GB1403028A - Programmable distance measuring instrument - Google Patents

Abstract

1403028 Pulse rate multipliers PENTRON INDUSTRIES Inc 10 Oct 1972 [1 Nov 1971] 46626/72 Heading G4D An electronic distance measuring instrument receives pulses representing an increment of distance or length and generates a preselectable number of clock pulses for each distance pulse, the clock pulses being counted. The system described measures the distance travelled by a vehicle in yards and feet. Displacement pulses are generated from the vehicle wheel either optically or magnetically and are cleaned and shaped by amplifier and noise filter 110, Schmitt trigger 116 and monostable 118. Calibration.-Calibration switch 156 is set to the ON position, the counters are reset and the vehicle is driven for an accurately known distance (say 1000 ft.). The reading in counter 158 is taken and from this the distance travelled per distance pulse (X ft.) is calculated. The value 1000X is then set into programme switches 144. Operation.-The counters are reset. With the reset and calibrate switches in the off position, flip-flop 126 is set by the first distance pulse. Gate 130 is enabled feeding pulses from oscillator 132 to 3-stage decade counter 136. Counter 138 is enabled by removal of the reset signal on line 140 and counts up oscillator pulses until the value set in the programme switches 144 is reached when flip-flop 126 is reset via gate 146. Each time the count in counter 136 reaches 999, the next pulse resets the counter and feeds an output pulse to 4-stage decade counter 158 and optionally to a printer. These output pulses correspond to 1 foot of displacement. Carry over gate detectors 162 detect a count of 279 in the foot counter, reset it on arrival of the next pulse and pass a pulse on to the low stage miles counter.