propscope usage


trying to learn how to use the prop scope with the book understanding signals with propscope.

page 11 measure tool figure 1.3 propscope measureing display says the top most right button is for the
time period between signal repetitions.
i am on page 76 at the paragraph (a closer look at average voltage).
i changed the pause command on my basic stamp to 100 and 400 as the book says.

why does the measuring tab for time period stay the same for channel 1 & 2 when i changed the pause
commands. i thought it would be differnt for channel 1 & 2 if they had a different time between high and low as
page 11 says the top right button is for time period between signal repetitions.

where am i going wrong?
thanks
john

Comments

  • Hi John,

    I can't answer your question personally, but I'm sure someone will help you soon, sometimes posts get buried under high traffic.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    What channel is the trigger set to? What level is the trigger set to? Is the scope in run auto run mode or single shot?
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  • chris,
    thanks for the reply.
    i set all of the scope setting the same as advised in the prop scope book for the lesson i was trying to learn.
    i will have to learn more about the scope before i can properly answer your questions.
    so i will have to end this discussion for now.
    again thanks for the help.
    john
  • The exercise is showing the effect of changing the percentage of time the output signal is high within a given cycle.

    Note that the time from the start of one pulse to the start of the next is the same and has not changed. This is the value reported as the period (1.05 sec's) or the frequency (0.952 Hz).

    I'm not familiar with the Stamp code, but I would guess that changing the sum of the two PAUSE values will change the period. For example, instead of 100 and 400, try 50 and 200 or 150 and 600.

    All of these values should give about the same average voltage, but they will have different periods.

    Good Luck!

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