A system for bi-directionally conveying biomedical signals between a patient and biomedical signal acquisition and processing devices, comprising: an analog input protection and filtering stage, configured to be coupled to a plurality of electrodes that conduct the biomedical signals, the analog input protection and filtering stage comprising a differential circuit with two paths configured to process the biomedical signals in an analog domain to and from the patient; a signal amplification stage comprising a differential amplifier circuit with a plurality of differential amplifier stages (410; 412; 414; 418), wherein the differential amplifier circuit is coupled to each of the two paths of the differential circuit and is configured to amplify a first output of the differential circuit by an amplification factor of less than or equal to about 50 for the biomedical signals within a frequency range of about 0.01 Hz to about 1000 Hz, thereby producing a second output; an analog-to-digital converter stage comprising an analog-to-digital converter coupled to the differential amplifier circuit and configured to digitize the second output of the differential amplifier circuit, thereby producing a third output, wherein the analog-to-digital converter has greater than 16-bit resolution; a communication module, coupled to the analog-to-digital converter stage and configured to provide a digital communication interface between the third output of the analog-to-digital converter stage and an input to a digital processing stage; a voltage reference circuit, configured to couple to the plurality of electrodes and configured to return a processed analog signal to the patient, wherein the voltage reference circuit provides a ground-equivalent electrode attached to the patient to remove common mode voltage, wherein the voltage reference circuit has a Twin-T feedback network configured to remove power mains harmonic noise from the biomedical signals, and the digital processing stage, coupled to the communication module, comprising: a memory with a signal path module comprising a plurality of signal modules configured to apply filtering comprising frequency-selective filtering and signal processing algorithms to the third output from the analog-to-digital converter stage to extract high-frequency and low-amplitude features of the biomedical signals; and at least one processor configured to execute the plurality of signal modules, wherein the at least one processor filters the biomedical signals in frequency ranges of interest. an analog input protection and filtering stage, configured to be coupled to a plurality of electrodes that conduct the biomedical signals, the analog input protection and filtering stage comprising a differential circuit with two paths configured to process the biomedical signals in an analog domain to and from the patient; a signal amplification stage comprising a differential amplifier circuit with a plurality of differential amplifier stages (410; 412; 414; 418), wherein the differential amplifier circuit is coupled to each of the two paths of the differential circuit and is configured to amplify a first output of the differential circuit by an amplification factor of less than or equal to about 50 for the biomedical signals within a frequency range of about 0.01 Hz to about 1000 Hz, thereby producing a second output; an analog-to-digital converter stage comprising an analog-to-digital converter coupled to the differential amplifier circuit and configured to digitize the second output of the differential amplifier circuit, thereby producing a third output, wherein the analog-to-digital converter has greater than 16-bit resolution; a communication module, coupled to the analog-to-digital converter stage and configured to provide a digital communication interface between the third output of the analog-to-digital converter stage and an input to a digital processing stage; a voltage reference circuit, configured to couple to the plurality of electrodes and configured to return a processed analog signal to the patient, wherein the voltage reference circuit provides a ground-equivalent electrode attached to the patient to remove common mode voltage, wherein the voltage reference circuit has a Twin-T feedback network configured to remove power mains harmonic noise from the biomedical signals, and the digital processing stage, coupled to the communication module, comprising: a memory with a signal path module comprising a plurality of signal modules configured to apply filtering comprising frequency-selective filtering and signal processing algorithms to the third output from the analog-to-digital converter stage to extract high-frequency and low-amplitude features of the biomedical signals; and at least one processor configured to execute the plurality of signal modules, wherein the at least one processor filters the biomedical signals in frequency ranges of interest. a memory with a signal path module comprising a plurality of signal modules configured to apply filtering comprising frequency-selective filtering and signal processing algorithms to the third output from the analog-to-digital converter stage to extract high-frequency and low-amplitude features of the biomedical signals; and at least one processor configured to execute the plurality of signal modules, wherein the at least one processor filters the biomedical signals in frequency ranges of interest.