Electronic scanning switch for sonar

Claim 1

For use in steering the beam formed by a sonar transducer which includes a plurality of transducer elements ordered in spaced array, electronic scanning switch means comprising: a. a selector bank of switchable amplifiers each having as an input the recEived signal from one of said transducer array elements, said amplifiers being arranged in a plurality of groups with the amplifiers of each group connected to provide a common output; b. an interpolator bank of switchable amplifiers each having as an input the output of one of said selector bank amplifier groups, said interpolator bank amplifiers being arranged in a plurality of groups with the amplifiers of each group connected to provide a common output; c. scan control means providing a digital count signal representative of desired beam position; d. first scanning signal generating means responsive to said beam position signal to generate a coarse control signal and including means applying such coarse control signal to said selector bank amplifiers to cause the same to pass the received signal inputs from at least two adjacent array elements for positioning the beam formed thereby in discrete steps of magnitude determined by the spacing between array elements; e. second scanning signal generating means including digital clock and clock counter means providing a clock count which recycles continuously and with periodicity defining an interpolation period, comparator means connected to compare said beam position digital count signal against said digital clock count and to produce a fine control signal each time correspondence therebetween is found, and means applying said fine control signal to said interpolator bank amplifiers for switching the same at a point during each interpolation period such that the output of each amplifier group represents an interpolation of the array element inputs passed therethrough during that period, to thus provide fine control of beam position between adjacent coarse positions.