Sample Rate / Nyquist Frequency Checker mechanism

Model scope

The core arithmetic formula is correct under consistent frequency units. The instrument should be revised to define sample-rate units, reject nonpositive rates, clarify the Nyquist-boundary wording, and either remove the aliasing-check claim or add a signal-frequency input and explicit aliasing rule.

• fmax=fs/2 is the standard Nyquist-frequency formula, but the wording "maximum representable frequency" is potentially misleading: frequencies at or above fs/2 are not safely representable without qualification, and exactly fs/2 is a boundary case.
• The claimed aliasing check is not implemented by fmax=fs/2 alone. An aliasing check requires a signal/input frequency and a defined rule, such as flagging frequencies at or above fs/2.
• The common-rate table output is not explicitly defined as a formula or output schema, although its values can be generated by applying fmax=fs/2 to each listed rate.

Units and conventions

• The sample rate and resulting Nyquist frequency must use the same frequency unit.
• If sample rate is supplied in Hz, the output is in Hz; if supplied in kHz, the output is in kHz.
• The listed common rates mean 44.1 kHz, 48 kHz, 96 kHz, and 192 kHz, equivalent to 44100 Hz, 48000 Hz, 96000 Hz, and 192000 Hz.
• A clearly labeled unit field or a fixed input convention is required; the current spec only says "sample rate".

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "sample_rate": 44100,
    "sample_rate_unit": "Hz"
  },
  "expected_outputs": {
    "nyquist_frequency": 22050,
    "nyquist_frequency_unit": "Hz"
  },
  "working": "fmax = fs / 2 = 44100 Hz / 2 = 22050 Hz."
}

Failure boundary

• A zero or negative sample rate is invalid and must be rejected; zero yields a mathematically defined result but no usable sampling capability.
• The implementation must avoid implying that a frequency exactly equal to fs/2 is generally safe to represent; use a boundary-aware label such as Nyquist limit or require frequency < fs/2.
• The aliasing claim is incomplete without a signal-frequency input and a comparison rule.
• Unit omission can cause a 1000-fold error, such as interpreting 44.1 kHz as 44.1 Hz.
• The common-rate table should explicitly state units and whether values are displayed in Hz or kHz.

Other records

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