Patent ID: 8497711

Claim:
An envelope detector, for performing squelch detection on a pair of differential signals to generate a squelch detection signal, the envelope detector comprising: a voltage divider, for generating a real-time reference signal according to the pair of differential signals; and a comparison module, for comparing the real-time reference signal with a first comparison signal and a second comparison signal associated with the pair of differential signals to generate the squelch detection signal, comprising: a transfer circuit, coupled between a first node and a second node, for providing a differential current according to the pair of differential signals and the real-time reference signal; a first load circuit, coupled to the first node and a third node, comprising a first resistor, for providing the first comparison signal according to a voltage formed at the first resistor by the differential current; a second load circuit, coupled to the second node and a fourth node, comprising a serial resistor, for providing the second comparison signal according a voltage formed at the serial resistor by the differential current; a resistance of the serial resistor being different from that of the first resistor; and a comparator, coupled to the third node and the fourth node, for comparing the first comparison signal and the second comparison signal to generate the squelch detection signal; wherein, the first comparison signal and the second comparison signal are low-frequency signals.