问测井中的尺度FFT结果频率

EN

private float[] getFrequencies(int min, int max, int nBands)
    {
        float[] returnVal = new float[nBands];
        double step = (Math.Log(max / min) / nBands) / Math.Log(2.0);
        returnVal[0] = (float)(min * Math.Pow(2.0, step / 2.0));

        for (int iBand = 1; iBand < nBands; ++iBand)
        {
            returnVal[iBand] = (float)(returnVal[iBand - 1] * Math.Pow(2.0, step));
        }
        return returnVal;
    }

private double[] getLogArray(double[] data, int nBands, int minFreq, int maxFreq)
    {
        float[] bandFreq = getFrequencies(minFreq, maxFreq, nBands);
        float df = (float)sampleRate / samples;
        float scalar = 1.0f / sampleRate;
        double[] bandOut = new double[nBands];
        int iBin = 0;
        int iBand = 0;
        float f0 = 0.0f;

        while (iBin <= (samples / 2) && iBand < nBands)
        {
            float fLin1 = ((float)iBin + 0.5f) * df;
            float fLog1 = bandFreq[iBand];
            float x = (float)data[iBin];

            if (fLin1 <= fLog1)
            {
                bandOut[iBand] += (fLin1 - f0) * x * scalar;
                f0 = fLin1;
                iBin += 1;
            }
            else
            {
                bandOut[iBand] += (fLog1 - f0) * x * scalar;
                f0 = fLog1;
                iBand += 1;
            }
        }
        return bandOut;
    }