Sorry if this is basic questions but I am new to jitter and phase noise.

If something is specified with jitter value, then the jitter is the same for any frequency? But if phase noise is specified, then it change with frequency and also quoted offset.

If I have 80dbc/Hz phase noise at 10kHz offset at 1G, if I divide that clock by two to 500M, what happens to the phase noise, is it increase by 3dB? So to find out acceptable phase noise at different frequency, I just scale the figure by the change in frequency?

Also can I work out phase noise at different offset too?

Thanks for helping.