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Can we understand the details of signals in frequency-domain?
Put simply, a time-domain graph shows how a signal changes over time, whereas a frequency-domain graph shows how much of the signal lies within each given frequency band over a range of frequencies. The “spectrum” of frequency components is the frequency-domain representation of the signal.
What is decimation and how it can be done in frequency-domain?
With this method you start decimating the signal in the frequency domain and recombine the signal in the time domain. Apart from that difference it follows the same pattern as the decimation in time method. The first stage is breaking the N point signal down into two N/2 point DFTs.
How to downsample a signal with Decimate signal?
In the second set of plots, the resulting decimated signal is no longer a single sample, but has been distorted. If I delay the signal with 5 – and any multiple of q – samples, I get the first set of plots again. The source code for the decimate function is, https://github.com/scipy/scipy/blob/master/scipy/signal/signaltools.py#L1570
How is frequency domain analysis used in real life?
The frequency domain representation of a signal allows you to observe several characteristics of the signal that are either not easy to see, or not visible at all when you look at the signal in the time domain. For instance, frequency-domain analysis becomes useful when you are looking for cyclic behavior of a signal.
How is a signal converted to a frequency domain?
A signal can be converted between the time and frequency domains with a pair of mathematical operators called a transform. An example is the Fourier transform, which decomposes a function into the sum of a (potentially infinite) number of sine wave frequency components.
What happens if you downsample a signal to 512hz?
If it was downsampled to 512Hz then the frequency content would now be reduced to 256Hz, due to the Nyquist theory. However, if there were frequencies present in the original signal between 256 and 512Hz they would be subject to aliasing and would cause incorrect frequencies to be displayed in the frequency domain.