Patent ID: 6307903
Filing Date: 2001-10-23
Classification: H03H,H04L

Abstract:
A low pass receive filter for filtering high frequency components from an input signal represented by a digital data stream, said digital data stream containing a plurality of digital data elements, with each digital data element containing a small number of bits, said low pass filter comprising:a converter to receive said digital data stream and to generate as output an integer in the interval K to -K, wherein K is an integer representing the range of the final output data stream;a Hogenauer decimating filter coupled to said converter, said Hogenauer decimating filter to decimate the output of said converter to generate a decimated output, wherein said decimated output exhibits a non-flat pass-band spectral amplitude response;an equalizer filter coupled to said Hogenauer decimating filter, said equalizer to process said decimated output to flatten said non-flat pass-band spectral amplitude response;a polyphase decimation filter coupled to said equalizer, said polyphase decimation filter to process the output of said equalizer filter; anda spectral cleanup filter coupled to said polyphase decimation filter, said spectral cleanup filter to process the output of said decimation filter to modify the spectrum at band edges of said decimating filter.