Building Signal Extension Harness Box

Discussion in 'Automotive Electronics' started by Paul Chung, Jul 21, 2016.

  1. Paul Chung

    Thread Starter New Member

    Jul 21, 2016

    We are an electronics company located in South Korea.
    In our recent project, we have a challenging circuit design requirement and I wanted to know if anybody here in "All About Circuits" can help us.

    : From vehicle 12 signals are provided including Vcc, Acc, Ground, Speed, and RPM.
    * For Speed & RPM, either square wave or open collector type signal is provided depending on the type of vehicle.
    Output 1: Ground, Speed, & RPM are outputs. Speed & RPM always need to be square wave type signals regardless of input signal type in TTL level (High in 4.5 ~ 5V range)
    Output 2: Always pass 12 signals from input directly without any change (the same signal type & voltage level in speed & rpm).

    Anybody can help us?
    Please let me know.
    Thank you so much in advance!
  2. wayneh


    Sep 9, 2010
    I'm not sure about anyone else but I'm a little confused. Is there a reason Output 2 wouldn't simply be a parallel connection to the inputs? As long as the circuit for Output 1 has a high impedance and does not change the input signal, it's still there to use for Output 2, right?

    For Output 1, you might use the input signal (with conditioning) to trigger a one-shot, like debouncing a switch. The output would be logic but not technically "square" waves, which implies 50% duty cycle. I'm assuming you didn't mean that, just that you need to square up the irregular input spikes.