Signal & DC power supply using single cable

Discussion in 'General Electronics Chat' started by pramod_bhu2k2, Jun 23, 2008.

  1. pramod_bhu2k2

    Thread Starter New Member

    Jun 23, 2008
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    Hi friends
    This is Pramod. I want to send amplified AC signal (12 Peak to Peak) on DC 24V power supply using 300 meters cable(RG-58). This is used in case of Pre amplifier and main amplifier which is separated by 300 meters. I want to send power supply to pre amplifier and receive signal on same cable. Please help me if any body has done this.My email id is pramod@rectuson.com
     
  2. theamber

    Active Member

    Jun 13, 2008
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    Can you use triax cables? what kind of signal ac and what magnitud you are trying to use? Radiated noise and crosstalk is your main concern.
     
    Last edited: Jun 27, 2008
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
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    When the signal is a large as that, not having it radiate back into your preamp will be a feat. What is the signal frequency? RG-58 is quite capacitive, and will eat signals of high frequencies.
     
  4. pramod_bhu2k2

    Thread Starter New Member

    Jun 23, 2008
    7
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    This sensor signal which generate ac signal(10mv) and this signal get amplified to send on signale cable which carry Dc 24V volatge.
     
  5. pramod_bhu2k2

    Thread Starter New Member

    Jun 23, 2008
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    frequency usage of my circuit is 10Hz to 650kHz. i have tried with RG174. Even in this case not working.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You will need a signal transformer at each end to isolate the DC power and couple the signal from the cable to the amplifier. This is done in TV cable systems, but the frequency range is much higher, and the impedance is 75 Ohms, not 50 Ohms.

    Impedance matching will be your big challenge at this point. You will need to do some research on finding signal transformers with that broad of a range. I think you will have to raise the lower frequency end significantly.
     
  7. pramod_bhu2k2

    Thread Starter New Member

    Jun 23, 2008
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    If i increased the lower frequency say 100Hz. Is it ok.Please tell me next soultion for this.
     
  8. Norfindel

    Active Member

    Mar 6, 2008
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    I had never donde something like this, but don't the engineers use current loops for situations like this? Take a look at the LM10 application notes, from National. If i'm not mistaken, i think that could help you.
     
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