| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio transmitter which, thanks to the improved phase noise performance of a local oscillator, can greatly reduce an adjacent channel leakage signal included in the transmitted signal. <P>SOLUTION: A radio transmitter comprises: a data signal generation circuit which outputs a digital data signal; a digital/analog conversion circuit which, after converting the digital data signal from digital to analog, outputs an intermediate frequency IF signal; and an orthogonal mixer circuit which, after mixing the IF signal and a local signal output from a local oscillator together, outputs a radio frequency RF transmission signal. The data signal generation circuit is composed to output such a digital data signal that the frequency of the IF signal output from the digital/analog conversion circuit is switched according to a transmission channel. The local oscillator is composed to switch between local signals at frequency intervals n times the channel frequency interval of the RF transmission signal (n=integer equal to or greater than 3) before outputting the local signals. <P>COPYRIGHT: (C)2013,JPO&INPIT |
