A system comprises a noise generator circuit and a noise envelope detector circuit. The noise generator circuit comprises a first amplifier including a single transistor pair that is operable to generate 1/f noise, an output amplifier coupled to the first amplifier and configured to generate a 1/f noise signal as a function of the 1/f noise. The noise envelope detector circuit comprises a low pass filter operable to pass low frequency signals of the 1/f noise signal as a filtered 1/f noise signal, and a second amplifier or a comparator coupled to the low pass filter and operable to output a direct current (DC) voltage signal according to an envelope of the filtered 1/f noise signal, where the DC voltage signal is a function of an envelope of the filtered 1/f noise signal.