{
  "revision": "bringup-1",
  "basis": "Engineering screening limits for first assembly, not a validated production or audio-performance specification. Nominal frequencies and nets come from the current PCB and schematic. The negative rail is a charge-pump output, not a regulated -5.000 V supply.",
  "rail_5v": [4.75, 5.25],
  "rail_3v3": [3.15, 3.45],
  "negative_rail": [-5.25, -3.5],
  "reference_positive": [2.35, 2.65],
  "reference_negative": [-2.65, -2.35],
  "reference_ratio_error": 0.03,
  "ripple_vpp_max": 0.15,
  "clock_relative_error": 0.02,
  "clock_duty": [0.35, 0.65],
  "logic_low": [-0.3, 0.45],
  "logic_high_5v": [4.0, 5.3],
  "logic_high_3v3": [2.7, 3.6],
  "logic_error_fraction_max": 0.005,
  "quiet_density": [0.35, 0.65],
  "tone_frequency_hz": 1000,
  "tone_r2_min": 0.25,
  "tone_amplitude_min": 0.003,
  "tone_gain_ratio": [1.5, 3.5],
  "input_peak_low_v": 0.1,
  "input_peak_high_v": 0.25
}