ADAU1781 Analog Devices, ADAU1781 Datasheet - Page 46

• Manufacturer Part Number: ADAU1781
• Description: SigmaDSP Low-noise Stereo Audio Codec for Portable Applications
• Manufacturer: Analog Devices

Specifications of ADAU1781

• Instructions/cycles: 1024
• Digital I/o Channels: 8/8
• Analog I/o Channels: 2/2
• Product Description: SigmaDSP low-noise stereo audio codec for portable applications

ADAU1781
SOFTWARE SLEW
When the values of signal processing parameters are changed
abruptly in real time, they sometimes cause pop and click
sounds to appear on the audio outputs. To avoid pops and
clicks, some algorithms in SigmaStudio implement a software
slew functionality. Algorithms using software slew set a target
value for a parameter and continuously update the value of that
parameter until it reaches the target.
The target value takes an additional space in parameter RAM,
and the current value of the parameter is updated in the non-
modulo section of data RAM. Assignment of parameters and
nonmodulo data RAM is handled by the SigmaStudio compiler
and does not need to be programmed manually.
Slew parameters can follow several different curves, including
an RC-type curve and a linear curve. These curve types are
coded into each algorithm and cannot be modified by the user.
Rev. B | Page 46 of 92
Because algorithms that use software slew generally require more
RAM than their nonslew equivalents, they should be used only
in situations where a parameter will change during operation of
the device.
Figure 54 shows an example of volume slew applied to a sine wave.
INITIAL
VALUE
Figure 54. Example of Volume Slew
NEW TARGET
VALUE
CURVE
SLEW