Hi everyone!

I’ve been using log power FFT block for signal power estimation. I’ve

fed

the output of Log Power block to my custom block in which I search for

peak

in power spectrum and then I sum up bins left and right from that peak

until the turn is reached. C++ code for power estimation:

```
// move right from the max
iCount = iMax_index + 1;
while (in[iCount] < in[iCount-1])
```

fTotalPower += in[iCount++];

```
// move left from the max
iCount = iMax_index;
while (in[iCount] > in[iCount - 1])
```

fTotalPower += in[iCount–];

I’ve set the frame rate property to 10 frames per second (each 32768

samples) and I use sample rate of 200kSPS. What happens is that every

fourth power estimate sample has magnitude for about 1dB lower than the

other three. I’ve looked deeper into situation and I found out that

every

fourth power spectrum from log power FFT block has about three of four

bins

thinner signal and that’s why the total magnitude of the signal is

lower.

I’ve tried lower frame rate (2 frames per second) but situation doesn’t

change.

Next I tried the FFT block instead of log power FFT and the problem

disappears. So I am guessing that there is some kind of problem in Log

Power FFT block. Has anyone experienced similar problem?

Regards,

Urban