The amplifier of videopulses intended for work as a source of a pulse feed of the Hannah diodes 3А763А-M of the short range radar system is described. Characteristics of the amplifier are: coefficient of amplification 16 dB; the maximal amplitude of output pulses - 6 V; the maximal current in a pulse - 2,5 A

Pushkarev, V. P.

Titov, A. A.

Electronic archive of Tomsk Polytechnic University

Technical sciences135come less than for the rotor without a liquid. Angularspeed at which the rotor cannot overcome critical frequency, for low power of the engine is calculated. The obtained results should be taken into account at designingand use of liquid LBDs for clearing fluctuations of unbalanced rotors with a vertical axis of rotation.Literature1. Pat. 6782722 USA. Drum washing machine // Yokoi e.a. SanyoElectric Co., Ltd.; 31.08.2004.2. Epishev L.V. On dynamic instability of a rotating rotor at incomplete filling of liquids. [in Russian] // Scient. Reports of vyssh. shkoly.Mashinostroenie i priborostroenie. – 1959. – No 2. – P. 66–74.3. Derendyaev N.V., Sandalov V.M. On stability of stationary rotationof the cylinder in part filled with a viscous incompressible liquid. [inRussian] // Prikladnaya matematika i mehanika. – 1982. – V. 46, issue. 4. – P. 578–586.4. Dimentberg F.M. Bending fluctuation of rotating shafts. [in Russian]. – M.: Izd. Akad. nauk SSSR, 1959. – 246 p.5. Rubanovskij V.N., Samsonov V.A. Stability of stationary movementsin examples and problems. [in Russian] – М.: Nauka, 1988. – 304 p.6. Gusarov A.A. Autobalacing devices of direct action. [in Russian]. –М.: Nauka, 2002. – 119 p.7. Nesterenko V.P. Automatic balancing of rotors for devices andmachines with many degrees of freedom. [in Russian]. – Tomsk: Izd.Tomsk. Gos. Univ., 1985. – 85 p.8. Dimentberg F.M., Shatalov K.T., Gusarov A.A. Fluctuation ofmachines. [in Russian]. – М.: Mashinostroyenie, 1964. – 308 p.At the present velocities of moving objects, forexample, automobiles, is measured with wide using ofthe short range radar systems, based on the Doppler effect. Generators of the SHF oscillations of the namedsystems are made more often on the Hannah diodesworking in the continuous mode. Abilities of such systems of a short range radar location can be expanded byconverting the generators in the pulse operating mode.In this case it becomes possible to measure not only thevelocity of objects, but and distance to them.According to the nominal data [2] to excite theHannah diodes 3А763АM it is required the generatorsof videopulses with positive polarity amplitude 5...6 V atthe output current 1,5...2 A. The standard generators ofvideopulse work as a rule for standard loading 50 Ohmand have a output voltage 1 V.The circuit diagram of the amplifier allowing to raise the output parameters of the standard generator ofpulse signals up to required values is shown on Fig. 1.The amplifier contains the input resistive divider ofvoltage, two cascades of amplification, the stable current generator, the control output.The resistive divider of voltage staying on the amplifier input and made on the resistors R1R3, ensures coordination of the amplifier with output resistance of thegenerator and stabilization of general negative feedbackdepth, covering the amplifier.In both cascades of the amplifier made on transistorsVT2 and VT4, it is applied active collector thermostabilization of rest currents [3]. The transistor rest currentsthemselves were chosen from the undistorted amplification of videopulses with pulse ratio changing from 10 upto ∞. For transistor VT2 the rest current is equal 70 mА,for VT4 – 300 mА that is found by selection of nominalof the resistors R5 and R12.During start of the generator on the Hannah diodeits resistance changes. To reduce influence of changingloading resistance the amplifier characteristics its output cascade is made by the circuit with the general collector, and the amplifier is covered with the general negative feedback consisting of elements R7, C8. As resultthe output resistance instant frequency of generation ofthe amplifier equal 0,4...0,6 Ohm is realized.It is known, that change temperature of Hannahdiode crystal results to change of the instant generationfrequency [4]. To reduce the named factor the stablecurrent generator on the transistor VT5, providing heating of the diode during the periods between arrival ofstart pulses is mounted in the amplifier. The stable current generator has limits of regulation 0,1...0,5 A.The control output (fig. 1) is foreseen in the amplifier, which allows to register amplitude of pulses givenon the Hannah diode. Diode VD1 is mounted for protection of the amplifier transistors against breakdown atUDC 621.375.026THE AMPLIFIER OF UNIPOLAR PULSES OF THE SHORT RANGE RADAR SYSTEMA.A. Titov, V.P. PushkarevTomsk State University of Control Systems and Radio ElectronicsEmail: titov_aa@rk.tusur.ruThe amplifier of videopulses intended for work as a source of a pulse feed of the Hannah diodes 3А763АM of the short range radar system is described. Characteristics of the amplifier are: coefficient of amplification 16 dB; the maximal amplitude of output pulses – 6 V;the maximal current in a pulse – 2,5 A.Bulletin of the Томsк Pоlyтеchnic University. 2006. V. 309. № 4136a wrong choice of feed voltage polarity. Diode VD2 isnecessary for restoration of a constant component onthe amplifier output.The photo of the amplifier explaining to feature ofits constructive realization is given on fig. 2.The amplifier has the following characteristics: amplification factor – 16 dB; input pulses polarity negative; output pulses polarity – positive; the maximal amplitude of output pulses – 6 V; the maximal pulsecurrent – 2,5 A; output resistance of the amplifier –0,4...0,6 Ohm; time of establishment of pulse front 5 ns;fall of flat top at pulse duration 500 ns no more than 3%; a feed voltage 12 V; duration of amplified pulses10...500 ns; pulses ratio – not less than 10; overall dimensions 80×79×30 mm.At pulse duration being 10 ns the system of a shortrange radiolocation allows to define distance to objectsfrom 1,5 m and more, at pulse duration being 500 ns speed of object movement is defined on distance up to 75 m.Fig. 1. The circuit diagram of the amplifierВход ВыходКонтрольныйвыход 1:10C1C2C4C7C6C10C11L1L2L3R1R2R3R4R6R5 R8R10R7R12 R13R15R21R18R19VT1VT2VT3VT4VT5VD22202205610 мк7500,33 мк2 кКТ315АКТ914А10 мГн200 104,7 мк4,7 мк4,7 мк22 мк33 мк2 к 390 4,3КТ361АКТ922БКТ914А8432,2 к+12 В20 мГн50КД509А10 мГн390R17504,7 мкC8R9110R141,1R11750VD1КД213АR16250R20360C347 мкC510 мкC94,7 мкC124 7 мк,Fig. 2. The photo of the amplifierLiterature1. Bakulev P.A., Stepin V.M. Methods and devices of selection of themoving targets. [in Russian]. – M.: Radio i svyaz, 1986. – 288 p.2. Semiconductor devices. Superhighfrequency diodes. Handbook[in Russian] / B.A. Nalivajko, A.S. Berlin, V.G. Bozhkov etc. Ed.B.A. Nalivajko. – Tomsk: MSE «RASCO», 1992. – 223 p.3. Titov A.A. Calculation of the active collector thermostabilizationcircuit and its use in amplifiers with automatic adjustment of consumed current. [in Russian]. // Electronic engineering. Ser. SHFtechnique. – 2001. – No 2. – P. 26–30.4. Tsarapkin D.P. SHFgenerators on Gahn diodes. [in Russian]. – M.:Radio i svyaz, 1982. – 112 p.

The amplifier of unipolar pulses of the short range radar system

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