Patent ID: 7389098
Filing Date: 2008-06-17
Classification: H04B

Abstract:
1. A heterodyne receiver for low noise and image frequency repression, comprising: a low noise amplifier for receiving an input signal from an antenna and amplifying the signal while reducing a noise figure of the input signal; and a frequency converter for receiving both the input signal outputted from the low noise amplifier and a local oscillation signal, filtering the signals to repress gain of the input signal at an image frequency band and to increase gain of the input signal at a signal frequency band, and converting the frequency of the signals to an intermediate frequency band; wherein the frequency converter comprises a local oscillation circuit for outputting a local oscillation signal being used for converting the frequency of the input signal; and a mixer circuit for converting the difference in frequency between the input signal outputted from the low noise amplifier and the local oscillation signal outputted from the local oscillation circuit to a predetermined intermediate frequency through a filtering process for image frequency repression and low noise; and wherein the mixer circuit comprises a drive for receiving the input signal outputted from the amplifier and the local oscillation signal outputted from the local oscillation circuit and performing a filtering operation on the signals for image frequency repression; a switch for switching the input signal and the local oscillation signal outputted from the drive over time; and an intermediate output section for outputting the intermediate signal converted from the input signal and the local oscillation signal by using a switching operation of the switch.