Patent ID: 8248137

Claim:
A reference amplifier apparatus for processing signals, in particular physiological measuring signals, the apparatus comprises: multiple channels with signal inputs for receiving input signals, the input signals each comprising a specific signal component and a signal component common to all input signals, wherein each channel comprises an impedance transforming input amplifier, wherein the apparatus is configured for supplying to each input amplifier a respective input signal and, an analog reference signal which is equal for all channels, wherein the apparatus further comprises a digital signal processor and one or more analog-digital converters for supplying the signals provided by the input amplifiers to the digital signal processor, wherein the digital signal processor is designed for converting signals received from the one or more analog-digital converters at least into one or more output signals, wherein said signal processor is designed for processing the signals received from the one or more analog-digital converters, for providing a digital reference signal, wherein the apparatus comprises a digital-analog converter for converting the digital reference signal into said analog reference signal.