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MPP Sampling Integrator Simulation

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  • #31
    Originally posted by green View Post
    Trying to understand some of the differences between a MPP and normal(1C or 2C)integrator. Charted some data. Target(5us TC)sampled decay starting at 5us increasing sample time in 5us steps. Not exactly what I was expecting, does the data make sense?
    Gain doesn't increase with sample time so output signal decreases as sample time is increased with the MPP. With the normal integrator example, output didn't decrease with an increase in sample time because gain increases? Both integrators, final stabilized output=DC gain*average sample volts. (MPP)increasing sample time decreases decayed output signal but might decrease noise. (1C or 2C)increasing sample time doesn't decrease signal but probably increases noise.
    Tried spice analysis to see what effect sample time has on noise. White noise, integrator DC gain=10, frequency cutoff 5Hz, sample time 10 seconds. Changed R4 when changing sample time to keep gain at 10. Don't know if simulation compares with real circuit and noise, probably depends on noise frequencies. Would have used MPP integrator but didn't know formula to keep frequency cutoff at 5 Hz when changing sample time. Should be the same result if DC gain is 10 and frequency cutoff is 5Hz.

    _2 was calculated with Excel. If gain is kept at 10, longer sample times can reduce the output signal a lot. Charts output at sample time/output with 1us sample time.

    Next, find the best target and ground sample times to cancel ground signal and best eliminate the holes with two integrators for short and long(any)TC targets. Any thoughts?
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    • #32
      Some tries at different sample times using an Excel program for a normal integrator. Could try for a MPP integrator, any suggestions what the multiplier should be for the ground sample with equal target and ground sample times. Forgot the question mark after Best two integrators to minimize the hole with one integrator

      All targets had same signal value at 3.9us

      Probably should try with a real circuit maybe with ground, 1x1 inch regular strength aluminum foil, US nickel and US quarter for targets but they might miss the hole.
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      • #33
        replied twice, it's late

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        • #34
          Best two integrators to minimize the hole with one integrator?
          I'm thinking bottom right and bottom left maybe top right. Wondering if I'm missing the obvious and missing some better timings, any suggestions?

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