VR2R-0301_r1

VR2R-0301

① SA Source

• Source: 開啟完整 SA 文章
• Section: PCB vs Flyover Cables
• Line hint: 272

Context Before

First, we must understand why high-speed signals perform worse on PCB versus flyover cables. As SerDes rates increase, high-speed channels become increasingly constrained by insertion loss introduced by PCB traces, vias, dielectric materials and conductor roughness. Insertion loss is defined as the signal power that is lost as a signal is traveling through an interconnect channel.

Evidence

The three main mechanisms contributing to insertion loss in a PCB channel are conductor loss from skin effect and copper surface roughness, dielectric loss from laminate absorption, and geometry loss from discontinuities such as vias and layer changes.

Context After

Conductor loss is driven by copper surface roughness. As signals travel down the copper traces in the PCB, energy is lost due to the resistance in copper. At higher frequencies, the signal traveling through the copper crowds toward the surface of the trace, which is known as the skin effect. On top of the natural resistance of copper, if the surface is rough, the current will not travel along a uniform path incurring more resistance and loss.

② Atomic Claim

PCB channel 的 insertion loss 主要有三種機制：由 skin effect 與 copper surface roughness 造成的 conductor loss、由 laminate absorption 造成的 dielectric loss，以及 vias、layer changes 等 discontinuities 造成的 geometry loss。

• Epistemic Mode: ASSERTED
• Mapping Status: PARTIAL

③ Semantic Frame

{
  "attribute": "INSERTION_LOSS_MECHANISMS",
  "context_nodes": [],
  "entity": {
    "id": "04_knowledge_base/PCB",
    "label": "PCB"
  },
  "frame_type": "ATTRIBUTE",
  "qualifiers": {
    "condition_text": "mechanism names are plain text in source claim",
    "numeric_mentions": [
      "three"
    ],
    "temporal_mentions": []
  },
  "value": {
    "numeric_mentions": [
      "three"
    ],
    "value_text": "conductor loss, dielectric loss, and geometry loss are the three main insertion-loss mechanisms."
  }
}

④ Canonical Entity Mapping

Role	Surface Label	Canonical Target
entity	PCB	PCB

⑤ Human Review

請在 Properties 逐項確認：

• 原文 → Atomic Claim 是否忠實
• Atomic Claim → Semantic Frame 是否忠實
• Canonical Entity mapping 是否正確
• Epistemic mode 是否保留原文語氣
• 最後選擇 review_action

Review state

Markdown 內文不是正式 approval。只有 Apply bridge 寫入的 Decision Ledger event 才是正式決策。