Investigation into Class E/F3 with Parallel Network

The system of equations for processes in the amplifier output network is analytically formulated. This system of equations considers parameters of resonant networks at higher harmonics. To calculate amplifier output network, the system of five equations was built for five unknowns, to which the condition of positive second voltage derivative at extremum of drain voltage was added. Two equations correspond to class E conditions, another two — quadrature waveforms at load and at additional resonant network. The last equation is the condition of extremum at the point near middle of drain voltage pulse. This system was solved using computer algebra program. The circuit elements and waveforms were calculated using the derived parameters. By choosing different parameters, it is possible to obtain various amplifier realizations, which will demonstrate features of different class F variants. The obtained amplifier parameters drain voltage and current waveforms were verified with calculated ones using the harmonic balance simulating software. The variant, which is closer to class E/F3 mode, was chosen to build an experimental amplifier prototype on frequency 2MHz using IRF530 MOSFET as a switch. The prototype was tested in the range of supply dc voltage up to 24V with the output power greater than 6W, while the amplifier efficiency was >80%. In the experiment, the ratio of peak drain voltage to dc supply voltage was measured to be 3.3 at the duty ratio 50%, unlike class E amplifier, where this value is around 3.65, and on practice, considering non-linear drain to source capacitance, it may achieve 4. The experimental second harmonic level amounted to be -20 dB relatively to fundamental, and the third one — 28.5 dB, which is due to an additional second harmonic filter. The paper results are useful for introduction of such circuits to practice.

Reduction of False Alarm Probability in the Measuring Node of the Hydroacoustic Monitoring System

The probability of a false alarm in the measuring unit of the hydroacoustic monitoring system can be reduced if the primary identification of the signal source is carried out. For this purpose, it is necessary to provide for the presence of noise portraits of targets in the database node. The signals from the pre-amplifier output of the measuring unit are compared with the signals stored in the database by calculating the standard deviation. The signal with the minimum deviation and its corresponding source are determined. Comparison of signals can be made by calculating the correlation function. This article presents the results of computer simulation of the primary classification unit of the measuring unit in the MATLAB&SIMULINK system. The compared signals are represented in the time domain

Идентификация источника сигнала в измерительном узле системы морского экологического и гидроакустического мониторинга

Вероятность ложной тревоги в измерительном узле системы морского экологического и гидроакустического мониторинга может быть снижена, если проводить первичную идентификацию источника сигнала. С этой целью необходимо предусмотреть наличие в составе узла базы данных шумовых портретов целей. Сигналы с выхода предварительного усилителя измерительного узла сравниваются с сигналами, хранящимися в базе данных, путём вычисления среднеквадратического отклонения. Определяется сигнал с минимальным отклонением и соответствующий ему источник. Сравнение сигналов может быть произведено и путём вычисления корреляционной функции. В данной статье приводятся результаты компьютерного моделирования блока первичной классификации измерительного узла в системе MATLAB AND SIMULINK. Сравниваемые сигналы представлены во временной области. Вероятность правильной идентификации может быть увеличена, если проводить сравнение спектров сигналов.The probability of a false alarm in the measuring unit of the marine environmental and hydroacoustic monitoring system can be reduced if the primary identification of the signal source is carried out. For this purpose, it is necessary to provide for the presence of noise portraits of targets in the database node. The signals from the pre-amplifier output of the measuring unit are compared with the signals stored in the database by calculating the standard deviation. The signal with the minimum deviation and its corresponding source are determined. Comparison of signals can be made by calculating the correlation function. This article presents the results of computer simulation of the primary classification unit of the measuring unit in the MATLAB AND SIMULINK system. The compared signals are represented in the time domain. The probability of correct identification can be increased by comparing the signal spectra.

AIR-COOLED 350 W X-BAND SOLID-STATE POWER AMPLIFIER

In this paper we present the results of the design and production of an air-cooled X-band solid-state power amplifier based on AlGaN/GaN/SiC Schottky FET. The power amplifier includes: preliminary power amplifier, output power amplifiers, set of secondary power supplies, digital control unit, monitoring system for the power amplifier performance, set of microwave power waveguide combiners.

Setup for the dynamic calibration of bridge amplifiers from DC up to 10 kHz

<p class="Abstract">Measurements of mechanical quantities are often carried out with transducers with a bridge output. The output signals are conditioned using bridge amplifiers. If dynamically changing quantities are going to be measured traceably, the bridge amplifier must be calibrated dynamically.</p>This paper describes a dynamic bridge amplifier calibration setup based on the new PTB dynamic bridge standard. The calibration is carried out by the synchronous sampling of the bridge amplifier output voltage and a reference signal provided by the calibrated dynamic bridge standard. The dynamic bridge standard enables calibrations in a frequency range from DC (static calibration) up to 10 kHz. An overview of the different measurement uncertainty contributions is given, and the first measurement results show good agreement with a previously established measurement setup.