Tunable CMOS current-mode sinusoidal oscillator with inherent automatic amplitude control

A high frequency CMOS current-mode sinusoidal oscillator is proposed which uses the difference between the output currents of two simple unequal bandwidth lowpass filters to obtain a frequency selective bandpass function. High oscillation frequencies are possible since the signal currents pass through only NMOS transistors. Both the gains and the limiting of the amplitudes of the oscillating currents are inherent in the lowpass units without using any extra transistors