| 摘要 |
PROBLEM TO BE SOLVED: To obtain the transmitter by which digital signal processing is executed with high accuracy in addition to miniaturization and cost reduction. SOLUTION: A transmission signal generated by a digital signal processing section 31 is given to D/A converters 321, 322, in which the signal is converted into an analog signal. Based on a reference frequency oscillated by a reference frequency oscillator 331, a 1st PLL 341 generates a 1st carrier and an orthogonal modulator 251 converts the analog signal directly into a signal at a transmission frequency band. The modulated wave is amplified by an amplifier 391 and outputted via a directional coupler 392. Part of the signal is mixed with a 2nd carrier generated in a 2nd PLL 343 based on a reference frequency oscillated by the reference frequency oscillator 331 and converted directly into signal at a low frequency band. Thus, an intermediate frequency stage is omitted, miniaturization and cost reduction are attained and the accuracy of signal processing is improved. |
