How is impulse calculated in REW?

[mkoijn9]

I was just wondering how the impulse is actually calculated in REW, is the sweep signal convoluted with it's inverse filter? Also, when windowing an impulse reponse in REW, is just the data in the window fft'd or is the data outside the window set to zero and then the whole lot fft'd?

Thanks

Albert

[JohnM]

The impulse response is calculated by dividing the FFT of the measurement by the FFT of the sweep, which is equivalent to convolving with the sweep inverse. The FFT's of windowed data zero the region outside the window and calculate the FFT of the whole length to maintain high plotting resolution. The frequency resolution is determined by the window length, of course.

[mkoijn9]

Thanks,

regards

Albert