Control apparatus

Claim 2

Apparatus including sonar signal receiving means on board a vessel which itself is the source of intErference signals, the apparatus incorporating means for receiving compensating input signals prior to the apparatus output for the purpose of reducing the amplitude of the components of the apparatus output signal arising from the interference signals, the improvement comprising, in combination: vibration sensing means mounted on board the vessel for sensing at least one interference signal of a given frequency; and means connecting said vibration sensing means to said sonar signal receiving means for passing only the interference signal of said given frequency and applying it as a compensating input signal which is continuously adjusted both in phase and amplitude in response to the phase and amplitude of the sensed interference signal so as to substantially reduce the amplitude of the component of the apparatus output signal resulting from the interference signal.

Claim 3

Apparatus as claimed in claim 1 wherein said means connecting said vibration sensing means to said sonar receiving means includes a variable frequency band-pass filter and two phase sensitive detectors operating in quadrature for supplying quadrature input signals which are adjusted in amplitude to effectively produce the compensating input signal which is phase and amplitude adjusted as a function of time.

Claim 4

Apparatus for reducing the amplitude of self-generated interference in signals received at a signal processing station utilizing a receiver which supplies received information signals plus received interference signals, through a summing amplifier having a plurality of inputs, to an information signal output, said apparatus comprising, in combination: interference signal sensor means connected to said station for supplying as an output at least one signal of a given frequency; first means including a narrow band-pass filter connected to said sensor means for receiving signals therefrom and providing as output signals first inphase and first quadrature output signals corresponding in frequency to the signal received from said sensor means; first feedback means connected to said apparatus output, an input of the summing, and said first means for providing a second inphase output signal, of the frequency of said first inphase signal, and indicative in amplitude of a first phase component in the received interference signals, which is of a phase to cancel the first phase component in the received interference signals and of the frequency of said second inphase signal; and second feedback means connected to said apparatus output, an input of the summing amplifier and said first means for providing a second quadrature output signal in quadrature with said second inphase signal, of the frequency of said first quadrature output signal, and indicative in amplitude of a second phase component in the received interference signal, which is of a phase to cancel the phase component in the received interference signal which is in quadrature with the first phase component and of the frequency of said second quadrature output signal.

Claim 5

Apparatus for reducing the amplitude of self-generated interference in signals received at a signal processing station utilizing a receiver which supplies received information signals plus received interference signals, through a summing amplifier having a plurality of inputs, to an information signal output, said apparatus comprising, in combination: interference signal sensor means connected to said station for supplying as an output at least one signal of a given frequency; first means including a narrow band-pass filter connected to said sensor means for receiving signals therefrom and providing as output signals first inphase and first quadrature output signals corresponding in frequency to the signal received from said sensor means; first feedback means connected to said apparatus output, an input of the summing, and said first means for providing a second inphase output signal, of the frequency of said first inphase signal, and indicative in amplitude of a first phase component in the received interference signals, which is of a phase to cancel the first phase component in the received interference signals and of the frequency of said second inphase signal; and second feedback means connected to said apparatus output, an input of the summing amplifier and said first means for providing a second quadrature output signal in quadrature with said second inphase signal, of the frequency of said first quadrature output signal, and indicative in amplitude of a second phase component in the received interference signal, which is of a phase to cancel the phase component in the received interference signal which is in quadrature with the first phase component and of the frequency of said second quadrature output signal.

Claim 6

Apparatus as claimed in claim 3 wherein said narrow band-pass filter has a variable center frequency.

Claim 7

Apparatus as claimed in claim 3 wherein said filter comprises a phase lock loop which will follow variations in the given frequency.

Claim 8

Apparatus as claimed in claim 3 wherein said first inphase and first quadrature phase output signals are maintained at a substantially constant amplitude.

Claim 9

Apparatus as claimed in claim 3 wherein said first and second feedback means each comprise a phase sensitive demodulator, an integrator and a signal amplitude adjuster for comparing the amplitude of a given phase component of a given frequency interference signal with a reference, integrating the difference, and adjusting the output signal in accordance with the integrated difference.

Claim 12

The method of claim 8 comprising the additional step of dividing the first isolated component into quadrature signals which are individually adjusted in accordance with the second isolated component to produce effectively a variable phase feedback signal to be combined with the received signals.

Claim 13

Apparatus for reducing the amplitude of self-generated sonar interference signals received by a sonar transducer on a vessel comprising, in combination: a sonar transducer; a receiver including a band-pass filter connected to receive signals from said sonar transducer and providing an output first signal comprising both information and interference signal components; summing means, including a plurality of input means, connected to said receiver for receiving the output first signal therefrom and including an output means for providing an output second signal; interference signal sensing means mounted on said vessel for providing an output third signal indicative of frequency components generated internal to the vessel; self-noise interference subtraction means connected to said interference sensing means and to said output means of said summing means for receiving interference signals of a given interference frequency and providing output fourth and fifth signals of said given frequency, which signals are in phase quadrature and individually vary in amplitude in accordance with their respective opposite phase components as received by said subtraction means from said output means of said summing means; and means connecting said output means of said subtraction means to said input means of said summing means for supplying said fourth and fifth signals thereto.

Claim 14

Apparatus for reducing the amplitude of self-generated sonar interference signals received by a sonar transducer on a vessel comprising, in combination: a sonar transducer; a receiver including a band-pass filter connected to receive signals from said sonar transducer and providing an output first signal comprising both information and interference signal components; summing means, including a plurality of input means, connected to said receiver for receiving the output first signal therefrom and including an output means for providing an output second signal; interference signal sensing means mounted on said vessel for providing an output third signal indicative of frequency components generated internal to the vessel; self-noise interference subtraction means connected to said interference sensing means and to said output means of said summing means for receiving interference signals of a given interference frequency and providing output fourth and fifth signals of said given frequency, which signals are in phase quadrature and individually vary in amplitude in accordance with their respective opposite phase components as received by said subtraction means from said output means of said summing means; and means connecting said output means of said subtraction means to said input means of said summing means for supplying said fourth and fifth signals thereto.

Claim 15

Apparatus as claimed in claim 10 comprising in addition a separate subtraction means for each of the interference frequency components generated on the vessel wherein each subtraction means receives input signals from the same source and supplies output signals to said input means of said summing means.

Claim 16

Apparatus as claimed in claim 10 wherein said subtraction means includes; a phase lock loop for receiving input signals from said interference sensor and providing said output fourth and fifth signals of quadrature phase; a first scaling circuit for comparing the output second signal of a given frequency and of a phase component opposite the phase of said output fourth signal to a reference in a first phase sensitive demodulator and integrating the output for adjusting the amplitude of said fourth signal; and a second scaling circuit for comparing the output second signal of a given frequency and of a phase component opposite the phase of said output fifth signal to a reference in a second phase sensitive demodulator and integrating the output for adjusting the amplitude of said fifth signal.