Patent ID: 7907005

Claim:
A demodulation circuit for ASK coded or amplitude modulated signals comprising: a circuit input being adapted to receive an ASK coded or AM signal comprising a carrier signal being ASK coded according to a base band signal or amplitude modulated; a first sampling mixer having a sampling signal input connected to the circuit input to receive the ASK coded or AM signal, a sampling clock input being adapted to receive a first sampling clock signal that defines first sampling points at which the ASK coded or AM signal when being present at the sampling signal input is sampled, and a sampling signal output being adapted to output the sampled signal; signal shaping means having a signal input connected to the circuit input and being adapted to provide a recovered clock signal at an output thereof; signal delay means being adapted to receive the recovered clock signal and to variably delay the recovered clock signal according to a delay control signal at a delay control input of the signal delay means, thereby generating a delayed recovered clock signal at an output thereof, wherein the delayed recovered clock signal is provided as the first sampling clock signal to the sampling clock input of the first sampling mixer; and amplitude maximum detection means being adapted to detect if the first sampling points of the first sampling mixer correspond to respective amplitude maxima of the signal being sampled and to generate the delay control signal being indicative for deviations in time of the first sampling points from said amplitude maxima, wherein the delay control signal is fed to the delay control input of the signal delay means to increase or decrease the delay added to the recovered clock signal in order to adjust the delayed recovered clock signal such that the first sampling points are set to the amplitude maxima of the signal being sampled by the first sampling mixer.