Comparison of AM and FM Reticle Systems

Abstract

The characteristics of both AM and FM tracking reticles are described and compared quantitatively. The space spectra of target and reticle are discussed. Expressions for the signal-to-noise ratio for both the large signal case and the small signal case are developed for both AM and FM systems. The relation of the error in the determination of the target azimuth to the S/N ratio is given. A comparison of the results for the two systems is presented. The results of the analysis are applied to a system utilizing a PbTe cell.