FREQUENCY RESPONSIVE SPEED CONTROL APPARATUS

摘要

A speed control apparatus for sensing over speed conditions of a vehicle. A signal source which produces signals at a frequency which are proportional to vehicle speed feeds an electronic high pass filter whose cut-off frequency is variable and settable to a frequency which is proportional to the predetermined speed above which an over speed condition exists. A relay driver is operated in response to signals passed by the electronic high pass filter to operate a relay. In order to check the cut-off frequency of the high pass filter, a check oscillator is provided which is turned to a frequency slightly in excess of the desired cut-off frequency of the high pass filter. The relay driver operates an electronic switch which intermittently provides the signals from the check oscillator to the electronic high pass filter.