Ageev Dmitriy V.( Scientist in the field of radio engineering)
Comments for Ageev Dmitriy V.
Biography Ageev Dmitriy V.
Dmitriy V. Ageev - doctor of technical sciences, professor, honored worker of science and technology of the RSFSR. The main area of his activity was teaching radio engineering. However, having huge creative potential and feeling promising trends of development of Radio, he put forward a number of important ideas which have entered the golden fund of the main provisions of the theory of communication.
By merit D. V. Ageyeva should also include the fact that he, as a professor of Gorky Polytechnic Institute, has created one of the largest in the country's scientific school, which was completed a number of highly original scientific papers. They trained 55 candidates and 11 doctors. Many of his students became well-known experts.
In our country, D. V. Ageev enjoyed great prestige among scientists and engineers. For his scientific achievements and work on scientific training, he was awarded the Order of Red Banner of Labor, the medal "For Valiant Labor", he was awarded the title of "Honorary radioman USSR.
Dmitriy V. Ageev was born February 21, 1911, Mr.. in St. Petersburg in the family working. Even in his school years he became interested in radio, and so after graduating from high school tried to do in the Leningrad Electrotechnical Institute (LETI). The first attempt was unsuccessful, but he was resolved to devote himself to radio technology. To prepare the institute Ageev enter public courses, where he studied for a year. During the course of his successes were so high, especially in mathematics, that he recommended to do the mathematics department of Leningrad University. But D. V. Ageyeva attracted radio engineering, and in 1930. He became a student of the Faculty of the Leningrad Institute of Radio Engineering and Communications - Liis (since before the Great Patriotic War was called the Leningrad Electrotechnical Institute of Communications (LEIS) of. Professor M. A. Bonch-Bruevich).
In 1935. Ageev successfully graduated and was left in graduate school. In the same year he published two fundamental theoretical work: "On the transition processes in the resonant amplifier" (jointly with Academician Yu. B. Kobzareva) and "Fundamentals of the theory of linear selection."
In the first paper to study the transient processes in multistage receiving-amplifying device was first applied the method of slowly varying amplitudes, developed in the 20-ies. famous Dutch scientist van der Pol. This work laid the foundation of our country critical studies of transients in resonant linear circuits, which continued academic A. N. Shchukin and domestic professors and. S. Gonorovsky and C. I. Evtyanov.
The second work was of fundamental importance for communication theory. It was shown that the use of linear methods, there are three separate types of signals: frequency, time and compensatory (in form).
Ph.D. thesis D. V. Ageyeva "The theory of selection and capacity problems" ether "(1939) was performed under the direction of M. A. Bonch-Bruevich - the largest national scientist, one of the founders of the famous Nizhny Novgorod Radio Laboratory, has carried out important research in the field of radio engineering and radio-wave propagation. This work, containing a number of innovative ideas, while protecting the Academic Council was recognized as an outstanding, meet all the requirements for the doctoral thesis, and defend it Ageev was recommended as a doctoral. But he was unable to defend twice the same work, and doing new research, in 1940. presented to the doctoral dissertation "A new method of multichannel telegraphy", . which was investigated by the group method of transmission of elementary signals, . application of which is allowed to weaken the effect of impulse noise in the tens or hundreds of times.,
. Timely publication of studies included in a doctoral thesis D
. V. Ageyeva prevented the Great Patriotic War. For a long time they were known only to a narrow circle of specialists. At the beginning of the war thesis Ageyeva lost in the depths of the Higher Attestation Commission and was found only in 1948. Based on this work Presidium of the Academy of Sciences awarded Dr.. V. Ageev degree of Doctor of Technical Sciences.
The winter of 1941-1942. D. V. Ageev and his family spent in the besieged Leningrad. Having survived the blockade, a scientist in the spring of 1942. with LEIS, which then worked, was evacuated in Kislovodsk, and then moved to Tbilisi, where he taught advanced mathematics, theoretical radio technician, he headed the department of higher mathematics.
In the summer of 1945. LEIS returned to Leningrad. But because health young daughter D. V. Ageyeva been undermined by starvation hibernation during the siege, he was sent to Odessa Electrotechnical Institute of Communications (OEIS), which in 1946-1949. He headed the department of radio receivers, and has lectured on theoretical electrical engineering, radio receiving and amplifying devices.
