I am using NSTimer to update peak power from iphone. From monitoring, it does not update very fast. I need high frequency of updating peak power in order of 100 micro second (100us). I also try with usleep(100) to update every 100us. Still very slow. Can someone help me to point out how to achieve this? I am thinking I need to use this code to measure distance. Thank you.
you capture the audio (record, input, or file), access its samples from the pcm cbr (uncompressed, with a fixed sampling rate) stream, and read the samples of the range you are interested in. considering the high frequency, you will only have to analyze a small number of samples (2-5, depending on the sampling rate). you may need to interpolate to improve accuracy with so few samples.