Merlin Integrated Signal Processor ISP-100, Руководство пользователя

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8-46
10 July 1998
Limiter
Figure 8-19 Limiter 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}.