Reading iPhone signal generated with Tone Generator Pro on a HAMEG oscillosope

Discussion in 'General Electronics Chat' started by Ioanp, Oct 18, 2015.

  1. Ioanp

    Thread Starter New Member

    Oct 18, 2015
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    I have an old Hameg 203-7 oscilloscope that seems to be working fine. On an iPhone I have Tone Generator Pro. I would like to display the various signal shapes on the oscilloscope. I would appreciate some help with setting up the scope. TY.
     
  2. wayneh

    Expert

    Sep 9, 2010
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    Have you read the manual?
     
  3. Ioanp

    Thread Starter New Member

    Oct 18, 2015
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    Thank you for your answer.

    I have and I will likely have to do it again and again. I am hoping for a patient helper, though, as the manual goes quite far beyond my basic understdanding of electrical engineering. For instance, I can see the test signals (0.2V and 2V). Acording to a youtube video, what I want to do is possible. If you wish, I can provide you with pictures of the current knob and switch settings. Would that help?

    To give you some background, I programmed an Arduino Leonardo once to simulate keyboard strokes. With the oscilloscope I've been having a hard time, though.
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    How are you coupling the iPhone to the scope?
     
  5. wayneh

    Expert

    Sep 9, 2010
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    Knowing nothing about operating the oscilloscope properly, I'd probably just charge ahead and connect the headphone audio-out of the iPhone to the probes of the scope. Let the scope auto-trigger if that's an option, and auto-scale also. Otherwise turn the scale dial until you see a trace.

    This is not totally blind and reckless. I know the output of the iPhone won't exceed a few volts, and the probes of the oscilloscope should not overload the iPhone. (Quite the opposite, the scope should place virtually no load on the iPhone.) So both devices should not be at risk from playing around this way.
     
  6. Ioanp

    Thread Starter New Member

    Oct 18, 2015
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    Thank you everybody. Based on Alec_t's question, I managed to make it work, after realizing I didn't connect the two correctly.

    Initially, I connected only the tip of the probe to one of the "hot" wires coming out of the phone jack. Given the fact that the phone is battery operated, it shares no ground with the scope, therefore I was playing around with an open circuit.

    After connecting both conductors coming out of the phone with both probe conductors, the scope started picking up the right signal. In the end I got to see a beautiful sinus and a nice triangle wave form. The square and sawtooth are not so nice, but I don't mind. Moreover, I got to see the modulated signal coming out of an audio player, that looks just like the Media Player visualisation plugins on a computer.
     
  7. wayneh

    Expert

    Sep 9, 2010
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    Glad you got it going.

    The wave shapes might be altered by the hookup, depending on the load on the player. If this is the case, I would expect to see different behavior at different frequency. For instance a capacitive coupling at low frequency will show a fading of the square wave, because you are seeing the voltage droop on the capacitor. This will disappear at a higher frequency. There are probably other artifacts possible as well.
     
  8. Ioanp

    Thread Starter New Member

    Oct 18, 2015
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    Thank you.
     
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