Research Information System
INTERNATIONAL JOURNAL OF ELECTRONICS, vol.100, no.1, pp.72-93, 2013 (SCI-Expanded, Scopus)
This article reviews the development and applications of harmonic injection technique. It discusses the impact of second harmonic injection on the linearity and linear gain of amplifiers. It reveals that amplifier characteristics and input drive level determine whether second harmonic injection enhances or reduces the linear gain of an amplifier. Furthermore, a method has been developed to predict this behaviour which can be used to identify amplifiers that are best suited to harmonic injection or build amplifiers that may particularly be used with harmonic injection. For experimental investigation, a second harmonic injected amplifier was used that employs a frequency-doubler. In laboratory experiments, third-order intermodulation distortion was suppressed by 18?dB at the expense of 0.7?dB linear gain whereas theoretical analysis has predicted that second harmonic injection could compromise the linear gain of the amplifier by up to 1.3?dB for 20?dB distortion suppression.