CZT vs FFT: Flexibility vs Speed

Journal Article · Wed Oct 01 04:00:00 EDT 2003 · Embedded Systems Programming magazine

OSTI ID:816417

Sirin, S ^[1]

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1. Remote Sensing Laboratory, Bechtel Nevada

Bluestein's Fast Fourier Transform (FFT), commonly called the Chirp-Z Transform (CZT), is a little-known algorithm that offers engineers a high-resolution FFT combined with the ability to specify bandwidth. In the field of digital signal processing, engineers are always challenged to detect tones, frequencies, signatures, or some telltale sign that signifies a condition that must be indicated, ignored, or controlled. One of these challenges is to detect specific frequencies, for instance when looking for tones from telephones or detecting 60-Hz noise on power lines. The Goertzel algorithm described in Embedded Systems Programming, September 2002, offered a powerful tool toward finding specific frequencies faster than the FFT.Another challenge involves analyzing a range of frequencies, such as recording frequency response measurements, matching voice patterns, or displaying spectrum information on the face of an amateur radio. To meet this challenge most engineers use the well-known FFT. The CZT gives the engineer the flexibility to specify bandwidth and outputs real and imaginary frequency components from which the magnitude and phase can be computed. A description of the CZT and a discussion of the advantages and disadvantages of CZT versus the FFT and Goertzel algorithms will be followed by situations in which the CZT would shine. The reader will find that the CZT is very useful but that flexibility has a price.

• Research Organization: Bechtel Nevada Corporation (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC08-96NV11718
• OSTI ID: 816417
• Report Number(s): DOE/NV/11718--833
• Journal Information: Embedded Systems Programming magazine, Journal Name: Embedded Systems Programming magazine
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
ALGORITHMS
DATA TRANSMISSION
FLEXIBILITY
FOURIER TRANSFORMATION
FREQUENCY ANALYSIS
POWER TRANSMISSION LINES
PROGRAMMING
SIGNAL CONDITIONING
TELEPHONES