Schmitt trigger low pass filter software version

Discussion in 'Homework Help' started by helloeveryone, Nov 27, 2013.

  1. helloeveryone

    Thread Starter Active Member

    Apr 8, 2011
    Switch debouncing

    Slide 9 in this presentation:

    We can see that there is an upper threshold and a lower threshold.

    How many thresholds does a digital software low pass filter use?
    a) none
    b) one
    c) two
    d) multiple, depending on the application.

    I'm not really sure. A threshold just means "when you go above this level do this" or "when you go below this level do that". Couldn't we use none and just say 0 do this, top value reached do that.
  2. panic mode

    Senior Member

    Oct 10, 2011
    slide 9 shows graph with 2 thresholds
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    If software is sampling an analog voltage (0 to 5V) wired to an ADC input, then you can program multiple thresholds or hysteresis, i.e. If V(in) > 3.25V Then X else Y.

    If the switch is wired to a logic port, then by definition, the signal is already a One or Zero, so all you do is "low-pass filtering" in the time domain... i.e. how long was it a One before it became a Zero, etc.
  4. ScottWang


    Aug 23, 2012