THE COMPUTER MODELING OF CLASS -D AND -DE SWITCHING-MODE POWER AMPLIFIERS FOR VHF DIGITAL RADIO BROADCAST EQUIPMENT

Abstract

Currently the transition to digital VHF radio broadcasting is being discussed more and more in different countries, which requires the design of new radio broadcast equipment devices. In classical method of amplifying the power of complex radio signals with a variable envelope, the new broadcast equipment will lose significantly to the existing broadcast equipment with frequency-modulated signal in many energy parameters. The most the promising ways to build high-efficiency broadcast equipment devices of complex radio signals with amplitude-phase modulation and high peak-factor are synthetic methods of linear amplification of radio frequency power (for example, basing on the scheme of L. Kahn) by using high-efficiency switching-mode circuits of powerful amplification. The present state of development of powerful radio-frequency transistors allows to assume that in the near future in the VHF-band switching-mode power amplifiers of Class -D and -F, which will be suitable for building digital radio broadcast equipment with the polar architecture of L. Kahn, will be everywhere used. These switching-mode amplifiers, in contrast to higher-frequency Class-E circuits, supply more steady characteristics in the frequency band. But when developing such broadcast equipment, it is also reasonable to deal with modified switching-mode power amplifiers of the Class -DE and -FE. The article deals with the questions of the computer modeling of switching- mode power amplifiers of Class -D and -DE in relation to the design of VHF radio broadcast equipment.