音圧レベルコンバーター

import math

# Audio level unit conversions (electrical, 600Ω reference)
# All conversions go through watts as base

def dbm_to_watts(dbm: float) -> float:
    return 0.001 * 10 ** (dbm / 10)

def watts_to_dbm(w: float) -> float:
    return 10 * math.log10(w / 0.001)

def dbu_to_watts(dbu: float, impedance: float = 600) -> float:
    volts = 0.7746 * 10 ** (dbu / 20)
    return volts ** 2 / impedance

def watts_to_dbu(w: float, impedance: float = 600) -> float:
    volts = math.sqrt(w * impedance)
    return 20 * math.log10(volts / 0.7746)

def dbv_to_watts(dbv: float, impedance: float = 600) -> float:
    volts = 1.0 * 10 ** (dbv / 20)
    return volts ** 2 / impedance

def watts_to_dbv(w: float, impedance: float = 600) -> float:
    volts = math.sqrt(w * impedance)
    return 20 * math.log10(volts / 1.0)

def dbw_to_watts(dbw: float) -> float:
    return 10 ** (dbw / 10)

def watts_to_dbw(w: float) -> float:
    return 10 * math.log10(w)

# SPL conversions (acoustic, different domain)
def dbspl_to_pa(dbspl: float) -> float:
    return 20e-6 * 10 ** (dbspl / 20)

def pa_to_dbspl(pa: float) -> float:
    return 20 * math.log10(pa / 20e-6)

# Convert from dBm to all electrical units
dbm_in = 0  # 0 dBm
w = dbm_to_watts(dbm_in)
print(f"Input: {dbm_in} dBm")
print(f"  dBW:  {watts_to_dbw(w):.4f}")
print(f"  dBu:  {watts_to_dbu(w):.4f}")
print(f"  dBV:  {watts_to_dbv(w):.4f}")
print(f"  dBm:  {watts_to_dbm(w):.4f}")

# SPL reference level
print(f"\n94 dBSPL = {dbspl_to_pa(94):.4f} Pa")
print(f"20 µPa = {pa_to_dbspl(20e-6):.1f} dBSPL (threshold of hearing)")