BrettG

What are the mute ramp times in the AD193x codecs?

Discussion created by BrettG on May 17, 2010

The AD193x codecs are often used in conjunction with the SigmaDSP products. Recently, a customer asked me how the volume ramping worked on the ADC and DAC mute controls.

 

The mute in the ADC is a digital mute with a 10-bit, 1024 LRCLKs ramp up/down time.

 

The calculation for the ADC mute ramp is:
Ramp Time (ms) = 1024 / Sample Rate (kHz)
For example, if the sample rate is 48 kHz,
1024 / 48 kHz = 21.333 ms

 

It is a linear ramp, not a logarithmic ramp.

 

The volume control is also linear and 10-bit, hence the 1024 steps.

 

In the DAC, is it a log scale, 8-bit, -96dB column, so the mute would take 256 LRCLKs.

 

The calculation for the DAC mute ramp is:
Ramp Time (ms) = 256 / Sample Rate (kHz)
For example, if the sample rate is 48 kHz,
256 / 48 kHz = 5.333 ms

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