Multi-channel reconfigurable systems and methods for sensing biopotential signals

A method of monitoring biopotential of biological tissue through a plurality of electrodes, comprising:

• receiving a plurality of commands into a biopotential sensing device, wherein the commands include commands for setting a high and low cutoff frequency and for selecting one or more channels from a plurality of channels for outputting biopotential measurements, wherein the commands further specify initiation of multiple impedance measurements of a particular electrode at a plurality of frequencies and specify an AC current or voltage waveform at the plurality of frequencies;
• the biopotential sensing device sensing a biopotential signal from biological tissue coupled with each of a plurality of electrodes coupled to the plurality of channels of the biopotential sensing device;
• the biopotential sensing device band-pass amplifying each biopotential signal based on the high and low cutoff frequency and outputting a digital representation of the band-pass amplified biopotential signal with substantially zero DC (direct current) offset for each selected channel by at least blocking any DC offset from the biological tissue that is coupled with the selected channel's electrode;
• the biopotential sensing device generating a capacitively-coupled AC (alternating current) current waveform, having an amplitude and frequency, that is applied to a particular input coupled to a particular channel to measure impedance of a corresponding particular one of the electrodes;
• determining the impedance by measuring a voltage signal received at the particular channel in response to the AC current waveform applied to the particular input;
• the biopotential sensing device generating the AC current waveform at the plurality of frequencies based on the specified AC current or voltage waveform at the plurality of frequencies;
• and
• the biopotential sensing device sensing the AC voltage waveform at the plurality of frequencies for the particular electrode and outputting the sensed AC voltage waveform at the plurality of frequencies to an analyzer device configured for measuring the impedance of the particular electrode based on the AC voltage output for the particular electrode, which AC voltage is proportional to the particular electrode's impedance value for such frequency.