Aircraft engine rotating speed signal acquisition circuit

Abstract

The invention belongs to electronic technology, is applied to the technical field of aviation electronics, and particularly relates to a frequency signal acquisition circuit with an adaptive threshold. The acquisition circuit comprises a clamping circuit, a filtering circuit, a comparison circuit, a threshold generation circuit and a digital shaping circuit, one branch of an inputted engine rotating speed signal of an input is insulated and clamped and then connected to a negative input end of the comparison circuit, the other branch is connected on the threshold generation circuit, and an output of the threshold generation circuit is connected at a positive input end of the comparison circuit. The acquisition circuit has the advantages that an acquisition circuit of a traditional engine rotating speed signal acquires, restrains and interferes signals through a hysteresis comparator, and the acquisition circuit solves the problems of fixed threshold of the acquisition circuit of the traditional engine rotating speed signal and poor interference resistance. The acquisition circuit can automatically change a comparison threshold of the hysteresis comparator according to change of an amplitude of the engine rotating speed signal of the input, and the interference resistance of an interface circuit is improved.

Description

technical field [0001] The invention belongs to the category of electronic technology and is applied in the technical field of avionics, in particular, it relates to a frequency signal acquisition circuit with an adaptive threshold. Background technique [0002] The airborne speed signal acquisition circuit is mainly used to collect the engine speed of the aircraft. The engine speed signal acquisition circuit mainly adjusts the engine speed signal into a standard pulse signal through resistors, capacitors, comparators, optocouplers and other devices for the controller to collect. The circuit principle is simple. However, the environment on the aircraft is complex, and various interference signals are often inserted into the normal engine signal, and the amplitude of the interference signal often increases with the increase of the engine speed. [0003] The traditional engine speed signal acquisition circuit, such as figure 1 Among them, a conditioning circuit composed of c...

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Problems solved by technology

[0004] Purpose of the invention: To provide a frequency signal acquisition circuit for an adaptive threshold of aero-engine speed, which can overcome the defects of fixed comparison threshold and poor interference suppression ability in traditional engine speed signal acquisition circuits

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