Why Use AC-coupled Differential Amplifiers?
• All Biomedical Signals are Analog Differential Signals – essentially all biomedical measurements involve selectively amplifying small differential analog signals that are contained in large common-mode signals. Even single-ended biomedical measurements must be made relative to a reference (or ground) electrode, which produces a differential measurement configuation. Only an AC-coupled differential amplifier will selectively amplify a small time varying analog biomedical signal while rejecting common mode signals, DC (and low frequency) signals, and DC input bias currents. In addition, since the AC-coupled inputs block low frequency signals, low frequency amplifier noise is reduced, which significantly decreases total amplifier output noise. Similar advantages also apply to other amplifier systems including audio amplifiers, analog amplifiers, etc. • No DC Bias Current – AC-coupled amplifiers with true AC-coupled inputs have capacitors on the inputs that form high pass filters. In add
