A. V. Varavin

Modernization and calibration of intrferometer of TOKAMAK “Compass”

This article presents “Compass” TOKAMAK microwave diagnostics calibration and results accuracy enhancing experiment methodology. Main subject is microwave diagnostic system phase measurements description. Additional interest is mistakes, attendant to phase measurement. Emphasis is put on phase detectors measurements mistakes correction methodology; two different phase meter configurations are described. Phase detectors, based on AD8302 CPLD, results processing methodology are presented.

Two-wavelength millimeter wave “unambiguous” heterodyne interferometer

The paper presents the results of upgrading and description a two-wavelength “unambiguous” microwave interferometer for line integrated electron density measurements at the “COMPASS” tokamak. The probing signals in the frequency range of 131 and 133 GHz are generated by IMPATT diode oscillators. Double conversion heterodyne receivers are used for detection. Use of each oscillator is twofold: as a source for the probing signals and as a local oscillator for heterodyne detection. The plasma is probed with two separate waves of different wavelengths traveling along identical paths to meet each other. Each probing beam experiences a different phase shift φ₁ and φ₂ and the “unambiguous” interferometer determines the difference φ₁-φ₂. The phase measurement is realized by using the 3 pieces of phase detectors based on pairs of phase/gain evaluation boards (AD8302). Application of the phase detectors provides information on the average plasma concentration in real time and restore the values of plasma density in the case of phase jumps by an amount > 2π.

Radar sensors for hump yard and rail crossing applications

A radar sensor as part of the automatic shunting system has been developed for the remote control of track occupancy in the hump yard and railroad switch territories, enhanced by the speed control of rolling stock when it passes by the retarder. The sensors are equipped with systems of remote control. They are provided with systems of internal parameter diagnostics and transmission of the radar and service information to the control point and can work in information networks.

Autodyne sensors for hump yard and rail crossing applications

The Ka-band radar autodyne sensors are suggested for railway applications, including the check and remote control of the track occupancy/vacancy and the car speed at hump yards and as part of an obstacle detection unit for monitoring the rail tracks and the block unit lids on guarded and non-guarded rail crossings in an effort to reduce the risk of accident on railroads.

Two frequency heterodyne interferometer based on phase locked 2 - millimeter wave transceivers

The report presents the results of the design and description of the two frequencies heterodyne millimeter wave interferometer for measuring the linear integral electron density in the tokamak “COMPASS”. Microwave part of the interferometer based on solid-state transceivers with a phase locked loop. The interferometer consists of two solid-state transmitters and two millimeter wave receivers operating on 139,6GHz and 138,9GHz. Signals of oscillators and heterodyne receivers are synchronized by phase-locked loop system. The phase measurement is performed using a three-channel phase meter, based on programmable logic arrays (PLA). The interferometer provides information on the average electron density in plasma in real time and is used in the plasma discharge control system.

Application of double-diode autodynes in control systems for technological processes

Options and application opportunities of double-diode autodynes in microwave sensors are considered to radio-wave control dimensions of products, vibration and displacement parameters, velocity and movement direction of reflecting objects.

Double-diode autodyne of 8mm-range on Gunn diodes

Operation principle, adjustment approach and construction description are given for double-diode autodyne module of 8mm-range made on the base of two mutually-synchronized partial oscillators on Gunn diodes. The block-diagram of a workbench is presented for determination of the motion speed and direction, vibration parameters and displacements of reflecting objects with the help of double-diode autodynes.

Experimental studies of the 8-mm wave Gunn diode autodynes

Data of the experimental studies of an energy potential and dynamic range of the normal and frequency stabilized by the external high-Q resonator autodynes based on planar 8-mm Gunn diodes are provided.

Improvement of range resolution of FMCW autodyne radar

The principals of range resolution improvement the self-mixing FMCW radar based on analysis of the spectrum of high-order harmonics of intermediate frequency is proposed. Developed the scheme and investigated the model of Ka-band surveillance self-mixing FMCW radar with digital control and spectral processing of receiving signal. Advantages of this radar are small size, low power consumption and use of scanning antenna.

Compact millimeter-wave distance and speed measurement sensor for railway applications

Radar sensor for use in automatic shunting system which executes remote control of track occupancy on hump yards and railroad switches and cut speed control passing along retarder position is developed. The sensors are equipped by systems of remote control and internal parameters diagnostics transmitting the radar and service information to the control point. The sensors could be applicable for use in the data nets. The main feature of the developed radar is the use of FMCW self-mixing transceiver with internal detection and digital control and spectral processing of the signal.