A special-purpose online processor for bandpass analysis

The design of a special-purpose on-line processor for bandpass analysis with application to spectral estimation is described. The processor utilizes a digital filtering procedure based on the frequency shift of the sampled signal spectrum. A peculiarity of the processor is that it performs a bandpass analysis by using a unique set of digital filter coefficients for all the analyzed bands. A small and simple memory is therefore used as coefficient memory, while a special, but not complex, organization with many sections is required for the sample memory. The processing of an audio signal to obtain a type of digital vocoder is also considered. From the point of view of the actual implementation, only MSI and LSI circuits are used for the memory and arithmetic units.