| 摘要 |
PROBLEM TO BE SOLVED: To obtain a desired signal by allowing a multi-beam forming device to synthesize digital signals from an A/D converter with a weight and adjusting a directivity gain through digital signal processing so as to simply control a reception level of a beam thereby avoiding interference between signals. SOLUTION: A signal received by an element antenna 1 is properly frequency- converted and the result is given to a A/D converter 2, where the signal is converted into a digital signal. A multi-beam forming device 3 generates a multi-beam including number of required beams retrieved from number of channels in the interior of the service area. Correlation devices 4 whose number is equal to the number of the beams apply correlation processing to the beams according to each assigned code. A threshold discrimination circuit 5 connects only beam terminals at which a power of a certain level or over is obtained through the correlation processing to a next stage demodulator 6. Thus, interference between signals is reduced by controlling simply the reception level of each beam and evaluating each beam independently and a desired signal is detected. |
