| 摘要 |
PURPOSE:To receive a desired radio wave with the influence of a ghost radio wave by electrically varying the directivity of an antenna through the adjustment of a phase shifter. CONSTITUTION:An output difference between antennas 1 and 2 is extracted by 1st mixer 5 and an output difference between antennas 3 and 4 is extracted by 2nd mixer 6 and inputted to phase shifter 7. Then, 3rd mixer 8 extracts an output difference between 1st mixer 5 and phase shifter 7 and outputs only the ghost component. Next, the phase-shifting value of phase shifter 7 is controlled by saw- tooth wave generating circuit 16, for example, so that this ghost component will be at the lowest level. Then, the functions of 1st mixer 5 and 2nd mixer 6 are changed from subtraction to addition and an antenna output is obtained from 3rd mixer 8. |
