Correlation system using matched signals

• US 3,939,461 A
• Filed: 11/19/1962
• Issued: 02/17/1976
• Est. Priority Date: 11/19/1962
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Parvulescu, Antares
• Primary Examiner(s): Farley, Richard A.
• Application Number:
  US04/238,810
• Time in Patent Office: 4,838 Days
• Field of Search: 343/17.1, 343/100.7, 343/17.2, 340/3, 340/5, 340/15.5, 340/6, 340/16, 340/15.5 C, 340/3 M, 340/15.5 F, 333/70, 333/70 T
• US Class Current: 367/191
• CPC Class Codes: G01V 1/00 Seismology; Seismic or acoustic prospecting or detecting
• CPC Class Codes: H04B 11/00 Transmission systems employing sonic, ultrasonic or infrasonic waves
• CPC Class Codes: Y10S 367/901 Noise or unwanted signal reduction in nonseismic receiving system

Abstract

4. A signal-reconstitution method for signals transmitted through a bounded medium comprising the steps of:

Propagating a first signal from one point in said bounded medium;

Receiving the propagated signal at another point in said bounded medium;

Propagating the received signal from one of said points;

Receiving the second propagated signal at the other of said points;

Reversing the second received signal with respect to time;

Propagating said reversed signal from one of said points in said bounded medium; and,

When a reflecting object is present at the other of said points, receiving an echo signal at the point at which the reversed signal was propagated, the form of said echo signal approximating the form of said first signal.

Claims

1. A method for reconstituting a signal which must be propagated between two points in a bounded physical medium so that an approximation of said signal is recoverable comprising the steps of:

propagating said signal from one point to another point within said bounded medium;

receiving the propagated signal at said other point;

reversing said received signal with respect to time so that it constitutes a signal matched to the characteristic response of the bounded medium between said two points; and

propagating said matched signal through said bounded physical medium from one of said points when a signal approximating said originally propagated signal is desired at the other of said points.

2. A method for reconstituting an impulse signal which must be propagated between two points in a bounded physical medium so that an approximation of the original signal is recoverable comprising the steps of:

propagating an impulse signal from one point to another point within said bounded medium;

receiving the propagated signal at said other point;

reversing said received signal with respect to time so that it constitutes a signal matched to the characteristic response of the bounded medium between said two points; and

propagating said matched signal through said bounded physical medium from one of said points when a signal approximating an impulse signal is desired at the other of said points.

3. A method for obtaining as an output a correlation-function signal approximating the input signal when an impulse must be propagated between two points in a bounded physical medium, said method comprising the steps of:

propagating said impulse from one point to another point within said bounded medium;

obtaining as an output the signal received at said other point;

converting said received signal into a signal reversed in time with respect to said received signal; and

propagating said reversed signal through said bounded physical medium from one of said points when a signal approximating an impulse signal is desired at the other of said points.

4. A signal-reconstitution method for signals transmitted through a bounded medium comprising the steps of:

propagating a first signal from one point in said bounded medium;

receiving the propagated signal at another point in said bounded medium;

propagating the received signal from one of said points;

receiving the second propagated signal at the other of said points;

reversing the second received signal with respect to time;

propagating said reversed signal from one of said points in said bounded medium; and

,

when a reflecting object is present at the other of said points, receiving an echo signal at the point at which the reversed signal was propagated, the form of said echo signal approximating the form of said first signal.

5. A signal-reconstitution method for signals transmitted through a bounded medium comprising the steps of:

propagating an impulse signal from one point in said bounded medium;

receiving the propagated signal at another point in said bounded medium;

propagating the received signal from one of said points;

receiving the second propagated signal at the other of said points;

reversing the second received signal with respect to time;

propagating said reversed signal from one of said points in said bounded medium; and

,

when a reflecting object is present at the other of said points, receiving an echo signal at the point at which the reversed signal was propagated, the form of said echo signal being that of a correlation-function signal having a peak at the center which approximates an impulse.

6. A method for reconstituting a signal which must be propagated through a filter network and will be distorted by the characteristics thereof comprising the steps of:

propagating said signal through said filter network and deriving a doubly-matched signal therefrom, the matching of the signal being to the characteristic response of said network; and

propagating said matched signal twice through said network, a signal approximating the originally propagated signal being derivable at the end of said second propagation.

7. A method for reconstituting an impulse signal which must be propagated through a filter network and will be distorted by the characteristics thereof comprising the steps of:

propagating said impulse signal through said filter network and deriving a signal doubly-matched to the impulse response of said network; and

propagating said matched signal twice through said network, a signal approximating said impulse signal being derivable at the end of said second propagation.

8. A method for reconstituting a signal which must be propagated between two points in a bounded medium so that an approximation of said signal is recoverable comprising the steps of:

propagating said signal from one point to another within said bounded medium and receiving said signal at said other point;

propagating the received signal between said two points and receiving the second propagated signal;

deriving a doubly-matched signal from the signal received as a result of the second propagation;

propagating said doubly-matched signal twice between said two points, the form of the signal at the end of said double propagation approximating the form of a signal to be reconstituted.

9. A method for reconstituting an impulse signal which must be propagated between two points on a bounded medium so that an approximation of said signal is recoverable comprising the steps of:

propagating said impulse signal from one point to another within said bounded medium and receiving said signal at said other point;

propagating the received signal between said two points and receiving the second propagated signal;

deriving a doubly-matched signal from the second received signal;

propagating said doubly-matched signal twice between said two points, the form of the signal at the end of said double propagation approximating the form of the signal to be reconstituted.

10. A system for the correlation of signals propagated through a bounded physical medium comprising:

signal propagating means in said medium at one location;

receiving means in said medium at another location;

means to record a signal received by said receiving means from said propagating means;

means to reverse said recorded signal whereby a matched signal is derived; and

means to propagate the matched signal through said bounded physical medium between said locations.