Patent ID: 7653151
Filing Date: 2010-01-26
Classification: H03D

Abstract:
1. A two-level differential amplitude-shift-keying (D-ASK) signal demodulator for demodulating an amplitude bit of an input signal, comprising: a first envelope detector for detecting an amplitude of the input signal and providing an amplitude signal of the input signal; a first delay unit for delaying the amplitude signal of the input signal to generate a delayed amplitude signal; a first subtractor for subtracting the delayed amplitude signal from the amplitude signal of the input signal; a second envelope detector for detecting an amplitude signal of an output signal from the first subtractor; a threshold value generator for receiving the amplitude signal of the input signal and generating a threshold value dynamically according to the input signal and a previously generated threshold value; and a comparator for comparing the output of the second envelope detector with the threshold value produced by the threshold value generator, determining if there is any change between the amplitude of the consecutive input signals, and outputting a comparison result as the amplitude bit of the input signal.