Patent ID: 8571154

Claim:
A method of adjusting a delay in a controlled propagation path of a first signal (S 1 ) to that of an uncontrolled propagation path of a second signal (S 2 ) using a time-delay based control architecture, the method comprising: a) generating a first autocorrelation value from a sampled first signal (S 1,0 ) received over the controlled propagation path and a delayed sampled second signal (S 2,1 ) received over the uncontrolled propagation path; b) generating a second autocorrelation value from a delayed sampled first signal (S 1,2 ) and the delayed sampled second signal (S 2,1 ); c) computing a first difference value by subtracting the first autocorrelation value from the second autocorrelation value; d) amplifying the first difference value by a first gain; e) selecting one of the first and second autocorrelation values as a first autocorrelation selection value; f) generating a third autocorrelation value from a sampled band-limited first signal (S′ 1,0 ) and a delayed sampled band-limited second signal (S′ 2,1 ); g) generating a fourth autocorrelation value from a delayed sampled band-limited first signal (S′ 1,2 ) and the delayed sampled band-limited second signal (S′ 2,1 ); h) computing a second difference value by subtracting the third autocorrelation value from the fourth autocorrelation value; i) amplifying the second difference value by a second gain; j) selecting one of the third and fourth autocorrelation values as a second autocorrelation selection value; k) comparing the first autocorrelation selection value to the second autocorrelation selection value to select the larger of the first autocorrelation selection value and the second autocorrelation selection value; l) selecting one of the first or second amplified difference value associated with the larger autocorrelation selection value as a control error signal; m) filtering the control error signal to form a variable delay control signal; n) applying the variable delay control signal to a variable delay device in the controlled propagation path of the first signal; o) repeating steps (a)-(n) until the magnitude of the variable delay control signal is less than a first predetermined threshold, thereby indicating a time delay match between the outputs of the first received signal and the second received signal, where S M,N is signal M with a delay of N ΔT, where S′ M,N is a band limited signal M with a delay of N ΔT, and where M is the signal index, N is the delay index, and ΔT is the unit delay time.