A method of adjusting a delay in a controlled propagation path of a first signal (S1) to that of an uncontrolled propagation path of a second signal (S2) using a time-delay based control architecture, the method comprising:
- a) generating a first autocorrelation value from a sampled first signal (S1,0) received over the controlled propagation path and a delayed sampled second signal (S2,1) received over the uncontrolled propagation path;
- b) generating a second autocorrelation value from a delayed sampled first signal (S1,2) and the delayed sampled second signal (S2,1);
- 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 SM,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.