Interestingly, one of the episodes from the biography of the D. V. Ageyeva, characterizing him as a principled and courageous man with dignity. Director of the Odessa Electrotechnical Institute of Communications, without any scientific publication, decided to obtain an academic title and defend his dissertation. At that time the only doctor of science at the Institute was Dr.. V. Ageev, and he was invited to speak with the assessment provided to the protection of. Having carefully reviewed the dissertation director, Dr.. V. Ageev not find anything new in it and honestly written a very negative feedback. As a result of the director started hounding the scientist, and he was forced to seek work in other cities. Since D. V. Ageev was well known as a prominent specialist in radio, he was invited to several universities. His choice fell on Gor'kovskiy Industrial Institute (later Gorky Polytechnic Institute - STI, now Nizhny Novgorod State Technical University), in which he worked all his life.
. With the shift in the GUI, a new, extremely fruitful period in the life of the D
. V. Ageyeva. In 1949, Mr.. he was elected to head the Department of Radio Engineering GUIs, and later he headed the Department of radio receivers. This department was part of the Faculty of Electrical Engineering, which appeared as a result of renaming in 1947. Radio Engineering Faculty. Realizing the importance for the country training in radio, D. V. Ageev proposed to restore the GUI Radioengineering Faculty, and in 1952. this department again became an independent. In the same year Ageev organized at the Faculty of two new faculty: "radio receiver", which he headed, and radio transmitting devices. In 1955-1959 he. D. V. Ageev was dean of the Faculty of Radio Engineering GUIs, which played a significant role in the preparation of national experts in the field of radio engineering.
In GUIs D. V. Ageev not only directed the scientific work of their employees, but busied himself with the decision of many actual problems of modern radio engineering. He owns a number of major inventions. A new type of detector signals phase telegraphy, . pulse method for amplifying low-frequency vibrations, . method of nonlinear selection, . number of ways to suppress the impulse noise, . method of increasing the selectivity of radio equipment, . communication system with multi-valued modulation characteristic, . - This is an incomplete list of his works,
. He also put forward new concepts of the theory of spectra, developed the theory of FM radio with servo adjustment. In 1951, Mr.. D. V. Ageev suggested that a key method for amplifying electrical oscillations, and in 1957,. proved important for the theory of connection between the theory of functions of time with a limited range. In 1958, Mr.. out written with I. G. Rodionov monograph "The FM radio reception with the servo control", which outlines developed by Dr.. V. Ageyev theory of this important type of reception, assessment of the potential noise immunity. Later (1973) they were defined limits of the separation of signals using filters with variable parameters.
Dmitriy V. Ageev died July 31, 1997
Academic Areas D. V. Ageyeva was unusually wide, and in some areas of communication theory, he made a fundamental scientific contributions.
. The most significant contribution to the theory Ageyeva connection is the work of "Fundamentals of the theory of linear selection", which became his master's thesis
. It was published in 1935. the Scientific-technical collection of communication Liis (? 10,. 35-41) and widely known among domestic experts. It was first defined the principles and limits of separating signals linear systems in the frequency and time domain, . as well as the form, . and proved, . necessary and sufficient condition for the separation of signals by linear methods is their linear independence,
. In 1970. Professor L. M. Fink, in his book "Theory of transmission of discrete messages, said:" Unfortunately, the theory of compression channels is not enough developed and our knowledge in this area not far removed from what was laid in 1935. in D. V. Ageyeva.
In dissertation Ageyeva was first given a geometric interpretation of the processes of transmission and reception of signals in the presence of noise, widely used now in information theory, and noise immunity. The theory posited a physically realizable model of signals of finite duration. In this work, first used by Ageev representation of signals and interference in multi-dimensional functional space. Later this idea was used in. A. Kotelnikov in his famous "Theory of potential noise immunity". Above the noise immunity of the theory of Professor Dr.. V. Ageev continued to work all my life.
D. V. Ageev, among the first, understood the importance of the problem of efficient use of radio frequency spectrum (RFS) caused a rapid increase in the number of radio stations operating in the air. One solution to this problem is the use of such methods of transmission, which would allow a limited band of frequencies to transmit signals to as many radio stations. The ideas of the group method of transmission of signals to control a brief breakdown of communication (eg, because of the powerful pulse interference), the proposed D. V. Ageyev in 1938. and included in his doctoral dissertation, led directly to the creation of systems of broadband signals (WBS), which is used to send messages is not harmonic, and broadband carrier. Article D. V. Ageyeva and his disciple Yu. N. Babanova "Transmission of signals with overlapping frequency spectra" ( "Radio Engineering", . ? 10, . 1964) was described by the system, . which broadband carrier formed by modulating the linear (or any other) to the periodic law of the master oscillator frequency,
. Useful signal modulated broadband carrier in such a way, . to its active range at any time held a small piece of frequencies and moved by a particular law within the frequency range, . width of which would be considerably greater than the width of the spectrum of active signal,
. Using modern terminology, we can say that this effort to transfer the information requested use of broadband signals with a large base. Today, broadband systems used in communications systems for various applications (both fixed and mobile).
