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Public evidence

electrical.pcb.diff_impedance

Machine-checked verification for calculation version 1.0.0 · tier internally_reviewed

Open calculator API Capability Download JSON CVP Manifest MCP Review policy

CVP: CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· Edge-coupled microstrip; S is edge-to-edge gap; H is dielectric height from trace to reference plane; zero copper thickness; homogeneous dielectric; no soldermask; no dispersion/roughness/weave. · Protocol · Schema · Production report

Declared partition coverage
PASS · 5/5 declared partitions (zdiff-wide, zdiff-wh-eq-1, zdiff-narrow, invalid-domain, metamorphic)
Versions
Calculation 1.0.0 · CVP protocol 1.0.0-proposed · Evidence 2026-09-13.cvp-self-consistency
Verification revision
2026-09-13.cvp-self-consistency · 4/4 property · digest 182774947424

Verification

Legacy regression suite: 12/12 calculation tests · Production surface contract 4/4

Three distinct suites: educational examples on the calculator page, this legacy regression count (12/12 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

    This calculator CURRENT · Public schema 1.0.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-13.cvp-self-consistency. Calculation version 1.0.0. CVP 1.0.0-proposed. 4/4 golden · 5/5 CVP boundary · 9/9 invalid · 4/4 property · 2/2 metamorphic · 2/2 cross-interface · 2/2 cross-calculator · 4/4 CVP contract. digest 182774947424.

  • Golden (oracle-backed) 4 / 4
  • CVP boundary 5 / 5
  • Invalid input 9 / 9
  • Property 4 / 4
  • Metamorphic 2 / 2
  • Cross-interface 2 / 2
  • Cross-calculator 2 / 2
  • CVP contract 4 / 4
  • Interfaces PASS · UI (SSR) / REST / MCP
  • Interface claim ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
  • Assurance Engineering
  • release artifacts aligned PASS
  • schema valid input executes PASS
  • engine success output validates schema PASS
  • schema rejects incomplete input PASS

Fingerprint sha256:616e85a5eca1c2d25b7f069f5fe2e6412da475cc6a14d094d89eba4ad18b8fdd

Input schema sha256:e81d3eefa501cc0d2222e7a0a1f38ec7865abeb040659a7376d526f25b930650 · Output schema sha256:0dbbec43e2eef498f984eaf82ba16410b6a6dae68847ad33a5fc3d61adc3467a · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool
pcb-diff-impedance
Engine
pcb-diff-impedance
Engine build
2026-09-12
Evidence core
2026-09-12T22:29:20.477Z
Rendered
2026-09-16T22:03:43.728Z
Last reviewed
2026-09-13

Assumptions

  • Zero copper thickness (T=0)
  • Homogeneous dielectric; no soldermask
  • Edge-coupled pair; S is edge-to-edge gap
  • H is dielectric height from trace to reference plane
  • No dielectric dispersion, copper roughness, or weave

Limitations

  • Zero copper thickness (T=0); homogeneous dielectric; no soldermask
  • S_m is edge-to-edge gap, not center-to-center
  • Not a field solver; omits dielectric dispersion, copper roughness, and weave

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

Legacy published checks

Golden and boundary cases from the legacy Evidence JSON. CVP property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the Manifest — including SKIP when a suite has no vectors.

IDKindStatusDetail
fr4-samplegoldenpassExpected Zdiff_ohm=92.82916802055753 · Z0_ohm=49.928090751070556 · Actual mode=zdiff · W_m=0.0002 · H_m=0.0001 · S_m=0.0002 · er=4.2 · er_eff=3.2047431568147635 · Z0_ohm=49.928090751070556 · Zdiff_ohm=92.82916802055753
wider-lower-ZgoldenpassExpected Zdiff_ohm=58.273049069904864 · Actual mode=zdiff · W_m=0.0004 · H_m=0.0001 · S_m=0.0002 · er=4.2 · er_eff=3.4000000000000004 · Z0_ohm=31.342110937151578 · Zdiff_ohm=58.273049069904864
wh-eq-1goldenpassExpected Zdiff_ohm=134.93104102488513 · Actual mode=zdiff · W_m=0.0001 · H_m=0.0001 · S_m=0.0002 · er=4.2 · er_eff=3.0437601569801833 · Z0_ohm=72.57254810185282 · Zdiff_ohm=134.93104102488513
narrow-branchgoldenpassExpected Zdiff_ohm=181.5106250902856 · Actual mode=zdiff · W_m=0.00005 · H_m=0.0001 · S_m=0.0002 · er=4.2 · er_eff=2.92 · Z0_ohm=97.6253386196932 · Zdiff_ohm=181.5106250902856
bad-WboundarypassExpected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
bad-HboundarypassExpected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
bad-SboundarypassExpected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
bad-erboundarypassExpected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
property-zdiffpropertypassZ>0
property-scalepropertypassscale-invariant
property-mono-Wpropertypasswider W → lower Zdiff
property-mono-Spropertypasslarger S → higher Zdiff