Patent ID: 8452828
Filing Date: 2013-05-28
Classification: H03H

Abstract:
1. A digital filter comprising: a filter input for inputting signal samples; a filter output for outputting a filtered sampled signal; a buffer coupled to the filter input, the buffer acting as a queue; a register having an input coupled to a first data output of the buffer; a subtractor having a minus input coupled to an output of the register and a plus input coupled to a second data output of the buffer for obtaining differences between a plurality of time-shifted signal samples and a second plurality of time-shifted signal samples output from the buffer, wherein each pair of samples of the first and second plurality of time-shifted samples output from the buffer represents a rectangular impulse response such that the incoming data sample is convolved with each of a plurality of rectangular impulse responses in time; an accumulator input coupled to an output of the subtractor for keeping a running sum of the plurality of differences, and an output coupled to the filter output; and a controller coupled to the buffer and accumulator, the controller configured to rotate through the buffer for addresses where a next incoming signal sample will be written to and where a previously written signal sample will be read from, and controls whether a difference is added to or subtracted from the running sum.