| 摘要 |
PURPOSE:To simplify the constitution of a connecting circuit without cutting off a transmission line and to eliminate assuredly the impulsive noise, by providing a noise blanker containing a noise amplifying circuit, a noise wave detecting circuit and a switch circuit to the transmission line of a signal receiver. CONSTITUTION:The desired wave S to be modulated and the impulsive noise N are amplified by a high frequency amplifying circuit 2 via an antenna 1 and then converted into an IF signal through a frequency converting circuit 5 to be transmitted to a transmission line 17. The IF signal of the line 17 is applied to a band pass filter 6 as well as to a noise blanker 18 via a single input/output line 19. The noise N is amplified by a noise amplifying circuit 20 and detected by a noise wave detecting circuit 21. A switch circuit 22 in which the output of the circuit 21 is used as an input is made to conduct for a period exceeding the pulse duration of the noise N. Then the line 19 is grounded in terms of AC. Thus the noise N can be completely eliminated without cutting off the line 17. |
