| 摘要 |
PURPOSE:To cancel interference wave signals completely by allowing a space diversity radio receiver to perform AGC over a main and a subordinate side intermediate frequency amplifier with a higher level between their detection outputs. CONSTITUTION:When the output level of a main side detector 9 is higher than the output level of a subordinate side detector 19, the current of a transistor TrT-1 is smaller than that of a TrT-2, and then the potential at a point (a) rises above the potential at a point (b) and the voltage across a resistance R1 equals the potential at the point (a). This voltage is amplified by a DC amplifier 24 and supplied to variable attenuators 3 and 13 to perform AGC operation, and circuits of an antenna 1 (main side) and an antenna 11 (subordinate side) become equal in gain. Therefore, main wave signals and interference signals inputted to the antennas 1 and 11 are amplified with the same gain, and the phases of the interference wave signals are adjusted by an infinite phase shifter 21 so that they cancel each other, thereby canceling the interference waves completely. |
