# Project Substrate - Technical Reference
## System Architecture
### Core Components
```
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│ ├── substrate.py # SubstrateInterferometer - timing measurement engine
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| threshold | 4.5 | Z-score threshold for event logging |
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# Numerically stable online mean/variance calculation
delta = value - self.mean
self.mean += delta / self.n
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decoded = bytes([(int(e['zscore']) & 0xFF) ^ 0x60 for e in signal])
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## XOR Key Discovery
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### events.json
```json
"ts": "2026-01-15T14:32:17.123456Z",
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# Outputs:
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## Version History
| Version | Date | Changes |
|---------|------|---------|
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**Access Level**: Project Team
**Last Updated**: February 2, 2026