Transit zone monitor circuit

Abstract From the Canadian patent

Abstract of the Disclosure A zone monitor circuit for a transit zone having plural entry-exit ports each equipped with a sensor that generates an arrival pulse signal when a vehicle or other movable object passes through the port into the zone and that generates a departure pulse signal whenever an object passes through the port out of the zone, comprising a synchronization circuit which develops time-segregated arrival and departure signals, an occupancy counter that maintains a continuous count of the total number of arrival signals minus departure signals to afford an occupancy count representative of the number of objects within the zone and a vacancy signal indicative of an empty zone, …