Abstract:
A demodulator includes input terminals (3a, 3b; 103a, 103b), for receiving an input signal (S M ), and an amplifier stage (4) having a gain (G). The input signal (S M ) is amplitude-modulated and is defined by a carrier signal (S CR ) at a carrier frequency (f CR ) and by a modulating signal (S M '). The demodulator includes, moreover, a gain-control stage (5; 105), coupled to the amplifier stage (4) for varying the gain (G) of the amplifier stage (4) according to a sinusoid of a frequency equal to the carrier frequency (f CR ), on the basis of the carrier signal (S CR ).
Abstract:
A signal-processing circuit (10) has a first and a second input (11a, 11b), which receive a first and a second differential signal (V P ,V M ), a third input (11c), which receives a common-mode signal (V CM ), the first and second differential signals (V P , V M ) having an equal and substantially opposite trend with respect to the common-mode signal (V CM ), and a first output (12a) supplying a first processed signal (V pp ), equivalent to the first differential signal (V P ) rectified with respect to the common-mode signal (V CM ), and satisfying throughout its course a first relation of comparison with the common-mode signal. The processing circuit (10) is provided with first formation means (14a, 16, 18) for formation of the first processed signal (V pp ), which operate on the basis of the first differential signal (V P ), and second formation means (14b, 16, 18) for formation of the first processed signal (V PP ), which operate on the basis of the second differential signal (V M ); the first and second formation means co-operate in the formation of the first processed signal.