the backround of the audio signal I captured with a ADMP441 contains a constant and audible buzzing in addition to the desired signal. I connected this microphone to a BF526 processor according to CN-0266.
(Whereas CN-0266 describes the setting of two microphones in stereoconfiguration I connected just one microphone. Additionally I decreased the clock rate to 1,024 MHz in order to obtain a 16kHz time resolution.)
At first I thought the problem is caused by a too far distant blocking capacitor. Therefore I took a second blocking cap and soldered it as near as possible to the VDD and GND pins of the microphone. However this amendment took no effect. Does anyone considers it thinkable that the noise can anyhow be introduced by a wrong configuration of the SPORT0 registers ?