ADAU1761BCPZ-R7 datasheet(49/92 Pages) AD

49 / 92 page

ADAU1761

Rev. C | Page 49 of 92

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.

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 70 shows an example of volume slew applied to a sine wave.

INITIAL

VALUE

SLEW

CURVE

NEW TARGET

VALUE

Figure 70. Example of Volume Slew

ADAU1761BCPZ-R7 Datasheet(PDF) 49 Page - Analog Devices