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Anti-Image Filter with Zeroes at Multiples of the Sampling Frequency

IP.com Disclosure Number: IPCOM000016707D
Publication Date: 2003-Jul-09

Publishing Venue

The IP.com Prior Art Database

Abstract

An analog anti-image filter, with zeroes at multiples of a Digital to Analog Converter (DAC) sampling frequency, processes analog data prior to the DAC. The anti-image filter may be implemented as a first, second, third, fourth, fifth, sixth, or higher order analog filter, and may be optimized to provide a flat group-delay (assuming ideal components) from DC through the cut-off frequency and beyond. The anti-image filter includes a sample-and-hold (S&H) circuit that may serve as a first stage of a Successive Approximation (SA) DAC. As with standard analog anti-image filters, the anti-image filter may derive additional benefits from over-sampling and digital decimation.