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missing pulse detectar

robhan visan over 16 years ago

i must have the code for detecting a missin g pulse?
do some one have some for me to see?

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0 Cpt. Vince over 16 years ago in reply to Sharon Lognek

robhan visan,

A way to detect it is to monitor the pulses, determine the time between them, and then determine if a pulse is missing based upon the expected time it should have occurred.

Pseudo-code:

    if( pulse )
    {
        capture time

        difference in time = (current time) - (previous time);

        if( difference > expected time )
        {
            missing pulse has occured
        }
        else
        {
            missing pulse has not occured
        }
    }

a close 'C' approximation:


#define EXPECTED_TIME_BETWEEN_PULSES    50  // >50ms means too much time

void pulse_isr( void ) // a logic pulse interrupts CPU
{
    static unsigned int current_time  = 0;
    static unsigned int previous_time = 0;
    int difference;

    current_time = Get_Timestamp( ); // needs a timing routine accessor

    difference = ( current_time - previous_time );

    if( difference > EXPECTED_TIME_BETWEEN_PULSES )
    {
        Flag_Missing_Pulse = TRUE;  // the flag that say's "Missing"
    }
    else
    {
        Flag_Missing_Pulse = FALSE;
    }

    previous_time = current_time;   // for next time


}

This example will let you know that a missing pulse occurred one pulse AFTER it has been 'missed.'

There are better ways to do this, but this is just an example.

I hope you get a good grade on this assignment.

NOTE: Per still needs some redeeming... his "H follows G" rule doesn't account for the field-tested sobriety research data collected over the past 30+ years. So the real-world missing pulse detector must not rely on this H-G relationship.

--Cpt. Vince Foster
2nd Cannon Place
Fort Marcy Park, VA

P.S. FYI... I found Jack's photo...

inpraiseofsardines.typepad.com/.../sardine_man_1.jpg

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