This version (16 Jul 2022 04:52) was approved by John Joseph.

Click here to return to the Basic page

Signal Detection


The Signal Detection algorithm is a cell that will output a flag once no signal has been present at the input for a given amount of time. The “Threshold” setting will determine the value the input is compared to in order to determine whether or not a signal is present. The “Trig Time” setting will determine how long, in seconds, the cell will wait to output the flag. The peak of the signal is detected, not the RMS value.

Targets Supported

Name ADSP-214xx ADSP-215xx/SC5xx ADAU145x/146x
—————————— ——————-- ——————————-- —————————-
SignalDetection B B S



———————- ————-- ———————-
InputX Audio Input channel X


  • X - Channel Index


———————- ————-- ———————-
Output0AudioOutput channel0

Configurable Parameters

GUI Parameter NameDefault ValueRangeFunction Description
—————————————- ———————- —————— —————————————-
Threshold(dB) -60-150 to 0Sets the value the input will be compared to. If the input is below this value for a given time determined by “Trig Time(s)”, a flag will be output
Trig Time(s) 120 2 to 200 Sets the amount of time, in seconds, that the signal level must be below the threshold before a flag is output. This value is an approximation
NumChannels 1 1 to 20Number of input and output channels. Change in this value requires re-compilation

DSP Parameters

Parameter Name Description ADSP-214xx/SC5xx/215xx ADAU145x/146x
—————————————- ——————————————————————————-- —————————————- —————————-
Threshold The input will be compared to Threshold value Float FixPoint8d24
TimeConstantTriggering time in ms Float Integer32
CounterDownFloat Integer32

DSP Parameter Computation

Threshold= 10^ (threshold/20)
TimeConstant = 10^(-1.0 * Log10(16.0 - 0.0001) / (TrigTime * FS / 2)
TimeConstant = TrigTime * FS ( Applicable for ADAU145x/146x)

resources/tools-software/sigmastudiov2/modules/basic/signaldetect.txt · Last modified: 16 Jul 2022 04:52 by John Joseph