Shifting of frequency range and bandwidth of receivers using a mixer attenuating the image frequency

摘要

The circuit arrangement utilizes both outputs of a mixer attenuating the image frequency, whereby one of the desired frequency bands is obtained from a “signal port” and the other desired frequency band from the “port of the image signal”. Thus a desired intermediate frequency signal band (IF) corresponding to the radio frequency Input signal (RF) can be selected using a switch (24), the intermediate frequency signal band (IF) being filtered by an intermediate frequency filter (20, 22). The frequency (LO) of the local oscillator is selected to be in the middle of the radio bands (RF).