Q
I want to configure the AD1836 to a sample frequency of 22.05 KHz. On page 19
of the data-sheet, there is an interpolater-mode described in the DAC control
register. Can I configure the part to 44.1KHz(bits 9-8) and use
interpolatermode 0 to obtain 22.05KHz?
Currently I have samples stored in 22.05KHz format and interpolates these in a
linear fashion. Since I am building a demonstrator with BF533 EZ-kit Lite, I
would like to use this codec. If the AD1836a cannot run on this frequency, is
there code available for proper interpolation, for example with a
sinc-function?
A
The AD1836A will work at slower sample rates with an appropriate master clock
and settings. The best way to get this on the BF533 EZ-kit Lite is to change
OSC003 from 12.288 MHz to 11.2896 MHz to allow 44.1 kHz related sample rates,
and set the AD1836A as follows:
DAC Control Register 1: Default (48 kHz interpolator mode) - note that bits
9:8 only set the deemphasis filter response. They do not change the operation
mode.
ADC Control Register 1: Default (48 kHz sample rate mode).
ADC Control Register 3: Set bit 6 for 512 x fs clock mode. This will divide
the 11.2896 MHz master clock by 512 for a 22.1 kHz sample rate. This applies
to both the ADCs and DACs.