Langford Analytic · Knowledge Base

PSD Units Reference

A quick reference for PSD units across different quantities — acceleration, velocity, displacement, force and stress — with conversion factors.

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referencePSDunitsg²/Hzconversionaccelerationstress

PSD Units

QuantityPSD UnitsRMS UnitsArea = Mean-Square
Accelerationg²/Hz or (m/s²)²/Hzg or m/s²g² or (m/s²)²
Velocity(m/s)²/Hz or (mm/s)²/Hzm/s or mm/s(m/s)² or (mm/s)²
Displacementm²/Hz or mm²/Hzm or mmm² or mm²
ForceN²/HzNN²
StressMPa²/Hz or Pa²/HzMPa or PaMPa² or Pa²

Conversion

1 g²/Hz = (9.81)² (m/s²)²/Hz ≈ 96.2 (m/s²)²/Hz

1 (m/s²)²/Hz = 1/96.2 g²/Hz ≈ 0.0104 g²/Hz

RMS: 1 g = 9.81 m/s² (factor NOT squared)
PSD: factor IS squared