A phase locked loop, PLL, frequency generator circuit , comprising: an oscillator circuit , said oscillator circuit comprising: a pair of transistors (M 1 , M 2 ) whose drain terminals are coupled to a first LC tank consisting of a primary winding of a transformer and a tunable switched capacitor bank (C P 122), and whose gate terminals are coupled to a second LC tank consisting of a secondary winding of the transformer and a tunable switched capacitor bank (Cs 125), the oscillator circuit being operative to generate a feedforward signal at said drain terminals containing a fundamental frequency component and a third harmonic frequency component; said oscillator circuit being operative to generate a second output feedback signal at said gate terminals containing substantially only said fundamental frequency component, characterized in that said feedback signal is utilized for purposes of phase detection in the PLL frequency generator circuit; and further characterized in that said oscillator circuit comprises an active fundamental cancellation circuit comprising a buffer for scaling a signal provided from said gate nodes and a combiner (M 3 , M 4 ) for combining the scaled signal with a signal provided from said drain terminals thereby canceling the fundamental frequency component resulting in an output signal containing substantially only said third harmonic frequency component. an oscillator circuit , said oscillator circuit comprising: a pair of transistors (M 1 , M 2 ) whose drain terminals are coupled to a first LC tank consisting of a primary winding of a transformer and a tunable switched capacitor bank (C P 122), and whose gate terminals are coupled to a second LC tank consisting of a secondary winding of the transformer and a tunable switched capacitor bank (Cs 125), the oscillator circuit being operative to generate a feedforward signal at said drain terminals containing a fundamental frequency component and a third harmonic frequency component; a pair of transistors (M 1 , M 2 ) whose drain terminals are coupled to a first LC tank consisting of a primary winding of a transformer and a tunable switched capacitor bank (C P 122), and whose gate terminals are coupled to a second LC tank consisting of a secondary winding of the transformer and a tunable switched capacitor bank (Cs 125), the oscillator circuit being operative to generate a feedforward signal at said drain terminals containing a fundamental frequency component and a third harmonic frequency component; said oscillator circuit being operative to generate a second output feedback signal at said gate terminals containing substantially only said fundamental frequency component, characterized in that said feedback signal is utilized for purposes of phase detection in the PLL frequency generator circuit; and further characterized in that said oscillator circuit comprises an active fundamental cancellation circuit comprising a buffer for scaling a signal provided from said gate nodes and a combiner (M 3 , M 4 ) for combining the scaled signal with a signal provided from said drain terminals thereby canceling the fundamental frequency component resulting in an output signal containing substantially only said third harmonic frequency component. <EOS>