the noise being essentially proportional to the inverse of the frequency, i.e. the so-called 1/f noise

Full Title

Aspects of oscillators relating to reduction of undesired oscillations > Reduction of undesired oscillations originated from natural noise of the circuit elements of the oscillator > the noise being coloured noise, i.e. frequency dependent noise > the noise being essentially proportional to the inverse of the frequency, i.e. the so-called 1/f noise