Search found 2 matches

by millroad
Sun Feb 26, 2023 8:25 pm
Forum: ESP-IDF
Topic: I2s microphone sample rate seems halft as big as it's supposed to
Replies: 5
Views: 4477

Re: I2s microphone sample rate seems halft as big as it's supposed to

I figured out the issue, when setting the sampling bit width to I2S_DATA_BIT_WIDTH_16BIT esp-idf sets the word length to 16 bits as well, so a whole frame is just 32 bits, the i2s bckl was only 327 680 hz. I was expecting 64 bit clock cycles per frame, which would make the bckl 655360 hz. Just setti...
by millroad
Sat Feb 25, 2023 7:51 pm
Forum: ESP-IDF
Topic: I2s microphone sample rate seems halft as big as it's supposed to
Replies: 5
Views: 4477

I2s microphone sample rate seems halft as big as it's supposed to

I'm using an INMP441 i2s microphone ( datasheet ) and using the esp-dsp library and esp-idf 5.0.1 to create an fft series. I'm sampling at 10 240 Hz but I can't see any signals higher than about 2500 Hz, and the plot of the fft shows an alias around 2500 Hz as well. Is there some error in my i2s set...