Sign in

Not a member? | Forgot your Password?

Search Online Books

Search tips

Free Online Books

Free PDF Downloads

A Quadrature Signals Tutorial: Complex, But Not Complicated

Understanding the 'Phasing Method' of Single Sideband Demodulation

Complex Digital Signal Processing in Telecommunications

Introduction to Sound Processing

C++ Tutorial

Introduction of C Programming for DSP Applications

Fixed-Point Arithmetic: An Introduction

Cascaded Integrator-Comb (CIC) Filter Introduction


IIR Filter Design Software

See Also

Embedded SystemsFPGA
Chapter Contents:

Search Spectral Audio Signal Processing


Book Index | Global Index

Would you like to be notified by email when Julius Orion Smith III publishes a new entry into his blog?


Overlap-Save Method

The classical overlap-save method [187], unlike OLA, uses no zero padding to prevent time aliasing. Instead, it

discards output samples corrupted by time aliasing each frame, and
overlaps the input frames by the same amount.

More specifically:

  • If the input frame size is $ N$ and the filter length is $ L\ll N$, then a length $ N$ FFT and IFFT are used.
  • As a result, $ L-1$ samples of the output are invalid due to time aliasing.
  • The overlap-save method writes out the good $ R=N-L+1$ samples and uses a hop size of $ R$, thus recomputing the time-aliased output samples in the previous frame.

The name ``overlap-save'' comes from the fact that $ L-1$ samples of the previous frame are effectively ``saved'' for computing the next frame.

Previous: Example COLA Windows for WOLA
Next: Time Varying OLA Modifications

Order a Hardcopy of Spectral Audio Signal Processing

About the Author: Julius Orion Smith III
Julius Smith's background is in electrical engineering (BS Rice 1975, PhD Stanford 1983). He is presently Professor of Music and (by courtesy) of Electrical Engineering at Stanford's Center for Computer Research in Music and Acoustics (CCRMA), teaching courses and pursuing research related to signal processing applied to music and audio systems. See for details.


No comments yet for this page

Add a Comment
You need to login before you can post a comment (best way to prevent spam). ( Not a member? )