deba

Hi,
The phase noise L(f) is defined as L(f) = Power in 1 Hz at offset (Fo+f)/Power of fundamental(Fo). This equation is in Voltage domain. If one consider small angle approximation for phase than, L(f) = Sphi(f)/2, where Sphi(f) is the single sided PSD of phase. Under what conditions, L(f) is not equal to Sphi(f)/2. In other words, if a voltage spectrum of clock is given, in which region does one can apply L(f)=Sphi(f)/2?
Thanks
