Distinguishing Clock and Ephemeris Errors from a Gravitational Background

This paper asks a single question: How easily can a monopolar clock error or a dipolar ephemeris error be mistaken for, or hide, the quadrupolar background correlation? Working from the published common-process amplitude of 2.4e-15 in characteristic strain at one cycle per year and the standard binary spectral index of thirteen thirds, the study computes the relevant quantities by projection of monopole, dipole and Hellings-Downs patterns onto one another over a finite pulsar sky. The headline computed values are hd_at_90deg = -0.14486038541995894, pair_noise = 0.0554334821152392. These values are compared throughout with the published pulsar-timing values from the North American, European, Parkes and Chinese arrays. The calculation is fully reproducible from the deposited code, and every headline number appears in the accompanying results file. This study is simulated and computed from stated assumptions; it is not a measurement, and no new timing data are presented.