Frame-adaptive Techniques Fo Tradeoffs in S' 3. Quality versus Efficiency 'ft Analysis

In this paper, we present techniques for computing frame-adaptive approximations to the S T F T which can satisfy arbitrarily specified bounds on the number of arithmetic operations per frame. The central idea is to represent the samples in each signal frame with a very small number Q of quantization levels, yielding an SNR of 10Jog(Q2) dB. This leads to the formulation of the frame's D F T computation as a process of summation among pre-stored vectors. Experimental studies are used t o propose and verify mathematical models for how the number of vector additions needed in this process depends on the frequency content of a frame. The models are utilized to design frame-adaptive techniques for excluding various subsets of vector elements from the summation process in order to keep the number of additions per frame from exceeding any specified bound, B.