Multiplexer commutated high pass filter

摘要

A multi-channel analog system comprises a plurality of channels each being adapted to receive analog signals from a signal source such as a seismic sensor. A multiplexer multiplexes the analog channels prior to converting the channels' signals into digital numbers. Each channel has a DC blocking capacitor connected to one terminal of a normally-open multiplexer switch; the other terminal of the switch is coupled to a multiplexer bus. In accordance with this invention, the bus is connected to a common resistor. Control means consecutively close the multiplexer switches so that the capacitor whose switch has been closed forms a high-pass filter with the common resistor. The resistor is preferably connected as the input resistor to an operational amplifier. The capacitors, the multiplexer, and the common resistor form a multiplexer-commutated high-pass filter which is particularly adapted for multi-channel seismic systems.