Asynchronous and non-data decision directed equalizer adjustment
First Claim
1. Apparatus for adjusting an equalizer which compensates for the distortion in a modulated carrier signal comprising component signals and a time-varying signal envelope, said apparatus comprisingmeans for extracting data signals individually from said carrier signal, each of said data signals having less distortion than an associated one of said component signals and each of said data signals being a component of said signal envelope,means for forming a predetermined combination of said data signals,first means for comparing said combination of data signals to a threshold, andmeans responsive to said comparing means for generating an equalizer adjustment signal from said data signals and said combination of data signals.
1 Assignment
0 Petitions
Accused Products
Abstract
Equalizers, which provide distortion compensation for a modulated carrier signal having a time-varying signal envelope, are adjusted at selected times in response to the signal envelope and the data signals regenerated therefrom. Each selected time corresponds to a time when the signal envelope has a preselected value. Advantageously, the disclosed equalizer adjustment is unaffected by loss of receiver synchronization to the modulated carrier signal and is applicable to a variety of communications systems and modulation formats.
63 Citations
15 Claims
-
1. Apparatus for adjusting an equalizer which compensates for the distortion in a modulated carrier signal comprising component signals and a time-varying signal envelope, said apparatus comprising
means for extracting data signals individually from said carrier signal, each of said data signals having less distortion than an associated one of said component signals and each of said data signals being a component of said signal envelope, means for forming a predetermined combination of said data signals, first means for comparing said combination of data signals to a threshold, and means responsive to said comparing means for generating an equalizer adjustment signal from said data signals and said combination of data signals.
-
14. Apparatus for compensating for distortion in a modulated carrier signal having a time-varying signal envelope, said apparatus comprising
means for demodulating said carrier signal to form data signals individually, each of said data signals being a component of said signal envelope, equalizer means for receiving said data signals and providing distortion compensation, said equalizer means having tap-weight coefficients which affect the compensation provided, means for forming a preselected combination of said data signals, means for comparing said combination to a threshold, and means responsive to said comparing means for forming an equalizer adjustment signal from said data signals and said combination, said adjustment signal altering said tap-weight coefficients.
-
15. A method of adjusting an equalizer which compensates for the distortion in a modulated carrier signal comprising component signals and a time-varying signal envelope, said method comprising the steps of
extracting data signals individually from said carrier signal, each of said data signals having less distortion than an associated one of said component signals and each of said data signals being a component of said signal envelope, forming a preselected combination of said data signals, determining when said combination has at least a preselected value, and forming said equalizer adjustment signal in response to said data signals and said combination when the latter has at least said preselected value.
Specification