Patent ID: 7317906

Claim:
An AM radio receiver comprising: an RF amplifier that amplifies a received radio station signal, a first mixer that mixes a RF signal supplied from the RF amplifier with a local oscillation signal from a local oscillator thus converting it to a first intermediate-frequency signal, a first bandpass filter that band-limits the first intermediate-frequency signal, a second mixer that mixes an output signal from the first bandpass filter with a crystal oscillation signal from a crystal oscillator, thus converting it to a second intermediate-frequency signal, a second bandpass filter that band-limits the second intermediate-frequency signal, an intermediate-frequency amplifier that amplifies an output signal from the second bandpass filter, an AM detector that AM-demodulates an output signal from the intermediate-frequency amplifier and provides output of an audio signal, and a noise detector for detecting and eliminating ambient noise present in the received radio station signal, wherein: the noise detector comprises a first noise detector that detects noise from the RF signal and eliminates that noise from the first intermediate-frequency signal, and a second noise detector that detects noise from the second intermediate-frequency signal and eliminates that noise from the second intermediate-frequency signal, and the AM radio receiver further comprises a halting device that halts the second noise detector for a predetermined period of time when the first noise detector has detected noise.