This article examines Gaussian processes generated by monotonically modulating stationary kernels. An explicit isometry between the original and the modulated reproducing kernel Hilbert spaces is established, preserving eigenvalues and normalization. The expected number of zeros over the interval $[0,T]$ is shown to be exactly $\sqrt{-\ddot{K}(0)}(θ(T)-θ(0))$, where $\ddot{K}(0)$ is the second derivative of the kernel at zero and $θ$ is the modulating function.