Patent ID: 6215116
Filing Date: 2001-04-10
Classification: E03C,G01S

Abstract:
A proximity detecting device for detecting the presence of an object in a target area and comprising an emitter, a circuitry for supplying electrical pulses of a predetermined energy level to said emitter for emitting detection pulses towards the target area, a receiver arranged for receiving said detection pulses and converting them into electrical signals, an amplifier for amplifying said electrical signals and for producing amplified electrical signals and a control circuitry for evaluating said amplified electrical signals to determine whether or not the object is present in the target area, said control circuit comprising means for determining on an ongoing basis the amplitude of said amplified electrical signals and means for increasing the energy level of said detection pulses when the amplitude of said amplified electrical signals is below a first threshold value and for decreasing the energy level of said detection pulses when the amplitude of said amplified electrical signals exceed a second threshold value, which second threshold value is greater or equal to the first threshold.