Patent ID: 6529721
Filing Date: 2003-03-04
Classification: H03D

Abstract:
A mixer circuit having a single-ended radio frequency input and an intermediate frequency output, comprising:a transistor having a base that receives the radio frequency input, a collector, and a common emitter; a transformer having a primary winding and first and second secondary windings, and said primary winding having a first end coupled to said collector and a second end coupled to ground through an element having an impedance; an electrical connection that couples the primary winding to the secondary windings such that DC current flowing through the electrical connection contributes to DC current flowing through said collector; and a first transistor pair and a second transistor pair, each transistor pair having a first and second transistor, and each transistor having a base, a collector and an emitter, the emitters of the first transistor pair coupled together and to the first secondary winding of the transformer, the emitters of the second transistor pair coupled together and to the second secondary winding of the transformer, the base of the first transistor of the first pair coupled to the base of the first transistor of the second pair, and said bases coupled to a local oscillating input; the base of the second transistor of the first pair coupled to the base of the second transistor of the second pair, and said bases coupled to a reversed local oscillating input; the collector of the first transistor of the first pair coupled to the collector of the second transistor of the second pair, said collectors providing a first intermediate signal output; and the collector of the second transistor of the first pair coupled to the collector of the first transistor of the second pair, said collectors providing a second intermediate signal output.