本文主要研究目的為以類比電路搭配單晶片微電腦實現一體積小、可攜式與低單價之穩態視覺誘發電位 (Steady-State Visual Evoked Potential, SSVEP) 量測電路，作為具即時性之大腦人機介面 (BCI) 系統前端腦電訊號的擷取和處理。 為了提高訊號量測的正確性與穩定性，論文所提之穩態視覺誘發電位擷取電路具有以下特點： (1)針對視覺誘發電位設計之濾波電路導通帶。 (2)硬體電路製做之雜訊隔離技巧。 (3)設計數位電路調整類比電路參數，使濾波電路具有自動增益控制 (Automatic Gain Control, AGC)、自動停帶控制 (Automatic Stop-Band Control, ASBC) 性能，而能降低環境相關因數干擾。 本論文設計之量測電路經由實驗證明可正確且穩定地擷取 SSVEP 訊號於 21Hz 附近頻帶，對於電路元件誤差造成的共振頻率偏移，以及皮膚和電極間阻抗變化所造成的腦波訊號變動，可藉由電路自動化微調機制改善，提高整體 BCI 系統的可靠度。 In this these novel methods for acquisition steady-state visual evoked potential (SSVEP) using automatic gain control (AGC), and automatic stop-band control (ASBC). That can enhance accuracy, stability and reduce power line interferences of brain-computer interface (BCI) implemented in real time. In addition, a narrow bandpass with center frequency of 21Hz is presented. The center frequency is set by the same frequency which generates visual stimulation. This would amplify the SSVEP component and cancel the electrode-specific noise, and thereby increase the signal-to-noise ratio (SNR).
