An amplitude-to-digital converter

An alternative approach to realize the amplitude detector for variable frequency sinusoidal signals is described in this paper. Based on the counter method of the A/D converter controlled by the designed logic circuit, the proposed converter can produce digital output signals proportional to the peak amplitude of analog input signals without low-pass filter. The conversion time is two cycle periods of the input signal. In addition, the output signal with small ripple can be achieved. Experimental results verifying the performances of the proposed circuit are in close agreement with the expected values.