An electrical circuit includes a photodiode that receives a light signal from a light source and generates a photocurrent signal, a trans-impedance amplifier that amplifies the photocurrent signal and generates a low noise signal, and a high pass filter that converts the low noise signal into an alternating current (AC) signal having a positive amplitude, a negative amplitude, and a zero cross-over point between the positive amplitude and the negative amplitude. The electrical circuit also includes a positive integrating amplifier that receives the positive amplitude of the AC signal and generates a positive integrated value over an integration period, and a negative integrating amplifier that receives the negative amplitude of the AC signal and generates a negative integrated value over the integration period. The electrical circuit further includes at least one analog-to-digital converter that receives the positive and negative integrated values.
