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oscilloscope with soundcard — Parallax Forums

oscilloscope with soundcard

ArchiverArchiver Posts: 46,084
edited 2002-08-29 15:00 in General Discussion
Hello all,

I want to use my soundcard as a oscilloscope, found plenty of
software, but never an explanation of how to connect my signal to
the card.

So, how can i connect my signal tot the card, and what are the max
voltages i can connect to my card if i use it as a oscilloscope? (And
can i increase with a voltage divider if nescessary?)

Thanks pieter-jan

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2002-08-28 20:34
    At 13:36 08/28/02, diepenpj wrote:

    >I want to use my soundcard as a oscilloscope, found plenty of
    >software, but never an explanation of how to connect my signal to
    >the card.
    >
    >So, how can i connect my signal tot the card, and what are the max
    >voltages i can connect to my card if i use it as a oscilloscope? (And
    >can i increase with a voltage divider if nescessary?)

    Your sound card is *NOT* designed to accept voltages and display them as a
    real oscilloscope does. It *IS* capable of accepting audio frequency
    signals and displaying them with proper software. The only connections I
    know are line-in, microphone, or other similar audio-type inputs your sound
    card may have. Please pay very careful attention to the voltage levels
    each of these inputs will tolerate or you can easily damage your sound
    card. I'd stick to 1 volt peak-to peak on the line-in and much less on the
    microphone in put. In fact, I'd rule out using the mike input unless the
    signal is very low level. You really need to look at the specs on your own
    sound card - visit the mfgr's web site if necessary.

    Voltage dividers are usable, but be sure to reference from a common very
    low impedance ground vs something that is floating and will (could) allow a
    much higher voltage to find a way to ground via an unexpected path thru
    your sound card. All this means is that I'd not be inclined to connect
    line-powered sources to the input of my sound card without using an
    isolation transformer. For audio frequencies a 600-to-600 ohm audio
    transformer from Radio Shack should do the trick.


    Jim H
  • ArchiverArchiver Posts: 46,084
    edited 2002-08-29 15:00
    I am using TrueRTA from www.trueaudio.com.

    Though it is just for the audio spectrum, it is a very good program.

    Most importantly, it is free!

    Signal is fed to the sound card via mic or line input. So a hand-made
    connection with a 3.5mm mic jack plug is needed. Just treat the signal as a
    common audio signal to the sound card will be fine.

    John


    Original Message
    From: "diepenpj" <diepenpj@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Wednesday, August 28, 2002 5:36 AM
    Subject: [noparse][[/noparse]basicstamps] oscilloscope with soundcard


    > Hello all,
    >
    > I want to use my soundcard as a oscilloscope, found plenty of
    > software, but never an explanation of how to connect my signal to
    > the card.
    >
    > So, how can i connect my signal tot the card, and what are the max
    > voltages i can connect to my card if i use it as a oscilloscope? (And
    > can i increase with a voltage divider if nescessary?)
    >
    > Thanks pieter-jan
    >
    >
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