Comments on "Oscillator with Odd-symmetry characteristics Eliminates Low-Frequency Noise Sidebands

The subject paper [1] concluded that the elimination of even-ordered nonlinearity in an oscillating system would prevent the transfer, of low-frequency flicker noise up to the oscillation frequency zone. This communication is a response prompted by the question: if such a simple expedient as achieving odd symmetry in an oscillator can eliminate phase noise, why is it that all oscillators are to some degree corrupted by flicker noise? The significance of the experimental method employed in [1] to demonstrate the desirability of achieving odd symmetry is questioned. Finally, some additional factors relating to oscillator flicker phase noise generation are considered.