dbr Noise Reduction System

dynamic bandwidth reduction is a single ended noise reduction system based on a variable lowpass filter that is controlled by the amount of high frequency content of the source material. When little or no high frequency information is present, the filter’s cutoff moves to a low frequency, rolling off the background noise. As high frequency content increases, so does the cutoff frequency. The design was based around the Signetics NE572 compander, configured as a VCF, controlled by the source signal through a highpass filter. Schematics were later input into OrCAD.

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The schematics for the dbr are available in PDF format here.