DocumentCode :
1103644
Title :
Digital methods for conversion between arbitrary sampling frequencies
Author :
Ramstad, Tor A.
Author_Institution :
Norwegian Institute of Technology, Trondheim, Norway
Volume :
32
Issue :
3
fYear :
1984
fDate :
6/1/1984 12:00:00 AM
Firstpage :
577
Lastpage :
591
Abstract :
The paper presents filtering methods for interfacing time-discrete systems with different sampling frequencies. The methods are applicable for sampling rate conversion between any two sampling frequencies; the conversion ratio may even be irrational or slowly time varying. Interpolation by irrational factors requires digital filters with nonperiodically varying coefficients. This is dealt with in two ways. 1) All possible coefficient values are precalculated. This is, in a sense, possible because of the finite resolution needed. Or 2), the coefficients can be updated in real time using either FIR or IIR filters. The first solution requires a huge coefficient memory; the second scheme, on the other hand, is computationally intensive. While discussing both of these solutions, more practical intermediate schemes incorporating both FIR-and IIR-type filters are suggested. The suggested practical implementations are either based on analog reconstruction filters where the derived digital filter coefficients are functions of the distances between current input and output samples or digital interpolators combined with simple analog interpolation schemes for finding the desired values in between the uniform output samples from the digital interpolator.
Keywords :
Bandwidth; Digital filters; Extrapolation; Filtering; Finite impulse response filter; Frequency conversion; IIR filters; Interpolation; Sampling methods; Time varying systems;
fLanguage :
English
Journal_Title :
Acoustics, Speech and Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
0096-3518
Type :
jour
DOI :
10.1109/TASSP.1984.1164362
Filename :
1164362
Link To Document :
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