US 6,188,723 B1 · Finite impulse response filter for wave-shaping digital quadrature amplitude modulation symbols

Abstract

A finite impulse response (FIR) filter for wave-shaping digital quadrature amplitude modulation (QAM) symbols is disclosed, in which multipliers are replaced with multiplexers, the replaced multiplexers are utilized to receive the symbols directly from a symbol encoder without zero (0) interpolations, and the critical path is reduced by shifting the position of a delay device. The filter includes a first FIR means for delaying the externally inputted symbol data, and for utilizing the delayed symbol data as selection signals to sum up the selected multiplication product (selected from among products obtained by multiplying the symbol values by a pre-set filter tab coefficient) and the selected value selected by a first multiplexing means. A second FIR means delays again the delayed symbol data of the first FIR means, and utilizes the delayed symbol data as selection signals to sum up the selected multiplication product and the output value of the first FIR means.

Claims18

Dependent claims

An FIR (finite impulse response) filter comprising:

a first multiplexing means for receiving input symbol data as selection signals to select a first multiplication product from among products obtained by multiplying symbol values by a pre-set filter tab coefficient;
a first FIR means for delaying the input symbol data, and for utilizing the delayed symbol data as the selection signals to sum up a second multiplication product selected from among the products and the first multiplication product;
and
at least one second FIR mans for delaying again the delayed symbol data of said first FIR means, and for utilizing the twice delayed symbol data as the selection signals to sum up a third multiplication product selected from among the products and an output value of said first FIR means.

1 more element

An FIR (finite impulse response) filter comprising:

a first FIR means for circulatively outputting products obtained by multiplying respective symbol values by filter tab coefficients in accordance with count signals (the multiplications being carried out in accordance with a sequence of input symbol data), to match an input operation speed to an output operating speed during a symbol period even without insertions of zeros(0);
a second FIR means for delaying the input symbol data to sum up circulatively outputted values of products obtained by multiplying symbol values by the filter tab coefficients in accordance with count signals (the multiplications being carried out in accordance with a sequence of the input symbol data) and the output values of said first FIR means, based on the delayed symbol data;
and
a third FIR means for summing up circulatively outputted values of products outputted in accordance with count signals and obtained by multiplying symbol values delayed by said second FIR means by the filter tab coefficients, and the output values of said second FIR means.

1 more element

An FIR (finite impulse response) filter comprising:

a first FIR means for circulatively outputting products obtained by multiplying respective symbol values by filter tab coefficients in accordance with count signals (the multiplications being carried out in accordance with a sequence of inputted symbol data), to match an input operation speed to an output operating speed during a symbol period even without insertions of zeros (0);
and
at least one second FIR means for sequentially storing the output values of said first FIR means, to sum up the sequentially outputted values and circulatively outputted values of the products obtained by multiplying the symbol values by a filter tab coefficient in accordance with input symbol data, the circulative outputting being done in accordance with count signals, whereby a critical path is reduced.

Dependencies are inferred from the claim text.

Finite impulse response filter for wave-shaping digital quadrature amplitude modulation symbols

Life of this patent

Finite impulse response filter for wave-shaping digital quadrature amplitude modulation symbols

Life of this patent

Abstract

Claims18