Unfortunately, the above-mentioned work in the 60-ies. could no longer be considered innovative, as in the U.S. broadband communication systems developed since the mid 40-ies. It should be noted that a similar proposal in Article D. V. Ageev and Yu. N. Babanova method for broadband connected with the change in frequency of the carrier signal during transmission of information symbols. This method has long remained a secret, though it was invented back in 1940. known American actress X. Lamar and her husband - composer D. Atseylom. In domestic literature, such broadband signals call signals with time-frequency matrix.
. Work for jam-resistant communications systems and develop effective methods of selection signals in the future students continued D. V. Ageyeva Doctor of Technical Sciences Yu. N. Babanov, A. A. Gorbachev and others. YU. N. Babanov researched methods of separating the two signals with amplitude modulation, transmitted to the common band with a small frequency detuning between the carriers, and A. A. Gorbachev carried out similar studies for signals with frequency modulation. Today, in connection with the transfer of all communications systems for digital transmission techniques, these studies have become obsolete. However, their significance lies in the fact that they have expanded our knowledge about possible methods of transmission of signals from channels.
. Another important aspect, which intensively (both theoretically and experimentally) studied in the GUI, under the leadership of Dr.
. V. Ageyeva, was to develop methods for the suppression of impulse noise (PI). This problem is very relevant to radio communication systems operating in the range of short and ultrashort waves, in which the action of atmospheric and industrial noise, wearing a pulse character, restricts the sensitivity of receivers. D. V. Ageev suggested an original method for the suppression of IP, called the method of transformation of the signal spectrum and its limitations. The gist of it was that useful (low frequency) signal is overlaid with the powerful IP, which occupies a wide range, passed through a linear differentiating circuit, diminishing the frequency components of the signal and slightly distorted FE. The output of a linear chain installed limiter, which has a linear plot, which extends up to the maximum possible values of the useful signal. This limiter hardly affected the useful signal, and the level of IP in it substantially limited. Over limiter followed integrating circuit, in which the signal was restored, and IE even more suppressed. Numerous methods and original device to combat interference developed and examined pupils D. V. Ageyeva - A. A. Gorbachev, A. M. Shabalin, B. I. Kuzmin, A. I. Grechikhin etc.
In 1955, Mr.. D. V. Ageev introduced and scientifically substantiated, the basic concepts of spectral analysis. They introduced a new concept - an active band of the frequency spectrum function of time and given way to calculate. D. V. Ageev proceeded from the, . that at any given time span that the main contribution to the formation of functions makes it not the whole spectrum, . but only some "active" part of, . reflected in the well-known in our country monograph "The spectra and analysis of Academician A,
. A. Kharkevich. The new concept was suitable for the analysis of systems that process signals, the instantaneous frequency of which varies slowly enough. Portfolio D. V. Ageyeva in this direction were associated with the work of other scientists: Academician A. A. Kharkevich, as well as American scholars P. Fano and K. Page, who introduced the concept of "instantaneous spectrum", defined as the spectrum of the final segment of the process immediately preceding the given moment.
In 1957. D. V. Ageev proved a remarkable theorem, which can reasonably be attributed words of the famous German writer with. Zweig, "truth is beautiful, seemingly implausible". The theorem reads as follows: Suppose that the interval (t1, t2) given any continuous function U (t) and arbitrary frequency F. Then we can construct a function whose spectrum does not contain frequencies higher than F, arbitrarily close (in the mean-square sense) to U (t) in the interval (t1, t2).
. For example, in the time interval of duration 1 s, you can specify a function that changes its sign a million times, and continue it beyond this period of time so that the spectral width of the extended function does not exceed the value of, say, 0.1 Hz
. On this, at first sight paradoxical theorem in detail wrote in his excellent history book "Signals, noise, errors ... (M.: "Communication", 1978) A prominent national scientists. M. Fink. In particular, he remembers that after the D. V. Ageev in 1957,. the All-Union Scientific Session of the Scientific-Technical Society of. A. S. Popov explained that theorem, most listeners did not believe in its fairness and even try to find errors in the presented proof. Theorem Ageyeva significantly expanded representation of engineers of the laws governing the formation of the spectrum of signals and has found practical application in creating digital sound systems.
