Source: https://guthlabs.ai/docs/instruments/tempo-milliseconds-converter/implementation/

instrument implementation / implementation-contract

# Tempo ↔ Milliseconds Converter implementation

A source-bound implementation contract for Tempo ↔ Milliseconds Converter; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-097

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification does not define input-domain rejection or note-value parsing. BPM = 0 is undefined, negative BPM yields an invalid negative duration, and the notation 1/4 can produce 125 ms or 2000 ms depending on convention.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "BPM": 120,
    "note_value": "quarter",
    "noteValueFactor": 1
  },
  "expected_outputs": {
    "ms": 500
  },
  "working": "60000 / 120 = 500 ms per quarter note; 500 × 1 = 500 ms."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/tempo-milliseconds-converter/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/tempo-milliseconds-converter/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/tempo-milliseconds-converter/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche4/tranche4-results.json`