Regarding white (uncorrelated) and coloured (correlated) timing jitter. I know that for free-running oscillators (such as VCOs), various kinds of noise causes the jitter, for example (1/f) coloured noise and white noise...As a result, the jitter is expected to be coloured in oscillators because the phase noise power spectral density will have regions of (1/f^3) and (1/f^2) due to (1/f) and white noise respectively.
However, I am wondering if the timing jitter at the output of PLL is white or coloured?
From one perspective, I can say that PLL acts as a lowpass filter, so it filters out the jitter, as a result: the white jitter becomes coloured. Therefore, we always expect to see coloured timing jitter at the output of PLL.
From another perspective, I can say that PLL is intended to reduce the jitter, so we end up with white timing jitter due to white noise (which is always there). Therefore we expect to see white timing jitter at the output of PLL.
Could you please help me to know if the jitter at the output of PLL is white or coloured?