Pre-distortion linearizer for high power amplifiers for land-based satellite stations

• Grant number: 99/06432-0
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• Start date: October 01, 1999
• End date: November 30, 2006
• Field of knowledge: Engineering - Electrical Engineering - Telecommunications
• Principal Investigator: Wilton José Fleming
• Grantee: Wilton José Fleming
• Company: Beta Telecom Consultoria e Comércio Ltda
• City: São José dos Campos

Abstract

The present work is designed to investigate the so-called pre-distortion linearizers, used in satellite communication systems. Initially, a solution for Cband satellite communication will be investigated, and subsequently, the possibility of using it in Kuband will be assessed. The pre-distortion linearizer creates a transfer function, which is opposed, from the standpoint of distortion, to that of the amplifier to be linearized. Among its main characteristics are broadband operation and the ability to operate regardless of internal alterations to the amplifier. Development of the technology of digital modulation and compression circuits enables (and even demands) that various carriers be transmitted in the same waveband previously occupied by a single carrier in satellite communications systems. The linear nature of the amplifiers is a predominant factor in avoiding interference with these signals and services. In satellite communication technology, the use of special valves is required. In this case, depending on the desired transmission power, there is no similar solid state valve, or when it exists (for low power), it is very high-priced. To solve the problem of the linear structure, manufacturers have adopted the system of making the power amplifiers (HPAs) run at substantially below their maximum power output. This condition is called back-off and, although technically correct, its cost is high. The solution to this type of problem is to introduce a linearizer, the purpose of which is to compensate for the intrinsic non-linear nature of the HPA gain and phase. (AU)