The fourth experiment of the
course was on Linear FIR Filtering Methods - Overlap Add Method & Overlap
Save Method. The Fast Fourier Transform Algorithm had an important limitation
in which it required all input values to be available for obtaining an output.
For a real world signal which can be arbitrarily long, waiting for the entire
signal to arrive and get stored would result in massive delays and also
increase the cost of storage equipment. Here OAM and OSM come into
picture. A long input data sequence was
taken and the impulse response was taken of a smaller length i.e. 3. The length
of decomposed signal came to be 5 whereas the length of output decomposed
signal came to be 8.
We concluded that for inputs having large lengths OAM and OSM are useful for getting outputs with reduced delay.This experiment took some time as the concept was new to us.
codes:
Is one better than the other?
ReplyDeleteOsm is slightly efficient as it doesn't include addition of overlapping transients. But we can use oam when we need to use the fft with zero padding rather than repeated samples.
ReplyDeleteThe overlap-add method is based on the fundamental technique in DSP: (1) decompose the signal into simple components, (2) process each of the components in some useful way, and (3) recombine the processed components into the final signal.
ReplyDelete