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Linearization is a critical process in communications, especially as the demand to transmit more data over limited spectrum grows. The rate of information per hertz is heavily influenced by signal distortion, so linearization is of particular concern at frequencies below 1 GHz, where bandwidth is scarce.

Power amplifiers (PAs) are most efficient – but least linear – when they operate near saturation; reducing the output power can improve linearity, but at the cost of efficiency. To achieve linear power, operators can either use a large amplifier and reduce (“back off”) its output power, or employ a smaller amplifier coupled with a linearizer (known colloquially as a “lin”). This latter option provides better efficiency and a smaller footprint for the same level of distortion and linear output power, making it a more attractive solution.

For narrow bandwidths numbering in the megahertz, digital predistortion linearization (DPDL) provides excellent distortion correction; however, DPDL requires significant computer processing power and DC power that can incur substantial cost, especially at higher frequencies. Analog predistortion linearization (APDL) offers instantaneous bandwidths of greater than 10 GHz and has been implemented at operating frequencies up to 100 GHz. Furthermore, APDL systems typically offer lower complexity, a smaller footprint, and lower power consumption than comparable DPDL systems.

MACOM Linearizers represent the state-of-the-art of APDL and act as complete front-end mini-systems that not only linearize but also act as driver amplifiers and equalizers for PAs. MACOM Linearizers include controls for predistortion input drive, predistortion shape and phase adjustment, output level control and output limiting. These controls allow for the maintenance of consistent performance over temperature, mission life, PA saturation point or position in a phased array; they may be made available to the customer via analog or digital inputs, or the adjustments may be pre-determined at MACOM and stored in an on-board microprocessor for set-and-forget operation.

As data transmission rates continue to climb, the importance of efficient and effective linearization grows, and the benefits of linearization become more pronounced as PA RF power increases. Linearizers can significantly reduce the size, cost and complexity of amplification systems, making them an essential component in modern communications systems that prioritize efficiency and resource-conscious design.