is sent to the input of the antenna and propagates in the form of a wave at the output. Antenna-feeder structures are one of the main elements of radio communication lines. Their incorrect selection and improper use lead to malfunction of radio communication lines. No matter how much we improve the transmitter and receiver, if the antenna-feeder structures work incorrectly, the quality of the radio communication systems will be poor as a result. Dedicated radio communication lines use directional antennas. When transmitting signals, such antennas reflect radio waves in a certain direction, and if the antenna's directional properties are high, it is possible to use a low-power radio transmitter.
Fixed receiver antennas improve the signal-to-noise ratio of a radio line. As a result, the signal-to-noise ratio at the receiver input increases and the quality of the radio communication line improves. The reliable operation of radio communication lines depends to a large extent on the selection of the direction of propagation of radio waves, in addition to the parameters of radio transmitting and receiving devices and antennas. Modern radio communication systems use various types of high-quality and sophisticated receiving and transmitting antennas. In modern radio communication, radio navigation, radiolocation, and other radio systems, along with parabolic trough dielectric antennas, in-phase antennas are widely used. Such antennas are used for a variety of purposes, from the decameter wavelength range to the longer millimeter wavelength ranges.
In phase antenna, the reflecting elements of the apertures are usually made in the form of a half-wavelength vibrator, and the reflecting elements are connected to each other by means of main line phase shifters in various ways, so that they form a flat phase front of the electromagnetic field. Synphase antennas are particularly suitable for use in terrestrial and space mobile radio communication systems. Such antennas are very suitable for mobile communication systems because the directional pattern can be controlled electronically and the reflecting elements can be implemented based on integrated microwave technology.
Antennas are structures designed to radiate and receive radio waves. The same antenna can serve as a transmitting and receiving antenna. For example: in DRL, several transmitters and receivers operating at the same time in the same direction, but with different frequencies, are connected to the same antenna. Appropriate filters will be applied for different heights. Classification of antennas according to their purpose: transmitting, receiving and transmitting-receiving antennas.
For stationary antennas, DH is shown in the vertical and horizontal planes. Activity diagrams are displayed in normalized or rectangular coordinate systems.
The portion of the DH located between two minimum radiating adjacent points is called the DH leaf of the antenna. The leaf where the antenna has maximum reflectance is called the main leaf. A leaf whose orientation is about 1800 different from the main leaf is called a back leaf. Leaves other than the head and back are called lateral leaves. The angle between two directions on a leaf that has a certain amount of excitation at its boundaries is called the width of the leaf. The area between the lowest frequencies (wavelengths) that an antenna can operate is called the range of an antenna.
The range of the antenna is also determined by other parameters that quickly exceed the specified range. Depending on the type of antenna, the input resistance, gain coefficient, and other parameters are used to determine the range.
The range of the antenna is determined by the average speed:
4Mr2(Lx imiiiM/rnax ^ fim) Range closure is defined by relationship.
finax / fmin
Antenna input resistance (Za) is the ratio of voltage to current at the input of the antenna. This resistance is a complex quantity and depends on the relative length of the antenna. The electrical circuit and auxiliary devices used to transmit radio signal energy to the antenna or from the antenna to the receiver are called feeders.
References:
1. Fundamentals of radio electronics" O. M. Nowruzov Polytechnic Institute, Ashgabat 2010
2. A. Charyev Ch. Seyitnepesov "Radio wave propagation and antenna-feeder structures" Ashgabat 2010
3. A. Jumaev, Ch. Seyitnepesov, B. Babaev "Mobile communication systems" Ashgabat 2010
© AMaH6epflMeB fl.O., 2023
УДК 338.48
Аннабаева Н.Р., преподаватель Туркменского государственного университета имени Махтумкули.
ДИНАМИЧЕСКОЕ ПРОГРАММИРОВАНИЕ Аннотация
В статье рассматривается динамическое программирование и анализируется его особенности.
Ключевые слова: динамическое программирование.
Динамическое программирование — это раздел оптимального программирования (оптимального управления), в котором процесс принятия решений и управления можно разделить на отдельные этапы (шаги). Все этапы могут быть разными или одинаковыми, а также могут перекрываться. Некоторые задачи оптимизации легко разбиваются на шаги естественным образом, а для других вводится искусственное разделение на шаги.
Динамическое программирование позволяет нам свести сложную задачу со многими переменными к множеству задач с меньшим количеством переменных. Это позволит существенно сократить объем вычислений и ускорить принятие управленческих решений.
Если удастся повлиять на его рост, то и экономическим процессом можно будет управлять.
Контроль - это совокупность решений, принимаемых на каждом этапе с целью повлиять на ход процесса.
Процесс представляет собой контролируемый процесс, то есть мы можем выбирать некоторые параметры, влияющие на ход процесса и обеспечивать выигрыш на каждом этапе, а также контролировать этапы процесса.
