US 5,790,784 AGranted

Network for time synchronizing a digital information processing system with received digital information

AssigneeDelco Electronics Corporation

InventorsTerrance Ralph Beale, Roger Alan McDanell

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Abstract

A synchronization network that provides frame timing that is particularly suited for a Eureka-147 system is disclosed. The synchronization network reduces the typical amount of computations required to provide for frame timing schemes and includes matched filtering operations that separate the waveforms of null and sine symbols contained in the multiple carriers of the Eureka-147 system. The matched filtering technique are accomplished before a fast Fourier transform operation and which accomplishments elimination of the need of an inverse fast Fourier transform operation normally performed by one of the receiver elements of the Eureka-147 system. This elimination is accomplished without degrading the performance of the Eureka-147 system.

Claims17

Dependent claims

A method of time synchronizing a digital information receiving system with received digital information defined by a number of synchronization symbols including a predefined null symbol followed by a predefined sine-sweep symbol, followed by multiple adjacent data carriers transmitted simultaneously over a predetermined frequency range, wherein each of the multiple data carriers is modulated over time, comprising the steps of:

(1) detecting the null symbol and determining therefrom a first estimate of time to occurrence of the sine-sweep symbol;
(2) delaying the first estimate of time and thereafter match-filtering the digital information with a replica of the sine-sweep symbol to produce a matched filter output;
(3) determining a frequency at which the matched filter output has peak energy;
(4) converting the frequency at which the peak energy occurs to a time offset representing a second estimate of time to occurrence of the multiple adjacent carriers of the digital information;
and
(5) delaying the second estimate of time prior to processing the multiple adjacent data carriers to thereby time synchronize the digital information receiver with the received digital information.

3 more elements

A network for time synchronizing a digital information receiving system with received digital information defined by a number of synchronization symbols including a predefined sine-sweep symbol, followed by multiple adjacent data carriers transmitted simultaneously over a predetermined frequency range, wherein each of the multiple data carriers is modulated over time, the system including a timer for controlling the rate at which the digital information is sampled, the network comprising:

a matched filter including an input and an output, said matched filter being operable to receive the digital information at its input, compare the digital information with a replica of the sine-sweep symbol, and provide a corresponding filter signal at its output;
means for transforming the filter signal to a frequency domain-energy distribution representation thereof;
a power analyzer having an input and an output, said power analyzer being operable to receive the transformed signal at its input, determine a peak energy from the energy distribution thereof and corresponding frequency at which the peak energy occurs, and provide a frequency value equal to the frequency at which the peak energy occurs at its output;
and
means for converting the frequency value to a time offset value and providing the time offset value to the timer;
wherein the timer is operable to adjust the rate at which the digital information is sampled in accordance with the time offset value to thereby synchronize the digital information receiving system with the received digital information.

3 more elements

Dependencies are inferred from the claim text.