Patent ID: 7423460

Claim:
Apparatus for generating a sine wave shaped output signal at an output, said apparatus comprising a first transistor and a second transistor being arranged as differential pair having two input nodes, circuitry for producing a triangular input signal with a given amplitude, the triangular input signal being applied between a gate of the first transistor and a gate of the second transistor, said differential pair having a node where a source of the first transistor and a source of the second transistor are connected, the sine wave shaped signal being provided between a drain of the first transistor and a drain of the second transistor, and a current mirror for feeding a predefined tail current into the node of said differential pair, said differential pair being biased to cause the first transistor and the second transistor to be operated in the saturation region such that the sine wave shaped output signal is a nonlinear function of the triangular input signal, wherein a capacitor is situated between the drain of the first transistor and the drain of the second transistor in order to suppress high-order harmonics present in the sine wave shaped output signal.