Patent attributes
An apparatus and method to decompose measured phase jitter into a deterministic component and a random component. After filtering a time-domain measured phase jitter signal, a discrete Fourier transform is applied, followed by squaring. A density function is formed from the square of the discrete Fourier transform, from which a noise floor is estimated. The frequency-domain phase jitter is processed by zeroing out those frequency components having a magnitude equal to or less than the noise floor, and the remaining frequency components are processed by subtracting out a pseudo-random sequence having a magnitude equal to the noise floor and having a uniformly distributed phase. This processing provides an estimate of the deterministic component in the frequency domain, and an inverse discrete Fourier transform may be applied to transform into the time domain to yield an estimate of the deterministic component of the phase jitter in the time domain.
