Texas Instruments Corporation

The United States of America As Represented by the Secretary of

William Dorsey Daniels

Leslie Alexander Priebe

Robert A Maher

James Benedict Couvillon

Michael C Stephens

Ronald Lee Gassner

The parameters of a digital signal are extracted by the application of autocorrelation and crosscorrelation techniques to effectively measure the frequency and time behavior of a digital signal. The method employs digital autocorrelation and crosscorrelation to determine these parameters. Autocorrelation allows the measurement of signal frequency by measurement of instantaneous signal phase. Crosscorrelation allows measurement of relative phase between two or more signals in two or more channels by measurement of instantaneous phase and by referencing the instantaneous phase to the autocorrelation function. The autocorrelation function and crosscorrelation function preserve relative amplitude and phase. Measurement of relative amplitude and phase allows direction finding calculation for any current class of system that uses amplitude and/or phase to derive angle or arrival. Signal time and frequency measurement at the output of a correlation receiver result in robust characterization of the parameters of the signal. Digital calculations are superior to current analog or hybrid analog and digital methods because errors due to component aging, drift and temperature effects are easily prevented.

Digital processing method for parameter estimation of synchronous,

Disclosed is improved distance measuring equipment comprising an airborne FM coded, chirp, interrogator transmitter in combination with a weighted matched receiver in a ground transponder. The airborne transmitter produces a long low power frequency modulated output pulse. Detection in the transponder receiver is accomplished by pulse compression matched filter techniques.

Distance measuring equipment

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Richardson, TX, United States of America

William Dorsey Daniels