Use phase-noise spot or mask limits when particular carrier offsets control reciprocal mixing, Doppler, EVM or close-channel behavior; use integrated jitter when a defined offset band must close a time-domain sampling or timing budget. Neither is complete without carrier frequency, operating mode, offset or integration range, and treatment of deterministic spurs.
Reject a comparison that quotes -dBc/Hz at one favorable offset or an RMS jitter number without lower and upper integration limits. For multiplication by N, reference phase fluctuations rise by roughly 20 log10(N) in the region where the reference dominates. For jitter, integrate the linear phase-noise density over the project band, include or separately budget discrete spurs, then convert RMS phase deviation to time using carrier frequency.
Required inputs are carrier and output state, the system bandwidth or coherent observation time, critical offset regions, modulation or sampling frequency, allowed error, and source architecture. Verify the full mask, the instrument residual floor and the exact integration settings; one number cannot be reused across RF carriers or different integration bands without recalculation.