The Significance of 1/f Noise

Due to their broadband spectral distribution, thermal and shot noise contribute to the circuit noise figure. The circuit (in terms of bias, gain, matching networks, etc.) is usually optimized to minimize or lower the noise figure.

Although the 1/f noise is generated at low frequencies, its contribution to the overall noise can be very significant to some RF circuits since its spectral power density is up converted in the band of interest by circuit nonlinearities. This is especially true in mixers and oscillators.