Telex ISP-100 manual 19Limiter component

8-46

Limiter

Figure 8-19Limiter component.

A limiter (see Figure 8-18) is used in situations where the output signal must not exceed a given level, regardless of any increase in the level of the input signal. Limiting is often used for system protection purposes, such as the avoidance of amplifier clipping or the prevention of mechanical or thermal damage to loudspeaker components.

Familiar Controls

Most of the controls in the ISP-100 Limiter are common to nearly all traditional dynamic range limiters. These controls should be familiar to anyone with experience in the operation of any limiter.

Threshold

The Threshold control adjusts the input signal level above which limiting is applied. When the input signal level is below the threshold value, no limiting takes place and the change in level of the output signal exactly matches the change in level of the input signal. When the input signal level is above the threshold value, limiting is applied such that the output signal level does not increase, regardless of any increase in the input signal level.

Threshold is adjustable in the range {-60 dBFS to 0 dBFS}.

Attack Time

A limiter monitors the level of the input signal and controls the level of the output signal accordingly. When the input signal level suddenly increases, a limiter allows the output signal level to also increase, but only up to the threshold setting and not beyond. Desirable sound effects can sometimes be created if a limiter is forced to ramp the output signal level to its new value gradually rather than instantaneously. The Attack Time control adjusts the duration of this ramp.

Attack Time is adjustable in the range {20 uSec (one sample) to 50 mSec}.

10 July 1998