| 摘要 |
PURPOSE:To attain calibration independently of the meteorological condition without using an external device by distributing two frequencies of local signals into two and using one as a pseudo signal. CONSTITUTION:A local signal generating section 10 generates either two frequencies (fR+ or -1/2fIF) being the sum and difference between a received signal frequency and a half the frequency of the intermediate frequency or a difference signal (fR-fIF) between the received signal frequency and the intermediate frequency. A switch 2 of each reception unit 8 is thrown to the position C at the calibration, the two frequency signals (fR+ or -1/2fIP) generated by the local signal generating section 10 are converted into an intermediate frequency fIP by a frequency converter 4, and the resulting signal is detected by a reception section and A/D-converted and sent to a digital beam shaping device 9 as a calibration signal Ci. Thus, the calibration signal generated in the inside of the device is injected in the inside of the device in this way, then no external device is required and the calibration is attained independently of the meteorological condition. |
