Circuit arrangement for reconstructing noise-affected signals

摘要

An analog input signal is applied to a timing circuit (2) for generating a sampling pulse in response to an impulse noise introduced to the signal and also to a first sample-and-hold circuit (7, 8, 9) through a buffer amplifier (6). The first sample-and-hold circuit includes a capacitor (7) and a switch (8) for applying the analog signal to the capacitor to develop a voltage therein which keeps track of the waveform of the analog signal in the absence of the sampling pulse and holding the voltage in response to the sampling pulse. A differentiator (11) is coupled in a feedback loop from the output of the first sample-and-hold circuit for generating a signal representative of the slope ratio of the analog signal. A second sample-and-hold circuit (15) is provided in the feedback loop for sampling and holding the slope ratio signal in response to the sampling pulse. Further included in the feedback loop is a bidirectional constant current source (20) which provides constant current charging and discharging of the capacitor (7) in response to an output signal from the second sample-and-hold circuit (15).