This repository contains two closely related papers (Version 1 and Version 2) that develop and extend a harmonic analysis of the Collatz problem based on the statistical structure of odd–even step ratios across consecutive starting values. Version 1 introduces the odd-ratio observable and demonstrates that its centered sequence exhibits strong, reproducible harmonic structure when analyzed via discrete Fourier methods. In particular, dominant spectral peaks appear at frequencies related to logarithmic functions of the golden ratio, revealing an unexpected and highly structured “Top Wave” governing the distribution of Collatz trajectories. Version 2 builds upon this foundation by refining the statistical analysis, expanding the numerical range, and exploring additional structural consequences of the observed harmonics. Together, the two papers establish a deterministic, arithmetic framework for understanding large-scale regularities in Collatz dynamics without invoking probabilistic assumptions or heuristic randomness models. These works form the mathematical and empirical basis that align with other developments, including the Trinity framework and phase- and geometry-based analyses. They are presented here together to preserve chronological priority, methodological clarity, and reproducibility. All results are derived from explicit computation and are fully reproducible. The full python validation suite from the Trinity Framework is also included. For further information about the ENSO Framework, please contact Eric Needham: ensotheory1@gmail.com