IMAGE REJECTION MIXER, MULTIBAND GENERATOR, AND CASCADE-CONNECTED POLYPHASE FILTER

摘要

PROBLEM TO BE SOLVED: To suppress a higher harmonic component without impairing the phase orthogonality of a pair of complex signals.;SOLUTION: This polyphase filter is configured so that K pieces of filter circuits each of which comprises a resistor R and a capacitor C are connected so as to be rotated in phases at angles of +360/K degrees along a connecting direction. Since counterclockwise rotation is generated when an expression is given in terms of a complex plane, a notch is formed in a negative frequency region. A CR product is set so that a notch is formed in a specified frequency band to suppress a (4N+1)-order harmonic component. Since the polyphase filter has a symmetrical structure, an unbalanced component contained in an input signal is eliminated at a frequency that agrees with a pole determined by the CR product. This action improves the orthogonality.;COPYRIGHT: (C)2005,JPO&NCIPI