Amplification of small signal

Discussion in 'General Electronics Chat' started by shyckh, Sep 12, 2014.

  1. shyckh

    Thread Starter New Member

    Jul 28, 2014
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    I have a small signal coming from the camera called vertical sync signal. This signal is so small that my dmm dose not give any value. I have tried to use this signal for switching using npn transistor but failed. Any help ??
     
    Last edited: Sep 12, 2014
  2. MrChips

    Moderator

    Oct 2, 2009
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    Generally speaking, you cannot detect and observe logic signals using a digital multi-meter (DMM).
    You need an oscilloscope of appropriate bandwidth in order to properly characterize the signal.
     
  3. shyckh

    Thread Starter New Member

    Jul 28, 2014
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    Ok
    ok than how can i use this signal for switching
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    Well first we have to find out the minimum and maximum voltage of the signal, or the amplitude and baseline.
     
  5. BeerBelly

    New Member

    Dec 16, 2013
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    What are you trying to switch? Signal detection for a switch could be done with a comparator such as LM339 or NE555 timer.
     
  6. shyckh

    Thread Starter New Member

    Jul 28, 2014
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    Here is the v sync signal.
     
  7. shyckh

    Thread Starter New Member

    Jul 28, 2014
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    Please s
    please search for eye writer 2 on the forum
     
  8. BeerBelly

    New Member

    Dec 16, 2013
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    The LM339 should easily amplify and square off the desired signal.
     
  9. shyckh

    Thread Starter New Member

    Jul 28, 2014
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    Lm339 will convert this signal to square signal but vsync signal changed rapidly with fps. Does it do any effect on input frequency?
     
  10. shyckh

    Thread Starter New Member

    Jul 28, 2014
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    Lm339 will convert this signal to square signal but vsync signal changed rapidly with fps. Does it do any effect on input frequency
     
  11. MrChips

    Moderator

    Oct 2, 2009
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    What is the voltage/div on the scope?
    Where is 0V on the scale?

    BTW, the frequency compensation on your scope probe needs adjusting.
     
  12. vk6zgo

    Active Member

    Jul 21, 2012
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    If you are just wanting to determine the absence or presence of such a signal,you can use a tone detector IC like a Lm567.
    Another way is to use an integrating network with a long time contant,so it charges up the C to a threshold voltage to trigger a bistable circuit.

    If you want each pulse to switch something which then returns to it off state between pulse,thats another thing altogether.
     
  13. shyckh

    Thread Starter New Member

    Jul 28, 2014
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    I want to use it for switching
     
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