# 📐 L2 Spec — Doppler Ultrasound (color / spectral) Mismatch-Only Spec
**ID:** `L2-046-001` · **Status:** ⊙ Testnet (genesis catalog)
**Parents:** ⬆ Principle [`L1-046`](/artifact/l1/L1-046)
> **🎯 Tolerance (ε):** expression
> **⚖ Difficulty score:** 0.5 · **Delta tier:** 5
> **⛓ On-chain block:** 41553361
---
## 1. Domain Ω
**Type:** `range`
| Parameter | Unit | Range |
|---|---|---|
| F mhz | MHz | 1 – 15 |
| Snr db | dB | 0.0 – 35.0 |
| Prf khz | kHz | 0.5 – 20 |
| Aliasing | — | 0.0 – 0.5 |
| Depth cm | — | 1 – 25 |
| N elements | — | 32 – 256 |
| Angle correction | — | 0.0 – 0.5 |
| Low velocity sensitivity | — | 0.0 – 0.3 |
| Wall filter bleedthrough | — | 0.0 – 0.3 |
## 2. Tolerance (ε)
**Type:** `fn`
```
16.0 + 0.3 * SNR_dB - 8.0 * angle_correction - 6.0 * aliasing - 4.0 * wall_filter_bleedthrough
```
## 3. Difficulty
| Property | Value |
|---|---|
| Difficulty score | 0.5 |
| Delta tier | 5 |
## 4. Fingerprint
`8a2eec7d4a3051bb2db1f0a6b2bcddece3433f7f777eebde8ead0c550f74891e`
## 5. On-chain Registration
- **Chain hash:** `0x20dec2341d2839dd6a8baf6742d2c004bdcffa2730939354b95a95ccb705a1d4`
- **Chain tx hash:** `0x49f656572906e99af36d0ac2ea75b63deeed15a782eaf1712482a634cbe91bc0`
- **Chain block:** `41553361`
---
## File Mapping
This bundle consists of: `L2-046-001.md`, `L2-046-001.json`.
| File | Role | How to regenerate |
|------|------|-------------------|
| `L2-046-001.md` | Source of truth — edit this | Human or LLM |
| `L2-046-001.json` | Structured metadata for the registry | LLM regenerates from the sections above |
**Prompt for your LLM after editing this Markdown:**
> Read the attached Markdown. Regenerate the sibling `.json` so every field matches.
> Preserve the schema documented in the rows above.
> Output each file in its own fenced code block tagged with the filename.
> Output only the JSON object.
_This Markdown was auto-synthesized from the catalog row for `L2-046-001`._
_Edit it, regenerate the JSON, and submit at [/submit](/submit) to claim the artifact._