Exponential Averaging

Exponential averaging is a continuous averaging process that weights current and past data differently. The amount of weight given to past data as compared to current data depends on the exponential time constant. In exponential averaging, the averaging process continues indefinitely.

The exponential averaging mode supports the following time constants:

  • Slow—Uses a time constant of 1,000 ms. Slow averaging is useful for tracking the sound pressure levels of signals with sound pressure levels that vary slowly.
  • Fast—Uses a time constant of 125 ms. Fast averaging is useful for tracking the sound pressure of signals with sound pressure levels that vary quickly.
  • Impulse—Uses a time constant of 35 ms if the signal is rising and 1,500 ms if the signal is falling. Impulse averaging is useful for tracking sudden increases in the sound pressure level and recording the increases so that you have a record of the changes.
  • Custom—Enables you to specify a time constant suitable for your particular application.

Exponential averaging requires time-continuous blocks of data. The measurement restarts when a discontinuity is detected.