| 摘要 |
PURPOSE:To reduce deterioration due to adjacent channel interference by detecting reception state deterioration and controlling the signal of that time by disconnection, amplitude limitation, or interpolation and also utilizing it for the logic of a selection of a diversity branch. CONSTITUTION:A signal received by a receiver 2 through an antenna 1 is sent to a reception state deterioration detector 7 through a frequency detector 3. The detector 7 detects the deterioration from the absolute value of an FM- demodulated signal as the output of an (a) detector 3 after it passes through a low-pass filter, the electric power of a (b) FM-modulated signal after it passes through a band-pass filter, the absolute value of the time differentiated value of a (c) FM-demodulated signal, or a combination of >=2 of them. The output of is sent to a means 80 which consists of a means 801 for determining a threshold value and a comparator 802 and controls a switch. The output of the means 80 is sent to the switch 4 and when the reception state deteriorates, the current received signal is disconnected to remove interference noises. |
