AnsweredAssumed Answered

white noise from ADMP441 I2S digital mic.

Question asked by abd.alsh@gmail.com on May 14, 2013
Latest reply on May 17, 2013 by abd.alsh@gmail.com

Hi

When using ADMP441 evaluation board connected to FPGA, the noise exceeds the sound signal ( audio sample attached).  3.3 DC supply is clean,+- 100 mV variation.  followed data sheet recommendations e,g, 100Kohm between serial data & GND.

DSC_0012.jpg

Bit clk = 500 KHz:

setup_1.bmp

 

serial data waveform:

setup_0.bmp

Notice that serial data gets distorted during left channel acquisition.  This is because it is high impedance between right channel acquisition.

What causes the noise?

Attachments

Outcomes