ABSTRACT
The term time weighting refers to the time window applied for the creation of the value displayed. Most instruments that display levels create the value displayed through an RMS averaging of the signal over time. The time constant is short, and a peak detector with an ensuing long time constant will ensure that impulses will take a long time to “die” out. The fallback time is the time that elapses from a continuous signal stops until the display reaches a specific lower point on the scale. For measurements with program level meters for audio recording and transmission, the averaging time windows or averaging times applied are typically 0.1 ms, 10 ms, 300 ms, 400 ms, and 3s. The time constant is a measure of how fast the exponential function “dies” out, or more precisely, it specifies the time before the exponential function is reduced to 69% of its beginning value.
