Howtosignalprocessing
- What is sampled amplitude?
- What does the amplitude of FFT mean?
- What is a good frequency resolution?
- What is the effect of increasing size of DFT on spectrum?
What is sampled amplitude?
The sampling rate is usually determined from the sampling theorem, which states that a baseband (information) signal of finite energy with no frequency components higher than W Hz is completely specified by the amplitudes of its samples taken at a rate of 2 W/sec.
What does the amplitude of FFT mean?
The amplitude of the FFT is related to the number of points in the time-domain signal. Use the following equation to compute the amplitude and phase versus frequency from the FFT. where the arctangent function here returns values of phase between –π and +π, a full range of 2π radians.
What is a good frequency resolution?
The frequency resolution is equal to the sampling frequency divided by FFT size. For example, an FFT of size 256 of a signal sampled at 8000Hz will have a frequency resolution of 31.25Hz. If the signal is a sine wave of 110 Hz, the ideal FFT would show a sharp peak at 110Hz.
What is the effect of increasing size of DFT on spectrum?
The DFT of the window is what would convolve with our original frequencies. As the time length of the window increases, the width of the main lobe of its transform in frequency gets more narrow (the nulls are located at 1/T) and therefore the frequency resolution increases.
