Noise eliminating circuit

摘要

A noise eliminating circuit for an AM receiver wherein noise pulse component included in an amplitude modulated wave are eliminated by making the RF or IF stage of the receiver an open circuit during such noise, while at the same time, compensating for the carrier components of the incoming signal that have lacked during such switching. The circuit comprises: (i) a noise detector for detecting the noise components and responsive thereto for generating a trigger output signal; (ii) a switch responsive to the trigger signal of the noise detector for making said RF or IF stage an open circuit; (iii) a signal generating circuit connected through the switch to the RF or IF stage; and (iv) a phase detector for controlling the oscillator frequency generated by the signal generating circuit so that it is coincident with that of the carrier of the incoming signal at the time just before the switch opens.