A low cost FFT chip set

The current generation of LSI signal processors has opened a whole range of new commercial applications using real time signal processing. Among the more attractive of these areas are speech compression, speech recognition, telephone line conditioning, and voice grade modems. This paper illustrates the feasibility of implementing an FFT on voiceband signals in real time. A compact, low cost chip set comprised of a Texas Instruments TSM320 signal processor, two 2kx8 CMOS RAMS, plus a couple of standard MSI components has been designed to perform a 1024 point complex FFT. Intitial analysis indicates that the system executes the transform in 78msec, a rate commensurate with real time processing at sampling rates up to 12.8kHz. The total cost of the components, in volume, is approximately $150, and is likely to decline as the TMS320 fabrication process traverses the learning curve.