Autoranging apparatus and method for improved dynamic ranging in analog to digital converters

An autoranging apparatus for optimally scaling inputs to an analog to digital converter (ADC) to thereby increase dynamic range, the apparatus comprising:

• an anti-aliasing (AA) filter for receiving the incoming signal and producing an AA filtered signal;
• an proposed gain detector for receiving in parallel the incoming signal, determining its peak of absolute value, and converting this value into a proposed gain;
• a gain setting rule processor for receiving the proposed gain and a resolution bandwidth (RBW) value and outputting a current gain which is received again by the gain setting rule processor, the current gain determined by these inputs;
• a variable amplifier means for receiving the current gain, setting a gain level, and producing an amplified signal from the AA filtered signal;
• a sample and hold device for producing a sampled signal from the amplified signal at a clock sample frequency f.sub.clk ;
• an ADC for converting the sampled signal to a digital word;
• a look-up table comprised of scaling ranges stored in an accessible memory device;
• and
• a scaling processor for appropriately scaling the digital word, based upon the scaling ranges stored in the look-up table, to compensate for added gain.