High noise immunity input level detector with hysteresis

摘要

A logic interface signal input with a high degree of electrical noise immunity, particularly suited for use in an automative environment for detecting an on/off control signal multiplexed with an information signal such as a voice audio signal. The invention provides a fast logic output signal in response to the level of the control signal, which is suitable for driving higher speed circuitry and which permits detection to be highly immune from electrical transients or variations in power supply voltage. The invention permits the information signal to be combined with the control signal through polarized means, such as an electrolytic capacitor.