autotune

const (
	// MaxHistory is how many recent error measurements feed the running
	// average. Matches trunk-recorder's MAX_HISTORY.
	MaxHistory = 20
	// PPMThreshold is the correction magnitude (in PPM, relative to the
	// channel centre frequency) above which the source is flagged as
	// mis-configured. Matches trunk-recorder's PPM_THRESHOLD.
	PPMThreshold = 3.5
	// SuggestedErrorRounding rounds the suggested config value to the
	// nearest N Hz. Matches trunk-recorder's SUGGESTED_ERROR_ROUNDING.
	SuggestedErrorRounding = 10
	// WarmupSamples is how many measurements must accumulate before the
	// running average is trusted enough to apply. Until then Ready() is
	// false and callers apply no correction, so a single noisy first
	// measurement can't yank tuning by hundreds of Hz before the average
	// has had a chance to settle.
	WarmupSamples = 3
	// MaxAbsErrorHz bounds a single measurement's plausible magnitude when
	// the channel centre is unknown (the voice path passes centre 0). A
	// real crystal error is a few PPM — single-digit Hz on a disciplined
	// USRP, low hundreds on a loose RTL crystal at VHF/UHF. A per-call AFC
	// residual far beyond that is a measurement glitch (an unconverged loop,
	// a data-dependent bias snapshot at end-of-call), not drift, and folding
	// it in produces the runaway kHz corrections this guard prevents. ~1.5 kHz
	// is ≈3.3 PPM at 450 MHz — comfortably above any correction worth making.
	MaxAbsErrorHz = 1500
)