Saturation-Tolerant Electrophysiological Recording Interface
SUMMARY
Researchers at UCLA have designed an electrophysiological signal processing device that can measure EEG, ECG, and EMG signals with high sensitivity in noisy environments that would otherwise drown out weak signals.
BACKGROUND
Weak electrophysiological input signals (EEG, ECG, EMG) are often detected by digitizing them using a large voltage gain in order to achieve a low background noise level. However, in noisy environments, the loud signals from motion artifacts, unrelated biological signals, or man-made interferers saturate the input signal. The saturation of the input signal in noisy environments prevents any hope of detecting and recording weak electrophysiological signals.
INNOVATION
UCLA researchers from the department of electrical engineering have designed a signal processing device that allows the recording of weak electrophysiological signals in the presence of large signals. This is accomplished by using a voltage-controlled-oscillator-based analog-to-digital converter to digitize the input signal utilizing a voltage-to-phase gain. This provides a saturation-free input range that permits the detection and recording of weak signals without having loud recordings saturate the signal.
APPLICATIONS
- Electrophysiological recording device
- Sleep EEG monitoring system
- Neural recording system
ADVANTAGES
- The signal does not saturate in the presence of other loud signal artifacts
- Weak electrophysiological signals can still be detected
STATE OF DEVELOPMENT
An on-chip system has been developed that shows a 20x improvement for saturation tolerance over existing systems of similar power, noise, and area. Performance improvements are underway, as well as the development of a complete system-on-a-chip for remote healthcare sensing applications.