| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize a digital modulator and its modulation control method, in which the delay time difference between each IF signal of each transmission wave between an active transmitter and a reserved transmitter is readily measured and no delay time difference is generated in the transmission wave, even if the active transmitter is switched to the reserved transmitter. <P>SOLUTION: Transmission waves from two transmitters 1A and 1B are measured using a phase comparator 4, the phases of the two transmission waves are aligned, when there is the delay time difference between each IF signal included in the transmission waves from the two transmitters 1A and 1B, pulse-like noise, generated in a phase difference error signal between each transmission wave measured by the phase comparator 4, is detected; and the delay time difference between each IF signal is minimized by adjusting a variably delay line 15 so that the pulse-like noise is minimized. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
