Patent ID: 8185067
Filing Date: 2012-05-22
Classification: H03C

Abstract:
1. A modulation circuit for use in a radiofrequency transmitter, said modulation circuit comprising: a local oscillator circuit configured to generate one or more local oscillator signals at a desired frequency and with a duty cycle at or about twenty-five percent; and a modulator configured to generate one or more modulated signals responsive to the one or more local oscillator signals and one or more baseband information signals; wherein the modulator comprises one or more transconductance transistors driven by the one or more baseband information signals and one or more switching transistors driven by the one or more local oscillator signals; wherein the one or more transconductance transistors each comprises a transistor having a base or gate driven by one of the one or more baseband information signals, a collector or drain coupled to a load circuit, and an emitter or source coupled to a transconductance element, and wherein the one or more switching transistors each comprises a transistor having a base or gate driven by one of the one or more local oscillator signals, a collector or drain coupled to one of the transconductance elements, and an emitter or source coupled to a signal ground.