Steerable parametric conversion array

Claim 3

The method of claim 1, further including the step of delaying each correlated cross-modulation product by the amount required to insure that said correlated products are in phase, whereby said correlated products can be summed to produce a single output proportional to the said incoming waves.

Claim 4

The method of claim 2, wherein the step of correlating said received products with delayed replicas of said noise signal includes the steps of: a. feeding said generated noise signal in parallel to a plurality of delay networks, each of said networks providing a delay corresponding to the time required for said projected noise signal to travel to a selected segment and back to a receiver, whereby each of said delay networks corresponds to one of said segments; b. feeding said received cross-modulation products in parallel to a plurality of correlators, each of said correlators receiving a delayed replica of said noise signal from a corresponding one of said delay networks; c. comparing in each said correlator the noise signal portion of said received cross-modulation products with the noise signal replica from the corresponding delay network; and d. producing an output signal from the correlator in which during a given time period the noise signal portion of the received crossmodulation products is coherent with the noise signal replica being supplied thereto.

Claim 5

The method of claim 3, further including the step of delaying by a selected amount the outputs of each of said correlators, whereby said virtual array will have a maximum response to incoming waves from a selected direction.

Claim 6

The method of claim 4, further including the steps of: a. generating a second substantially random noise signal and projecting said second signal in a direction to intersect said incoming waves, said second projected signal forming a second listening beam which diverges from the first said listening beam and which interacts with said incoming waves to produce second cross-modulation products; b. receiving said second cross-modulation products; and c. correlating said second received cross-modulation products with delayed replicas of said second noise signal whereby the cross-modulation products from selected segments of said second listening beam are obtained, said second selected segments forming a second virtual receiving array, said first and second noise signals thereby permitting split-beam cross-correlation signal processing.

Claim 9

The system of claim 6, further including variable delay means connected to each of said correlators, said variable delay means being adjustable to control the phase relationships of the output signals from said correlators, whereby the directional sensitivity of said listening bema can be controlled.

Claim 10

The system of claim 6, wherein said means for feeding a differently delayed replica of said noise signal to each of said correlators includes a plurality of delay networks, the delay time of each network corresponding to the time required for said projected noise signal to travel from said means for projecting to a selected segment of said volume of interaction and thence to said receiver means, and each delay network having a different delay time to thereby correspond to a different segment of said zone of interaction, whereby each said segment acts as an element of a virtual receiving array.

Claim 11

The system of claim 8, wherein said means for feeding a differently delayed replica of said noise signal to each of said correlators further includes means for supplying said noise signal simultaneously to each of said delay networks and means for feedng the delayed replicas of said noise signal produced by each delay network to corresponding one of said correlators.

Claim 12

The system of claim 9, further including a plurality of variable delay networks, each of said variable delay networks being connected to a corresponding one of said correlators and being adjustable to control the phase relationships of the output signals from said correlators, whereby the directional sensitivity of said listening beam can be controlled.

Claim 13

The virtual array of claim 10, further including summing mmeans for adding the output signals from said correlator to produce a single output corresponding to said incoming signal.

Claim 14

The system of claim 10, wherein the time delay of each of said variable delay networks is individually adjustable too control the phase relationships of the output signals from said correlators, whereby the direction of maximum sensitivity of said system can be varied.

Claim 15

The system of claim 8, wherein the cross-modulation products produced at a given one of said segments includes as a component thereof said noise signal, said noise component of said received crossmodulation products being correlated with the delayed replica that is produced by the delay network corresponding to said given segment, whereby the cross-modulation products from said given segment can be isolated.

Claim 16

The system of claim 13, wherein the cross-modulation products produced at said given segment include as components thereof signals representing the sum of said noise signal and said incoming wave and the difference between said noise signal and said incoming wave, said sum and difference signals appearing at the output of the correlator in which the noise component of said received cross-modulation signal is coherent with a delayed replica of said noise signal.

Claim 17

The system of claim 6, further including: a. second means for generating a substantially random acoustic wave noise signal distinct from the first said noise signal; b. second means for projecting said second noise signal in a direction to intersect said incoming waves, said second projected signal forming a second listening beam divergent from the first said listening beam and defining a second volume of interaction wherein the simultaneous propagation of said second projected signal and said incoming waves produces second cross-modulation products; c. second receiver means for receiving said second cross-modulation products, said second receiver means including a second plurality of correlators; d. second means for feeding said received second cross-modulation products simultaneously to said second plurality of correlators; and e. second means for feeding to each of said second plurality of correlators a differently delayed replica of said second noise signal for comparison to said second cross-modulation products, each of said second plurality of correlators producing an output signal corresponding to said incoming wave when the delayed replica fed thereto is coherent with an element of the received second cross-modulation products, whereby the outputs from said first and second correlators may be cross correlated to obtain said incoming signal.