Patent ID: 6178320
Filing Date: 2001-01-23
Classification: H03D

Abstract:
A radio receiver comprising means for receiving an input signal, local oscillator signal generating means and a frequency down conversion stage having a first input for connection to the means for receiving an input signal, a second input for receiving a local oscillator signal and an output for a frequency down-converted signal, the frequency down conversion stage including a mixer circuit comprising first, second, third and fourth transistors of the same conductivity type, emitter electrodes of the first and second transistors and of the third and fourth transistors, respectively, being coupled together to define first and second emitter junctions, collector electrodes of the first and third transistors and of the second and fourth transistors being connected to respective first and second output junctions, base electrodes of the first and fourth transistors and of the second and third transistors being coupled to respective first and second local oscillator junctions, first and second local oscillator inputs coupled to the first and second local oscillator junctions, respectively, first and second means for providing substantially identical currents to the first and second emitter junctions, first and second signal input terminals coupled to current paths between said first and second current providing means and the first and second emitter junctions, respectively, and signal damping elements coupled respectively between the first and second local oscillator inputs and the first and second local oscillator junctions and between the first and second signal input terminals and the first and second emitter junctions.