System for controlling and shaping the spectrum and redundancy of signalpoint limited transmission
DCFirst Claim
1. A method of spectrally shaping transmitted samples with a set of predetermined frequency characteristics and a predetermined set of allowable transmitted signal levels, wherein a transmitted sample is either of an unmodified source sample or a dependent sample, the transmitted samples being transmitted in data frames, said method comprising the steps of:
 (a) calculating, for each of the transmitted samples, a Running Filter Sum of unwanted components up to the current sample, wherein said Running Filter Sum is based on a biquad filter;
(b) computing an objective function in accordance with the Running Filter Sum obtained in Step (a);
(c) selecting, for each data frame of transmitted samples, at least one redundant sample to be added or modified within the data frame such that the objective function of Step (b) is optimized.
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Abstract
Methods and apparatus are disclosed for shaping and controlling the spectrum of transmitted samples with a set of predetermined frequency characteristics and a predetermined set of allowable transmitted signal levels are disclosed. In particular, methods of minimizing the energy of the signal at unwanted frequencies are described. For each of the transmitted samples, the system computes a running measure of unwanted components. It then computes, for each block (or "data frame") of the transmitted samples, an objective function, for example, a running filter sum based upon a biquad filter function. It then selects, for each block or spectral shaping frame of transmitted samples, a sign combination from a signcombination subset such that the objective function is optimized.
25 Citations
36 Claims

1. A method of spectrally shaping transmitted samples with a set of predetermined frequency characteristics and a predetermined set of allowable transmitted signal levels, wherein a transmitted sample is either of an unmodified source sample or a dependent sample, the transmitted samples being transmitted in data frames, said method comprising the steps of:

(a) calculating, for each of the transmitted samples, a Running Filter Sum of unwanted components up to the current sample, wherein said Running Filter Sum is based on a biquad filter; (b) computing an objective function in accordance with the Running Filter Sum obtained in Step (a); (c) selecting, for each data frame of transmitted samples, at least one redundant sample to be added or modified within the data frame such that the objective function of Step (b) is optimized.  View Dependent Claims (2, 3, 4, 5, 6, 7)


8. A method of spectrally shaping source samples to transmitted samples based on a set of predetermined characteristics of a frequency spectrum, wherein the allowable signal levels of the transmitted samples are limited to a prescribed set, and wherein the source samples are partitioned into data frames, said method comprising the steps of:

(a) calculating, for a current data frame and a predetermined number of additional data frames, a Running Filter Sum of unwanted signal levels, wherein said Running Filter Sum is based on a biquad filter; (b) computing an objective function in accordance with the Running Filter Sum obtained in Step (a); and (c) selecting, for the current data frame of source samples, at least one redundant sign for optimization of the objective function computed in Step (b).  View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)


20. A system for controlling and shaping transmitted data samples having predetermined frequency characteristics and allowable transmit signal levels, wherein the transmitted samples are partitioned into data frames, said system comprising:

a microprocessor configured to; (a) calculate, for a current data frame and a predetermined number of additional data frames, a Running Filter Sum to obtain a measure of unwanted signal components of source samples up to at least the current block, wherein said Running Filter Sum is based on a biquad filter; (b) compute an objective function based on the Running Filter Sum; (c) select, for the current data frame of source samples, at least one redundant sign to optimize the objective function; and a semiconductor memory device for storing and enabling the microprocessor to access the Running Filter Sum, the objective function, and the redundant sample.  View Dependent Claims (21, 22, 23, 24, 25)


26. A method of spectrally shaping transmitted samples with a set of predetermined frequency characteristics and a predetermined set of allowable transmitted signal levels, wherein each of said transmitted samples comprises an amplitude and a sign, and wherein said transmitted samples are transmitted in data frames corresponding to groups of input data bits, and wherein each of said data frames is divided into at least one spectral shaping frame, said method comprising the steps of:

(a) partitioning each of said groups of input data bits into; a first subgroup used to select the amplitudes of said transmitted samples in said data frame; and a second subgroup used to select a signcombination subset for each of said spectral shaping frames in said data frame, wherein said signcombination subsets comprise sign combinations which differ from each other by more than one sign bit; (b) calculating, for each of said transmitted samples, a Running Filter Sum of unwanted components up to at least the current spectral shaping frame for at least two of said sign combinations in said signcombination subset, wherein said Running Filter Sum is based on a biquad filter; (c) computing an objective function in accordance with said Running Filter Sum obtained in step (b); (d) selecting, for each of said spectral shaping frames of transmitted samples, a sign combination from said signcombination subset such that said objective function of step (c) is optimized.  View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36)

Specification