About VerenaSchmidt11

VerenaSchmidt11

Hi Francisco, thanks for your reply. However, as a novice to FFT I have no idea where to change the source code. My understanding so far is that the following function is looking for the frequency: void findHighestMagnitudeAndFrequency(float32_t* FFTmagnitudes, float32_t windowSize) { float32_t maxVal; uint32_t maxIndex; float32_t freqVal; float32_t samplingFrequency = 100; arm_max_f32(FFTmagnitudes, windowSize / 2, &maxVal, &maxIndex); float32_t freqBin = samplingFrequency/windowSize; freqVal = freqBin * maxIndex; printf("The maximal magnitude %f is at the frequency %f freqBin = %f maxIndex = %i \n\r",(float) maxVal, (float) freqVal, (float) freqBin, (int) maxIndex); } So far I understand this is that the function arm_max_f32 is looking for the frequency. &maxVal, &maxIndex are my return values. Therefore, I don't where I should change to index >= 1? Thanks a lot, Verena

VerenaSchmidt11

Hello, I am just trying out the FFT&Noise application shown on the Developer Page: https://developer.bosch.com/web/xdk/acoustic However, the FFT seems not to work properly, as I get the following results: INFO | XDK DEVICE 2: The maximal magnitude 0.038768 is at the frequency 0.000000 Can somebody please help me in order to get the frequency information. I just copied the original source code. The FFT part of the source code is what I am most interested in. I am a real beginner regarding FFT - so if somebody knows a good introduction webpage to this topic, I would be also greatful. Thanks a lot, Verena

VerenaSchmidt11

Hi Mahalingam, thanks a lot for that SNTP-example. What possible solutions are available if no WLAN / SNTP-Server is available to use? Thanks, Verena

VerenaSchmidt11

Hi, for IoT use cases I have to synchronise several XDKs as well as internal data of a component. For this use case the timer using is unfortunately not enough. current_timer = xTaskGetTickCount(); //not enough for this use case Is there a real time clock available without WLAN connectivity ? Is a bluetooth real time clock available? How could I use the SNTP-server (in case of availbe WLAN) for getting a timestamp - is there example available? Thanks, Verena

VerenaSchmidt11

Hi Franscisco, thanks for the reply. I also store the timer value and it shows me that independent from me writing on the SD-card, storing the values in an array seems to be very time intensive. Do you have an idea how to increase the speed with the data store. That I can store it then in the next step on block at a higher rate? Is there a more efficient way compared to copying arrays? ACC_X_Buffer[AccCounter] = sensorValue.Accel.X; If you have some code examples - that would be really great. Thanks, Verena

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Re: FFT Analysis for Noise

FFT Analysis for Noise

Re: Real-Time Clock

Real-Time Clock

Re: Storing data with high sampling rate (e.g. acc...

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