Patent ID: 7099646

Claim:
A single-ended-to-differential mixer, comprising: a differential input circuit, wherein the differential input circuit is configured to receive a single-ended input signal, wherein the differential input circuit comprises: a first transistor and a second transistor configured as a differential amplifier to convert the single-ended input signal from a voltage signal to first and second current signals; and a first cancellation circuit and a second cancellation circuit, wherein the first cancellation circuit comprises a third transistor, wherein an emitter of the third transistor is in communication with a base of the third transistor, wherein the second cancellation circuit comprises a fourth transistor, wherein an emitter of the fourth transistor is in communication with a base of the fourth transistor, wherein the first and second cancellation circuits are configured to receive the single-ended input signal, wherein collectors of the first and second cancellation circuits are in cross-communication with collectors of the differential amplifier of the differential input circuit, and wherein the first and second cancellation circuits cancel non-linear capacitance associated with the differential amplifier; a tank circuit, wherein the tank circuit comprises: an inductor; and a tuning capacitor arranged in parallel with the inductor, wherein a resonant frequency of the inductor and tuning capacitor is substantially centered around a predetermined frequency of the single-ended input signal, wherein the tank circuit is in communication between a ground and common emitters of the differential amplifier of the differential input circuit, and wherein the tank circuit is configured as a passive current source; and a mixer circuit, wherein the mixer circuit is in communication with the differential input circuit and configured to receive the first and second current signals, wherein the mixer circuit is configured to receive a second input signal, and wherein the mixer circuit is configured as a Gilbert cell double-balanced switching mixer for generating a differential mixer output signal as a product of the first and second current signals and the second input signal.