The hydraulic steering device of a dish antenna for satellite tracking works by adjusting the elevation using a hydraulic ram. Oil can be pumped into the ram to raise the elevation. The hydraulic seals leak pressure very slowly such that additional oil has to be pumped periodically to maintain a constant elevation. Two output signals are provided by the hydraulic system: ABOVE19 and ABOVE20 which equal 1 whenever the elev ation of the disk is above 19 and 20 degrees respectively from the horizontal. Design a circuit to keep the elevation of the dish between these tw o limits. Your circuit should have an output signal PUMP which equals 1 when you want the pump to increase the hydraulic pressure and hence raise the elevation of the dish.