Half-band filter and method
First Claim
Patent Images
1. A digital filter comprising:
- a first data stream input port for N-bit data samples;
first and second multipliers for downconverting said data samples;
adders for summing partial products of the downconverted data samples and filter coefficients, and with the K least significant bits of each partial product ignored for K a positive integer;
third and fourth multipliers for upconverting the summed partial products, said adders being connected between pairs of said multipliers; and
a local oscillator for providing sines and cosines to said multipliers for up and down conversion.
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Abstract
A digital half-band filter with mutliplications using Wallace trees which have lower bits truncated for reduction in size and with a true/complementer providing saturation compensation together with accumulator overflow compensation by monitoring bits more significant than the output bits.
22 Citations
12 Claims
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1. A digital filter comprising:
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a first data stream input port for N-bit data samples; first and second multipliers for downconverting said data samples; adders for summing partial products of the downconverted data samples and filter coefficients, and with the K least significant bits of each partial product ignored for K a positive integer; third and fourth multipliers for upconverting the summed partial products, said adders being connected between pairs of said multipliers; and a local oscillator for providing sines and cosines to said multipliers for up and down conversion. - View Dependent Claims (2, 3, 4)
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5. A digital filter comprising:
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two ports for receiving streams of data bits; an odd coefficient filter arm comprising a first of said input ports, a first downconversion multiplier, a first finite impulse response (FIR) filter, and a first upconversion multiplier all coupled in series; an even coefficient filter arm comprising a second of said input ports, a second downconversion multiplier, a second FIR filter, and a second upconversion multiplier all coupled in series; and an oscillator for providing sines and cosines, the sines being provided to said second downconversion multiplier and to said second upconversion multiplier, the cosines being provided to said first downconversion multiplier and to said first upconversion multiplier. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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Specification