An Experimental Investigation of the Reduction of Nonlinear Effects Using Passive Compensating Networks.

摘要

This report describes an experimental investigation to determine if a procedure reported upon for reducing third order Intermodulation Products (IMP's) in an RF amplifier stage could be implemented in the laboratory. The third order IMP reduction procedure is based upon altering the RF amplifier linear out-of-band response by adding passive compensating networks. For this experiment, an RF amplifier tuned at 10 MHz was selected. The RF amplifier was excited by two CW signals at frequencies f1 = 9.0 MHz and f2 = 9.5 MHz in order to obtain a third order IMP at the frequency 2f2 - f1 = 10 MHz. The objective of the experiment was to determine if a significant reduction in this third order IMP could be obtained by connecting properly designed compensating networks to the basic RF amplifier stage. A linear model for the basic RF amplifier stage was developed. This model yielded calculated results that were in relatively good agreement with measured results for the magnitude and phase of the linear transfer function VOUT/VIN. Using the linear model for the basic amplifier stage, compensating networks were synthesized.