In 1939, Mr.. American engineer J. G. Chaffee invented demodulator is a frequency-modulated signals (FM) with feedback on the frequency (demodulator PSD). As is known, the frequency modulation has a threshold. This means, . that for the FM signal demodulator can specify a threshold for the signal: if the received signal has a lower (relative to the threshold) level, . a reception is virtually impossible because of the sharp decline in the quality of reception,
. Experiments showed that the demodulator has a high purity as compared to conventional FM demodulator lower threshold, t. e. it is more resistant to interference. Prior studies undertaken in the STI D. V. Ageev and his pupil I. G. Rodionov (1955), theoretical studies of many complex issues relating to the demodulator PSD, including its sustainability and design, not been conducted. These scientists first developed the theory of tracking receiving FM signals, published in the Proceedings of the STI, but in 1958. - In the monograph "FM radio reception with the servo tuning". Tracking demodulators FM signals are widely used only in the mid 60-ies. in satellite and tropospheric communication systems, for which most pressing problem was to reduce the energy potential of communication lines.
In the results presented in the monograph D. V. Ageyeva and I. G. Rodionova, based later on the witness receive FM signals, the study of large domestic specialists L. YA. Kantor A. S. Winitzki, SW. A. Afanasyev et al
In addition to the significant contribution to the theory of communication, D. V. Ageev with pupils achieved notable results in the field of radio engineering, which is reflected in the book D. V. Ageyeva and C. S. Zelmanova "Fundamentals of the theory of resonance in linear systems". In addition, together with his pupil A. V. Kovich Ageev introduced a new concept of "dynamic resonance - resonance in the oscillator circuit with nonlinear resistance and depends on the amplitude of the fluctuations in its frequency, the phenomenon of resonance in linear systems with variable parameters, . and also developed methods for assessing distortions, . arising during the passage of FM signals through different paths connected,
. Since 1951. D. V. Ageev s. V. Malanova, K. P. Sexually etc.. developed a general theory of GPI amplification of radio signals, which is based on a large number of methods for improving the energy efficiency of amplifying devices. This promoted a way of improving efficiency (for. n. d.) amplifier using pulse-width modulation (PWM), proposed in 1932. major Soviet academician A radio personnel. L. Mintz and Professor C. V. Persson. In accordance with this method to be increased tone in the modulator is converted into a sequence of pulses of constant amplitude with double-sided PWM. The frequency of the pulse sequence substantially higher than the frequency in. A. Nyquist equal 2FB, (FB - the upper frequency spectrum of the amplified signal). Pulses of low power with PWM control switching current flowing through the powerful amplifier tubes. At the load of the amplifier is allocated amplified sound. Since the spectrum of double-sided PWM audio frequency spectral components have significant intensity, then to. n. d. amplifier operating on this principle, is close to 100%. In conventional amplifiers to the same. n. d. is only about 20%.
D. V. Ageev lived long and fruitful life, full of intense creative labor. He and his many disciples were made first-class work in many areas of radio engineering. These results influenced the research carried out later than other domestic scientists, and included in the book, which taught thousands of professionals.
Yet due influence on the development of world science research results D. V. Ageyeva not had since been published on time and in less accessible publications, and thus became known only to a limited circle of specialists. Very rarely they were published in leading professional journals abroad. Unfortunately, he E. V. Ageev paid insufficient attention to the publications of his works.
. Another important reason for the influence of domestic science in the world was not enough, is that for decades it was virtually isolated from the processes of development of world science
. Domestic scholars have generally been denied the opportunity to participate in international scientific conferences, to communicate freely with their foreign colleagues and published in foreign scientific journals. In addition, severely limited the ability of our scientists and strict rules of publication of scientific results in the open press. State policy, leading to a closed society that does not allow the national scientific achievements become part of the global science and, of course, reduces the overall cultural level of the nation. This is the beginning of XX century, wrote convincingly a prominent Russian physicist, H. A. Minds, whose words ring true today: "The political significance of the nation can be strong only under the condition that its cultural level corresponds to its weight lifting. In our time, weapons, courage is not the only factors that ensure success in the struggle of peoples for their development and existence .... If we turn to our country, you realize that we, unfortunately, still largely adopt and borrow and invest very little in the cultural life of mankind. "
. Russia's eminent scientist Dmitry V. Ageev was one of those people whose works are replenished world treasures of scientific thought and contributed to progress in the field of communications.