[Medical & Ham radio] AM vs FM ?

Discussion in 'General Technical Questions and Answers' started by F4VQW, Sep 19, 2017.

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  1. F4VQW

    F4VQW Ham Member QRZ Page

    Dear all,

    I may require your help, your advices.

    I am a cardiologist (and also a OM).. and I am now brainstorming some ideas to make possible something that I have in mind. My experiments use very low current (10 - 15 mAh) and AC (alternating current). I have to deliver some kind of shock (from 50 msec up to 4 - 5 seconds. this time could change as much as I desire). Frequency range : from 10 Hz to 1 KHZ.

    I am now modeling (simulation) the impedance of the skin - I believe we are around 50 - 100 ohm
    Which is , in your opinion, the best way to deliver this sort of impulse in order to get the best vector and be effective?

    AM vs FM vs FSK ...

  2. KM3F

    KM3F Ham Member QRZ Page

    AM, FM, and FSK are modes.
    Without knowing a bit more about the application, CW or Continuous Wave in the audio frequency range your considering would be the way.
    An audio amplifier being driven by a variable oscillator would provide the power level and frequency agility.
    The amplifier output can be made to match the impedance once you settle on the value.
    Normally the impedance match is to transfer max power to a speaker as a load with acceptable low distortion but to skin, depends on what you want the power to do and how deep is must travel, how big an area of effectiveness and what other interface you may use to accomplish the intent.
    The application times can be controlled by an electronic switch and adjustable pulse width controller at either the frequency driver or the amplifier output.
    You may be able to find an oscillator with these control features already built in for repetition rate and pulse width.
    In a development project an Oscilloscope might be a good tool to see the signal as you do testing and record the signal vs result.
    Just an example I was involved in many years ago was vacuum tube grid testing for movement.
    This consisted of an audio oscillator to an amplifier whos output was to a fixture the grid was set into.
    The power was set but the frequency was varied while looking at the grid's very small wire of .00039 inch wire through a microscope to tell when the wire began to vibrate from the AC field developed between the audio output terminals on the fixture.
    I am very well acquainted with cardiologist now and doing quite well for a long time thanks to them..
    Very good luck to you.
  3. WA9SVD

    WA9SVD Ham Member QRZ Page

    I believe modern "Nerve conduction" testing does that already. You should look at patents from manufacturers before you infringe, but may get ideas as well.

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