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AM-10HD / Aug 2008
A M - 1 0 H D G U I
Lookahead Limiter
If desired, the AM analog chain’s output may be peak controlled by a spe‑
cial high‑speed, feed forward limiter with a 0.5 millisecond lookahead time.
The control path (not the audio path) is highly oversampled in order to achieve
extremely precise peak control.
The primary goal of oversampling the control sidechain is achieving bet‑
ter peak control through finer definition of the audio waveform. Therefore
oversampling of the audio signal itself is not only unnecessary, but wastes
DSP resources. The graphic below illustrates why control signal oversampling
is effective.
By sampling the audio waveform with finer resolution we can detect peak
excursions that would be otherwise missed. In fact, if both the audio and control
signals were oversampled peaks would still be missed because their relative
time alignment would be identical to the non‑oversampled case!
