Digital partial response filter
First Claim
1. A digital partial response filter for forming a digital representation of the partial response channel response to input digital data, said input digital data having a data symbol period, comprising:
- means for storing digitized samples of a substantially partial response channel response to a representative input data symbol for n data symbol time periods, each data symbol time period divided into m samples, where n and m are finite numbers and for providing as outputs, in succession, m groups of n digitized samples, said n digitized samples provided as samples of said partial response channel response at n equally divided data symbol time periods, each successive group having the digitized samples shifted by one sample in said data symbol time period;
summing means responsive to said input digital data for successively summing the digitized samples of each of said m groups of n digitized samples so as to form said digital representation of the partial response channel response to said input digital data for a data symbol period; and
means for providing said input digital data to said summing means shifted by one data symbol every m groups, whereby to allow said summing means to form the digital representation of the partial response channel response to said input digital data for successive data symbol periods.
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Abstract
A digital partial response filter is disclosed. The digital partial response filter has particular application in an FM subcarrier (SCA) digital data transmission system wherein digital data is frequency modulated on an F.M. subcarrier. The partial response digital filter includes a digital memory wherein digitized samples of the partial response channel response to a representative input digital data symbol are stored and digital adding means for cumulatively summing the digitized samples in groups so as to produce the partial response channel response to an input digital data stream.
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Citations
11 Claims
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1. A digital partial response filter for forming a digital representation of the partial response channel response to input digital data, said input digital data having a data symbol period, comprising:
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means for storing digitized samples of a substantially partial response channel response to a representative input data symbol for n data symbol time periods, each data symbol time period divided into m samples, where n and m are finite numbers and for providing as outputs, in succession, m groups of n digitized samples, said n digitized samples provided as samples of said partial response channel response at n equally divided data symbol time periods, each successive group having the digitized samples shifted by one sample in said data symbol time period; summing means responsive to said input digital data for successively summing the digitized samples of each of said m groups of n digitized samples so as to form said digital representation of the partial response channel response to said input digital data for a data symbol period; and means for providing said input digital data to said summing means shifted by one data symbol every m groups, whereby to allow said summing means to form the digital representation of the partial response channel response to said input digital data for successive data symbol periods. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. The method for forming a digital representation of the partial response channel response to input digital data, said input digital data having a data symbol period, comprising the steps of:
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storing digitized samples of a substantially partial response channel response to a representative input data symbol for n data symbol time periods, each data symbol time period divided into m samples, where n and m are finite numbers and for providing as outputs, in succession, m groups of n digitized samples, said n digitized samples provided as samples of said partial response channel response at n equally divided data symbol time periods, each successive group having the digitized samples shifted by one sample in said data symbol time period; successively summing, in response to said input digital data, the digitized samples of each of said m groups of n digitized samples so as to form said digital representation of the partial response channel response to said input digital data for a data symbol period; and providing said input digital data shifted by one data symbol every m groups, whereby to form the digital representation of the partial response channel response to said input digital data for successive data symbol periods.
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Specification