Current Sampling Rate

Help and Troubleshooting
#1

Hi All,

I Opened a new issue here basically

I am using the “micarray_recorder” Demo?
I reduced the time to 5 seconds and build so
uint16_t seconds_to_record = 5;
And I am getting 160000 samples for every channel, which means that the sampling rate is
160000/5 = 32000
Am I missing some thing?

I noticedn in microphone_array.h
const uint32_t kSamplingRate = 16000;

What is wrong? Any help please?

Thanks

#2

Hi @alanwar,

  1. Are you trying to increase the sampling rate of the microphones?
  2. In the current release the only possible sampling frequency is 16kHz. So, that cannot be changed. We are close to release a version with higher sampling rates for audio.
  3. What are you trying to achieve , maybe we can help with ideas.

Yoel

#3

Hi Yoel,

Thanks for your reply. I am a new user and I would like to know the current sampling rate so that I can understand the data better. Why am I getting 160,000 samples for every channel during 5 seconds?
I should get only 80,000 samples only during the 5 seconds. I am sure that it is running for only 5 seconds as I changed the code and measured the time.
I am using simple “fopen” and “fread” to read the raw data in Matlab.
Where is the mistake?

Thanks again!

#4

First, the data in the raw files is formatted as a uint16, so you will have 2 bytes for each sample.
Can you share your matrix-creator-hal/demos/micarray_recorder.cpp file ?

#5

Here is my “file”

I see that “fread reads a file 1 byte at a time by default”.
I think this is the reason. I should do some thing like
fileID = fopen(‘mic_16000_s16le_channel_0.raw’);
samples = fread(fileID,‘uint16’);
I really appreciate your support and help.

By the way, Could you please tell me the job of mics "mics.CalculateDelays"
How to get more information about the file from the nineth channel which is called normally “mic_16000_s16le_channel_8.raw” ( the names starts from zero)
I see that matrix creator has 8 mics only not nine.

Thanks again for everything

#6

The nine file is for the beamforming channel. This channel is created merging all 8 mics audio into one channel, the signal here is stronger.

#7

Thanks for your reply.
Sorry what about the “mics.CalculateDelays” in the same code

Thanks

#8

one year from first news about the sampling rate increase work and still there is no news about this feature. will be implemented or there is any issues with that?.

for beamforming is a must increase the sampling rate to improve the beamforming angle resolution.

thanks
regards.