Brainwave Data Collection

The foundation of Hypnus entire product suite is the collection and analysis of EEG (electroencephalogram) brainwave signals. EEG signals are inherently weak (microvolt level), necessitating amplification by over ten thousand times to achieve reliable measurement. Thus, the signal collection system demands high standards for amplification, common-mode suppression, power suppression, and dynamic range. All these requirements are met through a complete hardware system including high-throughput collection chips.

The overall structure of the Hypnus solution includes a core self-developed chip, an amplifier pipeline composed of a differential instrumentation amplifier, an operational amplifier, and several filters (for removing DC offset, 60 Hz power line noise, and other artifacts). At the input end, the signals are transmitted to a microcontroller, where they are digitized by an ADC. Then, the data is sent to a terminal via a standalone USB UART connection through an FTDI chip. The terminal executes signal processing and is capable of providing feedback to users, thus creating a neurofeedback loop. The functional block diagram of the overall structure is as follows:

Given the extremely weak nature of EEG signals, typically in the microvolt range, and that environmental noise can be much stronger than these signals, amplification is essential to enhance the amplitude of these weak signals for better recognition and utilization in subsequent processing and analysis. By amplifying useful signals while minimizing noise (or only slightly increasing it), the signal-to-noise ratio, or the proportion of useful signal to background noise, is improved. A high signal-to-noise ratio is crucial for enhancing the quality of EEG signals, aiding in more accurate recognition and analysis of brain activity. We have designed a noise-shielding amplifier structure that effectively enhances signal clarity: