[Elecraft] discretize...

[Kok Chen]

On Mar 27, 2010, at 7:13 PM, David Christ wrote:

> I am not an expert on FFT and higher math, but 
> would someone please explain to me what discretize signifies that is 
> not covered by quantize.

The word "discrete" in DFT refers to discrete "time" samples, and not to the quantization of the samples into finite amplitude levels.  I.e., unlike the Fourier Transform, the input of a DFT is not a continuous function but defined only at discrete points, 0, T, 2T, ...(n-1)T.

Although it often is used that way, the input to a forward DFT does not have to be in the time domain -- the DFT is useful for other things than just estimating the spectrum of a time series.  A common example is the use of DFT to compute the discrete cepstrum of a signal.

References: 

http://en.wikipedia.org/wiki/Discrete_Fourier_transform
http://en.wikipedia.org/wiki/Cepstrum 

73
Chen, W7AY