US4439863A — Partial response system with simplified detection

Claim 1

Independent Claim 122 words

A method of processing output signals which result from quadrature channel partial response filtering of input signals, there being a complete set of possible output signals corresponding to a particular set of input signals, all of said signals having a pulse interval associated therewith, the method comprising: detecing modified output signals in a detection set comparable to said input signal set and generating estimates of input signals based on the modified output signals detected, and modifying said system output signals so that the set of modified system output signals which are possible in the next interval is a translated subset of said complete set and conforms to said detection set, thereby deriving estimates of said input signals from said system output signals.

Claim 2

Independent Claim 122 words

A method of processing output signals which result from quadrature channel partial response filtering of input signals, there being a complete set of possible output signals corresponding to a particular set of input signals, all of said signals having a pulse interval associated therewith, the method comprising: detecing modified output signals in a detection set comparable to said input signal set and generating estimates of input signals based on the modified output signals detected, and modifying said system output signals so that the set of modified system output signals which are possible in the next interval is a translated subset of said complete set and conforms to said detection set, thereby deriving estimates of said input signals from said system output signals.

Claim 3

Dependent Claim 25 words

The invention according to claim 1 wherein said subset has the same number of points and same distribution array pattern as said input signal set.

Claim 4

Dependent Claim 26 words

The method of claim 1, wherein said system output signals are modified based on at least one input signal estimate from the current and preceding intervals.

Claim 5

Dependent Claim 32 words

The invention according to claim 3 wherein said signal subset includes the signal point of the current interval and the locus of possible partial response output signal points for the next interval.

Claim 6

Dependent Claim 53 words

The invention according to claim 1 comprising generating said signal subset by quadrature decision feedback subtracting of any contributions to the signal of the current interval arising from signals in previous intervals due to partial response filtering, and wherein said signal subset is translated to a constant position within said output signal set.

Claim 7

Dependent Claim 90 words

In a quadrature channel partial response system having a set of input signals and having output signals giving rise to a complete output signal set and including means for detecting only a subset of said complete set, the improvement comprising quadrature interdependent channel decision feedback means, responsive to the detecting means, for selecting changes to be made in the output signals; and means, responsive to the selected changes and to the output signals, for generating a translated subset of the complete output set as an input for said detecting means.

Claim 8

Dependent Claim 90 words

In a quadrature channel partial response system having a set of input signals and having output signals giving rise to a complete output signal set and including means for detecting only a subset of said complete set, the improvement comprising quadrature interdependent channel decision feedback means, responsive to the detecting means, for selecting changes to be made in the output signals; and means, responsive to the selected changes and to the output signals, for generating a translated subset of the complete output set as an input for said detecting means.

Claim 9

Dependent Claim 41 words

The invention according to claim 6 wherein said generated output signal subset has the values, scaled down, of the input signal set, and said selecting and generating means provide determined translations of said signal subset within said complete output signal set.

Claim 10

Dependent Claim 46 words

The invention according to claim 7 wherein said detecting means provides input signal estimates associated with sample times, and said selecting and generating means provide said translations for each sample time, determined by the value of at least one input signal estimate of previous sample times.

Claim 11

Dependent Claim 23 words

The invention according to claim 6 wherein said generated output signal subset has the same number of points as the input signal set.

Claim 12

Dependent Claim 37 words

The invention according to claim 9 wherein said translated output signal subset has the same distribution array pattern as said input signal set, whereby said means for detecting can comprise means for detecting the input signal set.

Claim 13

Dependent Claim 150 words

Apparatus for use with a system in which quadrature channel input signals are partial response filtered to provide output signals, there being a complete set of possible output signals corresponding to a particular set of input signals, all of said signals having a pulse interval associated therewith, the apparatus comprising: means for detecting modified output signals in a detection set comparable to said input signal set and generating estimates of input signals based on the modified signals detected, and means responsive to at least one input signal estimate from the current and preceding intervals, for modifying said system output signals so that the set of modified system output signals which are possible in the next interval is a translated subset of said complete set and conforms to said detection set, forming an input to said means for detecting, thereby deriving estimates of said input signals from said system output signals.

Claim 14

Dependent Claim 150 words

Apparatus for use with a system in which quadrature channel input signals are partial response filtered to provide output signals, there being a complete set of possible output signals corresponding to a particular set of input signals, all of said signals having a pulse interval associated therewith, the apparatus comprising: means for detecting modified output signals in a detection set comparable to said input signal set and generating estimates of input signals based on the modified signals detected, and means responsive to at least one input signal estimate from the current and preceding intervals, for modifying said system output signals so that the set of modified system output signals which are possible in the next interval is a translated subset of said complete set and conforms to said detection set, forming an input to said means for detecting, thereby deriving estimates of said input signals from said system output signals.

Claim 15

Dependent Claim 34 words

The apparatus of claim 11, wherein said system output signals are modified so as to remove the residual response in the next interval due to input signals associated with the current and preceding intervals.

Claim 16

Dependent Claim 179 words

In a PSK or an APSK partial response filter system generating an output S k represented by ##EQU3## where: K is the current sample time of the channel output; S k is a vector representing both I and Q channel outputs; N is the number of signal intervals over which an input pulse is spread by the partial response filter; α i is the residual response of a unit amplitude pulse applied i signal intervals earlier; and E k-i is the input amplitude vector applied to the I and Q channels i intervals before the present sample time k, an improvement for obtaining estimates E k of input vector values E k , comprising: detector means for generating said estimates E k from a modified output vector S' k by detecting the components of a vector α o E k , where α o is a scale factor, and means, including quadrature interdependent channel decision feedback, responsive to said output vector S k and said estimates E k , for generating said modified output S' k according to: ##EQU4##

Claim 17

Dependent Claim 179 words

In a PSK or an APSK partial response filter system generating an output S k represented by ##EQU3## where: K is the current sample time of the channel output; S k is a vector representing both I and Q channel outputs; N is the number of signal intervals over which an input pulse is spread by the partial response filter; α i is the residual response of a unit amplitude pulse applied i signal intervals earlier; and E k-i is the input amplitude vector applied to the I and Q channels i intervals before the present sample time k, an improvement for obtaining estimates E k of input vector values E k , comprising: detector means for generating said estimates E k from a modified output vector S' k by detecting the components of a vector α o E k , where α o is a scale factor, and means, including quadrature interdependent channel decision feedback, responsive to said output vector S k and said estimates E k , for generating said modified output S' k according to: ##EQU4##

Claim 18

Dependent Claim 24 words

The invention according to claim 13 comprising delaying the feedback of each α i E k-i by iT where T equals one signaling interval.

Claim 19

Dependent Claim 27 words

The method of claim 1, wherein the values of the signal points in said subset are scaled down compared to signal points of said input signal set.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1987-03-27	1987-09-26	1988-03-27	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1991-03-27	1991-09-26	1992-03-27	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1995-03-27	1995-09-26	1996-03-27	$7700.00	Window Closed / Lapsed

Partial response system with simplified detection

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