Leeson's equation
Leeson's equation is an expression that describes an oscillator's phase noise spectrum.
Leeson's expression for single-sideband (SSB) phase noise in dBc/Hz (decibels relative to output level per Hertz) is
-
![L(f_m) = 10 log igg[ frac{1}{2} igg( igg(frac{f_0}{2 Q_l f_m}igg)^2 + 1igg)igg(frac{f_c}{f_m} + 1igg)igg(frac{FkT}{P_s}igg) igg]](http://upload.wikimedia.org/wikipedia/en/math/1/9/2/19223781dfc729d27b160011fb43884d.png)
- where f0 is the output frequency, Ql is the loaded Q, fm is the offset from the output frequency (Hz), fc is the 1/f corner frequency, F is the noise factor of the amplifier, k is Boltzmann's constant, T is absolute temperature in Kelvins, and Ps is the oscillator output power.
