Specify the physical transducer modality and multi-channel array topology engineered to intercept the biophysical neural contrast modeled in Worksheet 4.1.
Formulate the analog signal conditioning chain from raw energy transduction to analog-to-digital conversion (ADC).
| Hardware Stage | Component Selection / Topology | Target Specification | Engineering Trade-Off / Justification |
|---|---|---|---|
| Transducer Element | |||
| Impedance Matching | |||
| Preamplifier / TIA | |||
| Filtering & Anti-Aliasing | |||
| ADC Digitization |
Multi-channel arrays inevitably suffer from inter-element crosstalk. Formulate your isolation mechanisms to preserve independent spatial information channels.
Calculate the fundamental Johnson-Nyquist thermal noise limit of your transducer and evaluate whether your instrumentation operates in the desirable sample-noise-dominated regime ($R_{\text{sample}} \gg R_{\text{coil/sensor}}$).
Model the spatial sensitivity profile of your individual sensor elements and combined array across 3D brain coordinates.
Evaluate transducer patient safety constraints against FDA and IEC standards (IEC 60601-1 electrical safety, SAR limits, laser MPE limits).
| Safety / Regulatory Domain | Applicable Standard | Permissible Exposure Limit | Engineering Safety Interlock / Mechanism |
|---|---|---|---|
| Electrical Isolation & Leakage | IEC 60601-1 (Type BF / CF) | Auxiliary patient leakage < 10 ยตA (normal), < 50 ยตA (single-fault) | |
| Thermal / Energy Deposition | FDA SAR / Ultrasound ISPTA / Laser MPE | Head SAR < 3.2 W/kg; Laser MPE < Class 1 / IEC 60825-1 | |
| Biocompatibility | ISO 10993-5 / 10993-10 | Non-cytotoxic, non-irritating to human scalp epidermis |