CCS/AWR1843BOOST: The computations of the CFAR signal noise ratio SNR and CRLB in the SDK 3.2

Tool/software: Code Composer Studio

Hi,

In the SDK 3.2,the CFAR SNR expressed in 0.1 steps of dB is computed by the following formula:SNR=10*10lg(abs(S/N)^2),if I want to compute the variance according to CRLB,the fuction convertSNRdBToVar should be modified as follows:

float convertSNRdBToVar(uint16_t SNRdB,uint16_t bitW, uint16_t n_samples, float resolution)
{
    float fVar, RVar;
    int32_t inputActual;
    float scaleFac  = (n_samples*resolution);
    float resThresh = 2 * resolution * resolution;

   // float invSNRlin = antilog2(-SNRdB, bitW) * 2;
    float invSNRlin = antilog10((int32_t)(-SNRdB), 100) * 2; // My modification We assume our estimator is 3dB worse than the CRLB.

    /* CRLB for a frequency estimate */
      #ifdef MATLAB
      fVar = (float)invSNRlin * (6.0f/((2.0f*PI_)*(2.0f*PI_)))/(n_samples*n_samples - 1);
      #else
      fVar = (float)invSNRlin * (6.0f/((2.0f*PI_)*(2.0f*PI_))) * recipsp((n_samples*n_samples - 1));
     #endif
    /* Convert to a parameter variance using the scalefactor.*/
    RVar = fVar*scaleFac*scaleFac;

    if (RVar < resThresh)
    {
        RVar = resThresh;
    }
    return RVar;

}

The function antilog10 is defined as:

float antilog10(int32_t inputActual, uint16_t frac)
{
    float output;
    float input = (float)inputActual;
    input = divsp(input , (float)(frac));
    output =  exp10sp(input);
    return output;
}

The invSNR(equal to (N/S)^2) is computed by the function antilog10.Can anybody tell me my modifiction is right or not?

Thanks,

Regards,

Rata