Dual delayed sequence generator with read only memory control for 256 output triples for plane and spherical wave-front simulations

Claim 1

A dual delayed sequence generator for producing different sonar wavefront simulations comprising: a shift register of a plurality of multibit flatpac stages, each stage having an output with a predetermined combination of stage outputs coupled through exclusive OR gates to the first stage input as a feedback to establish a predetermined linear sequence of bits through said shift register providing an original sequence or reference delay on said stage outputs; a clock pulse source coupled in common to said shift register stages to drive same to shift the feedback input therethrough; a NAND gate switch coupled one each to one each shift register stage output, each gate switch having a gating input and an output; a read only memory having a plurality of outputs, one each output being coupled to one each NAND gate switch gating input, and said read only memory having a plurality of control inputs; a counter circuit having a plurality of outputs coupling said plurality of inputs of said read only memory, combinations of said counter circuit outputs being selectable to produce selected outputs of said read only memory to produce selected outputs from said NAND gate switches to select and gate through the aforementioned linear sequence as it appears at the various shift register stage outputs; a multiple exclusive OR circuit with the NAND gate switch outputs coupled to a modulo-2 manner through the circuit to a single output to reproduce the sequence of said shift register to any desired delay with respect to the reference sequence of the original shift register and thus to simulate a sonar signal received from one sonar microphone, said NAND gate switches, read only memory, and multiple exclusive OR circuit being repeated in modular form and coupled to said original shift register and counter circuit to simulate sonar signals received at other sonar microphones with different time delays to simulate wavefronts from a target to position same; and a signal conditioner coupled to said multiple exclusive OR circuit output to provide spectral shaping of these delayed signals and the combination of said repeated circuits provides simulated signals from a plurality of simulated sonar receiver microphones to establish a simulated wavefront from a simulated target object in inner space.