Quadrature modulation apparatus, radio transmission apparatus using quadrature modulation apparatus and quadrature modulation method

摘要

The fundamental waves and 3rd harmonics waves of two local signals output from a 90 phase shifter are suppressed by use of low-pass filters. The local signals in which the fundamental waves and 3rd harmonics waves are suppressed are respectively supplied to two multipliers and respectively multiplied by Ich and Qch base-band signals. The results of multiplication in the two multipliers are added together in an adder to create a modulation signal