What is an effect of excessive phase noise in an SDR receiver's master clock oscillator?
Why An oscillator with phase noise is not a pure tone; it has noise sidebands spread out on both sides of its nominal frequency. In a receiver, a strong signal on a nearby frequency mixes with those sidebands and lands right in the passband as broadband noise or hash, an effect called reciprocal mixing. The result is that the receiver's effective noise floor rises whenever a strong nearby signal is present, masking the weak signal you are trying to hear.
Watch out Frequency calibration depends on the oscillator's long-term accuracy and drift, not its short-term phase noise, and third-order intercept point is set by the non-linearity of mixers and amplifiers, not by clock purity.
Phase noise = reciprocal mixing: a strong neighbor plus a noisy clock puts noise right in your passband.