For implementing fast processing algorithms like FFT we need all data present at input at the same time. In practical implementation it is not possible to have all data together at same time. Hence it is necessary to decompose the incoming signal into multiple finite length signals to perform operations. This is done by using - Overlap Add Method (OAM) and Overlap Save Method ( OSM)
In Overlap Add Method x[n] is decomposed into non overlapping sequence of
length L and is performed using Linear Convolution.
In overlap save method, input data sequence x[n] is decomposed into number of
L point sequences, where each data block begins with the last (N-L) values in the previous data block, except the first data block which begins with (N–L) zeros and is performed using Circular Convolution.
In Overlap Add Method x[n] is decomposed into non overlapping sequence of
length L and is performed using Linear Convolution.
In overlap save method, input data sequence x[n] is decomposed into number of
L point sequences, where each data block begins with the last (N-L) values in the previous data block, except the first data block which begins with (N–L) zeros and is performed using Circular Convolution.
Can you please tell what is the application of Filtering of long data sequence?
ReplyDeleteIt's applications are - to fetch & process real time data like ECG signals
ReplyDeleteThese methods can also be used for communication and speech processing applications.
ReplyDeleteCan we use it for IIR filter ?
ReplyDeleteNo.
ReplyDeleteFor IIR Filter h[n] is of infinite length, hence it is not possible to compute output using it for signal of infinite duration.
Instead difference equations are used to determine its output
OAM and OSM are block processing techniques and and are used for real time signal processing applications.
ReplyDeleteOam osm can be used to find op of digital fir filter
ReplyDeleteThey cannot be used to find of IIR filter
ReplyDeleteBoth OAM & OSM are computationally same
ReplyDeleteOSM uses circular convolution. Hence, OSM is preferred. The length of the output signal after circular convolution must be selected such that optimum system performance is obtained.
ReplyDeleteWhich method is more efficient?
ReplyDeleteCan we use it for IIR filter ?
ReplyDeleteThese methods are suitable for real time signal processing.
ReplyDeleteBoth the methods are computationally equal.
ReplyDeleteHowever it cannot be used only for IIR filter design