This article is devoted to the  development of analytically  described self-oscillation  stability  research  technique.  The case when  the  linear part  of the  system contains transfer function with a zero pole is considered. Typically the transfer function study,  where  the  numerator degree  is two orders  of magnitude less than  the  denominator degree  is creates no problems. However, the presence of a zero pole makes the case special and requires  investigation.

A comparative evaluation of the results of self-oscillation analytical  calculation  and stability analysis is given, by means of technique developed for symmetric self-oscillations with half-period repetitions and asymmetric ones with period repetitions.

The presented technique is a significantly  new scientific step  in the development of methods for calculating  non-linear systems. It also allows  us to evaluate the  accuracy  of approximate calculation methods, which  is important for precision systems. The technique is relatively  easy  to  implement. It allows  to  find  a solution  as well as for the  cases  having  been unanalyzable so far.

This paper  provides  a study  of robust  TOA discriminators used  in ground-based retracking  of a space-based altimeter da-ta. Requirements to an on-board TOA tracking loop are limited  to reliable locking of received echo-signal  within the tracking  window,  while fine measuring of altimetry parameters (orbit height,  SWH, etc.) is a task  of the Earth-based retracking.  In the  robust  algorithms TOA-measuring  is performed without  using  any  echo  physical  model.  It can  improve space-based altimeter operation near the coastline  where  terrain areas falling into the illuminated spot distort  the received signal  significantly  versus  the  one  from  the  “pure” water  surface.  Analytic  calculation of  noise  errors  is fulfilled  for  the OCOG. Besides, the threshold discriminators and simulation results are presented, as well as comparison of the robust  discriminators against  the  optimal (within the  classical model  framework) one.  Despite the  robust  types  yield to the  optimal one  in the  accuracy  of TOA estimate, the  loss is not  catastrophic and  often  can be treated as an acceptable pay-ment for low sensibility  to the deviation of scattering  characteristics of a sounded surface  from  classical models.

An important task in designing  microwave industrial plants  is to determine actual power  going into a process  reactor.  A part  of magnetron power  reflects  from  the  microwave reactor  into  generator due  to  the  processed  material property changes. It results  from  dielectric  property changes,  due  to changes  of temperature, humidity,  variation  of boundary conditions in the reactor  when  moving  the product. Moreover,  the reflected  wave significantly  changes the  magnetron regime  of  operation. The article  shows  that  the  power  transferred to  the  processed  product can be determined based  on changes in the  current  pulse  form  when  using  a classic power  supply (high-voltage  transformer and  a voltage  doubling circuit) and  power  supply  with invertor.  Also it is possible  to estimate the mutual influence magnetrons on each other  in microwave installations with multi  generator scheme. The difference in the  operation of the  classic power  supply  and  inverted power  supply  leads  to necessity  for different power  determining algorithms. Microwave  power  in the  load  determined experimentally coincides  with  the  microwave power  calculated by the developed method, which confirms the reasoning of the algorithm used.

The possibilities  of increasing  the data  rate of adaptive HF communication systems by reducing  redundancy in the  form  of test  signals  used  for its operation are  considered. The problem is currently  pressing  due  to increasing  demands of modern adaptive data  transmission systems to efficient  use of allocated  frequency-time resource  of radio channel. For the  problem solution,  methods based  on the  analysis  of the  received  information signal, taking  into  account the used  signal-code  construction, are proposed. Approaches for solving problems of non-test adaptive signals correction  and channel state  estimation in serial data  communication systems using  convolutional encoder  are  proposed. Search  algorithm  for segments used  for channel impulse response and  equalizer coefficients calculation is shown.  In this case, neither a change in decoding algorithms nor calculating of equalizer  impulse response is required.  Expressions for estimation of the bit error rate for a convolution encoder of general form  are given. The presented approaches maintain operating of adaptive HF data  transmission systems in channels with intersymbol interference, ensuring  the  operative change  of its parameters when the state of the radio channel changes  significantly reducing the use of test signals, or completely abandoning them.

At present, multilateration systems are becoming increasingly  important in air traffic control.  This is due  to their significant advantages in compare with secondary surveillance  radar complexes. This article solves the problem of synthesizing an algorithm for object location estimation for multilateration system operating in passive mode. The synthesized algorithm is a combination of a procedure, the result  of which is a rough  estimate of the observed object  coordinates, and  an iterative  algorithm specifying  the resulting solution.  The rough estimate is the result of solving a linear system of equations. The iterative  refinement procedure is based  on the linearization of the observational equations and does not require a large number of iterations. The paper provides  a comparative statistical  analysis  of the  proposed algorithm and  the  known  Bancroft  algorithm. For an objective analysis of two algorithms, the paper derives the Cramer-Rao boundary for the correlation matrix of estimates of the observed object coordinates, which makes it possible  to determine the potential accuracy of the solution  of the problem. It is shown  that both algorithms allow obtaining estimates, the accuracy of which is close to the potentially achievable accuracy of the object location estimate. In contrast to the Bancroft  algorithm, the rough estimate of the object location is unambiguous. This virtue reduces  the total amount of computations during the algorithm implementation and reduces  the probability of anomalous errors.

Mechanical  properties of MEMS devices  are specified  by their structure and  process  parameters, such as temperature, films thickness, deposition conditions, etc. These features, in particular,  the deposition temperature and post deposition treatments, determine the residual stress in the films, which affect the initial deformation, stability of parameters, sensitivity and reliability. Prediction, control and minimization of residual stress are an important part of the structural and technological design  of MEMS devices.  The effect  of post  deposition thermal treatment on  the  residual  mechanical stress  of SiN_x, Al and SiN_x/Al films is studied. It is shown  that the tensile stress in Al film is critical for residual  mechanical stress of the SiN_x/Al structure and increases  with the increase  of temperature and time of post annealing. This allows to control the post annealing conditions  and the process  temperature budget to compensate the compressive stress in SiN_x films and to minimize the summary residual stresses  and initial deformations of SiN_x/Al structure. The residual stress of the bilayer SiN_x/Al structure has little effect on the film thickness, but the ratio of SiN_x and Al thicknesses is significant for the thermal deformation of SiN_x/Al microcantilever.

The article provides  characteristics of dispenser cathodes with admixture of nanocarbon particles,  i.e. sulfoadduct of carbon  nanoclusters (Ugleron®), into active material and polyhedral multilayer carbon  nanostructures of the fulleroid  type  and  toroidal  shape  (Astralenes®)  into  tungsten matrix.  The emitters are  considered as  electron  sources  for modern microwave devices,  in particular  travelling wave tube.  The results  of their accelerated life tests.  Emission  capacity measurement results  are provided. A comparative x-ray analysis  of modified and  typical cathode emitting  surfaces  and  respective  anodes is presented. The morphology features of DC metal  matrix  with  admixture of carbon  nanoparticles are mentioned. Moreover,  resistance of nanocarbon modified cathodes to operation under  insufficient vacuum  conditions is investigated.It is concluded that  the further  study  of nanocarbon modi-fied thermal cathode parameters, e.g. electron  work function and  active substance evaporation rate with Ugleron®, is reasonable. Recommendations on further  improvement of dispenser cathodes manufacturing technology with admixture of nanocarbonic particles.