Plate and grid modulated HF high-power tuned amplifier withincreased efficiency

The optimal design of a plate- and grid-modulated high-power tuned HF amplifier with increased efficiency is reported. The increased efficiency is achieved by introducing the third harmonic into the drive and output circuits. The analysis is carried out by applying a linear model of the constant plate current characteristics of an HF high-power triode. The initial CW (continuous-wave) working conditions are selected so that it is possible to realize a 100% modulation. Calculated values are presented graphically as functions of some relevant design parameters. A comparison is made with a tuned high-power amplifier without injection     

PSPICE analysis of HF high-power tuned amplifier and comparison torelated methods

Application of the PSPICE program for analyzing HF high-power tuned amplifier (HFHPTA) is described. The new method is compared to other known methods. Calculation results of the balance of power and the coefficient of efficiency, as well as the errors with reference to catalogue values are given for different methods of analysis     

MF-AM stereo broadcasting: the choice of modulation

Several AM stereo transmitting systems have been applied to local radio-broadcasting networks on the MF (medium-frequency) band in the US. These systems represent a certain compromise between two mutually contrary requirements: (i) that the broadcast spectrum be at the MF carrier within the determined boundaries (the channel occupancy criterion), and (ii) that the transmitted signal be compatible with MF-AM monaural receivers (the compatibility criterion). It is proved that a transmission system that perfectly satisfies both requirements does not exist. A modulation method called modified compatible quadrature amplitude modulation (MC-QAM) is proposed. The system has simpler circuitry and less distortion, and occupies, under many circumstances, a narrower frequency bandwidth. With slight modifications, existing receivers for C-QAM could be used for MC-QAM     

Synthesis of the general HF high power tuned amplifier model usingPSPICE package

Application of the PSPICE package for analysing the HF high-power tuned amplifier (HFHPTA) enables nonlinear active element modelling in the HFHPTA. The corresponding coefficients of the electronic tube model (for both triode and tetrode) in the HFHPTA are derived     

THE Drive-Wave Shape Influence on the Class C Tuned HF High-Power Amplifiers

The paper investigates the drive-wave shape influence on the performances of tuned HF high-power amplifiers. Using the linear model of high-power HF triode and changing the drive wave shape (cosine, triangular, trapezoidal and pulse) under the same conditions (conducting angle, drive level), the balance of power for the high efficiency design, representing the normalized maximum output power and the efficiency versus the conducting angle or other parameter, are compared.