AWR1642BOOST: Heart_beat settle time

Hi,

It is possible that this sample implementation does not support the higher heart rate.

The filters used by the algorithm may need to be adjusted.

What is the heart rate after exercise?

Thank you

Cesar

Hi,

the heart rate after exercise exist in between 170-180 range.

And which filter i need adjust for this?

Thank You,

Aditi 

Hi Cesar,

In Dss_data_path.h  file maximum heart rate allowed is defined as 120.

So my question is, if i change the value directly then will it be appropriate?

And in previous reply you mentioned that i need to adjust the filters, so the change in the coefiecients of IIR-Cascade Bandpass Filter (Dss_data_path.c) will be enough ?

I am a bigginer in this field so any help would be appriciated.

Thank you

Aditi karande 

Hi Cesar,

I have attached the snippit of the code.

In this code coefficients are calculated for 0.8 to 2 Hz. So if i design the coeffiecents for 0.8 to 3 will it work?

Thank you,

Aditi karande

Hi

We have to check with algorithm developer and get back to you tomorrow

thank you

Cesar

Hi Cesar,

I checked in Matlab, the Heart rate coefficients in the source code are calculated for 0.8 to 4 Hz.

So i guess there is no need to change the coefficients, so it should work if i directly set the max heart beat to 180 instead of 120.

So please let me know if is this the correct approach ?

Kind Regards,

Aditi Karande 

Hi,

Sorry for the delay, here is some input from algorithm developer

Thank you

Cesar

The demo is configured for 48 – 120 bpm and was never tested beyond that. Several parameters might require tuning to increase it to 180 bpm.  

The filter coefficients are fine they are tuned for 0.8 – 4.0 Hz.

There might be several places which might need to change such as

(1)    In “MmwDemo_dataPathInitVitalSigns()”

    // Vital-signs peak search frequencies may be different from the Band-pass filter cut-off frequencies

    obj->breath_startFreq_Hz = 0.1;   // Breathing-Rate peak search Start-Frequency

    obj->breath_endFreq_Hz   = 0.6;   // Breathing-Rate peak search End-Frequency

    obj->heart_startFreq_Hz = 0.8;    // Heart-Rate peak search Start-Frequency

    obj->heart_endFreq_Hz   = 2.0;    // Heart-Rate peak search End-Frequency

    // Auto-Correlation

    obj->xCorr_minLag = (uint16_t) obj->samplingFreq_Hz/2.1;    // (Fs/Freq)  Corresponding to f = 2.1 Hz at a sampling Frequency of 20 Hz

    obj->xCorr_maxLag = (uint16_t) obj->samplingFreq_Hz/0.8;    // (Fs/Freq)  Corresponding to f = 0.8 Hz at a sampling Frequency of 20 Hz

(2)    In dss_data_path.h change

#define MAX_HEART_RATE_BPM            (120)              // Maximum Heart-rate allowed

The current version of the algorithm also searches for the 2^nd harmonic of the heart-rate within a region [1.6 Hz – 4.0 Hz].  For instance if the heart rate is 90 bpm it will also search for a peak at 180 bpm. It can happen that if the heart-rate is 180 bpm, the algorithm might think it’s a 2^nd harmonic and not the true heart-rate and give an erroneous result.

Hence for now I’ll suggest that they log the output on the PC and look at the variable

       obj->VitalSigns_Output.heartRateEst_FFT = heartRateEst_FFT;  rather than the displayed output on the GUI.

Hello Cesar,

Thank you so much for the detailed explanation, it helped me a lot.

So even if i change all the above parameters, the result will be erroneous for higher heart-rate which will fall in second harmonic?

And i am also getting an error after flashing the ccs debug firmware image on evm.

Please have a look on this problem, and guide me through it.

Kind regards,

Aditi

Hi Cesar,

I succesfully connected the EVM and ccs , and it ran properly, but then after a while i recieved the following error. And now its not working:

Kind regards,

Aditi Karande