puce de détection d'un neurostimulateur RNS

Discussion in 'Embedded Systems and Microcontrollers' started by Essadaoui_Red, Feb 23, 2012.

  1. Essadaoui_Red

    Thread Starter New Member

    Feb 17, 2012
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    hello,
    We work on a topic concerning the RNS neurostimulator against epileptic seizures:
    http://latavernedes3i.free.fr/files/...20Valerian.pdf

    (RNS consists of a computerized device implanted into the skull with electrodes implanted in presumed epileptic foci in the brain. Brain electrodes send EEG signals at the input device that contains detection software. When certain criteria EEG seizure are satisfied, the device delivers a small electrical charge to the electrodes other near the epileptic focus and disrupt the seizure.).

    the system has two main parts:
    - Detection part:
    - Portion control (FPGA processor ...)

    detection is assured either by a sensor chip synchronous or asynchronous
    After much research, I can not differentiate between an asynchronous and the synchronous detection in this context :confused:
    and thank you for your help :)
     
  2. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Hello,

    1)
    The difference between asynchronous and the synchronous detection in digital systems is essentially the same as the difference between parallel and series data streams.

    2)
    In analog signal terms sychronous detection is effected by supplying a synchronous (same phase and frequency) signal to balance out the carrier. Then modulating signal is then recovered from the output of a low pass filter.

    Are you interested in 1 or 2 as regards your EEG signal?
     
  3. Essadaoui_Red

    Thread Starter New Member

    Feb 17, 2012
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  4. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Well on page 15 it says it is asynchronous, but on page 7 it says synchronous?

    Is there a misprint?

    I think in this context synchronous means that the logic is synchronised to a clock signal which is also described in the text.

    Does this help?
     
  5. Essadaoui_Red

    Thread Starter New Member

    Feb 17, 2012
    13
    1
    hello,
    On page 15 it says that there are two detection chip :
    - Chip synchronous ready.
    - Asynchronous chip in the process of development,

    but the chip that appear on the figure is synchronous,
    good that I realized is that when the synchronous detection has the same frequency and amplitude, and the transfer is still attached to the clock, against asynchronous detection: when it does not signal clock, or transfer is referenced to clock that within a given range limitted.
    but the question is why choice of synchronous instead of asynchronous,:confused:
    what the benefits of synchronous?:confused:
    thank's
     
  6. studiot

    AAC Fanatic!

    Nov 9, 2007
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    Whatever the type of detection we wish to avoid false signals (errors or glitches).

    The idea of synchronous system is that there is a certain time, during the clock cycle, where the data in the registers is guaranteed true.
    So if we only read or write to the data registers (or perform register operations) during this part of the cycle on all the bits in our data word then we can guarantee that the data word is true.
     
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