Two-point modulation type phase modulation apparatus, polar modulation transmission apparatus, wireless transmission apparatus and wireless communication apparatus

摘要

There provides a two-point modulation phase modulation apparatus capable of obtaining an RF phase modulation signal of superior modulation precision with low power consumption and a simple configuration even in the event of inputting a wide band baseband modulation signal. A differentiator ( 21 ) of the opposite characteristics to the attenuation characteristics of anti-alias filter ( 22 ) is provided at the front stage of a D/A converter ( 6 ). As a result, it is possible to sufficiently suppress an alias signal without raising the sampling frequency of the D/A converter ( 6 ) (i.e. low power consumption) using an anti-alias filter ( 22 ) of a simple configuration (i.e. low cost) with a low order for a narrower bandwidth than a PLL modulation frequency bandwidth, and it is possible to obtain an RF phase modulation signal where the entire frequency band of input digital baseband modulation signal (S 1 ) is reflected in a superior manner.