This version (18 May 2021 08:58) was approved by John Joseph.The Previously approved version (05 Jun 2020 11:08) is available.
Table of Contents
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Limiter With Hold
Description
The LimiterWithHold block computes the RMS level of the incoming audio signal and attempts to prevent it from exceeding the threshold by automatically reducing its gain. Hold controls the rate of the time limiter will respond to change in input signal.
Targets Supported
| Name | ADSP-214xx | ADSP-215xx/SC5xx | ADAU145x/146x |
|---|---|---|---|
| —————————————- | —————————- | ——————————-- | —————————- |
| Limiter with hold | B | B | S |
Pins
Input
| Name | Type | Description |
|---|---|---|
| ————————————— | —————————— | ———————————————— |
| Input0 | Audio | Input channel0 |
Output
| Name | Type | Description |
|---|---|---|
| ————————————— | —————————— | ———————————————— |
| Output0 | Audio | Output channel0 |
Configurable Parameters
| GUI Parameter Name | Default Value | Range | Function Description |
|---|---|---|---|
| ———————————————- | —————————- | ————————————- | —————————————————————- |
| RMSTC_Channel<n> | 5 ms | 0 to 10000 ms | Controls the tracking rate of the RMS-approximation calculation used to track the input level. |
| Decay_Channel<n> | 5 ms | 0 to 10000 ms | Controls the rate at which the signal compression ratio will subside after the input signal level has dropped below the limiter threshold. Larger values result in longer decays, with 23 never recovering to the original gain |
| Hold_Channel<n> | 0 ms | 0 to 2000 ms | Controls the time the limiter maintains its current gain before it starts new gain as the input level changes |
| Threshold | 1 dB | -24 to +24 dB | Sets the threshold point. If the input signal's approximated RMS level exceeds the threshold point, the limiter will apply compression in order to prevent the signal from exceeding that level. This threshold level does not need to be an integer; its resolution can be set in steps of less than 0.01 dB. A full-scale sine wave is a level of -3 dB, due to the RMS measurement |
| NumChannels | 1 | 20 | Number of input and output channels. Change in this value requires re-compilation |
DSP Parameters
| Parameter Name | Description | ADSP-214xx/SC5xx/215xx | ADAU145x/146x |
|---|---|---|---|
| ————————————— | ———————————————————————-- | ——————————————- | —————————————-- |
| RMSTC_Channel<n> | Time constant for RMS calculation | Float | 8.24 format |
| Decay_Channel<n> | Decay value | Float | 8.24 format |
| Hold_Channel<n> | Time to resopond the limiter to change in input level | Float | 8.24 format |
| Threshold_Channel<n> | limiter threshold | Float | 8.24 format |
*Note: <n> → indicates channel number
DSP Parameter Computation
Decay = 1/P^(1000/(Decay * FS))
Hold = FS * HOld/1000
Where P is 1/9 and FS is the sampling rate
Where FS is the sampling rate
resources/tools-software/sigmastudiov2/modules/dynamicsprocessors/limiterwithhold.txt · Last modified: 12 May 2021 09:35 by John Joseph