| 摘要 |
<p>PROBLEM TO BE SOLVED: To simply mount a directive antenna system on a radio unit not adopting an adaptive array antenna without the need for any revamping of the radio unit. SOLUTION: Each of frequency converters 15 converts each of reception signals received by antenna elements 13, each of A/D converters 16 converts the converted signal into a digital signal and gives the digital signal to a digital signal processing section 17. The digital signal processing section 17 provides weighting to the amplitude and the phase of each signal so that the directivity can optimally be controlled. Each of D/A converters 18 converts each weighted signal from the digital signal processing section 17 into an analog signal, an adder 19 sums the signals, a frequency converter 20 converts the sum into a signal with the frequency of the original received signal by each antenna element and gives the converted signal to an antenna terminal 122 of an existing radio unit 12.</p> |
