adjust signal- pulses from scintillation probe

Discussion in 'Analog & Mixed-Signal Design' started by ιωαννης χορτομαρης, Jul 1, 2018.

  1. ιωαννης χορτομαρης

    Thread Starter New Member

    Apr 11, 2018
    6
    0
    Hi all,

    I have scintillation probe and I connect charge sensitive amplifier which produce positive analog pulses 0v-5v with periode 200us.
    So the problem is that, how can I adjust the pulses to cut the upper and lower pulses from one adjusment window"not window comparator"

    I try with op-ampt adn I reach to control the lower pulses from lower level e.x with simpe connection on op-amp with Vref (-v) (inverting input ) power the lower level and signal to +v input . With thiw connection I have on output only the upper pulses from Vref .

    but I try days to cut the upper pulses from upper level but I can not yet !!! only with Zener diode I try to cut the upper pulses but I want to control with trimmer if it can because I'm not sure the window which I need

    what can I do? have some one an idea?

    I upload and the images

    blue color channel show the output

    yellow color channel show the input signal from charge sensitive amplifier -all pulses from 0v to 5 v

    John
     
    Last edited by a moderator: Jul 1, 2018
  2. ScottWang

    Moderator

    Aug 23, 2012
    6,360
    985
    The links is linked to the non-english site without image file and it was deleted, I can't see the image, please upload it to our forum.
     
  3. MrChips

    Moderator

    Oct 2, 2009
    17,075
    5,281
    I cannot see how you can do it without a window comparator. You need two analog comparators, one to set the minimum level (called the Low Level Discriminator or LLD) and the other to set the maximum level (called the Upper Level Discriminator or ULD).
     
  4. Bordodynov

    Well-Known Member

    May 20, 2015
    1,918
    578
    See
    Draft20.png
     
    ebeowulf17 likes this.
  5. ιωαννης χορτομαρης

    Thread Starter New Member

    Apr 11, 2018
    6
    0

    many thanks dear Bordodynov,

    my project is same with on the following link but I would like to count pulses on one Dspic... (also I buy 24bit ADC to do easier the discriminator job
    )

    what kind of op-amp must I use? I have LM833, LM358 ,LMC8462 , LM339, LM139 must I use op-amp on circuit?
    Moreover, I have 0-5v pulses 200μS - 200us stable period

    look at the following link it can't cut upper pulses from upper level reference voltage

    [​IMG]

    https://forums.parallax.com/discuss...ndow-comparator-that-doesnt-mess-with-my-head

    thanks for your apply

    John.
     
  6. ιωαννης χορτομαρης

    Thread Starter New Member

    Apr 11, 2018
    6
    0
    Dear Bordodynov,

    It is possible to explain and your circuit?? (Or someone else) .

    Why you use only the non inverting inputs of op amps as a reference voltage??

    Must I build the simple circuit with other op amp to cut the lower signal from lower level connecting the reference voltage on inverting input and the signal on non inverting input?? (This can I do, to cut the lower signals of reference voltage :) )

    I'll try to test your circuit in few hours
     
  7. Bordodynov

    Well-Known Member

    May 20, 2015
    1,918
    578
    I applied a fast operational amplifier from Rail to Rail.
    This is a scheme, such I thought of it, with the supply of a reference voltage to the non-inverting input. I made a double-sided limiter. If you do not need a limit from below, then throw out some of the circuitry. An operational amplifier with a diode and a reference signal is an ideal zener diode, which together with a resistor form a limiter.
     
  8. ιωαννης χορτομαρης

    Thread Starter New Member

    Apr 11, 2018
    6
    0
    Many thanks dear Bordodynov.
    Yes I would like window -upper and lower voltage limits
    I'm trying to build it.
     
  9. ιωαννης χορτομαρης

    Thread Starter New Member

    Apr 11, 2018
    6
    0
    Dear Bordodynov,

    it can'twork! your circuit, because without folloers on start and and of circuit the input signal going straight on output. the signal follow the sorter way.
    tring again and again and I see that after stading the circuit
     
  10. eetech00

    Senior Member

    Jun 8, 2013
    1,168
    240
    HI

    Bordodynov probably has a better answer.
    But I think you need to add resistors (R2 and R3) so it sums the output correctly.

    eT

    Draft20-1-ckt.png
     
  11. ιωαννης χορτομαρης

    Thread Starter New Member

    Apr 11, 2018
    6
    0
    dear eetech00,

    nothing again!!!!


    now I build it and I test it and measure the output following the input!!!!!


    this circuit is an follower voltage!!!! nothing more!!!

    I would like to pay for one circuit window comprator if you can built it!!!

    Several days I spend my time to build thiis circuit but I can do that.

    I believe that, opw amp compare voltage only one stage and only one direction . The inverting input (reference voltage) is the limit . So, if the input voltage-signal is higher than that limit , voltage-pulses from non inverting input (+) release on output if not the inverting input (reference voltage) is higher than the non inverting input (+) then the output is ZERO !!!

    I can't upload image from my oscilloscope from circuit

    I'm electrical enginner and I sady the op-amp's generally. Electronics are my hobby , I haven't expirience and I'm not expert in this area,but my result's and my opinion it that!!!

    have you an other idea? how can I take all pulses from input to output of an window -espesially area of voltages???
    how can analog to digital converter works??? how it can single votages??

    thanks,
    John.
     
  12. Bordodynov

    Well-Known Member

    May 20, 2015
    1,918
    578
    No, then the very meaning of the voltage limiter is distorted.
    2018-07-09_08-13-31.png
     
  13. Bordodynov

    Well-Known Member

    May 20, 2015
    1,918
    578
    The first operational amplifier, included by the repeater, can be discarded if you are satisfied with the input impedance of 100 kΩ.
     
  14. ebeowulf17

    Well-Known Member

    Aug 12, 2014
    2,457
    441
    Are you sure you've built it exactly as drawn? @Bordodynov's circuit sure looks right to me.
     
  15. Janis59

    Active Member

    Aug 21, 2017
    579
    92
    emmmm, would You be sure that any opamp be capable to work with scintillations?? I suggest the scintillation may take the picoseconds or at least nanosecond, while opamaps never are able for Megahertzs except few.
     
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