Direction detector for flying spot scanner with digital indicator therefor

Claim 1

IN A FLYING SCANNER OF THE CURVE FOLLOWING TYPE, INCLUDING A CATHODE RAY TUBE AND DEFLECTION MEANS FOR POSITIONING THE CATHODE RAY TUBE BEAM TO SUCCESSIVE POSITIONS ALONG A PATTERN OR CURVE TO BE TRACED, THE COMBINATION COMPRISING SINUSOIDAL VOLTAGE GENERATOR MEANS FOR PROVIDING A BASE SINUSOIDAL VOLTAGE OF PREDETERMINED AMPLITUDE AND FREQUENCY; PHASE SHIFTING MEANS CONNECTED TO SAID VOLTAGE GENERATOR MEANS FOR DERIVING A POLURALITY OF ANGULARLY RELATED SINUSOIDAL VOLTAGES FROM SAID BASE SINUSOIDAL VOLTAGE; DEFLECTION CIRCUIT MEANS CONNECTED TO SAID PHASE SHIFTING MEANS TO PROVIDE A CIRCULAR TYPE OF TRACE BY THE COMBINED ACTION OF AT LEAST TWO OF SAID ANGULARLY RELATED SIGNALS; AND DIRECTION INDICATING MEANS CONNECTED TO SAID PHASE SHIFTING MEANS FOR INDICATING THE DIRECTION OF MOTION OF THE SPOT OF THE CATHODE RAY TUBE INCLUDING COMPARING MEANS FOR COMPARING DIFFERENT ONES OF SAID ANGULARLY RELATED SIGNALS WITH OTHER ONES OF SAID ANGULARLY RELATED SIGNALS TO PRODUCE A PLURALITY OF DIGITAL SIGNALS VALUES INDICATIVE OF THE RANGE OF MOTION OF THE SPOT OVER SEMICIRCULAR PORTIONS OF THE CIRCULAR TRACE; AND DIGITAL LOGIC MEANS FOR INDICATING SELECTED COMBINATIONS OF SAID DIGITAL SIGNAL VALUES INDICATIVE OF SPECIFIC SPOT MOTION DIRECTIONS.