Patent ID: 6985540

Claim:
An AM demodulator that receives and demodulates an AM modulated input signal using a wave-detection signal generated by a phase locked loop, said AM demodulator comprising: a voltage controlled oscillator which outputs a wave-detection signal; a phase locked loop including a detection unit which detects whether a detection signal, obtained by AM wave-detection of the wave-detection signal, has a specific relationship with respect to a threshold amplitude level; a first multiplying unit which raises an AM modulated input signal to a 2n-th power, where n is an integer and at least 1; a second multiplying unit which raises the wave-detection signal output from said voltage controlled oscillator to the 2n-th power; and a phase control unit providing phase control using outputs of said first and second multiplying units; and a switching unit which resets said phase locked loop in response to the detection signal.