| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a digital modulator which can omit regulation of DC offset voltage when regulation of amplification degree of an amplifier which amplifies a baseband signal input to an orthogonal modulator without damaging a function to obtain non-modulation output. <P>SOLUTION: Switches SW1 and SW2 are connected between respective input terminals of amplifiers 13Bi and 13Bq which compose a final stage of a driving circuit and ground, for a connection between input terminals of an initial stage of a driving circuit 13 which is installed in an early stage of an orthogonal modulator 14 in order to amplify baseband signals Si and Sq and a circuit of its preceding stage, and interstage connections in the driving circuit 13 as AC connections. By closing the SW1 and the SW2, direct voltage is impressed from the amplifiers 13Bi and 13Bq to the orthogonal modulator 14, and the non-modulated output is generated. <P>COPYRIGHT: (C)2007,JPO&INPIT |
