Resolution

FFT size

Number of data point in each FFT block or subseries. The length must be a power of two and cannot exceed the total number of data points.

Number of frequencies

Is the half the FFT size.

FFT duration

Gives the length of the FFT analysis in seconds

Frequency interval

The difference between two discrete adjacent frequencies. If manually changed, the value is automatically adjusted to the nearest possible value (function of time step and FFT size).