Patent ID: 6469489
Filing Date: 2002-10-22
Classification: H03F

Abstract:
An electrical circuit for the adaptive detection of a modulated signal within a selected modulation frequency range, comprising:sensor means for transducing the modulated signal into an electrical signal, amplifier means with an input and an output, feedback means with an input and an output, the input being connected to the output of the amplifier means, the feedback means including frequency filter means for passing electrical signals modulated with frequencies within a selected frequency range and for blocking electrical signals modulated with frequencies out of the selected frequency range, the frequency filter means comprising a low-pass filter followed by an integrator; and a current source with an input and an output, its output current being controlled by an electrical input signal, the input being connected to the output of the feedback means and the output being connected in series with the sensor means in a common node, wherein the common node of the current source and the sensor means is connected to the input of the amplifier means.