Digital signal processing method for real-time processing of narrow band

Abstract

A digital signal processing method for real-time processing of narrow band signals to provide for reconstitution of dynamic amplitude and harmonics beyond the passband. The method utilizes a digital microprocessor implementing a digital algorithm upon a digitized sample of the analog signals. After processing digital-to-analog conversion circuitry may be used to reconvert the processed digital signal into a processed analog output signal for further use. The digital processing effectively provides a primary voltage compressor (PVC) function for processing signals in m different frequency sub-bands by gain factors, and a summing function for digitally summing the gain products so realized, to provide a primarily compressed signal. The processing method then further effectively provides a secondary dynamic voltage compressor (SDC) function for processing the PVC signal in within n different frequency sub-bands by digitally multiplying signals with each of such sub-bands by gain factors. The further gain products so realized are digitally summed to provide a processed digital output. An AGC gain calculation is also provided by the digital processor for providing a gain-corrected digital output which may then be supplied to D/A converter circuitry. Both fast and slow gain averaging are utilized in making the gain calculation for gain multiplication within each of m sub-bands of the PVC function. The sub-bands m and n of the PVC and SDC functions may be equal in number and have corresponding frequency domains.