FAIL-SAFE TRANSISTORIZED OVERSPEED CIRCUIT ARRANGEMENT

摘要

A FAIL-SAFE TRANSISTORIZED OVERSPEED CIRCUIT ARRANGEMENT This invention relates to a vital type of vehicle overspeed circuit arrangement for receiving variable frequency signals from a speed sensing device. The variable frequency signals are applied to a single break passive low-pass filter which attenuates the signals at a rate of 6db per octave. The attenuated signals are fed to an input amplifier which couples the amplified filtered signals to a selection network. The selection network includes a plurality of active switching stages a select one of which is activated for controlling the gain of a variable gain amplifier. The variable gain amplifier is coupled to an output amplifier which produces an output voltage having a value which is proportional to the frequency of the signals and the gain of the variable gain amplifier.