# Meridian field signals

Fictional, MIT-licensed recordings following the three retained sourcebook recipes.
No ELDÆON recordings, physical calibration or measured synchronization.

## Reproduce

With Node 22 and the canonical packages built at
`88bcbfcc8b17af30837313aff596cec8e1bde43a`, run:

```
node build.mjs /path/to/canonical .
```

`specifications.json` retains the approved recipes. `methods.json` states the
implemented parameters, units, encoding and limitations. These synthetic examples
use little-endian float32 arrays, not a decoder for partner NDJSON or SDR formats.
Raw means unmodified authored samples, not physical acquisitions. All native
float32 samples are retained; the interface only rounds display text.

- Pressure: 24,000 samples at 100 Hz. A 4 Hz, 0.08 Pa sinusoid plus seeded bounded
  noise. Full coverage, no authored clipping. No audible or pitch-shifted version.
- Spectrogram: computed from the retained pressure samples. Eight-second periodic
  Hann windows, four-second hop, one-sided power spectral density in Pa²/Hz.
  Window starts span 0–232 seconds; the final window ends at 240 seconds.
- Magnetic field: 240 three-component vectors, in authored east/north/up axes.
  Magnitude is a separate derived product. Orientation and uncertainty have not
  been physically characterized. All 720 components have canonical measurements.
- Radar: 120 authored maps at two-second cadence, each 64×64, in Doppler Hz and
  excess path length km. Excess path length is a bistatic delay coordinate, not
  target range. No transmitter/receiver geometry or geodetic conversion supplied.
  The detection history selects each map's maximum cell; it is not a statistical
  detector or a statement about an object.
- IQ: an independent 0.1-second, 2 MHz, dimensionless complex tone. It has its own
  relative clock. It is not used to derive the authored radar maps. The inspector
  retains the exact sample, quadrature and byte offset.

Canonical observation, acquisition, bindings, measurements and product-source
selection contracts describe the packet. Every interactive selection uses the
standard reader; the receipt exercises all magnetic measurements, representative
pressure/spectral samples, every map maximum and independent IQ endpoints.
Structural and semantic checks pass. Physical acquisition profiles intentionally
remain incomplete. A software test is not scientific or calibration validation.